Well stimulation continues to be a hot topic in our industry, particularly with hydraulic fracturing of shales. Having been in the industry since the Dark Ages, (at least, it seems like it at times), it is interesting to see the technology changes over time and what areas are currently in the spotlight. Certainly, hydraulic fracturing continues to lead the industry interest; however, we do pump a lot of acid, and we have not forgotten its importance. Our acid blends have not changed much since the very early days— the late 1800s—of acidizing. Hydrochloric acid has been the mainstay, with primarily hydrofluoric acid and formic and acetic acids being the complimenting acids. Specialty acids, such as phosphonic, sulfamic, and others, have also been playing a role.
Major technology developments in nonproppant-fracturing well stimulation, as evidenced by the numerous publications over the last few years, have been primarily in carbonate acidizing. This is a continuing trend brought about by the significance of the carbonates to the world’s oil supply. However, our industry does use a lot of acid in the noncarbonates. One of those areas is in spearheading fracturing treatments to reduce near-wellbore tortuosity, most of these in sands and shales. My experience with this approach in horizontal shale wells has not always been successful; however, one of the papers selected for this month’s feature shows a unique acid blend that has shown some success in tight-gas-sand fracturing. Perhaps this and other unique acid blends could provide increased success in shales.
Horizontal wells in all reservoir types are now quite common, allowing our industry to exploit lesser-quality reservoirs economically. Shales are excellent examples. Many reservoirs have a high water cut, and stimulating wells in these reservoirs can be a real challenge. Acid-placement techniques, as well as diagnostics while acidizing, are a significant challenge to our industry. Of course, in our industry, challenges beget solutions. A recent development helping with well stimulation and production diagnostics is distributed temperature sensing (DTS) and distributed acoustic sensing (DAS). From reviewing numerous technical papers from worldwide SPE meetings held in the last year or so, the development and application of DTS and DAS appear to be in the forefront. Two of the papers selected for this month’s feature reflect on these developments and applications.
Readers are advised to review the following synopsized papers as well as the recommended additional reading to gain information on recent advancements in well stimulation.
Read the paper synopses in the June 2012 issue of JPT.
Gerald R. Coulter, SPE, is a consulting petroleum engineer and president of Coulter Energy International. He is involved in consulting and technology transfer of well-completion, formation-damage, and well-stimulation technology. Coulter is currently an instructor with PetroSkills. His industry experience includes work with Sun Oil/Oryx Energy Company, Halliburton, and Conoco. Coulter has authored numerous technical papers and holds numerous patents, has been chairman of and has served on numerous SPE committees, and is currently serving on the JPT Editorial Committee. He holds a BS degree in geology and a BA degree in chemistry from Oklahoma State University and an MS degree in petroleum engineering from the University of Oklahoma.
The coiled-tubing (CT) industry has experience unparalleled growth in the past year, driven directly by the massive expansion in multistage-fracturing operations in North America. Various sources estimate that the US consumed 50% of the world’s CT in the past 12 months, helping to contribute to a massive 80% growth in product coming off the CT production lines.
The growth in the United States was fueled primarily by three applications: milling out composite plugs, milling out fracture-sleeve ball seats, and toe shoots (the name given to the first perforating operation before plug-and-perforate operations). Because toe shoots take place without any pressure on the well, the amount of CT life consumed by fatigue during the operation is small. Plug or seat milling, on the other hand, takes place after fracturing operations are complete and with the wellbore fully pressure charged by the formation; therefore, the CT life consumed by fatigue is high. Superimposed over the wellbore pressures are the pressures arising from circulating fluids through the CT and the milling assemblies. In some of the higher-pressure shale plays, CT strings last only for a few jobs.
Accordingly, any technology that reduces the superimposed pressure could lead to longer CT life and potentially to lower completion costs. Two of the papers selected for this month’s issue involve new technologies that might be helpful to operators in this respect.
However, of possible greater concern to CT companies in North America is the fact that CT use is now clearly dominated by well-completion operations, or, to put it another way, by rig count. Until recently, the CT intervention business was primarily remedial in nature and, thus, was partially cushioned from the extreme cycles experienced by drillers. However, in North America, a change has already arrived and, with gas prices at historic lows, CT service companies, CT pipe manufacturers, and CT equipment manufacturers probably need to prepare for the same swings that the rest of the well-construction industry is used to.
Read the paper synopses in the June 2012 issue of JPT.
John Misselbrook, SPE, is senior advisor global coiled tubing with Baker Hughes. Previously, he was with Nowsco Well Service Company, which merged with BJ Services in 1996. Misselbrook has worked in various operational, engineering, research, and management roles involving CT in the North Sea, Canada, Southeast Asia, and theUnited States. He was a member of the original team of engineers involved directly in the development of improved engineering techniques for underbalanced drilling in western Canada in 1991. Misselbrook subsequently became responsible for Nowsco’s initiative to develop underbalanced-drilling technology by use of CT. He holds several US patents and has authored several SPE papers on the use of CT. Misselbrook is a mechanical sciences graduate of Cambridge University. He served on the 2008 and 2009 SPE/ICoTA Coiled Tubing and Well Intervention Conference Committees and serves on the JPT Editorial Committee.
The number and economic contribution of unconventional (tight gas/shale and steamflood) wells continued to increase rapidly in 2011, as did the participation of major operators. That increased industry focus was evident again in the distribution of papers. Also, there were more papers relating advances in plug-and-abandonment, Arctic, high-pressure/high-temperature (HP/HT), and carbon-capture technologies.
Manny Gonzalez, Chevron Energy Technology Company’s Alliance Manager, noted that the huge interest in shale-formation completions calls for efficient controlled fracturing technology to ensure economic viability and an environmentally responsible well completion. SPE 152185 outlines a direct comparison of openhole vs. cased-hole fracturing in a tight gas reservoir. The presented results are surprising, and the effects on incremental production, fracture height, and fracture half-length are significant—a good read.
Operators have been plugging nonproductive and storm-damaged wells at an increasing rate, and effective abandonment operations can prove costly and challenging. SPE 148640 relates a novel and well-detailed approach to a more efficient plug-and-abandon process and to the process of confirming plug integrity across an uncemented section of annulus. Check it out.
Industry emphasis on long-term well reliability has continued to increase, especially for steamflood projects. SPE 150022 details a very thorough look into the many design and operational factors that affect well reliability in a high-temperature (285°C) steamflood. While only briefly mentioned, the authors undertook controlling the rate of temperature change, and thus controlling temperature disparity (∆T) between casing, cement sheath, and formation during injection cycles. Controlling injection events can have a strong effect on the reliability of a steamflood well or even a deepwater or HP/HT well. This is the first field effort at controlling such events that I recall.
Read the paper synopses in the May 2012 issue of JPT.
Bob Carpenter, SPE, Research Consultant with Chevron Exploration and Technology Company’s Cement Team, has 33 years’ experience in field operations, technical support, and R&D. Previously, he was with Arco Exploration and Production Technology and BJ Services’ Technology Center. Carpenter serves on the SPE Drilling and Completions Advisory Committee, along with other industry groups. He has authored or coauthored 15 SPE papers and several JPT articles and has been granted 23 US patents. Carpenter’s areas of expertise include technical support and R&D of all areas of primary and remedial cementing. He also has extensive expertise in coiled-tubing cementing, spacer-fluid development, and remediation of sustained casing pressure. Carpenter serves on the JPT Editorial Committee.
Mitigating Risks in Development Projects
Our industry has been involved in incidents that demonstrated the need of a new approach for evaluating and mitigating the risks in well construction.
The “what’s worked well in the past” conservative approach is not possible anymore, in face of the damaged trust of the public about upstream activity. Though the criticism soars against exploration and production activities, the industry has allocated substantial investments in research for new technologies aimed to preclude risk events of recent years. New procedures and technologies, in addition to existing ones, will be deployed in the near future to eliminate blowouts or underground contamination from upstream operations.
The initial results can be seen in field operations such as the application of managed-pressure drilling (MPD) for offshore and onshore, the use of long horizontals or extended reach in the shale plays, and new fluids and techniques for fracture treatments that minimize the amount of water required in such operations.
The effects of drilling operations in the shale plays of the USA are clear, but recent research will result in a consistent reduction of environmental damage. Research is minimizing fluid losses into reservoirs and helping with mitigation of well-control situations when applying the MPD technique.
The use of nanotechnology will provide fluids that improve fracture treatments through the control of fluid losses, with a subsequent reduction in the amount of fresh water required. Today, an average fracture treatment in the Barnett shale requires 235,000 bbl of water. These treatments are essential to reduce the number of wells and to improve the performance of the fracture treatments for environmental-impact reduction.
The use of extended-reach drilling or long horizontal wells, combined with multilaterals, will reduce the number of wells without impairing expected production. This will mitigate the effect on aquifers or shallow formations with a reduction in surface infrastructure. Some of the papers featured or listed for reading show advances in the technology of extended-reach and multilateral wells that will help achieve such objectives.
Finally, the combined use of extended-reach and multilateral wells, nanotechnology fluids, and MPD will result in a more environmentally-friendly operation with a cost-effective development plan, which is essential for improving the industry’s image.
Read the paper synopses in the May 2012 issue of JPT.
Alvaro Felippe Negrão, SPE, is Senior Advisor for Woodside Energy USA. Previously, he was with Repsol, Halliburton, and Petrobras. In his 33-year career, Negrão has been involved in drilling and completion engineering and operations for wells in deepwater Gulf of Mexico, Brazil, the North Sea, West Africa, the Mediterranean, the Caribbean, and North/South America and in new-ventures evaluation and asset management. He has served on several SPE committees and currently serves on the JPT Editorial Committee and serves as vice chairperson for the SPE Subcommittee for the Offshore Technology Conference. Negrão holds a BS degree in civil engineering from the Universidade de São Paulo in Brazil, an MS degree in petroleum engineering from the Universidade de Campinas in Brazil, and a PhD degree in petroleum engineering from Louisiana State University.
No word defines deepwater projects better than “innovation,” and on 25 February 2012, one of the most innovative field-development projects came on stream: Cas- cade and Chinook (C&C) in the US Gulf of Mexico (GOM). One well is producing from Cascade to the first floating production, storage, and offloading (FPSO) vessel in the US GOM. The project brings several firsts and innovations that will be available to the entire oil industry in the near future. I would like to call attention to some of those innovations. First, the FPSO uses a detachable buoy that allows early installation of the buoy and all umbilicals before arrival of the FPSO. This feature will allow the FPSO to disconnect and sail away from hurricanes, avoiding damages to the facilities. C&C also presents the first freestanding riser in the US GOM. Subsea boosting will increase production and reduce workover costs. These examples are just a few that show inno- vation applied to a deepwater development. I believe strongly that C&C will lead the way for future development of Lower Tertiary plays in the GOM.
I selected one paper for this feature that describes the planning, logistics, and technology of the two largest deepwater high-pressure perforation jobs executed suc- cessfully in the GOM; certainly, this provides very interesting reading if your company is in the Tertiary play or is planning to be.
Drilling management in deep water has always been a great challenge because of several constraints, including high cost; well engineering (exploratory wells); logistics (remote locations); health, safety, and environmental (local and international laws); licenses; and personnel management. One of the papers presents a very objective and clear explanation of the well-management process, describing the design methodolo- gy and the well-execution procedures used by Petrobras International in a remote and challenging area. This methodology can be applied to any well and could bring huge benefits for any drilling operation.
Are you lost in a “cloud” of drilling data? You are not the only one! Drilling-data management is one of the biggest challenges in our industry today. One of the feature papers presents solutions, gives examples, and shows the benefits of a correct use of drilling data.
Enjoy your reading.
Read the paper synopses in the May 2012 issue of JPT.
Jacques Braile Saliés, SPE, is the Drilling Manager of Queiroz
Galvão E&P. His 30-year career at Petrobras included various engineering and management positions in E&P: coordination of the Petrobras Technological Program on Ultradeepwater Exploitation Systems— PROCAP 3000, drilling manager for Petrobras America, and well operation manager for Petrobras International. Saliés holds a BS degree in mechanical engineering from the Military Institute of Engineering, Brazil, an MS degree in petroleum engineering from the Federal University of Ouro Petro, Brazil; and a PhD degree in petroleum engineering from the University of Tulsa. He has authored or coauthored several papers on drilling and subsea technology. Saliés served several terms on the SPE Board of Directors for the Brazil Section and serves on the JPT Editorial Committee.
Exciting operations are ongoing on the shallow-water US offshore continen- tal shelf (OCS) that will influence the entire high-pressure/high-temperature (HP/HT) community going forward. McMoran and their operating partners are actively drill- ing, evaluating, testing, and bringing to production several deep HP/HT plays. These prospects are named in the Treasure Island theme with identities such as Davy Jones, Blackbeard, and Lafitte. The Davy Jones 1 is in the completion phase, incorporating multiple Eocene Wilcox sands, and it represents the first 25,000-psi completion of its kind in the world. The Davy Jones 2 encountered confirmed pay and is progressing well. The original Blackbeard well was taken to 32,997-ft total depth, and operations on Blackbeard East have been permitted to 34,000 ft. As with Davy Jones, these wells represent substantial extensions to or step changes in current HP/HT technologies.
To address the substantial engineering challenges associated with these wells, the operator formed a significant project team and is drawing on the expertise of several vendors in a collaborative manner to make the many advances necessary in HP/HT drilling and completion procedures and in production equipment and proce- dures. Downhole tools have been upgraded to 30,000 psi and 500°F. It will take con- siderable effort to catalog all of the “industry firsts” and “Serial-Number 1s” associat- ed with these ongoing operations. Both Davy Jones wells are expected to be flow tested and put on production later this year.
HP/HT continues to be of international interest, with global operations ongoing from the North Sea, to Latin America, to the Middle East, and of course in the “ring- of-fire” regions in Southeast Asia. Operators, service companies, equipment suppli- ers, drilling contractors, and other involved parties share a common goal of address- ing the many HP/HT challenges successfully and in a safe and efficient manner. These goals create a need to exchange information effectively, openly share lessons learned, and embrace a collaborative spirit that respects the competitive nature of business while valuing the shared interest that we all have in safe and reliable operations. Thus, the industry looks forward to learning more from the success of these HP/HT step changes in the US OCS ventures and from advances in other HP/HT operations around the globe.
Read the paper synopses in the April 2012 issue of JPT.
Mike Payne, SPE, is a Senior Advisor in BP’s Exploration and Production Technology group. He has 29 years’ experience including drilling operations, computing technology, and consulting. Payne holds BS and PhD degrees in mechanical engineering from Rice University, an MS degree in petroleum engineering from the University of Houston, and an Executive Business Education degree from the University of Chicago. He has extensive industry publications and has held key leadership positions with the American Petroleum Institute and the International Organization for Standardization. Payne has been an SPE Distinguished Lecturer and received the SPE International Drilling Engineering Award in 2000. He has chaired or cochaired several SPE Advanced Technology Workshops and serves on the JPT Editorial Committee.
In the 2 years since the Macondo incident, we have seen a lot of action toward new regulations, procedures, and norms to be implemented in an attempt to reduce the risks of those tragic events happening again. But the industry did not stop working; wells were drilled and completed, even in the Gulf of Mexico after the long period of inactivity. As expected, we saw a big focus on subsea-equipment testing and procedures and on needed equipment improvements. But we also saw many reports highlighting improved operational performance, confirming that the industry continues with significant activity.
We should work proactively with the public and regulators to bring a framework that will lead to a safer environment for everyone. And we should not be happy with just more paperwork that may not bring needed effective improvement. For obvious reasons, the first step has been focused on the equipment responsible for providing the last barrier of protection, the blowout preventer (BOP). One paper describes BOP upgrades, and another one discusses software-based deepwater-BOP testing. We all must recognize that there has not been a significant advance in terms of BOP testing in
the last 30 years. We are still relying, most of the time, on the old paper disks to record tests and on forms filled in by hand to confirm the pressure and duration of the tests prepared on each component tested. We should do much better than that.
The third paper highlights the drilling campaign in a promising offshore area in Brazil. But do not forget the underground blowout that leaked oil into the ocean offshore Brazil a few months ago, reminding us that continuous improvement of all offshore operations must take place. The alternative is that we again will face setbacks like those in the Gulf of Mexico after the Macondo accident.
Read the paper synopses in the April 2012 issue of JPT.
Helio Santos, SPE, is President of Safekick Limited. In his 29 years in the industry, Santos worked as a Drilling Engineer for Petrobras both onshore and offshore and led several projects in the Research and Development Center. He also was with Impact Engineering Solutions as Vice-President of Technology, President of Impact Solutions Group, and President of Secure Drilling, which was acquired by Weatherford. Santos earned BS and MS degrees in civil engineering from Catholic University of Rio de Janeiro and a PhD degree in geological engineering from the University of Oklahoma. He has authored several SPE papers, holds two patents, has served on SPE conference and Advanced Technology Workshop committees, and serves on the JPT Editorial Committee.
See the entire March 2012 issue.
See the current issue at http://www.spe.org/go/spedc.
Hydraulic Fracturing: 2012 and Beyond
It is a good time to be in the oil industry. The rig count, drilling activity, and oil prices are high, and shale plays are a significant reason for each. And, because it is shale, it is an especially good time to be a completion engineer!
Even though we have been able to make these unconventional reservoirs economic by drilling horizontal wells and by multistage fracturing, it is important for us to realize (especially with low gas prices) that there is still plenty to learn about shale fracing (not spelled “fracking”). Buzz words fly around the industry: complex fractures, brittle vs. ductile shale, proppant transport in slickwater, and more. Each is a start, but what I challenge everyone to do is to ask the questions: What is really happening when we are fracturing the various shale plays; and how do we model it so that
we can predict and optimize performance?
Economic and political implications of shale are enormous. The USA recently, for the first time in many years, became a net exporter of energy. The USA has clear shale development advantages compared with other countries at this time because it has the rigs, hydraulic horsepower, personnel, and a long history of hydraulic fracturing.
But truth be told, there are disadvantages that must be dealt with. The USA is dealing with an oversupply of gas, which is reducing prices and making shale-gas plays marginally economical. To date, despite industry efforts, there still is no political will to substitute fuel sources on a large scale, create a widespread gas-fueling infrastructure, or increase automobile shale-gas usage appreciably.
So even though it is a good time to be in the oil field, remember that as completion engineers it is our job/duty to understand what is happening downhole when we are fracturing—Do we really have complexity? Does complexity occur in every shale interval or just the brittle ones? Does proppant “turn the corner” and go into the natural fractures? Knowing the answers to these and other questions can make the economics of shale plays become even better.
Read the paper synopses in the March 2012 issue of JPT.
Karen Olson, SPE, is the Completion Expert for Southwestern Energy. She has worked in the oil industry for 28 years, including positions with the Western Company of North America; Mobil E&P, working in west Texas, the Gulf of Mexico, and Norway; and most recently with BP as a Deepwater Completion Engineering Team Leader. Olson has written and presented many SPE papers and has been a discussion leader at SPE workshops and forums. She has served on several SPE committees and serves on the JPT Editorial Committee. Olson earned a BS degree in petroleum engineering from Louisiana State University and an MS degree in petroleum engineering from Texas A&M University.