Comprehensive and Integrated Research to Develop Predictive Models for Shale Oil and Gas Reservoirs in Texas by The Crisman Institute for Petroleum

Transcription

1 Comprehensive and Integrated Research to Develop Predictive Models for Shale Oil and Gas Reservoirs in Texas by The Crisman Institute for Petroleum Research, Harold Vance of, College of Engineering, Texas A&M University and The Berg-Hughes Center for Petroleum and Sedimentary Systems, of, College of Geosciences, Texas A&M University

2 EXECUTIVE SUMMARY Shale reservoirs are not inert. Essentially, all of the physical, chemical and mechanical properties change through time due to production induced changes in the reservoir. Also, formation pressure and hydrocarbon fluid types can change in such formations due to complexities in the reservoir and time-dependent changes. In the past, the industry has developed models to history match or analyze data from existing wells. What is lacking are comprehensive geologic and engineering models that are predictive. Industry needs predictive models to shorten the learning curve and cut finding and development costs in new geologic plays or even in existing plays. Texas A&M faculty have extensive experience in the multiple geological and engineering disciplines important to unconventional resources and a demonstrated record of research accomplishments in this area. The value proposition for industry partners is access to this multidisciplinary group of faculty and to help educate highly qualified geoscientists and engineers for the industry to recruit and continue the development of technology for decades. The value proposition also lies in investing in a program that has an opportunity to contribute to increasing recovery efficiency and lowering overall costs if unconventional resources are to be produced in a low oil and gas price environment. Program Objectives Develop technology to go from trial and error solutions to predictive models that will improve recovery efficiency to levels that are comparable to conventional reservoirs; Produce graduates to lead industry in futture challenges related to unconventional resources, and Enable society to benefit from continued production of unconventional resources in an environment of increasing regulatory and environmental restrictions. Key Program Elements Develop two comprehensive geologic and engineering data sets one for the Eagle Ford/Eaglebine and one for the Wolfcamp that can be used by all research participants. Although we will use local data sets our predictive models should application of other global unconventional resources. Participation by more than 25 faculty and their graduate students in geoscience and engineering. Partnership with National Laboratories as warranted to apply their work on shale science and have access to massively parallel numerical modeling capabilities. Open membership to industry and opportunity for industry-directed research with a technical steering committee to help set the goals and deliverables. Contractual mechanism to safeguard proprietary information. Gated research deliverables corresponding to key phases in the research plan. Five year collaborative participation with option to drop/continue at three years. RATIONALE FOR THE RESEARCH Two of the most important shale plays are located in Texas - the Eagle Ford/Eaglebine across southcentral Texas and the Wolfcamp-Spraberry Formations in the Permian Basin. These two basins have been areas of major drilling and technology development in shale reservoirs over the last 10 years. These organic-rich, fine-grain deposits tend to be self-sourcing reservoirs with rock properties varying with sedimentary facies, kerogen type(s) and richness, depth, and thermal maturity. As such, the rock mechanical, petrophysical, and compositional properties will vary vertically and laterally. Also, formation fluid pressure and hydrocarbon fluid types can also change in such formations due to complexities such as pore size distribution. 2

3 Most of the reservoirs the oil and gas industry has developed over the last 150 years have been in sandstone or carbonate reservoirs that are essentially inert over the life of the field development. However, unconventional shale reservoirs are not inert. We plan to study how shale reservoir properties change as field development and production occurs. Understanding these changes will be the key to developing predictive models and better stimulation treatments, leading to improved recovery in these reservoirs. Essentially, all of the important rock and fluid properties change through as a consequence of production induced changes in the reservoir. These changes will be a focus of the proposed comprehensive and integrated, multi-year research project at Texas A&M University. INTRODUCTION Some advances in geoscience and engineering have led to improved production from unconventional resources. However, much like the early years of the oil industry, many of the learnings for unconventional resources today are empirical. The prevailing approach has been to use brute force - fracture the reservoir without a full understanding if this is being done optimally to allow maximum recovery or if there is longterm reservoir damage being done that could ultimately reduce recovery. Fundamental questions still remain, such as resource estimation and recovery limits, movement of oil through these nano-porous rocks, propagation of hydraulic fractures through a naturally fractured highly anisotropic medium, chemical changes in the rock through the introduction and production of fluids, and the resultant changes that these cause to the reservoir over time. Our research has demonstrated that intrinsic rock properties established during deposition and diagenesis control the availability of chemical constituents that, through production, may influence fracture propagation and hydrocarbon mobility through the fractures to the wellbore. In particular, the solid phases containing different elements, the nature of their chemical bonds and their total abundances in the reservoir rocks determine the propensity of rock constituents to partition into fluids. Transfer of chemical species from rocks to fractures and production fluids is complex and governed by a number of factors. Operators control or influence the starting composition of the fluid and the duration of waterrock interactions. The mechanical response of the rocks, changes in state of stress, and induced fracture density are influenced by the operator trying to control fracture size and thus the fracture contact area over which mass transfer takes place. This supports the critical insight that shale reservoirs are not inert rocks, though this is not fully recognized in many of the ongoing studies that examine the state of the reservoir at one point in time. Understanding the impact of current production practices on the state of the reservoir is required to enable new engineering solutions that will improve recovery efficiency (over the life of a well) in the future. The proposed research program is unique in that its goal is to describe the EVOLUTION of the physical, chemical and mechanical state of unconventional shale reservoirs, such as the Eagle Ford/Eaglebine and the Wolfcamp from pre-drill to production decline and depletion. This comprehensive and integrated research program will test the hypothesis that by describing these changes in the state of the reservoir, largely as a result of production-induced fluid-rock interactions, we will be better able to predict future reservoir performance. New, process based, deterministic models will enable additional oil and gas recovery from these reservoirs. Application to other global unconventional resources is an additional expected benefit of this program. PROGRAM OBJECTIVES Develop over the next five to ten years the next-generation, integrated solutions 3

4 involving geologic processes at all times scales with engineering design and practice to improve total recovery to levels that are comparable to conventional reservoirs. Educate students to lead industry in future challenges related to unconventional resources, and Enable society to benefit from continued production of unconventional resources in an environment of increasing regulatory and environmental restrictions. KEY PROGRAM ELEMENTS Development of two comprehensive integrated geological, geophysical and engineering data sets one for the Eagle Ford/Eaglebine and one for the Wolfcamp that can be used by all research participants in a truly comprehensive and integrated research endeavor. Partner companies to contribute data for the two data sets. Participation by more than 25 faculty (and their students) from Geology & Geophysics,, Geography, Civil Engineering, Texas Engineering Experimental Station and others with demonstrated record of contributions to unconventional resources. Partnership with National Laboratories as warranted to take advantage of their work on shale science and massively parallel numerical modeling capabilities. Open membership to industry and opportunity for industry-directed research with technical steering committee to help set the goals and deliverables. Contractual mechanism to safeguard proprietary information. Participant rights for individual consultations with faculty and students. Gated research deliverables corresponding to key phases in the research plan. Five-year collaborative participation with option to drop/continue at three years. EXPLANATION OF DELIVERABLES The deliverables for this program will be mutually agreed upon by the industry steering committee and the research faculty in each focus area. It is initially envisioned that the deliverables will consist of a series of reports to industry members on a yearly basis. Other deliverables will be solutions, algorithms and computer code developed to solve the algorithms and generate the solutions. Final deliverables will be fine-tuned and directed by industry partners and may be subject to certain confidentiality and intellectual property agreements required by partners. Delivery methods will also include faculty and student publications and conference presentations during the program duration, with one or more landmark special edition publications such as an AAPG, SEG or SPE. Last, but very important, this project should deliver dozens of highly qualified geoscientists and engineers to the industry to continue this work. The program offers participants opportunities to interact with students that may be viable recruiting candidates. PROPOSED NEW INTEGRATED RESEARCH PLAN FOR 2016 Personnel: At Texas A&M University, we have substantially increased our faculty in both the and Geology & Geophysics departments. Texas A&M has more graduate students in than any other US university. Graduate enrollment in 4

5 Geology and Geophysics has also dramatically increased in the last few years. We have substantial and diverse talent to put to work helping industry develop the knowledge and technology to produce a significant increase in production and recovery efficiency in unconventional oil and gas reservoirs, and to do so profitably. Objectives for 2016: Develop data sets for shale gas and tight oil formations in the Eagle Ford/Eaglebine in south-central Texas and the Wolfcamp in the Permian Basin, to foster integrated analyses and technology development by the faculty and graduate students in engineering and geosciences at Texas A&M University. Enhance existing synergies among faculty from both Colleges, including how project elements are funded, so they will work in collaborative groups to analyze the field data sets, develop technologies to learn from the data sets, and develop predictive solutions to some of the most pressing problems faced by industry. Develop solutions in a form that can be used by the Crisman-Berg Hughes member companies in their daily work. We envision that these solutions will be in the form of spreadsheets, visual basic programs, and other software packages that will be made available. The work product will not be in the form of commercial software, but will be solutions that can be used and improved upon by the Crisman-Berg Hughes member companies with an overarching objective of improving recovery efficiency in these reservoirs. With faculty developing technology using the same data set, develop synergistic solutions that will far exceed what has traditionally been the academic research model of professors working on their own problems with their own. data sets. We will hold monthly internal research meetings to be sure our work is progressing as planned and helping the graduate students and faculty make the most of working together as a team hopefully limiting the silo approach traditionally employed. Proposed Deliverables As with all research projects, the sponsors of the projects expect deliverables at the conclusion of the research. Each of the individual projects will list the deliverables for that project, but we envision the Crisman-Berg Hughes portfolio will provide the following, as a minimum. Detailed analyses of the data sets that no one company has the time or manpower to conduct on their own, with the additional benefit that on an FTE basis academic research is less costly. New insights on oil and gas in place. New insights on the physical, chemical and geomechanical changes in the reservoir affecting recovery. New insights into the processing of geophysical data (micro-seismic and electromagnetics) that contribute to the knowledge of fracture propagation, geometry and interconnectivity. New models that describe the nature of the geo-mechanical state of the reservoirs (natural and induced fractures) that can be used to analyze fracture treatment data and predict fracture dimensions for fracture design. Comprehensive analyses that help identify the factors affecting optimal well bore length, vertical well bore placement and well spacing for specific formations in specific basins. New reservoir analysis methods and models that incorporate molecular and nano-scale mechanisms to improve our understanding of the reservoirs and our ability to forecast future behavior. 5

6 RESEARCH THEME We plan to organize our research efforts into inter-related themes that for purposes of presentation are geosciences, hydraulic fracturing, reservoir modeling and nano-molecular investigations. All of the faculty will be working in a synergistic manner to develop comprehensive and integrated research results but some faculty may contribute with their specialty to selected research tasks identified in the overall project. GEOLOGICAL AND GEOPHYSICAL CHARACTERIZATION OF UNCONVENTIONAL RESERVOIRS Our faculty has in the past and continues to work in all key aspects of geology and geophysics required to characterize the reservoirs, including extensive experience with the Eagle Ford formation. Geology and Geophysics will contribute to: Establish the framework of the depositional systems. Date key stratigraphic intervals tied to global events of maximum organic productivity. Shale dynamics and how the physical properties affecting oil and gas in place, production, changes with time and chemical interactions with in-situ and injected fluids. Characterize the mechanical stratigraphy of these layered and highly anisotropic reservoirs; examine the propagation of mixed-mode fractures, the interaction of natural and hydraulic fractures and the coupling and time-dependent behavior of thermal-mechanical processes. Geophysical expertise in seismic acquisition, processing and modelling, coupled with new techniques for electromagnetic imaging, to enhance the understanding and prediction of the geomechanical properties of the reservoirs. Geologic and ultimately reservoir simulation models and what are key geologic controls on nanno-molecular phenomena affecting fluid and gas flow. HYDRAULIC FRACTURING Our faculty has in the past and continues to work on the following areas dealing with natural and hydraulic fracturing. Mapping of natural fracture networks in the Eagle Ford to describe the mechanical 6

7 stratigraphy according to lithology and total organic content. Tri-axial geomechanical tests under realistic confining pressures to correlate with mechanical stratigraphy framework. Experimental and numerical modeling of mode I and II fracture propagation with Eagle Ford cores to study changes in hydraulic fracture propagation and their interaction with natural fracture networks. Analyses of fracture propagation data. Testing of fracture conductivity in shales. Testing of fracture fluids. Wellbore diagnostics for fracture identification. Analyses of post-fracture flow-back data. Analyses of pre-fracture and post-fracture production data. Analyses of pre-fracture and post-fracture pressure transient data. Optimization of fracture treatments. RESERVOIR MODELING Our faculty is well known for developing reservoir models and using models to analyze field data. We have expertise in the following areas and have a number of current projects in which we are developing and improving models that can be used to analyze the Crisman- Berg Hughes data sets. Detailed stratigraphic analyses and high resolution photogrammetry to provide inputs to geologic models for reservoir simulation. Finite-element and finite-difference modeling to incorporate fluid flow, geomechanics and microseismic predictions. Specifically, we aim to couple fluid-rock, chemicalthermal processes and their time dependent behavior. Sophisticated gridding systems to better model fractures and complex fluid flow. Analytical, semi-analytical and other simple models that can be used for quick analyses of data sets and for running multiple realizations for probabilistic treatment of uncertainty in the data. NANO AND MOLECULAR SCALE INVESTIGATIONS It is clear that fluid storage and fluid flow in these nano-darcy, fine-grained rocks that we call shalegas and tight-oil formations do not follow the Darcy flow principals that the industry has developed over the past 100+ years. We use our current technology to match the field data and predict the future, but the current methods are not ideal. Our faculty has several on-going projects looking at molecular- and nano-scale behavior of water and hydrocarbons in shale or fine-grained rocks. We have expertise in the following areas: Measuring nano-pore size distribution of the rock and relating this information to: o Initial oil and gas in-place amounts including (i) pore volume adjustments due to rock compressibility and adsorbed phase effects; and (ii) fluid behavior adjustments due to nanopore pore confinement effect. o Fluid transport in reservoir matrix using apparent matrix permeability model including non-darcian effects. Quantifying nano-pore storage and transport effects on well production decline. Identifying key injectants for improved shale oil recovery using molecular models of chemicals and water (e.g., brine, surfactants, emulsions, CO2, N2, gel, etc.) and performing simulations of fluid-fluid and fluid-solid interactions: o To predict miscibility of a gas-oil mixtures in nanopores. o To predict pore pressure, threshold pressure, IFT and capillary pressure in water-oil mixtures in nanopores. o To predict chemical potential, ionic concentration, osmosis pressure in water-clay systems. 7

8 Quantifying mechanical behavior of model clays, organic solid materials and their combinations: o To understand rock failure mechanisms at nano-scale by o To predict geomechanical properties that lead to brittle behavior. We believe continued research in these areas will lead to much better formation evaluation and reservoir modeling technology and to new innovative IOR/EOR methods. PROPOSED STEPS IN 2016 RESEARCH The purpose of this document is to propose a way forward for the Crisman Institute in conjunction with the Berg-Hughes Center. We envision that with more faculty input and with substantial input from industry, we will mold the vision of the Crisman-Berg Hughes program in the months to come. We plan a meeting with industry on September 22 to obtain feedback and, hopefully, buy-in to our plan so we can increase the number of Crisman-Berg Hughes member companies and fund much needed research. Step 1 Determine the Basins and Formations to Evaluate We envision developing two major data sets for the Eagle Ford/Eaglebine in south-central Texas and the Wolfcamp in the Permian Basin. We will rely on the literature, public records, but mainly on our Crisman-Berg Hughes member companies to help us develop the exact locations of the comprehensive data sets that will fuel our research. complete data sets and integrated groups of professors and students using these data sets for their research, we should be able to substantially improve the knowledge obtained from the analyses of the data. Step 3 Develop Proposals for Crisman-Berg Hughes Members to Evaluate As soon as practical, our faculty will develop proposals for projects consistent with the Crisman- Berg Hughes goals and vision. These proposals will be vetted by the appropriate faculty to organize these proposals into a comprehensive and realistic research program. Step 4 Selection of Projects Once the portfolio of projects has been developed, the portfolio will be submitted to all Crisman-Berg Hughes member companies to solicit input regarding the projects that are of most interest to them. Step 5 Obtain Commitments for Providing Data Sets Once the research program is planned for 2016 and we know how many companies will participate, we will set out to build our data sets. This may require some of our graduate students to work closely with the companies to acquire the data and make it available for the faculty and graduate students. Step 2 Develop Comprehensive Data Sets We will work with industry to build comprehensive data sets using public information, but most likely, data from specific companies. We need to have as complete a data set as possible for each formation to achieve our objectives of developing analysis methods, solutions and technology. Attachment A is a list of data we would like to obtain for each of the formations we will include in our work. With 8

9 APPENDIX A DESCRIPTON OF CRISMAN AND BERG- HUGHES AND DETAILS OF THE ENVISIOND RESEARCH CRISMAN INSTITUTE FOR PETROLEUM RESEARCH Mission Statement The mission of the Crisman Institute for Petroleum Research is to produce significant advances in upstream petroleum engineering technology through the combined efforts of faculty, post-doctoral researchers, and highly qualified graduate students, in close cooperation with industry. Brief History In 1984, Mr. and Mrs. Wayne Crisman donated $1 million for the of Petroleum Engineering to organize an Institute for Reservoir Management. The idea was that industry has all the data and limited manpower, while the university has professors and graduate students but very little data from actual fields. The industry could provide data and could mentor the university by framing the problems that need to be solved. The university could conduct reservoir management studies to both improve technology and provide reservoir management plans that would benefit the companies supplying the data. In 2004, a proposal was made to revive the Crisman Institute and return it to its original purpose. The Crisman Institute was reorganized into 4 centers and 3 of the centers were endowed by $1 million gifts from Schlumberger, Halliburton and Chevron. For the past 10 years, the Crisman Institute has been very successful in attracting member companies, producing graduates with M.S. and PhD degrees, publishing papers and generating intellectual property (including source code) for our members. One of the unique features of the Crisman Institute has been that all member companies get the lifetime, paid-up, irrevocable license to use any intellectual property developed during any of the projects that are being funded by Crisman. So even if a company is mainly interested in only a few of the projects in the Crisman portfolio, it still gets the results from every project every year to use as they wish no strings attached. Part of that agreement includes all code written by a student or professor to solve the problems and algorithms that are developed during a Crisman project. The same is true for any new developments in laboratory equipment or measurement methods. BERG-HUGHES CENTER FOR PETROLEUM AND SEDIMENTARY SYSTEMS Mission Statement Integrate geoscience, engineering and other disciplines to collaborate with industry and others to advance research and education in petroleum sciences. Brief History In 2009 the Board of Regents at Texas A&M University approved forming the Berg-Hughes Center with the mandate of integrating geosciences and petroleum engineering disciplines. The Center is housed in the of Geology & Geophysics in the College of Geosciences. Within the College, the Center easily integrates faculty from the Oceanography and Geography s as well as the Center for Tectonophysics, the Geochemical Environmental Research group (GERG) and the International Ocean Discovery program (IODP). The Center s name recognizes the legacy of Dr. Robert Berg, a distinguished petroleum geoscientist at Texas A&M and honorary member of the National Academy of Engineering and the Hughes family that generously contributed $1M to form the Center, with the remaining needed funds being contributed by former students and friends. The Berg-Hughes Center has three core research and educational areas. The first focuses on 9

10 unconventional resources, building on several years of extensive research on the Eagle Ford. Courtesy of BP, the Center has unique access to complete Eagle Ford outcrops in Lozier and San Antonio canyons in south Texas, which has resulted in numerous studies of the stratigraphy, chemostratigraphy, chrono-stratigraphy, petrophysics and geomechanics of this Formation. Most recently, Center faculty are undertaking an extensive highdefinition, drone-based, photogrammetry data acquisition which will provide a level of stratigraphic detail unlike any as input to a geologic model. The second research area focuses on conventional carbonate reservoirs, building on years of carbonate research excellence at Texas A&M. The program focuses on pore-systems characterization and understanding aimed at improving recovery factors and resource estimation in carbonate reservoirs, high-resolution 3D visualization of carbonate deposits using new technologies to describe geometries of the depositional systems, new insights into facies analysis/reservoir characterization from recent to modern carbonate studies, and development of clumped isotope geothermometry for application to basin thermal history. The third research area is generously supported by Chevron and its focus is on basin modeling. Specifically, it focuses on the generation, retention and expulsion of hydrocarbons in a variety of basin settings and play types, integrating petroleum engineering, geochemistry, organic & inorganic rock fluid interactions, fluid properties, sedimentology, geophysics, petrophysics, stratigraphy and data analysis. Modeling software (for example; Trinity, Petromod and others) provide students with industry standard platforms. Most of the research conducted by the Berg- Hughes Center has been and is done in close collaboration with faculty and students in the at Texas A&M. 10

11 APPENDIX B Ideal Data Sets All geologic maps in the study area to include structure, gross and net pay isopach maps, and other maps with useful information. Seismic (including micro-seismic) data to include both processed data and analyses of the data. Drilling data to include all morning reports, mud logs, drilling mud reports, and information on the trajectory and wellbore length for all wells in the study area. All core analyses records. We would also like to have any core that is still available that we can analyze. All open-hole logs for all wells in the study area. We would prefer both paper copies and digital copies of the logs. We would also like to have any analyses of the logs and copies of the processed logs showing both measured data and values calculated from those measurements. All completion reports to include details of casing and cementing, and any casedhole logs for all wells in the study area. All fracture treatment records for all wells in the study area to include details of the perforation and diverting methods, fluids, proppants, and pumping records. All microseismic data to include raw signals as well as the processed results. All flowback data after the fracture treatments to include oil, gas and water flow rates as well as flowing pressures. All production data from the wells in the study area and other wells in the vicinity that can be used to determine regional reservoir quality. All reservoir fluid property analyses, as well as analyses of produced surface fluids from wells in the study area. To include samples of production fluids over time. All well tests that are used for production allocation and all pressure transient tests. Information concerning gathering systems, midstream processing and line pressures if such information is necessary to analyze the production data. 11

12 Participating Faculty Sara Abedi Assistant Carlos A. Dengo Daniel W. Goldberg Assistant Yucel Akkutlu Associate Benchun Duan John Killough Walter B. Ayers Visiting Eduardo Gildin Assistant Jihoon Kim Assistant Maria A. Barrufet Thomas A. Blassingame David Burnett Research Project Coordinator, Frederick M. Chester Mark Everett Richard L. Gibson, Jr. Berna Hascakir Assistant Dan Hill Professor & Dept. Head, Michael J. King Professor & Assistant Dept. Head, Juan Carlos Laya Assistant Jenn-Tia Liang John Lee Regents Akhil Datta-Gupta Stephen A. Holditch Duane McVay Professor & Assistant Dept. Head,

13 George J. Moridis Visiting Julia Reece Associate Ding Zhu Nobuo Morita David S. Schechter Associate Hadi Nasrabadi Assistant Jerome Schubert Associate Hisham Nasr-El-Din Yuefeng Sun Sam Noynaert Assistant Mike Tice Assistant John Pantano Research Professor Peter Valko Michael Pope Professor & Dept. Head, Rudd Weijermars Bobby Reece Assistant Kan Xu Assistant