Abstract Monitoring the performance of the Kuparuk River Unit waterflood at a multi-well, pattern level is a critical part of field operations. The reservoir performance analysis optimizes allocation of injected fluid, helps identify well work and infill drilling opportunities, supports reservoir management strategies, and provides a basis for development planning. Faulting and stratigraphy of the reservoir make it difficult to determine areal and vertical allocation factors for fluids in the surveillance patterns; therefore material balance calculations are required to judge their validity. The problem is exacerbated by the number of patterns analyzed and the need to share intermediate results between all of engineers that need to be involved in the process. To help solve the problem, a suite of programs for interactive pattern material balance was developed. The program suite includes a principle material balance calculation application along with several ancillary programs for interactive database updates and post-processing. The program suite allows engineers to interactively change input parameters and review material balance results. Internal checks ensure consistency throughout the field. The programs are fully integrated with a large central relational database which includes tables for areal and vertical allocation factors, production, injection, and static pattern information. Introduction The Kuparuk River Field is located west of the Prudhoe Bay Unit on the North Slope of Alaska. The field is a highly faulted reservoir with an areal extent of over 200 square miles. The field is under active waterflood with some areas also under immiscible or miscible WAG (water, alternating with gas) flood. A formal review of reservoir performance at the pattern level is done on an annual basis. The review includes defining patterns and allocating fluids produced from or injected into the patterns. This is followed by a comprehensive review of the performance on a pattern-by-pattern basis and rate forecasts. The review is necessary to help identify workover and infill drilling opportunities to optimize the waterflood It is also required to help with operational considerations such as allocation of injected fluids throughout the field. The validity and usefulness of the surveillance review is highly dependent on accurate allocation of production and injection to each pattern in the Kuparuk River reservoir. This is a difficult problem because over 600 patterns in 2 zones are analyzed. The process is led by a team of five to six engineers. An additional 15 to 20 engineers and geoscientists are involved in defining patterns and evaluating allocation factors. Because of the large number of individuals involved and the large amount of data, a group oriented solution was required in order to achieve consistency across the field. Internal data checks were also required so that wells could not be over or under allocated and to accurately account for all fluids. History of Software Development Efforts. Several computing solutions have been explored. The first software solution was a mainframe material balance program tied to SAS databases. Iterations required editing ASCII text files and overnight batch runs to update databases followed by a batch processing for pattern analysis. Visualization consisted of batch programs that submitted plots to central printers, often with half-day turnaround times. A major advantage of the system was its use of a centralized database and enforced consistency. The disadvantages of long turnaround times and other difficulties within the mainframe environment made the process inefficient and manpower intensive. As personal computers became more popular, much of the process was ported to spreadsheets. The analysis process consisted of downloading data from mainframe databases into a text format that was read into the spreadsheets. Engineers manipulated and modified the data within the spreadsheets to perform individual pattern analyses. The process was somewhat more efficient in terms of manpower, but consistency was nearly non-existent. P. 41

Abstract This paper presents a new parallel ILU preconditioner. It is based on the technique of Sequential Staging of Tasks (SST) which overcomes the difficulty of recursiveness arising from ILU factorization. This new parallel ILU preconditioner is easy to reconstruct from the sequential version. The only requirement is to insert the synchronization codes of stages of tasks into the sequential version, and any other modifications to the original serial codes are not needed. The characteristic of matching various ordering schemes is still maintained, and the new merit of handling different numbers of processors is obtained. Numerical results were obtained using a thermal model with different grid system. The parallel speedup is satisfactory. Introduction Simulation of thermal recovery processes using a fully implicit treatment of component concentrations, phase saturations, pressure and temperature requires solution of large systems of linear equations. Currently, the most robust techniques for solving this large system of linear equations are preconditioned conjugate gradient like methods such as ORTHOMIN which is widely used in traditional solvers for sequential computers. The major computation of ORTHOMIN is vector inner product and is easy to be paralleled. However, the most robust preconditioners such as ILU factorization and nested factorization are not suitable for parallel computer because of their intrinsical recursiveness. It is difficult to parallel ILU preconditioner directly. At present, the general methods to parallel preconditioners are the use of new preconditioning methods such as parallel nested factorization preconditioning. These new preconditioning methods have high parallel efficiency in parallel computers, but also have limitations: limited types of ordering schemes; comprehensive modifications of the sequential codes; slow convergence. This paper presents a new parallel ILU preconditioner based on the technique of Sequential Staging of Tasks (SST). Using the SST technique, the new preconditioner exploits the small scale parallelism of ILU factorizations, and achieves a temporal, larger scale parallelism within certain computing domain, consequently obtains an applicable parallel preconditioner. The new parallel preconditioner maintains all the characteristics of the sequential version, and is easy to reconstruct from the sequential version. The new preconditioner is applicable to computers with different number of processors. The numerical experiments show that the parallel speedup is satisfactory. On an NP 1/52 Mini-Supercomputer System (produced by GOULD Co. in 1989, shared main memory, symmetrical operation system UTX/32) with two processors, the parallel speedup is 1.85. ILU factorization Consider the linear system, Ax=b As a preconditioner of ORTHOMIN, ILU factorization provides a matrix M, a "good" approximation to coefficient matrix A and easy to factor, convergence may be accelerated by solving the equivalent system, [M1A]x=M1b Such preconditionings should offset the added cost of factoring M and performing a forward and back solution with each matrix-vector multiplication by reducing the number of iterations substantially. Main stages of ILU factorization are as follow: A symbolic factorization, defining the non-zero structure of the incomplete factorization. For k=l, NB Do Inverting the main elements (1) P. 135

Abstract The computer information industry is seeing a revolutionary growth with the introduction of the Internet and especially the World-Wide Web (WWW). There is no doubt that this trend will affect the petroleum industry tremendously in the near future. This paper analyzes the current tools available and tries to forecast the state-of-the-art use of these tools in this industry. Web browsers are getting mature everyday with security features and interactive capabilities. Java (and JavaScript) provides yet another powerful object-oriented way of writing tools on the Internet. Already, more and more oil and gas companies are using these for inter-company and intra-company data transfer, advertising, and many other purposes. This paper was submitted to SPE using a Web browser. With so many advantages, it is easy to foresee that these same companies want to use them more and more often in their daily work and life. This entails using them for log acquisition and analysis, reservoir simulation, well testing, production data analysis, reserves, and filling regulatory reports, etc. Users will also be satisfied with the openness, ease of use, common interface (low-cost training) and widely available tools (such as the numerous Java applets) that they can use to design and customize to their own taste. This paper gives some examples of using Web browsers to do engineering calculations such as oil and gas correlations and field calculations. It is the hope of the author to inspire other colleagues in this industry to start in this direction and bring this bright future nearer. Introduction In the beginning, the computers were scattered all around, separated from each other. Then the Internet was created. The academians used it at first to exchange ideas among themselves through e-mail, telnet and ftp. It was seen as good, but difficult to use for the normal population or the critical mass. Then came along the Internet browsers. It was those browsers that made the Internet popular and connected those networks of internets and intranets into a World-Wide Web. The ease of use of these browsers made it a breeze to navigate (surf) the Web. Nowadays, almost every company, university, and organization has an appearance on the Web. However, it is important to note that up until today, most of these Web pages are relatively static information published and updated regularly or irregularly. With the introduction of Java Script and Java, the browsers are taking in more functions and usability for the scientific and business circles as they are more interactive. As a matter of fact, Java is threatening to take over many of the traditional programming languages such as Visual Basic and Visual C++ because of its ease of use, better portability and ever-increasing popularity. The petroleum industry, in the author's opinion, is not too late jumping on the bandwagon with this new and developing technology. Already, many upstream E&P companies, service companies are appearing on the net. But again, most of these Web pages are also static information. The scientific computing on the Web is still in its infant stage. This paper illustrates the ease of use and the possibility of petroleum computing on the Web through some simple engineering applications. It's the author's hope that with this paper, more applications will be introduced in this industry dealing with wider variety of daily routines such as log analysis, seismic interpretation, financial analysis, reserves estimates and management, well testing, geostatistics, and reservoir simulation, etc. P. 245

Abstract This paper presents a PC based alternative procedure for determining the water saturations within the hot water zone of a thermal project for use in analytical oil recovery calculations. Conventional analytical calculation of oil recovery under steam and hot water injection requires the tracking of the movements of the saturations advancing within the variable-temperature hot-water zone. This involves an adaptation of the Buckley-Leverett theory to this variable temperature zone after dividing it into a number of constant temperature or isothermal zones. If the number exceeds two, the calculation can become very tedious unless done with a computer program. FORTRAN programs have generally been used but they are not as intuitive or easy to use as modern PC based programming tools such as MathematicaTM. In this paper. MathematicaTM was used because it is relatively easy to program. easy to use, and is fast and robust. Unfortunately. depending on the number of isothermal zones, the time step size and the time at which the recovery calculation is desired, the tracking of saturations can tax the capabilities of even the most modern PCs. Therefore, an alternative method is introduced that eliminates the need for saturation tracking. This method calculates the instantaneous saturations within each isothermal zone at the time of interest. Oil recovery results by this method were found to be comparable to those by the saturation tracking method with considerable saving in computation time. Two examples are presented to demonstrate the utility of the method. Introduction For one-dimensional models, the analytical calculation of steamflood oil recovery with time requires calculating the following: the position of the steam front and its rate of advance or velocity. the temperature profile in the hot water zone and its rate of advance, the fluid saturation profile and its rate of advance. The location of the steam front at any time can be calculated by the equations of Mandl and Volek who showed that before a critical time tc, the steam zone can be described by the equations of Marx and Langenheim. Beyond tc, Mandl and Volek present an approximate equation to calculate the steam front location with time. This equation was later improved by Prats and Vogiatzis and communicated to Myhill and Stegemeier who presented the solution in graphical form. The temperature profile in the hot water zone can be calculated using the equation by Lauwerier for both hot waterflood and steamflood. However, for a steamflood, a simpler approximation assumes a linear temperature drop from the steam temperature to the cold reservoir temperature. The saturation profile in the steam and hot water zones can be calculated using the Buckley-Leverett theory provided that the non-isothermal hot water zone is first divided into an appropriate number of isothermal zones. Several procedures are available to calculate the saturation profile with time. This paper is concerned with the method whereby characteristic saturations are picked and their motions tracked. The tracking process is very time consuming and can easily exceed the capabilities of PCs' when small time steps are used together with many isothermal zones at long times. An alternative to tracking is used whereby instantaneous saturations in each temperature zone are calculated at any given time. The saturations to be tracked can be picked in different ways. Farouq Ali determines the flood front saturation at the cold reservoir temperature (just as in a waterflood) and arbitrarily picks saturation values greater than this value ending at the maximum water saturation. This has the advantage of giving greater saturation definition where needed. However, it has the potential of using more saturations than is needed leading higher computation time on personal computers. Willman et. al. suggest a somewhat narrower range of saturations by finding as the starting point, that saturation in the cold zone that have the same velocity as the cold temperature at tc. Prats extends this further by finding a particular saturation for each isothermal zone referred as characteristic saturations. These are calculated as the saturation in each zone that has the same velocity as the cold temperature at tc. This way, there are only as many characteristic saturations to be tracked as there are isothermal zones as opposed to tracking an arbitrarily large number of saturations. Even with these improvements in the choice of saturations, the tracking process of calculating their locations at each time step is time consuming even for personal computers. P. 83

Abstract In the Shell Group, we have developed a state-of-the-art data management system for the storage of resource (field, reservoir, etc.) related data. It iscalled RISRES (Reservoir Information System - REServoir module). First released in 1993, it is currently in operational use in eight Shell Group operating companies around the globe. This article describes the specification and construction process, as well as various aspects of the system which make it a powerful resource data management system. Introduction The ability to store, retrieve and share data relating to oil and gas reservoirs is critical to their efficient management. Inordinate amounts of time are often spent collecting, verifying, storing, sharing, re-collecting and re-verifying data for the purposes of studies, analyses and reports. RISRES is a state-of-the-art resource data management system which was developed to meet this challenge by addressing a set of business requirements described below. Features which make it state-of-the-art include: – extensibility to store any data – unambiguous versioning and time-stamping – flexible definition of subsurface and reporting structures – ability to store data in any form from numbers to document files – auditing and security features – transparent interfacing to applications. These features, and others which position RISRES as a general resource data management system both inside and outside the Shell Group, are discussed in some detail below. Although it clearly satisfied the stated business requirements, introduction of RISRES to the majority of the Shell Group led to considerable initial resistance in the user community. These experiences are discussed, and the resulting set of data-organization and interfacing concepts, in particular close integration with Shell Group petroleum engineering applications, are also described. Business requirements The data explosion has resulted in the need to handle ever-increasing quantities of data for life-cycle management of petroleum resources. In the late 1980s it was observed that just the gathering and validation of data for reservoir-related studies occupied a significant fraction of each study'sresources, and that data gathering or analysis would often have to be repeated because previous study data and results would get "lost". One area of particular concern at this time was resource volumes. Companies in the Shell Group were working with a combination of legacy systems and spreadsheets. The "old technology" legacy systems were generally inflexible to the evolving requirements of resource classification and were often seen as a "black hole" into which data disappeared, never to be seen again. These problems tended to be addressed by the use of mainframe and PC based spreadsheets, or other "quick fixes", to fill in the gaps not covered by the legacy systems, in some cases replacing them altogether. However, these spreadsheets and files were usually in disparate and undocumented locations on hard disks around the company offices, generally included little or no validation, and often contained hidden errors. In short, they represented an inappropriately fragile audit trail for the main assets of the companies: their hydrocarbon resource volumes. The Shell Group lacked a database to hold gathered, validated and processed data, including hydrocarbon volumes, applicable at a resource level (i.e. fields, reservoirs, blocks, etc.). This led to the establishment of the Reservoir Information Systems (RIS) project in 1990. P. 27

NodalBc: A Unique Program for Optimum Production of Sucker Rod Pumping Oil Wells Abstract Sucker rod pumping is the oldest artificial lift method used in production of oil wells. This method is usually designed and analyzed with the assistance of programs based on simplified models, such as the API RP 11L, or with a wave equation simulator. In many cases, however, a technique that permits consideration of the inflow and outflow performance of the well is a more efficient way to design and analyze an oil well. This technique, referred to as Total Analysis or System Analysis (SA), has been successfully applied to flowing and artificially lifted wells. This paper presents a computer program developed by Intevep S. A., called NodalB, created to perform the SA of sucker rod pumping wells. NodalB 's unique characteristics make it a competitive program in today's market of design and optimization software. This program allows consideration of the inflow performance of the reservoir depending on the drilling scheme, either vertical or horizontal, and determination of the sensitivity of the rod pumping system to its most relevant parameters, such as: pumping speed and stroke, pump diameter, gas oil ratio, gas separation efficiency, tubing diameter, pump depth, rod string design, oil viscosity, injected diluent (diesel, kerosene, etc.) ratio, water cut, reservoir pressure, productivity index, and different production schemes (i.e. production through the tubing or through the casing-tubing annulus). These features show the power of this program as a predictive tool. NodalB is specially applicable to design, optimization and troubleshooting of heavy and viscous oil wells, taking into account the viscosity effects in the rod pumping system. Introduction The current total oil production of Venezuela is approximately three (3) millions of barrels per day. One million of it is produced from almost 7000 sucker rod pumping wells, and consists, in its majority, of heavy oil and bitumen, which typical downhole viscosity ranges from 500 cp up to 7000 cp. The corresponding API gravity ranges between 8 and 12. Due to the high viscosity of the oil, cyclic steam injection has become a typical production scheme for those wells in which static reservoir pressure is below 1000 psi (up to 2500 ft of well depth). Also, other alternative production schemes have been developed to reduce 1) the drag forces between the rod string and the fluid and 2) the pressure drops in the tubing string and flowline. Such schemes involve the injection of a low viscosity fluid (diesel, kerosene) in a continuos basis into the wellbore and flowline. Furthermore, the oil being produced usually flows through the tubing-casing annulus instead of the tubing. Recently, a new completion scheme, called the Downhole Stuffing Box Production Scheme, has been successfully tested in the field, revealing several advantages over the other heavy oil production schemes currently applied in Venezuela. P. 33

Abstract Microsoft Visual Basic for Windows (VB) allows Engineers to develop engineering applications that run in the Windows environment. VB provides the engineer a programming tool to write simple programs quickly that meet their needs. It is relatively easy to learn and use. Development of a Windows-like user interface is easy to do and there is a growing base of users and add-in applications. The technological advances that have allowed engineering workstations to convert from a mainframe environment to a stand alone PC connected to a network have also provided new programming tools. Modern programming languages allow the programmer to quickly design screen panels and easily reuse code. This paper discusses the features available in VB and provides several program examples. Example programs written using VB include gas and oil fluid correlations, interpolation software, gas well bottom hole pressure from surface conditions, volumetric reserve calculations, simple log analysis, water pattern analysis and bottom hole pressure analysis. These applications were developed with Visual Basic version 3.0 Professional. Introduction Over the last decade, engineering workstations have transitioned from the mainframe to the PC environment. Engineers have seen a need to have their applications rewritten for the PC. To make up for the loss of applications, engineers have turned to spreadsheets & macros or DOS based programs written in Basic or FORTRAN. The Hewlett-Packard 41 C calculator with a petroleum fluids pac was also very popular. Writing DOS interfaces can be very time consuming and tedious. P. 291

Abstract A computer software package for simulating coiled tubing operations has been developed at Rogaland Research. The software is named CriTi-CAL, for Critical Coiled Tubing Calculations. It is a PC program running under Microsoft Windows. CriTi-CAL is designed for predicting force, stress, torque, lockup, circulation pressure losses and along-hole-depth corrections for coiled tubing workover and drilling operations. CriTi-CAL features an user-friendly interface, integrated work string and survey editors, flexible input units and output format, on-line documentation and extensive error trapping. CriTi-CAL was developed by using a combination of Visual Basic and C. Such an approach is an effective way to quickly develop high quality small to medium size software for the oil industry. The software is based on the results of intensive experimental and theoretical studies on buckling and post-buckling of coiled tubing at Rogaland Research. The software has been validated by full-scale test results and field data. Introduction Coiled tubing has been widely used for logging, well clean out, well stimulation, gas lift, cementing and drilling. The applications of coiled tubing in horizontal wells have increased dramatically in recent years, often pushing coiled tubing to its operational limits. Therefore, better understanding and precise prediction of coiled tubing operational limits has become important. One of the main limitations associated with coiled tubing is assumed to be helical buckling and lockup due to the additional wall friction force generated by buckling. The critical buckling load in inclined well sections is determined by the Dawson formula for sinusoidal buckling and the Chen et. al. formula for helical buckling. The buckling theory has been extended to the curved wells and verified through small-scale tests. A post-buckling algorithm has also been proposed in this paper. The buckling theory in curved wells was further verified by McCann and Suryanarayana. In 1994 an industrial project supported by oil companies was established to develop a coiled tubing simulation software by implementing the new achievements in theoretical studies. The software utilises improved buckling and post-buckling force models, and also addresses other aspects in coiled tubing operations, such as pressure drop, pump capacity, stress and along-hole-depth corrections. SYSTEM DESIGN AND DEVELOPMENT The main objective of the project is to develop a PC Microsoft Windows based user-friendly coiled tubing simulation software in a quick and economic manner. Due to this requirement, different software development solutions were evaluated and a combination of Visual Basic and C programming language was selected. This approach has the following advantages: – Time saving. Visual Basic provides an easy-to-use platform and facilities to build sophisticated Window interfaces in a cost-effective way. In addition, there are rich selections of third-party plug-in modules (in the format of VBX and DLL) for a variety of tasks. No need for computer expert. The development of both interface and analysis code were done by petroleum engineers with reasonably good computer knowledge. Petroleum engineers can design the interface that they think is logical and necessary. This eliminates the cost and time needed for communication between petroleum engineers and computer experts for such a medium-sized applications. – Acceptable performance and good quality. The speed of the interface developed by using Visual Basic is acceptable. The time-consuming calculation tasks for were coded with C in the format of DLL (dynamic linked library). P. 167

Abstract This paper describes a technically advanced, user-friendly, PC-Windows-based reservoir simulation tool (SIMTOOLS) that allows construction of realistic reservoir models using a geostatistical approach. This PC-Windows based product has three application tools: digitizing, mapping and geostatistics. It has been designed primarily to enable reservoir engineers to apply the geostatistical gridding technique in mapping and reservoir simulation practices. Introduction There are many gridding methods (e.g., triangulation, local sample mean, inverse distance, etc.) used in commercial mapping packages. These deterministic methods are similar to kriging, but not as accurate on a point by point basis. The distinguishing feature of kriging is the minimization of the error variance. Consequently, the standard deviation of the errors is lower for the kriging estimate than for any of the other techniques. Kriging estimation takes into account the effects of both scarce sampling and spatial variability. Like all deterministic methods, kriging smoothes the original data. So the kriging estimates are more appropriate for mapping reservoir properties where small scale features are not important, such as depth to top structure and formation thickness. When excessive smoothness is not desired, e.g., generating a permeability grid for reservoir simulation, conditional simulations can be used. Conditional simulation is another gridding technique from geostatistics. It adds correlated variations to the smooth kriged surface to produce models which satisfy the available data at sample locations and fill in unsampled locations with properties that have desired statistics. There are two distinct features in conditional simulation. One is that heterogeneity in terms of Dykstra-Parsons Coefficient and spatial continuity of the grid can be produced to specification. Conventional gridding methods, on the other hand, usually result in a much smaller Dykstra-Parsons Coefficient than the data would suggest. P. 187^

Abstract The main motivation for storing drilling data is to use them for post-analysis and efficient planning. Conventional drilling data storage systems often exhibit two major shortcomings that make such use difficult: In the first place, the data is often stored with depth as the primary key. Such a depth-based storage strategy may cause loss of valuable data if the depth is miscalculated at the time of recording, or when there is no steady depth progression. It also makes it difficult to analyse situations where the depth is set backwards due e.g. to sidetracking or to drilling of cement. Another problem is the amount of data collected during a drilling operation. This soon becomes unmanageable if there is no structured way of extracting information from such data. This paper outlines a database model for drilling data storage, which aims at providing a high degree of data availability for efficient post-analysis. It also suggests an organisational model that should be adhered to in order to utllise the database efficiently. Introduction The amounts of data collected while drilling a well can be considerable. Far too often these data are only archived, never to be seen again. There is however often a lot to be learned from post-analysis of a drilling operation. Particular sections of a well can be closely Inspected and analysed, allowing drilling personnel to gain knowledge based on real cases from real wells. By applying this knowledge in future drilling operations, a greater degree of safety and efficiency can be achieved. It is here suggested that a time based database model, combined with selective logging based on knowledge about the drilling process is a valid model for achieving this goal. P. 61^

Abstract This paper presents the newly developed computer package IPDOS, an Integrated Pipeline Design and Operation System. The developed package provides a useful tool in assisting the pipeline engineers in compiling and processing the massive amounts of data needed for the various phases of pipeline design, construction, operation and maintenance. IPDOS, which operates in a DOS environment, is made up of two main integrated modules: the database module and the processing module. The database module consists of a set of relational databases that are used to store the environmental, constructional, operational and maintenance parameters of the different pipeline systems within a company. These parameters can be entered, accessed, or reported via a number of easy-to-use interactive user menus. The processing module consists of a suit of programs that allow the user to perform a wide variety of data processing and analysis. These programs include wall thickness calculations, pipe size selection, stability analysis, pipeline lay-stress analysis and fluid flow analysis for gas, liquid, and multiphase pipelines. The paper provides a summary description of the main features of the software. The application of IPDOS as an information channel and an analysis tool for field and office pipeline personnel to completely evaluate the available data in an expedient manner is also presented. Introduction The current trend in the petroleum industry towards offshore and marginal field development has led to increasing construction activities of long and expensive submarine pipelines and/or networks of interlinking pipelines to enhance the economic exploitation of these resources. The ultimate target of any pipeline project is the transportation of the specified production requirement at an acceptable level of risk, whilst incurring minimum life cycle costs. As a result, a total system viewpoint approach has been emerged which recognises the integration of the design, fabrication, installation, operation, inspection, and maintenance procedures. The principal objective of pipeline design is to select the optimum pipeline dimensions and route as well as its method of fabrication, installation and protection. P. 179^

Abstract A new multiphase flow analysis and design system for DOS-based personal computers is described. Examples are also presented and analyzed using different multiphase flow techniques. These techniques are investigated using flow map and three-dimensional pressure surface comparisons and a new mechanistic model is discussed which attempts to overcome many of the problems associated with existing multiphase flow analysis methods. Introduction The simultaneous flow of-oil, gas and water in pipes is a common problem for the oil and gas industry. Multiphase flow often exists in wells and gathering systems for both on-shore and off-shore reservoirs producing oil, gas or condensates. Complexity of the production system, changing oil and gas properties with pressure and temperature, and availability of a multitude of correlations for fluid properties and pressure drop calculations, all combine to make the design of multiphase systems a difficult problem for the production engineer. Since the early seventies, computer programs have been commercially available for performing fluid property, well, and pipeline calculations involving both single phase and multiphase flow. With the arrival of personal computers (Pcs) in the early eighties, many of these programs have been ported over to this platform without extensive reprogramming to take advantage of the special features of the PC. Now, a new generation of design and analysis programs is appearing that eases the design task by making the process interactive through the use of on-line multilevel help and graphics. One such suite of programs which has recently been introduced is the multiphase flow analysis system by ASA Systems. All of the results presented here are generated with this suite of programs. Program Description The complete software package includes a program for analyzing flow in pipes (ASAPIPE), another for wells (ASAELL) and a program for calculating fluid properties (ASAPROP). A recent addition to these is the program, ASAMAP, which is extremely helpful in providing an understanding of how the various correlations for predicting flow patterns, pressure drop and holdup differ from each other. Flow pattern maps can be generated that show the flow pattern transitions using a common set of coordinates so that direct comparisons between methods are easily made. Furthermore, all significant quantities (frictional, hydrostatic, and total pressure drop, liquid holdup, liquid height for stratified flow, film thickness for annular flow, etc.) can be plotted in a variety of formats. P. 271^

Abstract This paper describes a new material balance calculation by coupling a statistics based history matching program with a material balance program. The procedure is to match the historical reservoir pressure data with the calculated pressures obtained from the material balance program — the so-called pressure match method — with the help of the history matching program. The combination of the history matching and material balance programs proves to be a very simple and powerful tool for material balance calculations. A user who does not know different material balance methods under various reservoir conditions is able to calculate the material balance with great accuracy. This is because the new procedure is based on the pressure match method which is known to be applicable to all types of reservoirs, i.e., oil or gas reservoir with or without gas cap and/or aquifer, with accurate results. In this paper, the calculation of pressure in the material balance method is briefly reviewed and the mechanism of pressure history match is cursorily discussed. Three case studies, comprising an abnormally pressured gas reservoir, a gas cap drive reservoir and an aquifer water drive reservoir, are presented to illustrate the use of the now method. The calculation results of these cases are comparable to or better than those of using the material balance program alone. Moreover, the matches were obtained in only a few number of runs. Introduction Among all the material balance methods, such as, Schilthuis method, Havlena and Odeh's method, etc., that have been publicized, the most robust and accurate method is the pressure match method. The method is to match the observed reservoir pressures with the calculated pressures. However, the pressure match normally requires a substantial computational time and effort. This paper describes a new procedure that will overcome this shortcoming and provide fast and accurate results for the material balance calculation. With the new procedure, an engineer need not know various methods, such as Ramagost and Farshad, Havlena and Odeh, Cole, or Campbell — just to name a few — for the material balance calculation. The current procedure can be applied to all the oil reservoirs as well as the gas reservoirs. It is not necessary to distinguish an abnormally pressured gas reservoir from a regular gas reservoir. There is no need to fit the data with a straight line, most conspicuous in the Havlena and Odeh method. P. 179^

Abstract Before the advent of graphical user interfaces (GUIs), cement job simulation programs were difficult to use, requiring large computer systems and occasionally yielding results that were difficult to understand. Often, the data input task was cumbersome enough to limit usage of these simulators. With the wide variety of today's Windows™*-based PC graphics packages, however, complicated results can be made understandable through visual displays. This paper describes a technically advanced, user-friendly, PC-based primary cement job design system that can use temperature-dependent rheology and Critical Reynolds Number when calculating frictional losses. INTRODUCTION An effective primary cement job design system is an important part of a sound cementing program. This type of system provides the user with a tool to fine-tune job designs, helping to obtain a safe completion for all planned cement jobs. When developing this program, designers wanted a truly user-friendly program that would require minimal training, reduce design time, and be used more often. To meet these requirements, they chose a GUI under the PC environment, and developed extensive error-checking routines. The system is composed of three major elements: the user interface, the simulator, and the output system. USER INTERFACE By providing a Windows™-based GUI, designers have simplified the complex task of transferring information from the user through the design system to the computer. In addition to simplifying information transfer, this interface ensures that the information the system transfers is the information the simulator actually required. The subject GUI accomplishes this task with the four following features: data verification -comparisons automatic calculations error checking graphical display of input volumetric calculations built-in data tables on-line help

Introduction Economic efficiency, cost control, and productivity enhancement are strong themes in the petroleum industry as the decade of the 90s emerges. Multidisciplinary teams are being used successfully to address fundamental issues impacting the profitability of all kinds of projects. It is generally accepted that computer hardware and software contribute to enhanced productivity, which in turn, tends to maximize profitability. Two major barriers to the use of software are skepticism and lack of functionality. The potential software user wants to know precisely what he or she can expect to gain before making a commitment to learn a program. Potential users also want functionality which automatically leads them into the investigative and design aspects of a particular problem. Software products such as word processors, spreadsheets, and graphics packages greatly assist individuals and teams engaged in the operational aspects of problem solving, including data collection and reporting. However, these software products are generally designed to facilitate business communication, hence they lack the specific functionality required to investigate technical problems in a cost-effective manner. One technical problem which often appears in a multidisciplinary setting is the issue of pore pressure and fracture gradient analysis. Pore pressure regimes in the subsurface greatly affect drilling and completion designs, well costs, and prospect or project economics. Pore pressures can be analyzed in several ways. One of the most reliable technique is based on well log data and this is the method preferred by many drilling engineers and explorationists. Log-based methods are extremely data intensive. Valid design and investigative conclusions cannot be drawn on the basis of several calculations or chains of calculations. To obtain the "higher" value from the underlying data, time-consuming clerical and operations-engineering work must be performed first. Failure to perform pore pressure analyses can be expensive. Well control, stuck pipe, and borehole stability problems tend to consume drilling budgets at astonishing rates. The high stakes involved and the quantity of preparatory calculations required make pore pressure and fracture gradient work an ideal candidate for computer application. The "low" level preparatory processing of data is performed error-free by machine and the "high" level interpretation is performed by the engineer, interacting with the computer to speed the process along. This paper documents the engineering productivity enhancement attributed to the geopressure evaluation software. It also describes the effectiveness of the software as a technology transfer/training device and estimates the economic impact of the software. Software Description The Geopressure Estimation Software (GPES), is an integrated, interactive personal computer-based formation pore and fracture gradient analysis tool designed for use by drilling engineers and geologists to evaluate formation pressures using digital wireline log, drilling and processed seismic data. Several empirical and crossplot models are available which a user can select from during an analysis session. A decision was made to write this computer program which would allow engineers to directly address the design and investigative aspects of pore pressure and fracture gradient work. P. 231^

Abstract Within less than a generation, dramatic changes in the computing needs of petroleum engineering graduates have occurred. Slide rule techniques gave way to hand calculators, which, in turn, has given way to solving problems using personal computers. The rapid change in technology has caught the academic community off guard. with some asking if the petroleum engineering curriculum prepares students for the advanced computing technology that is in use today. This paper addresses the problem and proposes an approach to computer use in undergraduate petroleum engineering curricula. Introduction The problem of integrating computer technology with petroleum engineering education has become the focus of debate petroleum engineering education has become the focus of debate among professionals both in industry and in education. Some experienced engineers may suspect that graduates enter the work force lacking the ability to successfully use whatever computer knowledge they have to solve petroleum engineering problems. Hence, employers may frequently question the usefulness of the computer as a tool in the petroleum engineering field, especially for use by engineers in their first year of work. However, many educators continue in the attempt to introduce computer applications to their students because successful use of the computer as a tool can yield a more capable petroleum engineer. Ideally, petroleum engineering students should receive appropriate computer training as part of their undergraduate coursework. However, two questions need to be answered: What computer training should be provided? and, How is this additional training to be fitted into the already stringent curriculum requirements of most petroleum engineering schools? This paper describes an approach to this problem that is being developed and that is under evaluation in the Petroleum Engineering Department at Louisiana State University. The key to this approach is establishing a "floor of knowledge among the students at each academic level so that faculty will be able to expect a certain minimum level of computer competence among petroleum engineering students. Students enter the university with a wide range of computer experience, from no previous computer exposure to advanced knowledge of computer previous computer exposure to advanced knowledge of computer systems and programming. If instructors are to create useful class assignments involving both petroleum engineering and computers, all students must have some common level of computer knowledge. This approach allows for the growth of student computer knowledge to meet the requirements of petroleum engineering courses, with computer skills being treated as any other prerequisite knowledge, such as math, physics, geology, and chemistry. This floor of knowledge is essential in teaching the appropriate use of the computer as a tool in petroleum engineering calculations and operations. Conversely, students should have a means of anticipating the specific computer requirements for each petroleum engineering course. By building on a base of computer petroleum engineering course. By building on a base of computer skills over the entire four-year curriculum, these needs would be met. History of Previous Computing Tools In earlier times, the tools used for calculations by petroleum engineers have been relatively universally accepted. P. 187

Abstract A Well String Simulator (WSS) computer program has been developed to analyze well string performance in high-angle and horizontal wells. The program can calculate the axial force, pick-up/slack-off loads, bending moment, rotating torque, buckling load, and stress along the well string (drill string/casing/coiled tubing) in any well profile. The effects of well string running speed and rotating speed on the axial forces and torque can be considered in the calculations. A menu-driven data input interface with on-line help and a graphics post processor has been integrated into the program for easily inputing data and visualizing results immediately after the calculations. Dynamic memory allocation and overlay techniques are used to minimize the memory requirements of the program. As a result, the program can run comfortably on an IBM PC with 512 KB memory. Introduction Drilling and completion of high-angle and horizontal wells has become common practice in recent years. The maximum horizontal displacement depends on drag, torque, hole size, build-up rate and well string strength. For drilling operation, the main concerns are the rotation torque, buckling and the strength of the drill string; for casing operation, the main concerns are the running depth and the pick-up load; for coiled-tubing helical buckling seems to be the main obstacle. Theoretical calculations of these values are helpful in planning operations. planning operations. THE MATHEMATICAL MODELS The 3-D computer model (Figure 1) is based on the finite element method where the well string is divided into small elements. The length of each element is automatically chosen according to the well's radius of curvature at the current point to simulate the dog leg effects. Axial Force: The equations for axial force, torque and bending moment calculations are as follows: (1) (2) (3) (4) Where: In the above equations the positive sign is used for pick-up and the negative sign for slack-off. pick-up and the negative sign for slack-off. P. 275

SPE Members Abstract As part of a strategic effort in drilling computer technology. ARCO Oil and Gas Company is developing automated systems to produce drilling AFE cost estimates and allow detailed tracking produce drilling AFE cost estimates and allow detailed tracking of actual booked costs. Retrievals of booked costs from mainframe accounting databases, along with retrievals of drilling performance data from ARCO's Drilling Database System (DDS) are used to provide "calibrated input to an automated well planning and cost estimating systems An AFE documentation is automatically generated by the system. Historically the preparation of drilling cost estimates, associated AFE documentation, and the verification of booked costs has required significant time and effort within drilling organizations. Moreover drilling costs are a major portion of total expenditures. A consistent, calibrated cost estimating tool combined with an efficient cost tracking program improves well planning, estimating accuracy and cost control. On a work load basis, these systems also increase productivity by reducing the time and effort required to review booked costs and produce drilling AFE's, thereby freeing time for other produce drilling AFE's, thereby freeing time for other important engineering, operations and business tasks. Introduction The preparation of drilling cost estimates and AFE packages is a major responsibility of drilling organizations. Unless automated, the process is time consuming, involving hours of data gathering to accumulate design, performance and cost information from offset wells. Necessary information is usually scattered and in a form requiring manipulation in order to be correlated to the new well being estimated. Depending on the availability and complexity of data, a single AFE may require several days or weeks of combined effort from an engineer, technician and secretary. Offset costs may not be available, and if' they do exist, often cannot be easily collected. These costs, such as rig rates, boat operations, shorebases, BHA equipment, and directional drilling can vary significantly on a time basis as the market fluctuates, and also from area to area and operator to operator depending on drilling philosophy and bid pricing. Finally, most of the information is in the form of field estimated cost with associated discrepancies unknown, rather than booked cost which reflect paid invoices. It is informative to review recent cost estimating and booking performance. Figures 1, 2 and 3 show a comparison of AFE performance. Figures 1, 2 and 3 show a comparison of AFE versus actual cost for development wells drilled in two lower 48 ARCO Districts. The data shows similar trends spanning a period of over 3–1/2 years, 1986 – 1989. The comparisons period of over 3-1/2 years, 1986 – 1989. The comparisons are conservative with regard to magnitude of error, as the data was associated with established domestic development fields. exploratory wells were excluded, and drilling costs were relatively stable during the time period. As shown on the figures, AFE estimates when averaged as a whole, exceed the actual cost by +5% to +9%. An +8% figure was also obtained in a recent study of Alaska North Slope wells. These figures are distorted due to the random cancelling of over and under estimating errors, so that standard deviation and absolute errors should also be studied. The standard deviation for the data. a measure of both accuracy and precision, was, 43%, 27% and 36% respectively. The average absolute values of the differences between AFE and actual cost were 21%, 25% and 34%. In other words, there was an average 20% to 35% divergence between the original AFE estimate and the actual cost for all development wells. These results are even more telling when one examines estimated and booked costs on a detail (i.e category) basis. Figure 4 extrapolates this comparison on a AFE cost code level by showing a recent development well from an established field where drilling has been underway for over 10 years. P. 61

Abstract The collection of data concerning well characteristics, cement properties, and corresponding cement tests has been of primary interest to field operators, laboratory technicians, and service companies. Such data provides the designer a tool which allows him to critically evaluate past jobs in order to design a cement systems' for a particular well. It is therefore important that the data can be retrieved for this purpose. purpose. Previously, data was stored using a paper filing system. Difficulties encountered with such a system were loss or misplacement of data, and inaccessibility of data at critical times. The determination of correlations between well and slurry characteristics becomes difficult if rot impossible. Computer data filing of well characteristics, slurry design, and test results aids in archiving and retrieving of cement information. One such system is a menu-driven PC software package written to fulfill the heeds of field and package written to fulfill the heeds of field and laboratory personnel. Using this system, analysis required for job designs can be performed without the inconvenience of manual searching in a paper filing systems. This paper discusses the implementation of such a system in an actual laboratory environment. Added features such as automatic reporting and computing, locating needed information, and networking further increase laboratory efficiency, thus practicing faster turnaround time for creating job designs. Introduction Providing the capability to design a computer software system which is flexible, easy to implement, but has world-wide application, presents a challenging problem. Differences in presents a challenging problem. Differences in slurry design terminology, test applications and results, and units of measure combine to present unique difficulties for computer software design. Generically designed software-that is, software which can operate on a variety of personal computers, printers and plotters-is also a demanding state-of-the-art consideration. Development of such software system requires an understanding requires an understanding of cementing operations for design of input, search, and reporting displays as well as software and hardware configurations. Major features of the software system include the capability to enter, store, retrieve, search, and report on slurry design, slurry testing, well information. Slurry design includes such factors as water type and volume, cement type and weight, additives and a measured amount added to the cement, and the surface and downhole volume and weight. Surface and downhole volume and weight calculations are performed and presented as part of the package. Cement tests presented as part of the package. Cement tests performed include rheology, API crush tests, performed include rheology, API crush tests, static gel strength, free water, thickening time, set and wait-on-cement times. Some in-house tests are also provided. Well information includes such pertinent data as the bottom hole static and circulating temperatures, lease name, well number, well depth, drilling mud and spacers, casing and hole sizes, and bottomhole pressure. P. 327

SPE Member Abstract To be fully effective, engineering software must be easy to learn and easy to use for the casual first time user, as well as powerful enough to satisfy the experienced power user. The "human interface" represents how the user and the software communicate via keyboard, mouse, digitizer, screen, plotter, and printer. Better human interfaces make the software printer. Better human interfaces make the software less mysterious and easier to use and improve the quality of the output but at the cost of more programming time. programming time. The term "user friendly" is much over used without ever being defined. The more recent term "robust" has not provided better definition. Every individual or organization has at least a subconscious definition of these terms and has formed an opinion of the minimum acceptable level of software human interface. Whether developing or buying software, it is necessary to establish firm criteria of exactly what is the minimum acceptable. In addition, thought must be directed toward the optimum human interface balancing features that are "nice to have" against development cost. This paper suggests a reasonable balance between the hypothetical ultimate human interface and the cost of development. Introduction The software/human interface encompasses both how a human being can communicate to a computer program through keyboards, digitizers, mouses, and touch screens; and how the computer program communicates it's data and option setting requirements, and it's results back to the human being though' screens, printers, plotters, and tone generators. We should printers, plotters, and tone generators. We should also include some machine to machine communications since the saving of data and results, possibly for use in other applications may be critical to the human beings ease of use of the results. software/human interface may be poor or excellent. The excellent interface is often referred to as "User Friendly" which is much over used but highly sought feature of software. The term "Robust" has also been used for software which will not fail catastrophically. Robust computer software issues clear warning messages and will not go into infinite loops or drop the user back into the operating system with the loss of input data or results. Recently, much of the effort related to the development of professional engineering software has been devoted to the improvement of the software/human interface. Perhaps this interest in improved interfaces is related to the economic availability of better equipment which permits a better interface. We have learned how to calculate properly and now we are primarily adding a better properly and now we are primarily adding a better interface to existing calculation code. However nothing in this discussion should suggest that Flash" is everything and substance is less important. By definition it is assumed that professional engineering software uses proper, professional engineering software uses proper, calculation procedures with the latest established techniques to solve the problem at hand. Finally, it must be understood that what is critical and necessary to some may be considered not only unnecessary but also a distraction and inconvenience to others. Therefore the conclusions of this caper must be viewed only as an opinion and cannot be considered as a final criteria. It is hoped that the paper leads to a healthy discussion and perhaps paper leads to a healthy discussion and perhaps provides some guidelines for individuals or provides some guidelines for individuals or companies to develop their own criteria when selecting computer software. Finally, most of the discussion in this paper relates most directly to DOS microcomputers, primarily because most of the author's recent experience is with this system. However the principles may be extended to other computers and other operating systems. P. 233