The successful extraction of gas from the Barnett Shale formation in Texas in the 1990s by George Mitchell (known as the father of the Barnett Shale)—considered to be the event that kicked off the U.S. shale gas revolution—was enabled by the first successful application of horizontal drilling, microseismic imaging, and hydraulic fracturing. GTI played a key role in developing those hydraulic fracturing and microseismic technologies that are widely used to this day.
Much innovation in unconventional gas has stemmed from public-private research and commercialization efforts on key gas recovery techniques. Significant investments were made by the U.S. Department of Energy (DOE) and Gas Technology Institute (GTI)—then known as Gas Research Institute (GRI)—that were able to dramatically improve production results. In the early 1980s, GTI launched a new collaborative research model that brought together a world-class team of experts from industry and academia. Together, the DOE/GTI R&D programs became a catalyst for experimentation and new technology development.
This early research work by DOE and GTI were critical elements in unlocking the vast potential of America’s “new” natural gas, providing the world with a promising new energy future. This collaborative model has been proven successful in field programs that explored coalbed methane, gas shale, and tight sands, and has led to significant advances in best practices, processes, and procedures. Consider this: In 1990, unconventional gas accounted for approximately 10 percent of total production. In 2012, it accounts for nearly 60 percent of total production, with gas shales driving this growth.
GTI’s hydraulic fracturing research began as early as 1983, leading to “proof-of-concept” experiments at its Hydraulic Fracture Test Site (HFTS) in the Rocky Mountains. Leading-edge technologies were verified in these field tests. One of the GTI’s major achievements was the development of a model for designing and predicting the behavior of hydraulic fractures that included the real-time monitoring of fracturing parameters such as rate, pressure, and viscosity. The industry is still using the technology today, as a model known as FRACPRO available from CARBO Ceramics Inc.
Hydraulic fracture modeling was validated by both mini- and post-fracture measurements to establish a scientific basis for hydraulic fracturing, which up until that time was more an art than a science. The work went beyond just analytical models — GTI developed diagnostics and ran lab experiments in the field to determine where a fracture goes (propagates), how far it goes, and what parameters control its destiny. One of GTI’s shallow coalbed methane wells was mined back, so pictures of the actual fractures were taken as the seams were exposed, providing amazing validation.
From the 1980s through the 1990s, GTI developed methods for monitoring the creation of hydraulic fractures, which led to the development of microseismic imaging of fractures, and worked with Sandia National Laboratories to develop a downhole tool.
A key technique, FracSeisSM microseismic hydraulic fracture mapping for fracture diagnostics, was developed by GTI to help gas producers plan and conduct effective and economical hydraulic fracturing operations. It is now available as a suite of services from Pinnacle Technologies.
As a result of its early work in the 1980s, GTI provided a fundamental understanding about coalbed methane upon which others have built their technologies. We determined that, because of the way natural gas is adsorbed onto the coal and, in some cases, the presence of significant volumes of water, coalbed methane is not produced like other resources. As a result, a new strategy was developed that took into account the mechanisms needed for dewatering, resource evaluation, determining the amount of gas in place in an adsorption environment, and fracturing in coal. As cost-effective alternatives to reinjection, methods for environmentally acceptable discharge of the mineral-laden water often produced with coalbed methane were developed. GTI also developed guidebooks to help producers optimize all aspects of coalbed methane operations, and created computer-based simulators and other tools to explore options for fracturing a coal formation to boost gas production.
Our researchers, working with dozens of partner organizations from industry and academia, led a comprehensive program to document those regions with the greatest coalbed methane potential, providing assessments of recoverable coalbed methane in six major geologic basins and comprehensive models for two major basins in New Mexico and Alabama that Amoco and Arco (now both BP) and other producers used to evaluate drilling risks, design fracture treatments, and educate investors. When GTI started its coalbed methane R&D in the early 1980s, production across the U.S. was less than 50 Bcf per year. In 2012, it is now upwards of 1,800 Bcf per year.
GTI contributed to the industry’s understanding about how to increase the amount of cost-competitive gas recoverable from tight gas sands. While significant amounts of potentially recoverable natural gas exist in low-permeability sandstone formations in sedimentary basins throughout the U.S., a combination of technical and economic constraints had historically been preventing the widespread commercial exploitation of these resources.
An integrated research program led by GTI focused on improved geology and resource parameter quantification, enhanced stimulation techniques, and improved fracture diagnostics for determining fracture azimuth, fracture height, and overall fracture dimensions.
The research team designed and implemented open-hole data acquisition programs on a series of wells identified as the staged field experiments (SFEs) that worked to determine the most effective combination of formation evaluation (geological, petrophysical, and engineering), fracture diagnostics, hydraulic fracturing, and fracture modeling techniques to reduce the cost of producing gas from tight formations.
The SFEs were critical because of the need for field testing, interaction with producers, enhanced technology dissemination, and technology development. Though they were costly, dedicated research sites in the field were essential to move technology forward — a real-world laboratory that enabled model validation and optimization of fracture dimensions, and included coring, MWD logging, wireline logging, open-hole stress testing. Pre-fracture, mini-fracture, and post-fracture analysis were also conducted.
GTI research on gas production from shale resources has yielded significant new knowledge. An early effort in the Michigan geologic basin involved field experiments in the Antrim Shale that helped the industry better understand fracture geometry in this complex formation—eventually taking it from a little-known resource to a cost-competitive source of natural gas. Reservoir engineering methods were developed for the Antrim, and field-based research projects identified restimulation and recompletion candidates, estimated the potential production improvements in these candidates, and developed cost-effective workover procedures.
By studying 2,000 wells, GTI developed methods that could double production rates. Because of the properties of shale, GTI was able to capitalize on results from earlier and parallel research on tight-sands fracturing and coalbed methane, using two-stage, deeper hydraulic fracturing to release more gas, establishing more efficient methods to promote gas flow from fractured rock, and using mechanical pumps to remove water from gas wells.
We also devised new ways to assess gas content in core samples in as little as one day and to use existing well logs and the new sampling method to help find gas beyond current wells.
In the Appalachian basin, GRI developed a fairly sophisticated understanding of the character of shale reservoirs through log analysis, reservoir testing and geologic models to target more productive zones and better predict productivity of the wells. This allowed for better size fracture treatments based on a more accurate estimate of the reservoir’s productivity. Vertical wells had limited potential and very large treatments did little to improve production. GRI research showed producers how to optimize the economics of fracture treatments by sizing of the treatment to real expectations of the reservoir conditions.
GTI also pursued research on gas production from shale formations in Illinois and Texas. Several horizontal wells in the Barnett Shale were tested and evaluated with multiple fracture treatments, and a calibrated formation evaluation was performed with a cooperative Mitchell Energy well.
A big breakthrough occurred when GTI drilled the Stella Young well with Mitchell Energy in the Barnett Shale—a novel well drilled at a high angle, rather than vertically, then stimulated with modern-day technology—resulting in three times greater production. It established that the productivity of deep shales can be significantly improved if the well can be fractured and reservoir contact increased.
In 2002, when Devon Energy Corporation acquired Mitchell Energy, it combined hydraulic fracturing with horizontal drilling to further improve the productivity of shale gas wells. This activity truly kicked off the significant production at Marcellus and all of the other shales that are now producing gas in greater volumes than ever before thought possible.
For over 20 years, GTI has worked with academia, government, and industry to develop solutions for the conditioning of produced waters to enable environmentally sound and cost effective management, by-product recovery, and beneficial use or reuse of produced water streams.
GTI has led Water Conservation and Management Committees in the Barnett and Appalachian shales, exploring water management methods and technologies that will reduce demands for freshwater, reduce environmental impact of brine disposal, and ensure supplies of water for well drilling and completion for natural gas development.
Opportunities for reducing water-related costs of permitting for shale gas development for the Marcellus Shale Coalition were identified. An information base on the composition of flowback water generated from completions of shale gas wells in the Marcellus Shale region was developed. Samples of supply and flowback water from 19 locations were collected and analyzed for over 300 constituents in accordance with a purposefully-designed integrated plan that was reviewed by industry and the Departments of Environmental Protection of Pennsylvania and West Virginia. GTI has also been elected to lead the MSC Research Collaborative Committee along with CONSOL Energy.
GTI has also performed research in the New Albany Shale, and assessed water management and reuse technologies for RPSEA. Currently, researchers are utilizing water-based life cycle modeling to provide timely planning and technology guidance for sustainable shale gas water and solid waste management.
In 2011, a techno-economic assessment of water management solutions was completed, a joint industry project with 22 companies. The study defined current water management practices, emerging solutions, and benchmark costs; categorized best-in-class options; and identified technology gaps and opportunities for cost reductions and efficiency improvements.
Under contract to the Research Partnership to Secure Energy for America (RPSEA), GTI managed the unconventional natural gas research program funded by the U.S. Department of Energy from 2006-2011. GTI continues to serve as a major technical performer in the program, leading field-based research projects in shale plays to advance technology and best practices. The program focus is on developing shales in an environmentally acceptable manner, including the development and deployment of technology to mitigate the impact to land, air, and water resources.
GTI led a project on New Albany Shale gas wells for RPSEA, developing techniques and methodologies for increasing the success rate and productivity of unconventional gas resources. GTI researchers on this project were recognized with a best paper award at the 24th World Gas Conference (WGC) in Buenos Aires, Argentina in late 2009. The conference was attended by over 3,500 industry participants from 83 countries.
GTI is now working on characterization of the Marcellus Shale and development of advanced well completion technologies and best practices that address technical and environmental challenges for this resource. The project is focusing on identifying the optimum techniques for enhanced fracture stimulation and reliable reservoir assessment.
In 2012, GTI was awarded RPSEA funding to develop advanced methods and techniques for design and execution of environmentally safe and economically efficient hydraulic fracturing operations. The two-year project will develop a real-time hydraulic fracturing control methodology through coupled analysis of geophysical fracture diagnostic data and pumping pressure, rate, and fluid density; and verification of results by detailed production testing.
GTI is now sharing lessons learned from the U.S. unconventional gas revolution with the rest of the world. One key international initiative is the Global Unconventional Gas (GUG) Summit that was held in Beijing, China in November 2012. The event, building on the success of the 2011 meeting in Beijing and the 2010 conference in Amsterdam, focused on the exchange of ideas about the enormous potential of gas shale and the unlocking of unconventional gas resources in an environmentally and economically sustainable way.
Co-hosted by GTI and the China Energy Research Society, the event provided a meeting place for more than 220 senior-level International and Chinese energy experts, along with first-class speakers from the global gas industry and governmental bodies. A series of high-level signing ceremonies and networking events took place at the Summit, including the signing of a framework cooperation agreement for a training and learning center between SPT Energy Group and GTI.
In addition to these global meetings, GTI has delivered customized workshops on best practices and technical solutions for unconventional gas development and produced water management to European producers and service companies. Papers and presentations by GTI experts are sharing the U.S. expertise and advocating for unconventional gas development across the nation and across the globe, in far-flung locations that include Austria, Poland, Istanbul, France, the Netherlands, and Korea.
GTI completed a study in 2012 in support of the Polish operator’s association to assess industry best practices toward addressing potential environmental impact of shale gas exploration and appraisal activities. The public report is being used by Polish industry in external communications regarding technology applications and sustainable practices, both with government and communities.