Mitchell

Managerial Changes

This issue is my last as executive editor for SPE Drilling and Completions. When I took this job, there were some major problems to address. Some progress has been made, but more improvements are going to be needed. My successor, Curtis Cheatham, is also dedicated to improving this journal, so expect to see quicker reviews and a smaller backlog of papers to be published. Much appreciation is due the Technical Editors, who do the majority of the heavy lifting, and to the Associate Editors, who keep the process moving. They are all listed next to this page, so find out who they are and thank them. You might consider volunteering yourself, it would be greatly appreciated. The SPE staff has always been pleasant and helpful, with special mention of Glenda Smith, Mattie Tanner, and special thanks to Stacie Hughes.

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

Drilling Papers:

Measuring Drillpipe Buckling Using Continuous Gyro Challenges Existing Theories. Full scale buckling tests were performed in a 2020 m measured depth research well, with a buildup and 60° tangent geometry. Various configurations of a tapered string with 5- and 3½-in. drillpipe were used. Results indicated that pipe buckled between tool joints and that lockup occurred during lateral buckling. Some helical buckling was seen only in the vertical section of the well. These tests clearly indicate the importance of connector size and clearance in the prediction of buckling behavior and the surprising importance of lateral buckling in generating friction loads. Surge and Drag Analysis for Extended Reach Casing and Casing Flotation Operations With Centralizers: A Design Challenge? The challenge of running casing to its desired target depth using floated casing requires a more comprehensive in-depth analysis than is currently available. Operational experience and past studies have brought new insights to the complexity and operational difficulties involved. This paper presents a comprehensive model and documents comparisons between the results of the mathematical model and actual data. Improving Hole Quality and Casing-Running Performance in Riserless Top Holes: Deepwater Angola. The operator and coventurers are developing several Angola Block 15 fields in water depths of up to 1400 m. Most have experienced hole quality issues in the riserless interval that are manifested as tight hole while tripping the bottomhole assembly (BHA) and as abnormal/excessive drag while running casing. The operator undertook a study that identified microtortuosity as the root cause of casing-running difficulties. Changes to drilling practices have resulted in improved riserless hole quality and smoother casing-running operations. Application of an Innovative Conveyance Risk Management Methodology for Long or Tortuous Wells. Some of the most important aspects to consider during the design, construction, and productive life of a well are the amount and nature of the risks associated with the conveyance of downhole and downhole-tool strings. A new methodology, based on forces modeling and best practices has been developed to take full advantage of new conveyance technologies intended to alleviate or eliminate these risks. Case Study: Drillstring Failure Analysis and New Deep-Well Guidelines Lead to Success. Three drillstring fatigue failures occurred while drilling two deep wells below 16,500 ft true-vertical depth. All the failures occurred across 2°/100 ft- to 3°/100 ft-dogleg severity intervals from 6,000 to 8,000 ft. A cumulative fatigue indicated that drillstring failures would occur across shallow doglegs mainly because of high hang-down loads combined with slow ROP. The results of the study led to the development of new deep-well design criteria and implementation of new drilling guidelines. Offshore Field Test of a New System for Model Integrated Closed-Loop Drilling Control. A new system for real-time optimization and automated control of the drilling process has been tested successfully on the Statfjord C platform in the Norwegian sector of the North Sea. Results from active and passive testing indicated that the new methodology has the ability to improve drilling-process reliability, safely increase drilling efficiency, and reduce the risk of human error. Drilling Difficult Formations Efficiently With the Use of an Antistall Tool. Antistall technology is a mechanical downhole solution that aims to adjust the drilling torque automatically in real time. The paper describes in detail, both in theory and on field experience, how the bit-induced torque fluctuations are significantly decreased to improve penetration, and how bottomhole-assembly damage is prevented to increase run lengths. Delivering Steering Success in Problematic Soft-Formation Directional Wells. To deliver consistent directional performance in very soft formation applications requires solving issues such as hole washout, inappropriate drilling parameters, stabilization, and hole quality. Case studies document where these solutions, in combination with both push and point RSSs, have proven extremely successful. Finite Element Modeling of Casing in Gas-Hydrate-Bearing Sediments. Casing integrity in shallow marine sediments could be challenging if natural gas hydrates exist in the sediments. A numerical model has been developed using a finite-element code to simulate the stability of casing in gas-hydrate-bearing sediments by considering the interaction between the formation, the casing, and the cement. Generalized Hydraulic Calculation Method for Axial Flow of Non-Newtonian Fluids in Eccentric Annuli. The flow of non-Newtonian fluids through eccentric annuli occurs during drilling and cementing operations. The flow pattern in an eccentric annulus can differ greatly from that in a concentric annulus, and this difference affects both the pressure drop and the flow rate. The predictions of this method were compared with an extensive set of data, showing that the new method was capable of reliably predicting the pressure drop of most drilling fluids in both laminar and turbulent flow regimes for eccentric annular geometries of practical interest. Fiber Sweeps for Hole Cleaning. Cuttings transport in highly deviated wellbores is more challenging and critical than in vertical wells. Results from this study indicate that a fiber-containing sweep has better hole-cleaning capabilities than the base fluid, even though these two sweep fluids have very similar rheological properties. Use of New Hydrostatic-Packer Concept To Manage Lost Returns, Well Control, and Cement Placement in Field Operations. A hydrostatic packer consists of a column of light fluid pumped into the annulus or drillstring to cause the total hydrostatic head to be equal to or less than the fracture-closure stress. Hydrostatic packers have been used effectively in more than 30 fields and have contributed greatly to the operator’s high success rate in treating lost returns events. Particulate-Based Loss-Prevention Material--The Secrets of Fracture Sealing Revealed! Owing to the narrow drilling margin that exists between the pore-pressure and the fracture-pressure gradient, drilling in depleted-reservoir, high-pressure/high-temperature, and deepwater environments is universally recognized as being technically challenging. This paper discusses particulate-based-treatments design for sealing fractures. Parameters critical for optimizing the treatment have been identified and are discussed in the context of laboratory and field experience. Cement-Slurry Performance and Set-Cement Properties vs. Microsilica Densification. Because of its extremely fine nature and high reactivity, microsilica has been used to improve slurry stability and the mechanical properties of the hardened material. Contrary to common belief, not all grades of microsilica are equal. Only moderately compacted microsilica have been found to offer the adequate compromise between proper handling characteristics and good slurry and set cement performance. Modeling of an Underbalanced-Drilling Operation Using Supercritical Carbon Dioxide . A mechanistic model of an underbalanced-drilling operation using carbon dioxide (CO₂) is developed in this study. The unique properties of CO₂, both inside the drillpipe and in the annulus, are shown to optimize 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 several drilling-fluid parameters automatically. The paper describes in detail the design for an integrated tool combination and the results of a full-size yard test of such a combined set of tools for measuring drilling-fluid parameters and formation properties automatically.

Completion Papers

Completion Design, Installation, and Performance--Cannonball Field, Offshore Trinidad. The Cannonball field is a one-trillion cubic ft gas-condensate development in offshore Trinidad producing at an initial rate in excess of 800 MMcf/D from three wells. This paper discusses the completion basis of design, detailed engineering assurance of the design, qualification of critical engineered equipment, and actual results. Completion Design for a Highly Compacting Deepwater Field. The Magnolia field, located in the deepwater region of the Gulf of Mexico, produces oil and gas from a tension leg platform in 4,673 ft of water. The reservoirs are significantly overpressured, highly compartmentalized, highly compacted, and have experienced significant pressure declines in excess of 8,000 psi in some cases during production. The wells were completed with cased-hole frac packs and each completion included a permanent downhole gauge, enabling interpretation of the K*H and skin throughout the producing history of the wells to date. Well productivity has met or is above expectations, and the longevity has exceeded expectations in most cases. Parametric Analysis of Stress Reduction in the Caprock Above Compacting Reservoirs. It is well known that the fracture gradient is significantly reduced when drilling through depleted reservoirs. However, the magnitude and extent of fracture-gradient reduction in the caprock above depleted reservoirs have not been well characterized. A practical method to estimate the extent and magnitudes of stress reduction in the caprock, using the correlations of shale elastic modulus and permeability with respect to shale porosity, is proposed in this paper. Field Implementation of Gravel Packing Horizontal Wells Using a Solids-Free Synthetic Fluid With Alpha-/Beta-Wave Technology. This article details the planning and execution phases of the first openhole gravel-pack operation performed with the alpha-/beta-wave deposition technique using a nonaqueous system as a carrier fluid. An optimized procedure was proposed for the operation, including a broad description of the technical aspects, field pumping profiles, and packing quality. New Effective-Stress Law for Predicting Perforation Depth at Downhole Conditions. Well productivity is proportional to the depth of the perforation, and perforation depth is generally inversely related to the formation effective stress. Accurate productivity modeling, therefore, requires accurate knowledge of the relationship between the downhole stress environment and perforation depth. A comprehensive experimental effort suggested a new definition of effective stress. Furthermore, this new effective stress better fits published historical penetration results. Pore pressure’s influence on penetration depth is, therefore, weaker than previously thought. Propellant-Assisted Perforating--An Alternative Stimulation Solution in Heavily Karstified Carbonate Reservoirs. Applying propellant-assisted perforating technique in three subsea wells in heavily karstified carbonate reservoirs has proved that this technique can offer a highly effective stimulation method. Additionally, its usage eliminates the need for conventional, separate acid stimulation, saving rig time and costs while reducing HSE risks. Using Ultrasonic Techniques to Accurately Examine Seal-Surface-Contact Stress in Premium Connections. This paper covers the basic concepts of premium connection design, and the use of ultrasonic technology as a technique to assess the contact stress along the metal-to-metal seal band and methods used to monitor changes in the contact-stress profile induced by many installation and service loads.