Summary The historical challenges and high failure rate of using standalone screen in cased and perforated wellbores pushed several operators to consider cased-hole gravel packing or frac packing as the preferred completion. Despite the reliability of these options, they are more expensive than a standalone screen completion. In this paper, we employ a combined physical laboratory testing and computational fluid dynamics (CFD) for laboratory scale and field scale to assess the potential use of the standalone screen in completing the cased and perforated wells. The aim is to design a fit-to-purpose sand control method in cased and perforated wells and provide guidelines in perforation strategy and investigate screen and perforation characteristics. More specifically, the simultaneous effect of screen and perforation parameters, near wellbore conditions on pressure distribution and pressure drop are investigated in detail. A common mistake in completion operation is to separately focus on the design of the screen based on the reservoir sand print and design of the perforation. If sand control is deemed to be required, the perforation strategy and design must go hand in hand with sand control design. Several experiments and simulation models were designed to better understand the effect of perforation density, the fill-up of the annular gap between the casing and screen, perforation collapse, and formation and perforation damage on pressure drop. The experiments consisted of a series of step-rate tests to investigate the role of fluid rate on pressure drop and sand production. There is a critical rate at which the sand filling up the annular gap will fluidize. Both test results and CFD simulation scenarios are comparatively capable to establish the relation between wellbore pressure drop and perforation parameters and determine the optimized design. The results of this study highlight the workflow to optimize the standalone screen design for the application in cased and perforated completions. The proper design of standalone screen and perforation parameters allows maintaining cost-effective well productivity. Results of this work could be used for choosing the proper sand control and perforation strategy.

Summary Previous studies showed that different parameters influence the plugging of completion tools. These parameters include rock mineralogy, reservoir-fluid properties, and type of completion tools. Although different methods have been used for unplugging these tools, there is still debate regarding the performance of these methods on damage removal. In this study, we assessed the performance of high-power shock waves generated from an electrohydraulic-stimulation (EHS) tool on cleaning completion tools plugged during oil production. These devices were extracted from different wells in Canada, Europe, and the US. First, we quantified the extent of cleaning for the plugged slotted liners using the EHS tool at the laboratory scale. Next, we analyzed the mineral composition of the plugging materials removed after the treatment by conducting scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS), inductively coupled plasma mass spectroscopy (ICP-MS), colorimetric, and dry-combustion analyses. Finally, we reviewed the pulsing-stimulation-treatment results applied to several field case studies. The results of unplugging slotted liners at the laboratory scale showed that up to 28.5% of the plugged slots are cleaned after 120 pulses of shock waves. The mineral-characterization results showed that the main plugging materials are calcite, silicates, and iron-based components (corrosion products). The cleaning performance (CP) of the EHS tool increases by increasing the number of pulses and the output energy (OE) applied to the tool. The CP parameter is high at (i) high concentrations of carbonates, barium (Ba)-based components, and organic matter, and (ii) low concentrations of corrosion products and sulfates. The results of field case studies showed that the cleaning of the EHS tool is not limited to the sand-control devices and it can clean other tools that are less accessible for other techniques, such as subsurface safety valves. This paper provides a better understanding of the performance of shock waves on damage removal from plugged completion tools. The results could open new insight into the applications of shock waves for cleaning the completion tools.

Summary Most of the test protocols developed to evaluate sand-screen designs were based on scaled‐screen test coupons. There have been discussions regarding the reliability of such tests on scaled test coupons. This paper presents the results of tests on wire‐wrapped screen (WWS) and slotted liner (SL) test coupons for typical onshore Canada McMurray formation sand. A unique sand control evaluation apparatus has been designed and built to accommodate all common stand‐alone screens that are 3.5 in. in diameter and 12 in. in height. This setup provides the capability to have a radial measurement of pressure across the sandpack and screen for three‐phase flow. Certain challenges during testing such as establishing uniform radial flow and measuring the differential pressure are outlined. Produced sand is also measured during the test. The main outputs of the test are to assess the sand control performance and the mode of sanding in different flow directions, flow rates, and flow regimes. It was possible to establish uniform radial flow in both high‐ and low‐permeability sandpacks. However, the establishment of radial flow in sandpacks with very high permeability was challenging. The pressure measurement at different points in the radial direction around the screen indicated a uniform radial flow. Results of the tests on a representative particle size distribution (PSD) from the McMurray Formation on the WWS and SL test coupons with commonly used specifications in the industry (aperture sizes of 0.012, 0.014, and 0.016 in. for WWS and 0.012, 0.016, 0.018, and 0.020 in. for SL) have shown similar sanding and flow performances. We also included aperture sizes smaller and larger than the common practice. Similar to previous tests, narrower apertures are proven to be less resistant to plugging than wider slots for both WWS and SL. Accumulation of fines close to the screen causes significant pore plugging when conservative aperture sizes were used for both WWS and SL. In contrast, using the test coupon with a larger aperture size than the industry practice resulted in excessive sanding. The experiments under linear flow seem more conservative because their results show more produced sand and smaller retained permeability in comparison to the testing under radial flow. This work discusses the significance, procedure, challenges, and early results of physical modeling of stand‐alone screens in thermal operation. It also provides insight into the fluid flow, fines migration, clogging, and bridging in the vicinity of sand screens.

Summary Kazakhstan owns one of the largest global oil reserves (approximately 3%). This paper aims at investigating the challenges and potentials for production from weakly consolidated and unconsolidated oil sandstone reserves in Kazakhstan. We used the published information in the literature, especially those including comparative studies between Kazakhstan and North America. Weakly consolidated and unconsolidated oil reserves in Kazakhstan were studied in terms of the depth, pay‐zone thickness, viscosity, particle‐size distribution (PSD), clay content, porosity, permeability, gas cap, bottomwater, mineralogy, solution gas, oil saturation, and homogeneity of the pay zone. The previous and current experiences in developing these reserves were outlined. The stress condition was also discussed. Furthermore, the geological condition, including the existing structures, layers, and formations, were addressed for different reserves. Weakly consolidated heavy‐oil reserves in shallow depths (less than 500‐m true vertical depth) with oil viscosity of approximately 500 cp and thin pay zones (less than 10 m) have been successfully produced using cold methods; however, thicker zones could be produced using thermal options. Sand management is the main challenge in cold operations, while sand control is the main challenge in thermal operations. Tectonic history is more critical compared with the similar cases in North America. The complicated tectonic history necessitates geomechanical models to strategize the sand control, especially in cased and perforated completions. These models are usually avoided in North America because of the less‐problematic conditions. Further investigation has shown that inflow‐control devices (ICDs) could be used to limit the water breakthrough, because water coning is a common problem that begins and intensifies the sanding. This paper provides a review on challenges and potentials for sand control and sand management in heavy‐oil reserves of Kazakhstan, which could be used as a guideline for service companies and operators. This paper could be also used as an initial step for further investigations regarding the sand control and sand management in Kazakhstan.

Summary Sand control screens are installed with an internal string (wash pipe) as required which, among other functions, provides a circulation path. In long horizontal wells, running a wash pipe consumes considerable rig time and may limit the ability to reach target depth. In cases in which fluid losses are experienced after screen installation, isolating the open hole with a fluid‐loss control valve can be prolonged. This paper describes a wash‐pipe‐free solution for screen installation using a check‐valve inflow control device (CV‐ICD). ICD screens are commonly used to delay/restrict the influx of unwanted fluids such as gas or water. The wash‐pipe‐free solution integrates a check valve with the ICD to prevent outflow through the screen during circulation and allows inflow through the screen when placed on production. This solution uses a check ball that seals against the ICD during circulation but falls back on a porous retainer plate during production. The check ball and retainer plate can be dissolved by spotting a reactive fluid inside the screen or made to erode over time with production. Laboratory testing yielded the following results: the ICD with the check ball was shown to seal up to 5,000 psi; the check ball and retainer plate can be dissolved by a reactive fluid, which can be tailored to bottomhole temperature and the required time of dissolution; and the pressure activation test demonstrated that the maximum differential pressure to seat the ball was less than 5 psi. This CV‐ICD solution has been applied worldwide in more than 35 wells, most of which were targeted to avoid running a wash pipe. However, in two wells the technology was successfully used to set openhole packers with a 5,000‐psi setting pressure. In this paper, we present the wash‐pipe‐free ICD screen installation with a dissolvable check valve and the capability of setting a hydraulic packer without a wash pipe or intervention in the open hole. The novel contribution presented herein is the ability to integrate a ball and cage to existing nozzle‐based ICDs by using dissolvable material to achieve the preceding results in this application.

Summary Multilayered metal-mesh screens (MMSs) are widely used as standalone screens for sand control in unconsolidated formations. The nominal rating of such screens is usually determined on the basis of the specifications of the filter layer. It is often found that screens with the same filter-layer nominal rating perform differently. It is shown in this study that the primary reason for this is that the sand-retention performance of multilayered MMSs is a strong function of not only the filter layer but also the protection and the support layers. This paper presents a systematic study that shows how the overlap between different mesh layers, the alignment of the protection and support layers, and the relative pore-size ratio, defined as the ratio of pore size of the protection/support layer to that of the filter layer, have a large impact on the sand-retention performance of an MMS. The pore-size distribution (PoSD) of multilayered plain-square-mesh (PSM) and plain-Dutch-weave (PDW) screens is calculated with a novel numerical technique. Influences of screen sintering, coupon sampling, and screen designs on the PoSD of a screen are modeled by varying the layer overlap, shifting the layer alignment, and modifying the design of the protection and support layers. The PoSD data are used as an input into an analytical model for evaluating sand production of PSM screens in slurry-type sand-retention tests (SRTs) for screen-design optimization. For PSM screens, the results show that the PoSD of a multilayered screen can be very different from the PoSD of the filter layer. In general, a decrease in sand production with an increase in layer overlap is observed; the trend exists irrespective of how mesh layers are aligned. A change in mesh alignment is found to cause a variation in sand production even with the same filter-layer pore size and layer overlap. The nominal rating of the filter layer of a multilayered PSM screen should be used to estimate sand production only when the pore sizes of the protection and support layers are much larger than the pore size of the filter layer. For PDW screens, layer overlap is shown to dominate the screen performance by affecting the filter-layer pore size. The PoSD of a PDW screen is found to be less affected by variations in layer alignment and relative pore-size ratio. This study clearly shows that the layer overlap, layer alignment, and relative pore-size ratio between mesh layers can have a significant impact on the sand-retention performance of a multilayered MMS. As such, widely different screen performances can be expected for screens with the same nominal screen rating. Our results have a direct bearing on how MMSs are manufactured, selected, and specified. Increasing the relative pore-size ratio appears to be a promising screen-design approach for obtaining consistent screen performance for multilayered MMSs.

Summary Discrete-element-method (DEM) simulations were shown to be useable for selecting screens with simple geometries (e.g., wire-wrap screens) under prepack test conditions (Mondal et al. 2011 ). Metal mesh screens (MMSs) (commonly referred to as premium screens) can have multiple (sometimes sintered) layers with different weave patterns. Any model for estimating sand production in such screens must account for these complexities. The objective of this paper is to explore different techniques to create accurate representations of complex filter media and to use them in numerical simulations and/or analytical models for improved screen selection. In this paper, we used computed-tomography (CT) images of real-screen coupons to construct 3D replicas of two MMS types: plain square mesh (PSM) and plain Dutch weave (PDW). An entirely computer-based method of creating 3D screen assemblies is also presented. These virtual screens were compared and validated against those generated from the CT images. We conducted DEM simulations of prepack tests through these multilayer MMS assemblies. The retention efficiency of MMSs for different particle sizes was also calculated for better slurry-test modeling. We quantitatively showed that the effective size of MMS assemblies can be significantly lower than the nominal rating of the filter layer. This paper augments the prepack-test and slurry-test models for mesh-type screens presented earlier (Mondal et al. 2012 ; Chanpura et al. 2013 ). Determination of the retention efficiency of MMSs, which is currently characterized by a single filter-cut point, is also a step forward in quality assurance and quality control of these screens. Finally, we demonstrate that one can conduct in-depth screen design and optimization studies with virtual meshes in a consistent way and at a fraction of the cost and time that would be required otherwise by use of conventional experimental techniques.

Summary Openhole sand-control technique selection has been a topic of interest since the late 1990s and was discussed most comprehensively in SPE 85504 (Price-Smith et al. 2003 ), which proposed guidelines for selection between standalone screens (SASs), α/β packing, and shunt-tube packing. Proposed guidelines were based on formation characteristics such as formation strength, particle-size distribution (PSD), mineralogy across the well path; risk factors involved in execution as well as reliability/longevity; and cost considerations. From a PSD standpoint, their guidelines were based on the criteria proposed earlier in SPE 39437 (Tiffin et al. 1998 ), whereas risk evaluation was based on the technologies available at that time. Since then, significant advancements were made in understanding sand-retention mechanisms and failure modes of SASs, and in technology development to extend the limits of openhole gravel packing. These combined with the field experience in the last decade certainly warrant re-examination of their guidelines, which is the objective of this paper. In this paper, we begin with a critical review of the current sand-control technique-selection methodologies for openhole completions, including the way some of the risk factors are being evaluated to eliminate a given completion technique. On the basis of the technologies developed in the last decade, we propose a new approach for selecting sand-control technique, along with techniques/tools for proper evaluation of the risk factors. The proposed approach significantly extends the application limits of SASs and α/β packing compared with what was proposed in SPE 85504 (Price-Smith et al. 2003 ).

Summary Sand-particle-size distributions (PSDs) are used for various purposes in sand control: for example, decision making between various sand-control techniques and sizing of the filter media (sand screens and/or gravel packs) through either rule of thumb or physical experiments or theoretical models. PSDs of formation-sand samples are also often used to generate “simulated” formation sand for laboratory experiments. The two most commonly used techniques for PSD measurements are sieve and laser. Although some engineers use one technique for no obvious or justifiable reasons, others use both techniques for measurements and do not know what to do with the data when significant differences exist in PSDs obtained from each technique. Although the inherent limitations of (and the differences between), these two techniques as well as other factors affecting the measurements are well-known, a systematic study as to which of these two techniques is relevant to sand-control-screen selection and why is lacking. In this study, we critically review the current practices in PSD determination and the use (and misuse) of the information obtained from these measurements, propose a methodology toward determining what is relevant under gradual-formation-failure conditions for wire-wrap screen, discuss when it should be used and why, and present initial experimental results that support our conclusions.

Summary Expandable-sand-screen (ESS), a technology concept envisaged by Shell and initially developed by Petroline, was first field trialed in 1997 with the idea that eliminating the annulus between the sand screen and wellbore would improve downhole sand control and allow enhanced reservoir performance and management. By the end of 2012, ESS was installed in 677 wells, with 418,184 ft of screen deployed globally. As such, ESS has matured as a viable sand-control technology combining openhole-gravel-pack functionality with the installation simplicity of a standalone-screen (SAS) completion. With performance, reliability, and long-term well life expectancy of paramount importance to field-development economics, an extensive internal installation database has been maintained for Weatherford's ESS systems. Over the past 15 years, observation and analysis of design, planning, field implementation, and useful life cycle have been documented in this database. This performance insight provides the foundation for future reliability and has been used to identify learning opportunities, influencing the product evolution and technology-application envelope. With performance and reliability analysis provided and discussed in detail, the applicable ESS envelope is outlined. Product-design enhancement, methodical application evaluation, and rigorous operating procedures result in improved successful use. Analysis of both infant and production failure trends are presented and show improvement. These data are used to estimate future life predictions by use of recognized reliability-analysis tools. The applicability of ESS in openhole wells is highlighted, with continuing performance in oil producers, gas producers, water injectors, and underground-gas-storage applications. There are various sand-control technologies successfully used in reservoirs around the globe. This study outlines the applicable envelope for ESS use, providing insight to enable informed evaluation, life-of-well risk appraisal, and, ultimately, reliable sand-control-completion selection for existing or new field-development appraisal.

Summary The Vincent project is an offshore oil field developed by subsea multilateral (ML) wells with sand control. This paper provides an insight into how completion practices were developed to maximize well productivity and how they were balanced against risks for constructing ML junctions. The fluids used for drilling and cleaning up openhole laterals can have a significant impact on well productivity in standalone-screen applications, especially with respect to sand-screen plugging. This paper details the development of openhole fluid selection and cleanup practices for completing long 7,000-ft+ horizontal laterals with standalone screens. The Vincent wells are more complex because of drilling trilateral wells that include two technology-advancement ML (TAML) Level-5 ML junctions requiring openhole connections. The paper identifies the key risks for installing the ML junctions in a weak formation, including risks imposed from cleanup practices. The paper reviews the lessons learned during execution, how the ML-junction installation risks were mitigated, and how the Vincent wells were delivered with a well-performance meeting expectation.

Summary Many completion engineers use laboratory sand-retention testing as a tool to select a screen for standalone sand-control applications, some focusing on prepack and others on slurry testing. Those who use slurry tests for screen selection typically do so on the basis of the conventional wisdom that slurry testing is more challenging; thus, it represents the worst-case scenario for sand production. Furthermore, the general belief in the industry has been that metal-mesh screens with a "pore structure" are better for sand retention compared with wire-wrap screens (WWSs) of slot geometry, although they are more prone to "plugging." These are just a few of the many myths that exist in screen selection for standalone screen (SAS) applications. Recent papers on the modeling of sand retention by screens of various geometries, and supported by laboratory experiments, provided the tools for predicting sand production in both prepack and slurry conditions, as well as allowing for a systematic performance comparison of various screens by use of the entire particle-size distribution (PSD) of formation sands ( Mondal et al. 2011 and 2012 ; Chanpura et al. 2012 , 2013 ). In this paper, we discuss and challenge many myths in the screen selection for SAS applications and substantiate our findings with modeling and experimental data. The conditions under which a slurry or a prepack test would be more conservative are identified, highlighting the mechanisms of sand retention (size exclusion or bridging dominated). We demonstrate that the current thinking that prepack tests are always more conservative from a sand-production standpoint is incorrect. We also show that the concept that metal-mesh screens are always superior for sand retention than WWSs is incorrect, highlighting the factors that affect sand production through various screens [e.g., open flow area (OFA), wire thickness, and fraction of bridging-sized particles in the formation sand]. Finally, a methodology for screen selection in SAS applications is proposed.

Summary There are two types of sand-retention tests (SRTs) generally used in the industry to evaluate the performance of sand-control screens for standalone-screen (SAS) applications—prepack tests and slurry tests. They represent complete hole collapse and gradual rock failure around the wellbore, respectively. In this paper, we present analytical models and Monte Carlo (MC) simulations to estimate sand production in slurry-type SRTs with square-mesh screens while taking into account the full particle-size distribution (PSD) of the formation sand. We also compare the model results with four sets of experimental data and demonstrate that this approach can be used to predict sand production for different sand-size-distribution/screen-size combinations without the need for physical tests (provided that both an accurate representation of the formation-sand PSD and an accurate representation of screen pore sizes are available). This work augments previously published slurry-test models that were limited to wire-wrapped screens (WWSs), and enables the comparison of the performance of square-mesh screens with WWSs. The analytical model and the MC simulations provide a direct and reliable way to estimate the amount of sand that will be produced for a given sand-size distribution and a given screen size. Because the proposed methods are much more quantitative, they represent a significant improvement that surpasses current methods that rely on single design points or rules of thumb for screen selection.

Summary A slurry-type sand-retention test (SRT) that simulates gradual rock failure around the wellbore has been used widely in the industry to evaluate the performance of sand-control screens for standalone-screen (SAS) applications. Using the test results, screen selection is achieved generally on the basis of the relative ranking of screen performances rather than absolute performance. Chanpura et al. (2011) highlighted recently the drawbacks of the current practices in slurry-type SRT procedures and proposed a new testing and interpretation methodology. Mondal et al. (2011) proposed simulation methods and results that, to the best of our knowledge, modeled screen performance numerically for the first time and presented comparisons to physical experiments. However, the approach used by Mondal et al. (2011) considers cases in which hole collapse occurs on wire-wrap screens (WWSs) and simulates "prepack" testing as opposed to the slurry-type tests considered in this work. In this paper, we present an analytical and a numerical [Monte Carlo (MC)] approach for the prediction of sand production through sand screens with slot geometry. We show that the proposed methods can estimate both mass and size distribution of the produced solids in a slurry-type SRT, taking into account the full particle-size distribution (PSD) of formation sand for WWSs. Simulations show that once the slot opening is covered by particles larger than the slot opening, sand production becomes negligible unless there is a true "fines" problem, which is characterized by a bimodal size distribution. The effect of slot-size variation in screen coupons on sand production demonstrates the importance of proper quality control or at least accurate determination of slot sizes in these tests. The proposed methods can be used to estimate sand production in slurry-type SRTs for different screen sizes and thereby can enable screen-size selection on the basis of a defined acceptable level of sand production. Final screen selection can be confirmed through an SRT.

Summary Woven-metal-mesh sand screens, commonly known as premium screens, have been used extensively by the industry. Sand-retention testing is often executed to evaluate the performance of these screens and to establish empirical guidelines for screen-size selection. These tests are tedious, however, and the results are prone to artifacts and have been used, at best, to correlate trends in sandretention performance with select sand-size-distribution parameters. A new method incorporating results from numerical modeling, in addition to experimental data, is presented to estimate the mass and size distribution of the produced solids in prepack sandretention tests (SRTs) through premium screens. This method provides a fast, reliable correlation to estimate sand production through premium mesh screens when the size distribution of the formation sand is known. This paper presents results from a wide range of pre-pack sand-retention experiments. In these tests, which represent complete hole collapse, the mass of sand produced and its size distribution over time are measured. Results of 3D, discrete- element computer simulations of woven-screen geometry placed in contact with granular sandpacks of approximately 100,000 particles are also presented. On the basis of both the simulations and the experiments, a new method for screen selection is presented. This method is based on a correlation that allows one to use the entire sand-size distribution of the formation sand and to estimate the mass and size distribution of the produced sand. The method is validated by comparisons with experimental data. A new method and new correlations for estimating the mass and size distribution of produced solids in prepack tests through premium screens are presented. Key differences in sand-retention mechanisms between premium screens and wire-wrapped screens (WWSs) have been identified. The method uses the entire-formation sand-size distribution (as opposed to a single design point), and has been validated with laboratory tests. The method also helps in screening anomalous test results.

Summary Pumping a gravel slurry between a downhole screen and the rock matrix has been used to prevent production of undesirable solids or sand from the formation in traditional oil and gas completions. Recently developed expandable technology attempts to eliminate this operation by expanding metallic sand-control screens against the wellbore. However, one problem with this process is borehole irregularity. It is desirable to have a smart downhole-screen structure that is capable of self-expanding and conforming to the borehole surfaces in certain downhole conditions. Use of an advanced shape-memory-polymer (SMP) structure offers breakthrough performance for sand-control applications. Proper characterization and full understanding of the thermal, mechanical and functional behavior of the SMP structure in simulated downhole pressure, temperature, and fluid conditions are critical for successful applications. This study used a high-pressure/high-temperature (HP/HT) in-situ mechanical test system and test method to characterize the in-situ hot-wet mechanical and functional behavior of the SMP foam, including deployment and contact-pressure-development functional properties, compressive resistance, and time-dependent stress-relaxation and creep mechanical properties. These properties were determined during immersion in a fluid environment at various temperatures under ambient pressure and 3,000- to 5,000-psi hydrostatic pressure. Effects of the test temperature, fluid condition, and the hydrostatic pressure on mechanical and functional properties of the SMP foam were identified. Study results were used to establish the operational window of the SMP screen as a sand-control solution.

Summary The selection of optimum screens for standalone screen (SAS) applications has historically been based on experimental data, rules of thumb, or correlations. Recent sand-retention tests conducted in various laboratories offer empirical screen-selection criteria on the basis of different sand-size-distribution parameters. Unfortunately, these experiments have their own limitations. They provide substantially different results, depending on how the tests are conducted and interpreted, leading to significant differences in the recommended screen type and screen-opening size for any given sand sample. To resolve these inconsistencies and to understand the physics of the problem better, this paper presents 3D numerical simulations to evaluate the performance of wire-wrapped sand screens and ultimately to develop systematic screen-selection criteria. In this paper, a new method is presented to estimate the mass and size distribution of the solids produced through wire-wrap screens. The method uses the entire particle size distribution of the formation sand and is validated with experimental and numerical data. The new method allows us to evaluate the performance of different screens without running expensive and sometimes inconclusive experiments, enhances our understanding of screen performance, and helps to design sand screens better to meet performance criteria under a wide variety of conditions. We first present results from 3D, discrete-element computer simulations of sand screens placed in contact with granular sand-packs of approximately 100,000 particles. The numerical model computes the mass and the size distribution of the solids produced. The effect of the most important parameters, such as friction coefficient, fluid viscosity, pressure gradient, and ratio of screen-opening size to sand size, on the mechanism of bridge formation and amount of sand produced is studied using both monodispersed and polydispersed systems. The results have helped resolve some key questions about the physics of sand bridge formation. Numerous simulations are conducted to replicate the experimental conditions over a wide range of screen-opening/sand-size ratios for wire-wrap screens. Good agreement is observed between laboratory experiments and the simulations.

Summary Four expandable completion liners (ECLs) have been run in Algeria in two fields—these are the first fully compliant ECLs in Algeria, the first worldwide in gas wells, and the first worldwide in multilateral wells (from Weatherford database). This paper presents the first detailed benchmark study of ECL performance. All systems to date have been run in 8½-in. hole using 5½-in. base-pipe ECL compliantly expanded, and the installations went well. It has been possible to compare ECL performance data against a comprehensive surveillance data set for the two fields where data from existing openhole completions allow meaningful comparisons. The other completions consist largely of slotted liners and some barefoot completions. The tested production rates in each of the wells have been high relative to normal field trends; however, the predominant factor in this is the reservoir character. Pressure-buildup (PBU) analysis indicates that the second well has reduced Darcy skin, while it is considered unproved in the first well (more data over time are needed). There is, however, consistent evidence for a reduction in the rate-dependent proportion of total skin in both wells. This is supported by other studies and a consideration of basic principles. The reduction in the rate-dependent proportion of skin has given an increase in production rate of 5–20% as compared with the computed rate from a slotted liner. This difference assumes no borehole collapse, with analyses and discussion presented of the effect on well performance should borehole collapse occur. The joint venture (JV) is investigating the further use of this technology in smaller hole sizes and possibly in conjunction with fracture stimulation

Summary Standalone screens (SASs) in open hole can provide highly reliable sand-control completions at a lower cost and with less operational complexity than other openhole sand-control completions and can provide long-term productivity performance comparable to other openhole completions when applied in the "right environment with the right procedures." Although many in the industry would agree with the preceding statement, there is no consensus on what the right environment is and what the right procedures are. Even when there is agreement on the applicability of SASs for a particular sand-size distribution, there are considerable differences in the recommended screen type and screen opening between various laboratories. In this paper, we critically review the various laboratory testing procedures used in the industry and the interpretations made to evaluate screen performance and screen selection for SAS applications. We demonstrate that the way some of the laboratory tests are performed makes them biased toward one type of screen (wire wrap) and that some are interpreted without sufficient information such that they almost always favor another type of screen (premium mesh). We show that severe screen plugging with clean formation sand is almost never an issue and that the probability of screen plugging because of other factors can be minimized when proper precautions are taken. We propose that candidates for SAS applications be initially selected on the basis of sand-retention performance, with the final selection confirmed on the basis of screen/sand pack permeability measurements. In addition, on the basis of approximately 185 laboratory tests performed on various types of wire-wrap (6 to 16 gauge) and premium mesh (60 to 600 μm) screens for unconsolidated sands and using a set criterion for sand retention, we conclude that many of the currently used criteria in the industry for selection between gravel packing and SAS are highly conservative and unduly limit the possible application of SASs.

Summary Within the sand-control-technology sector today, there are many sand-exclusion screen options available for use in completion design. Sand-control screens have steadily improved with the introduction and enhancement of metal sand-retention-media-based sand-exclusion products in the early 1990s. However, recent catastrophic sand-exclusion failures have led some operators and independent laboratories to perform additional testing and quality control checks on sand-exclusion products to ensure full life cycle field value. This paper describes a process to select sand-exclusion products by uniquely qualifying an individual product design, which includes retention media, metallurgy, subcomponents, manufacturing process, and the final assembled product. The technical evaluation is based on a two-tier qualification process that "uniquely qualifies" products for purchase consideration. Step 1 of the process tests the sand-retention media for plugging potential and solids retention. Step 2 then tests full-joint screens manufactured using media qualified during Step 1 for burst and collapse to ensure the product meets downhole performance specifications. Recent testing has illustrated a range of significant conclusions that the industry should be aware of: Published screen burst and collapse ratings are not always equivalent to actual screen performance. Burst and collapse pressures are not equivalent to basepipe rating. Welds can vary by plant; therefore, screens may vary by manufacturing location. Excessive drainage layer gap leads to premature burst or collapse failure. Not adjusting screen design for changes in metallurgy may lead to premature failure. Delamination has been observed in some sintered retention media. Scaling a product design up or down without conducting a detailed engineering analysis may lead to premature failures.