Cheatham

Big shoes to fill. That is one thing I inherited from past executive editors of SPE Drilling & Completion. The last four executive editors were Rob Mitchell of Halliburton, John Mason of BP, David Curry of Baker Hughes, and Brian Tarr of Shell. Over the years, I have had the privilege of working with each of them on SPE committees. Their commitment to excellence is a key reason why our journal is so well regarded today. The task of taking over from such dedicated professionals is indeed daunting.

Fortunately for me, the technical editors (TEs) and associate editors (AEs) do the hard part--perform peer reviews of papers. We now have more TEs and AEs than ever. This is a testament to the desire of SPE members to serve and reflects recent efforts to improve the quality and timeliness of our peer reviews.

Currently, there are 126 TEs whose job is to provide thorough, high-quality, timely peer reviews of the 300+ papers submitted each year. These volunteers are selected on the basis of their expertise and desire to serve. It is an honor to be a TE, and we place great value on each one.

Our ten AEs do the heaviest lifting. As team leaders for the review of each paper, they are responsible for quality and timeliness. Their job has several facets. First, AEs invite TEs to review a paper on the basis of subject matter expertise and availability. Next, AEs ensure reviews are submitted in a timely fashion, in conformance with SPE policy guidelines for peer review, and with clear justification for the recommendation. Often, AEs review papers themselves. Their dedication and service to SPE Drilling & Completion is a major reason why they were elevated from the ranks of outstanding TEs. Without a doubt, AEs represent the backbone of our journal’s technical competence.

Congratulations to our four newest AEs: Fionn Iversen is in charge of reviews for real-time data acquisition and analysis, and automated drilling systems; Dan Stone manages reviews for drill bits and hole enlargement devices; Kaibin Qiu heads our review team in geomechanics and wellbore stability; David Kulakofsky is our journal’s guru for all things related to cementing.

In the future, I will highlight our other six outstanding AEs. The entire team is listed at http://www.spe.org/papers/pubs/DCjournal.php.

Print and Online Versions

Today, there are two choices for subscriptions to SPE Drilling & Completion: print + online for USD 70 per year, or online only for USD 45 per year. Therefore, all subscribers have access to the online version. It costs a mere USD 25 more per year to receive the print version too.

History of Print and Online Versions of SPE Drilling & Completion:

• 1986 - Inaugural issue (print only of course)
• 2006 - Online version is born
• 2009 - Two-thirds of our subscribers chose print + online while the other one-third chose online only

The online journal has two important things the current print issue does not--the past and the future. Check out the online version at http://www.spe.org/ejournals/jsp/journalapp.jsp?jid=EDC&pageType=Issue and log in the same way you do for http://www.spe.org. It is available to all our subscribers. (You've already paid for it, so you might as well use it!) The archives contain every back issue through 2005. "Online First" contains papers that have been peer-reviewed, edited, and published by SPE but are waiting for inclusion in a future issue. It allows you to read new, peer-reviewed papers before they appear in the print journal or in OnePetro.

Maybe it is just because I am old, but the print journal is also very important to me. In the next issue, I will write more about our print and online journals. Drop me an email: cheatham@spemail.org and tell me what you like about each version and how you use them.

Now to the papers. This issue contains fourteen papers on the following topics: drilling fluid, cementing, and completions (three papers each, respectively), and mechanics of drilling at the bit, an innovative drilling method, an innovative logging method, backreaming best practices, and liner drilling (one paper each, respectively). The geographic diversity virtually encompasses the globe, with wells discussed in seven countries--Egypt, Canada, Saudi Arabia, Indonesia, Brazil, Australia, and Trinidad.

Drilling Papers

Mechanical specific energy (MSE) continues to be a hot topic. MSE has become a required parameter for real-time drilling optimization. But, fundamental questions remain regarding why MSE increases so significantly with differential pressure. Experimental Study of MSE of a Single PDC Cutter Interacting With Rock Under Simulated Pressurized Conditions shows that increased confining pressure alone cannot explain why rocks become more difficult to drill. The authors propose a new theory based on frictional forces and the cutting mechanism under pressure to explain their unexpected laboratory results.

Interested in reducing well construction costs? From Lean to Extreme-Lean Well Profile: Field Experience in the Mediterranean Sea provides a new way to achieve lower costs by drilling and completing slimmer casing programs. A key enabling technology is a novel automated vertical-drilling and integrated reaming technology.

Backreaming is a controversial subject. Over the last 25 years, the widespread use of top drives made backreaming a common practice. However, sometimes it causes a problem it aims to prevent--stuck pipe. A Guide to Successful Backreaming: Real-Time Case Histories presents in-depth best practices. The practical, detailed, operational guidelines presented in this paper are a must read regardless of your views about backreaming.

Oil-based muds improve wellbore instability, right? True, they are superior to water-based muds for combating shale hydration, which is a primary cause of wellbore stability problems. But, Entrance Pressure of Oil-Based Mud Into Shale: Effect of Shale, Water Activity, and Mud Properties demonstrates that, even with oil-based muds, wellbore instability can occur when mud filtrate moves into shale and increases pore pressure. This paper presents experimental data that show the factors that control the movement of oil filtrate into shale, as described by its "entrance pressure." The results promise to improve design of oil-based muds for improved wellbore stability in shale.

Detection of gas kicks is difficult in oil-based and synthetic-based (SBM) drilling fluids. But, failure to do so can be costly and hazardous. This has long been recognized because of the solubility of formation gas in the oil phase of the drilling fluid. Study of the PVT Properties of Gas--Synthetic-Drilling-Fluid Mixtures Applied to Well Control develops a mathematical model based on experimental pressure/volume/temperature properties of a methane/SBM mixture. Examples are presented comparing gas kicks using water-based and SBM. The results show that kick detection practices using SBM should be different from those using water-based mud.

"Slop" is oily waste liquids that result when water contaminates synthetic drilling fluids. The usual practice is to haul slop from the wellsite to a waste disposal facility for treatment. Design and Development of a Novel Process To Treat Drilling-Fluid Slops: A Positive Environmental and Economic Impact describes a new method to treat slop at the wellsite, which has the potential to reduce waste volume and disposal costs.

Designing cement that will withstand steam injection is a serious challenge. Steam-assisted gravity drainage (SAGD) is a technique for producing heavy oil by reducing its viscosity. SAGD operations impose severe thermal loadings on the cement sheath, which must maintain its seal to prevent steam release at the surface from these shallow wells. An Innovative Methodology for Designing Cement-Sheath Integrity Exposed to Steam Stimulation describes a comprehensive method to compute cement properties necessary to withstand stresses generated in the cement sheath, whether mechanically or thermally induced. Extensive computer simulations were carried out to model rock mechanics stresses for the field, followed by thermal stresses in the wells. Laboratory experiments were conducted to evaluate candidate cement formulations under conditions selected as worst cases based on simulations. A successful case history is described in Joslyn Field, Canada for which model simulations and laboratory experiments were conducted at temperatures as high as 180°C (356°F).

Obtaining a good one-stage cement job above and below a lost circulation zone is often not possible. Two-stage jobs are commonly used to solve this problem. Evaluation and Optimization of Low-Density Cement: Laboratory Studies and Field Application presents a new option of using low-density cement in one stage. Hollow microspheres have been previously used in low-density cement formulations, but the cost is prohibitively high for some applications desired by the authors. Therefore, the novelty in this paper is the development of “optimized” low-density cement that is achieved by eliminating microfine cement from the blend. Extensive studies were conducted in the laboratory to ensure satisfactory performance of the optimized blend. The new blend has been successfully applied in the field by Saudi Aramco.

What happens to cement exposed to H2S long after a well has been abandoned? Nobody knows. Durability of Oilwell Cement Formulations Aged in H2S-Containing Fluids addresses the problem by conducting aging tests (up to 12 months) under high-pressure/high-temperature conditions using representative wellbore fluids. Degradation mechanisms for cement exposed to H2S are identified. Results show that strong impairment of conventional cement properties occurs under certain circumstances.

Drilling through zones with severe lost circulation sometimes prevents setting a casing or liner at desired depth. Use of Liner Drilling Technology as a Solution to Hole Instability and Loss Intervals: A Case Study Offshore Indonesia thoroughly describes the use of a liner-drilling system to overcome known problems in the Banuwati field. Critical issues studied before application of the liner-drilling system included fatigue analysis of casing connections and consideration of torque, drag, and buckling issues. The system was successful in drilling 349 ft to the target depth in a highly deviated well despite massive losses in the annulus.

Under-Rig-Floor Openhole Logging in the Gulf of Thailand--Engineering Design of the Oil Industry’s First Simultaneous Openhole Wireline Logging and Drilling Operation is the first of two parts describing an innovative system for conducting simultaneous rig operations. The goal is to save rig time by conducting wireline logging operations in one well while simultaneously drilling another well. It is applicable for batch drilling situations with close well spacing. Although the concept is simple, the integration of the new method into long-standing drilling systems is not so simple. The results to date have achieved 10% reduction in time with a similar reduction in cost. This paper covers the engineering aspects. In the next issue, the second part will describe operational aspects of the method.

Completion Papers

The first hydraulic fracture in a subsea horizontal well in the Quissamã formation, a low-permeability limestone, is described in outstanding detail in Case Study of Multiple-Hydraulic-Fracture Completion in a Subsea Horizontal Well, Campos Basin. It is part of a research project to evaluate selective stimulation methods for subsea horizontal wells. The project team treated this well as a laboratory for direct comparison of propped and acid fractures. Previous stimulation efforts in the 1980s and 1990s used massive acid stimulations with disappointing results because of the lack of sustained medium and long-term high productivity. In the subject well, six stages were hydraulically fractured and one stage was acid fractured. Extensive laboratory tests are presented for cores taken from the well itself, including rock mechanics, proppant embedment, compaction measurements, and basic mineralogy. The hydraulic-fracturing treatments are described with detailed discussion of analysis of calibration tests, fluid-efficiency tests, and lessons learned. The well has been producing for over three years. Production results are presented and compared to conventional methods and other subsea horizontal wells in Campos Basin.

Are you interested in reading a solid case history of how to apply technology that (a) is new to your geographical location, and (b) requires complex operations? If you are, then I recommend Successful Implementation of Horizontal Openhole Gravel Packing in the Stybarrow Field, Offshore Western Australia. If you are a completions engineer involved in sandface completion challenges, then this step-by-step account of selection, design, planning, and execution of a sand management plan is right up your alley. Local problems included lateral reservoir quality variations and challenging sand/shale heterogeneities. Keys to success included a novel "smart" reservoir drilling fluid, extensive formation damage testing, detailed sand screen selection, and gravel pack modeling. The result was the delivery of four high-quality wells capable of producing per basis of well design and proved by early production performance (since November 2007).

When a well produces at higher rates than expected, it is mostly good news. Erosion Study for a 400-MMcf/D Completion: Cannonball Field, Offshore Trinidad provides an excellent study of one situation when high production rates could have caused a major problem. The initial well produced at 333 MMcf/D, which is higher than typically experienced and raised concerns about potential for metal erosion. To address these concerns, erosion was evaluated at various rates over the life cycle of the well to ensure the completion design and materials selection was suitable. The study included use of a multiphase erosion model, CFD modeling, and a liquid-film-thickness analysis. (If a liquid film occurs, then it forms a protective layer on the pipe that can reduce the erosion rate.) As a result of this study, the final well design required several equipment modifications to mitigate potential erosion areas. The field was brought on November 2006 at 800 MMcf/D with individual well rates as high as 333 MMcf/D with no equipment, reliability, or erosion issues.

That's all for this issue. Enjoy reading these papers. I certainly did. Till next time, write me at cheatham@spemail.org. My inbox is always open.

Curtis Cheatham