Executive Summary

Robert F. Mitchell, Halliburton

Managerial Changes

This issue is my last as executive editor for SPE Drilling andCompletions. When I took this job, there were some major problems toaddress. Some progress has been made, but more improvements are going to beneeded. My successor, Curtis Cheatham, is also dedicated to improving thisjournal, so expect to see quicker reviews and a smaller backlog of papers to bepublished. Much appreciation is due the Technical Editors, who do the majorityof the heavy lifting, and to the Associate Editors, who keep the processmoving. They are all listed next to this page, so find out who they are andthank them. You might consider volunteering yourself, it would be greatlyappreciated. The SPE staff has always been pleasant and helpful, with specialmention of Glenda Smith, Mattie Tanner, and special thanks to StacieHughes.

This issue contains sixteen drilling papers and seven completion papers, fora grand total of 23!

Drilling Papers:

Measuring Drillpipe Buckling Using Continuous Gyro Challenges ExistingTheories. Full scale buckling tests were performed in a 2020 m measureddepth research well, with a buildup and 60° tangent geometry. Variousconfigurations of a tapered string with 5- and 3½-in. drillpipe were used.Results indicated that pipe buckled between tool joints and that lockupoccurred during lateral buckling. Some helical buckling was seen only in thevertical section of the well. These tests clearly indicate the importance ofconnector size and clearance in the prediction of buckling behavior and thesurprising importance of lateral buckling in generating friction loads.Surge and Drag Analysis for Extended Reach Casing and Casing FlotationOperations With Centralizers: A Design Challenge? The challenge of runningcasing to its desired target depth using floated casing requires a morecomprehensive in-depth analysis than is currently available. Operationalexperience and past studies have brought new insights to the complexity andoperational difficulties involved. This paper presents a comprehensive modeland documents comparisons between the results of the mathematical model andactual data. Improving Hole Quality and Casing-Running Performance inRiserless Top Holes: Deepwater Angola. The operator and coventurers aredeveloping several Angola Block 15 fields in water depths of up to 1400 m. Mosthave experienced hole quality issues in the riserless interval that aremanifested as tight hole while tripping the bottomhole assembly (BHA) and asabnormal/excessive drag while running casing. The operator undertook a studythat identified microtortuosity as the root cause of casing-runningdifficulties. Changes to drilling practices have resulted in improved riserlesshole quality and smoother casing-running operations. Application of anInnovative Conveyance Risk Management Methodology for Long or TortuousWells. Some of the most important aspects to consider during the design,construction, and productive life of a well are the amount and nature of therisks associated with the conveyance of downhole and downhole-tool strings. Anew methodology, based on forces modeling and best practices has been developedto take full advantage of new conveyance technologies intended to alleviate oreliminate these risks. Case Study: Drillstring Failure Analysis and NewDeep-Well Guidelines Lead to Success. Three drillstring fatigue failuresoccurred while drilling two deep wells below 16,500 ft true-vertical depth. Allthe failures occurred across 2°/100 ft- to 3°/100 ft-dogleg severity intervalsfrom 6,000 to 8,000 ft. A cumulative fatigue indicated that drillstringfailures would occur across shallow doglegs mainly because of high hang-downloads combined with slow ROP. The results of the study led to the developmentof new deep-well design criteria and implementation of new drilling guidelines.Offshore Field Test of a New System for Model Integrated Closed-LoopDrilling Control. A new system for real-time optimization and automatedcontrol of the drilling process has been tested successfully on the Statfjord Cplatform in the Norwegian sector of the North Sea. Results from active andpassive testing indicated that the new methodology has the ability to improvedrilling-process reliability, safely increase drilling efficiency, and reducethe risk of human error. Drilling Difficult Formations Efficiently With theUse of an Antistall Tool. Antistall technology is a mechanical downholesolution that aims to adjust the drilling torque automatically in real time.The paper describes in detail, both in theory and on field experience, how thebit-induced torque fluctuations are significantly decreased to improvepenetration, and how bottomhole-assembly damage is prevented to increase runlengths. Delivering Steering Success in Problematic Soft-FormationDirectional Wells. To deliver consistent directional performance in verysoft formation applications requires solving issues such as hole washout,inappropriate drilling parameters, stabilization, and hole quality. Casestudies document where these solutions, in combination with both push and pointRSSs, have proven extremely successful. Finite Element Modeling of Casing inGas-Hydrate-Bearing Sediments. Casing integrity in shallow marine sedimentscould be challenging if natural gas hydrates exist in the sediments. Anumerical model has been developed using a finite-element code to simulate thestability of casing in gas-hydrate-bearing sediments by considering theinteraction between the formation, the casing, and the cement. GeneralizedHydraulic Calculation Method for Axial Flow of Non-Newtonian Fluids inEccentric Annuli. The flow of non-Newtonian fluids through eccentric annulioccurs during drilling and cementing operations. The flow pattern in aneccentric annulus can differ greatly from that in a concentric annulus, andthis difference affects both the pressure drop and the flow rate. Thepredictions of this method were compared with an extensive set of data, showingthat the new method was capable of reliably predicting the pressure drop ofmost drilling fluids in both laminar and turbulent flow regimes for eccentricannular geometries of practical interest. Fiber Sweeps for HoleCleaning. Cuttings transport in highly deviated wellbores is morechallenging and critical than in vertical wells. Results from this studyindicate that a fiber-containing sweep has better hole-cleaning capabilitiesthan the base fluid, even though these two sweep fluids have very similarrheological properties. Use of New Hydrostatic-Packer Concept To Manage LostReturns, Well Control, and Cement Placement in Field Operations. Ahydrostatic packer consists of a column of light fluid pumped into the annulusor drillstring to cause the total hydrostatic head to be equal to or less thanthe fracture-closure stress. Hydrostatic packers have been used effectively inmore than 30 fields and have contributed greatly to the operator’s high successrate in treating lost returns events. Particulate-Based Loss-PreventionMaterial--The Secrets of Fracture Sealing Revealed! Owing to the narrowdrilling margin that exists between the pore-pressure and the fracture-pressuregradient, drilling in depleted-reservoir, high-pressure/high-temperature, anddeepwater environments is universally recognized as being technicallychallenging. This paper discusses particulate-based-treatments design forsealing fractures. Parameters critical for optimizing the treatment have beenidentified and are discussed in the context of laboratory and field experience.Cement-Slurry Performance and Set-Cement Properties vs. MicrosilicaDensification. Because of its extremely fine nature and high reactivity,microsilica has been used to improve slurry stability and the mechanicalproperties of the hardened material. Contrary to common belief, not all gradesof microsilica are equal. Only moderately compacted microsilica have been foundto offer the adequate compromise between proper handling characteristics andgood slurry and set cement performance. Modeling of anUnderbalanced-Drilling Operation Using Supercritical Carbon Dioxide . Amechanistic model of an underbalanced-drilling operation using carbon dioxide(CO2) is developed in this study. The unique properties ofCO2, both inside the drillpipe and in the annulus, are shown tooptimize the drilling operation by achieving a low bottomhole pressure range.Automatic Measurement of Drilling Fluid and Drill-Cuttings Properties.To remotely control the drilling process, it is necessary to measure severaldrilling-fluid parameters automatically. The paper describes in detail thedesign for an integrated tool combination and the results of a full-size yardtest of such a combined set of tools for measuring drilling-fluid parametersand formation properties automatically.

Completion Papers

Completion Design, Installation, and Performance--Cannonball Field,Offshore Trinidad. The Cannonball field is a one-trillion cubic ftgas-condensate development in offshore Trinidad producing at an initial rate inexcess of 800 MMcf/D from three wells. This paper discusses the completionbasis of design, detailed engineering assurance of the design, qualification ofcritical engineered equipment, and actual results. Completion Design for aHighly Compacting Deepwater Field. The Magnolia field, located in thedeepwater region of the Gulf of Mexico, produces oil and gas from a tension legplatform in 4,673 ft of water. The reservoirs are significantly overpressured,highly compartmentalized, highly compacted, and have experienced significantpressure declines in excess of 8,000 psi in some cases during production. Thewells were completed with cased-hole frac packs and each completion included apermanent downhole gauge, enabling interpretation of the K*H and skinthroughout the producing history of the wells to date. Well productivity hasmet or is above expectations, and the longevity has exceeded expectations inmost cases. Parametric Analysis of Stress Reduction in the Caprock AboveCompacting Reservoirs. It is well known that the fracture gradient issignificantly reduced when drilling through depleted reservoirs. However, themagnitude and extent of fracture-gradient reduction in the caprock abovedepleted reservoirs have not been well characterized. A practical method toestimate the extent and magnitudes of stress reduction in the caprock, usingthe correlations of shale elastic modulus and permeability with respect toshale porosity, is proposed in this paper. Field Implementation of GravelPacking Horizontal Wells Using a Solids-Free Synthetic Fluid WithAlpha-/Beta-Wave Technology. This article details the planning andexecution phases of the first openhole gravel-pack operation performed with thealpha-/beta-wave deposition technique using a nonaqueous system as a carrierfluid. An optimized procedure was proposed for the operation, including a broaddescription of the technical aspects, field pumping profiles, and packingquality. New Effective-Stress Law for Predicting Perforation Depth atDownhole Conditions. Well productivity is proportional to the depth of theperforation, and perforation depth is generally inversely related to theformation effective stress. Accurate productivity modeling, therefore, requiresaccurate knowledge of the relationship between the downhole stress environmentand perforation depth. A comprehensive experimental effort suggested a newdefinition of effective stress. Furthermore, this new effective stress betterfits published historical penetration results. Pore pressure’s influence onpenetration depth is, therefore, weaker than previously thought.Propellant-Assisted Perforating--An Alternative Stimulation Solution inHeavily Karstified Carbonate Reservoirs. Applying propellant-assistedperforating technique in three subsea wells in heavily karstified carbonatereservoirs has proved that this technique can offer a highly effectivestimulation method. Additionally, its usage eliminates the need forconventional, separate acid stimulation, saving rig time and costs whilereducing HSE risks. Using Ultrasonic Techniques to Accurately ExamineSeal-Surface-Contact Stress in Premium Connections. This paper covers thebasic concepts of premium connection design, and the use of ultrasonictechnology as a technique to assess the contact stress along the metal-to-metalseal band and methods used to monitor changes in the contact-stress profileinduced by many installation and service loads.