Cheatham

2011 SPE Drilling & Completion Readers' Survey

Each year, SPE conducts a survey of readers for its journals. In this issue, we will discuss the results of the 2011 survey for SPE Drilling & Completion. (Note: We discussed the 2010 survey in the March 2011 issue of SPE Drilling & Completion.)

When the survey was conducted last summer, we had 4,498 subscribers, up 1.5% from a year earlier (4,432). Roughly 7% of all subscribers responded to the survey, a total of 330 respondents (down from 383 last year). Of those who responded, 71% were print and online subscribers and 29% were online-only subscribers.

These percentages match our overall subscriber base pretty closely, which is 67% print and online vs. 33% online only.

The survey was composed of 21 questions designed to assess how well your Editorial Review Committee is performing and what changes might benefit our readers.

The primary mission of our journal is to provide the best technical content possible. Consequently, the following question and data are supremely important: "Overall, how do you rate the technical content of SPE Drilling & Completion?" The data can be found in Table 1.

Overall, the results are encouraging. Note that 60% rated technical content as very good or excellent while 7% said it is fair or poor. Last year’s survey results were 62% as very good or excellent and only 3% as fair or poor.

The following question is also important: "How would you compare SPE Drilling & Completion now with one year ago?" Thirty-six percent said SPE Drilling & Completion either improved or significantly improved compared to the previous year, and 60% said it is about the same. No one said it is worse or significantly worse. The remaining 3% said they did not subscribe last year. The results are very similar to last year, with the main difference being that 15% of respondents in the 2010 survey said they did not subscribe the previous year.

Overall, the survey results are positive and tend to confirm we are headed in the right direction. But they also indicate there is room for improvement. One survey question asks readers to write in suggestions for improving SPE Drilling & Completion. Eighty-two readers did so. The most common suggestion was submitted by 14 readers who want improved access to the journal. The second most common area for improvements came from nine readers who requested more practical papers and case histories. Next in frequency were eight readers who want more papers on specific topics such as managed pressure drilling, cementing, coiled tubing, sand control, drill bits, drilling and completion fluids, completions, and environmental issues. This input is valuable to us, and we thank all our readers who responded to the survey.

The relatively high number of comments about the need for improved access to the journal is intriguing. This could be a reflection of the rapidly changing ways that all of us access digital information today. From smart phones to tablets, we are seeing a mind-boggling explosion in the many ways we obtain and use reading material. Here are a few of the readers' comments that seem to support this hypothesis:

• "There should be as well a version which would be downloadable to iPad. Basically, the effort to manage to come to read an article is too big, so I forget to read the articles"
• "Please have an index so that I can readily come to know about a topic from SPE online. I do not find SPE helpful like the goggle. It would help us immensely to get a readily available dictionary kind of a system so that we can make the membership more paying and worthy of the money we pay for its membership. Thank you."
• "Email table of content, and make it accessible with Amazon Kindle, Nook and other online software!"
• "Everything is working good, although I would like to have a more simplified method for downloading articles."

These suggestions provide some food for thought that we will carefully consider to keep up with the times.

There are other actions underway to try to improve our journals. During the recent SPE Annual Technology Conference and Exhibition in Denver, Dr. Stephen Holditch, SPE Editor-in-Chief, held his annual meeting with the seven Executive Editors of SPE's peer-reviewed journals. Several actions were taken from the meeting to improve how our journals meet readers' rapidly evolving needs. First, focus groups with subscribers will be conducted to gather specific satisfiers and dissatisfiers with SPE journals. Second, routine surveys will be conducted of all authors after their paper has been published in an SPE peer-reviewed journal to determine their feedback on the review process. Third, we are reevaluating our criteria provided to our Technical Editors to determine which papers will be accepted. These actions will take time to implement, but we are optimistic they will help us continue to improve our journals.

New Associate Editor

We welcome Steve Nas as a new Associate Editor. He will manage reviews for managed pressure drilling, underbalanced drilling, and related topics. Steve was promoted from the ranks of Technical Editor, and we are thrilled to have him working in his new capacity.

Now to the papers. This issue contains 13 papers:

• Two on completion design and execution
• Four on drilling and completion fluids
• Two on wellbore strengthening
• One on well abandonment
• One on underbalanced drilling
• One on drilling systems automation
• One on drilling operations
• One on tubulars

One note: We are pleased to see the global diversity in these papers, with the following countries having major focus in at least one paper: the Russian Federation, China, Canada, United States, and Norway.

Completion Design and Execution

Our first paper, Completing the First Big-Bore Gas Wells in Lunskoye--A Case History provides a very interesting account of a large gas condensate field offshore Sakhalin Island in the Russian Federation. The authors give a thorough description of the completion of the first seven big-bore gas wells from the Lunkskoye-A platform. The narrative gives not only the big picture for a large field development but also fundamental details for the reservoir setting, selected drilling aspects, comprehensive completion design, the actual completion of the wells (well cleanout, installation perforating, cleanup, beanup), and initial production performance. The paper is recommended to readers interested in designing and executing completions for a large field development program.

Many deepwater sandstone reservoirs are completed openhole and require sand control. Gravel packing is widely used in these applications as the gold standard. However, our second paper contends that standalone screens applied in the appropriate environment with appropriate procedures can yield comparable results to gravel packs but at lower cost. A key problem has been that the state-of-the-art selection methods--based on experimental data, rules of thumb, or correlations--are flawed. Numerical Simulations of Sand-Screen Performance in Standalone Applications presents an improved tool to evaluate performance of wire-wrapped screens. The 3D, discrete-element computer simulation results are compared with experimental results that were previously published by one of the paper’s coauthors, with good agreement. For theoretically inclined readers, the model results help resolve some key questions about the physics of sand bridge formation. For practical readers, a new method is presented to estimate the mass and particle size distribution (PSD) of produced sand. This method is shown to provide much more accurate predictions of screen performance than past methods. This paper may be useful to readers involved in selecting sand control methods.

Drilling and Completion Fluids

Global interest in shale gas reservoirs naturally extends to the drilling phase because current strategies to exploit low-permeability reservoirs require drilling many wells--often horizontal--to provide sufficient reservoir contact. Efficient methods for drilling wells in a repetitive fashion have been developed in various shale plays. When the next new shale play is found, there is a natural tendency to use what has worked in previous plays. However, experience has shown that differences from shale play to shale play generally require customization for each new drilling environment. The drilling fluid in the reservoir section is a good example of this, as reported in Development of Water-Based Drilling Fluids Customized for Shale Reservoirs. Differences in shale mineralogy--especially clay content and type, bottomhole temperature of the wells, and geomechanic properties such as Young’s modulus and Poisson's ratio--and the possible presence of mud contaminants such as salt stringers or carbon dioxide in the shale are crucial factors in customizing water-based muds for each new shale play, as described in this paper. Examples of new fluids developed for the Barnett, Fayetteville, and Haynesville shales are presented to validate the method. The paper concludes with a discussion of the application of the customization process for new shale plays around the globe. This paper is a must-read for anyone involved in drilling-fluid design for shale gas reservoirs.

It may seem as though all formations are shale if one paid attention to mainstream media. In fact, carbonate reservoirs are still important and are the subject of our next paper. Protecting Reservoir With Surfactant Micellar Drill-in Fluids in Carbonate-Contained Formations introduces a novel polymer-free and solids-free drill-in-fluid system for carbonate reservoirs. Conventional water-based drill-in fluids typically contain high molecular weight polymers and different size distribution solids to reduce fluid loss and carry cuttings out of the hole. Unfortunately, these polymers and solids usually cause formation damage near the wellbore. To avoid such formation damage, the new drill-in fluid proposed here uses chemistry to replace the functions of fluid loss and cuttings carrying capacity usually delivered by polymers and solids. The novel fluid is evaluated in laboratory experiments and seems to be ready for field testing.

Viscoelastic surfactant systems (VES) are the preferred gelling and viscosity agents for fluids used in the production zone because of their nondamaging effects on the reservoir. Historically, VES systems have had limitations in high-density brines, such as viscosity reduction, phase separation, and low salt tolerance. Stabilizing Viscoelastic Surfactants in High-Density Brines presents an innovative method to stabilize VES systems in high-density brines. The paper details the laboratory work performed that includes extensive rheology experiments. The self-breaking nature of VES systems when in contact with hydrocarbons is experimentally demonstrated, which the authors conclude makes the system attractive as lost circulation material for completion brines because they readily dissipate upon contact with hydrocarbon.

Computation fluid dynamics (CFD) analyses have been performed for decades. Today CFD is arguably a commonplace engineering tool because of continuing improvements in high-speed digital computing, particularly data storage and processing speed. For specialists in drilling hydraulics modeling, CFD is an essential tool to support theoretical and experimental work. It is particularly useful in studying complex geometries, such as an eccentric annulus between coiled tubing and the borehole or casing. Our last fluids paper, Laminar and Turbulent Friction Factors for Annular Flow of Drag-Reducing Polymer Solutions in Coiled-Tubing Operations, examines steady, fully developed laminar flow of non-Newtonian power-law fluids in concentric and eccentric annular geometries to investigate the effect of eccentricity, flow-behavior index, and diameter ratio on axial frictional pressure losses. The frictional pressure-loss predictions by CFD simulations were validated by comparison with published studies and flow data from a field-scale experimental setup. Then, experimental studies were performed to investigate frictional pressure-loss behavior of drag-reducing polymer solutions flowing turbulently through the annulus. A new correlation was developed to calculate frictional pressure losses for varying annular configurations. The correlation can be used with commonly available field data.

Wellbore Strengthening

Our first paper on wellbore strengthening is highly controversial. At the same time, it is of major significance. Avoiding Losses in Depleted and Weak Zones by Constantly Strengthening Wellbores asserts two competing mechanisms could explain what is commonly called borehole strengthening: wellbore stress augmentation (WSA) and fracture propagation resistance (FPR). (Editor's note: Searches in OnePetro show only one paper title contains "borehole strengthening" while 20 paper titles contain "wellbore strengthening." Hence, we prefer the term wellbore strengthening.) The paper raises serious questions about the two prevailing and well-known WSA theories--stress caging and fracture closure stress. Further, it contends that field evidence that has been presumed to support these two WSA theories are actually more likely supportive of the authors' own FPR theory. After a thorough literature review and discussion of other theories, the authors explain their FPR approach to wellbore strengthening in great detail. Extensive laboratory and field-testing results are discussed to support their viewpoint. This paper is an absolute must-read for anyone interested in drilling weak or depleted zones--in other words, everyone associated with drilling. The naïve side of me hopes this paper will--finally--result in the first paper discussion in our journal in more than two years. (Editor's note: Although paper discussions are an important element of scientific journals, it is regrettably true that there has not been a single paper discussion submitted for SPE Drilling & Completion during the last two years.)

Data is necessary to make good decisions, but sometimes the perceived cost of data acquisition exceeds its perceived value. A good example of this observation is so-called extended leakoff tests (XLOT). Proponents claim that XLOT are necessary to calibrate accurate geomechanics modeling. Opponents claim the severe damage to the wellbore by XLOT creates subsequent drilling problems. Understanding the Effects of Leakoff Tests on Wellbore Strength investigates this issue and discusses various aspects to give practicing engineers the necessary insight to determine when conducting XLOT may be a concern. The discussions are supported with results from analytical and numerical simulations based on rock mechanics principles.

Well Abandonment

This case study examines the complex re-entry and re-abandonment of a well in the Peace River region of Alberta, Canada. Field-/Well-Integrity Issues, Well-Abandonment Planning, and Workover Operations on an Inadequately Abandoned Well: Peace River, Alberta, Case Study describes a methodology for abandonment planning. Three essential requirements were adopted. (1) The abandonment should provide effective isolation of all critical zones. (2) Operations should allow for evaluation and confirmation of zonal isolations. And, (3) the final conditions of the well should allow for a simple re-entry to remediate future isolation problems. The authors state a key to success was linking the local regulatory group into the operations to ensure government requirements were met. They also recommend the operations reported here should be considered as best practice for verifying that abandonment has provided the desired isolation to prevent gas migration or cross flow. Following reabandonment, the subject well described here met or exceeded all regulatory and technical requirements and is currently being used for injection and storage purposes that ultimately are extending the life of the Peace River complex. For readers who want more case studies, this paper is highly recommended.

Underbalanced Drilling

China National Oil Companies have employed underbalanced drilling (UBD) to eliminate formation damage and improve productivity. Experience in China suggests that inappropriate application of underbalanced reservoir drilling may have an adverse effect on protecting reservoirs. Which Reservoirs in China Are Best for Underbalanced Drilling? reports results of a China UBD basins study. Candidacy is determined by evaluating a number of formation-damage mechanisms and related risks. The objective of the study is to evaluate and rank suitability of reservoirs for exploitation by UBD compared with conventional drilling and completion processes. This paper is recommended to readers interested in global potential of UBD or in learning something about China’s reservoirs.

Drilling Systems Automation

Automation of Drawworks and Topdrive Management to Minimize Swab/Surge and Poor-Downhole-Condition Effects describes a novel drilling-control system that has been developed and tested on a fixed platform offshore Norway. Continuously updated safeguards are applied to the drawworks and topdrive to maintain downhole pressures within acceptable limits for openhole formations. The system automatically stops movement of the drillstring in case of abnormal hookloads or surface torques. Some standard procedures have been fully automated, including backreaming and friction tests for torque and drag (pickup, slackoff, and rotate). Numerical models are continuously calculating maximum permissible accelerations and velocities for the drillstring. An automatic calibration of the physical models, on the basis of surface measurements, is at the heart of the system. The calibrated mechanical models are used to determine limits for abnormal surface torques or hookloads. It is, therefore, possible to take actions automatically in case of overpull, set-down weight, or high torque. The authors note that a key vulnerability of such a system is access to high-precision measurements. This paper is recommended reading for those interested in staying abreast of the industry's advancements in drilling systems automation.

Drilling Operations

When your drillstring is irretrievably stuck in an ultradeep well, the prospects of a junked wellbore loom. Historically, pipe cutting or severing in high bottomhole pressures has been problematic. Drillpipe Cutting At Ultrahigh Pressure Proven for Remediating Deepwater Stuck-Pipe Hazards relates the development of jet cutters and severing tools for use in downhole environments up to 30,000 psi. This paper is recommended for those interested in high-pressure drilling or anyone who enjoys reading practical papers describing the development of new downhole tools.

Tubulars

For the third consecutive year, we are pleased to provide another groundbreaking paper on buckling to our faithful readers. Serious questions were raised about existing buckling theories by SPE-115930-PA, Measuring Drillpipe Buckling Using Continuous Gyro Challenges Existing Theories, which was published in the December 2009 issue of SPE Drilling & Completion. It presented high-quality field data that did not match well against prevailing buckling theories of sinusoidal and helical buckling limits. A subsequent paper published in our last issue (September 2011), SPE-139824-PA, Lateral Buckling--The Key to Lockup, offered further analysis of the buckling data from SPE-115930-PA. This second paper postulated even more serious challenges to conventional buckling theories. That brings us to the final paper in this issue, Comparing the Results of a Full-Scale Buckling-Test Program to Actual Well Data: New Semiempirical Buckling Model and Methods of Reducing Buckling Effects, which provides compelling experimental evidence that drillstring buckling occurs at loads far lower than predicted by current industry standard models, possibly caused by minor deformations inherent in real drillpipe. The paper offers a new, semiempirical model that matches experimental data reasonably well, although there is much scatter in the data. Three case histories showcase the value of the new model compared to existing published models in diagnosing and resolving field problems related to drillstring buckling. The authors recommend additional testing to verify their model in other operational conditions, including effects of varying friction, whirl and other vibration, different mud types, and varying hole inclination. This paper is essential reading for all interested in drillstring design and field problems potentially related to tubular buckling.

That wraps up this issue. On behalf of your entire Editorial Review Committee, thank you for your continued support of SPE Drilling & Completion.

Curtis Cheatham
cheatham@spemail.org