Multi-Site Application of the Geomechanical Approach for Natural Fracture Exploration

In order to predict the nature and distribution of natural fracturing, Advanced Resources Inc. (ARI) incorporated concepts of rock mechanics, geologic history, and local geology into a geomechanical approach for natural fracture prediction within mildly deformed, tight (low-permeability) gas reservoirs. Under the auspices of this project, ARI utilized and refined this approach in tight gas reservoir characterization and exploratory activities in three basins: the Piceance, Wind River and the Anadarko. The primary focus of this report is the knowledge gained on natural fractural prediction along with practical applications for enhancing gas recovery and commerciality. Of importance to tight formation gas production are two broad categories of natural fractures: (1) shear related natural fractures and (2) extensional (opening mode) natural fractures. While arising from different origins this natural fracture type differentiation based on morphology is sometimes inter related. Predicting fracture distribution successfully is largely a function of collecting and understanding the available relevant data in conjunction with a methodology appropriate to the fracture origin. Initially ARI envisioned the geomechanical approach to natural fracture prediction as the use of elastic rock mechanics methods to project the nature and distribution of natural fracturing within mildly deformed, tight (low permeability) gas reservoirs. Technical issues and inconsistencies during the project prompted re-evaluation of these initial assumptions. ARI's philosophy for the geomechanical tools was one of heuristic development through field site testing and iterative enhancements to make it a better tool. The technology and underlying concepts were refined considerably during the course of the project. As with any new tool, there was a substantial learning curve. Through a heuristic approach, addressing these discoveries with additional software and concepts resulted in a stronger set of geomechanical tools. Thus, the outcome of this project is a set of predictive tools with broad applicability across low permeability gas basins where natural fractures play an important role in reservoir permeability. Potential uses for these learnings and tools range from rank exploration to field-development portfolio management. Early incorporation of the permeability development concepts presented here can improve basin assessment and direct focus to the high potential areas within basins. Insight into production variability inherent in tight naturally fractured reservoirs leads to improved wellbore evaluation and reduces the incidence of premature exits from high potential plays. A significant conclusion of this project is that natural fractures, while often an important, overlooked aspect of reservoir geology, represent only one aspect of the overall reservoir fabric. A balanced perspective encompassing all aspects of reservoir geology will have the greatest impact on exploration and development in the low permeability gas setting

Feasibility of heavy-oil recovery

reportThis paper presents the results of a study completed in June 1984 that assessed the size, technical categorization, and potential of the U.S. heavy-oil resource base. Based on a proprietary data base containing nearly 1100 heavy oil reservoirs, the study concluded that heavy-oil resources in place in the United States amount to over 100 billion barrels. Heavy oil has the potential to become a significant source of domestic liquid fuel in the near to mid-term. Initial required capital investment for heavy-oil development is on the order of $10,000-20,000 per daily barrel of sustained capacity, considerably less than many other synthetic fuels. The current potential of domestic heavy-oil is about 6 to 7 billion barrels of recoverable reserves and a production rate of 700,000 bbl/d in the early 1990s. Advances in technology will be required to reach the full, domestic heavy-oil potential

Major tar sand and heavy oil deposits of the United States

journal articleThis paper presents a current assessment of U.S. tar sand and heavy oil resources. It is based on an independent appraisal of all tar sand deposits with 100 million barrels in place or more and the construction of a heavy oil reservoir and data base of fields containing more than 20 million barrels in place. The U.S. tar sand resource is estimated to be 63 billion barrels, distributed in 11 states. This resource estimate is considerably larger than reported in previous studies, which had estimates ranging from 5.5 to 36.4 billion barrels. No estimate is available of how much of this resource is recoverable. The U.S. heavy oil resource is estimated to be about 100 billion barrels in place. With advanced extraction technologies, as much as one quarter of this resource, or 24 billion barrels, may be recoverable

Enhanced recovery of unconventional gas. Executive summary. Volume I (of 3 volumes)

R and D efforts in enhanced gas recovery of near-conventional and unconventional gas sources are needed in order to augment domestic supplies. Unconventional gas sources could provide 200 to 220 Tcf of additional gas supply, if a combination of economic incentives and publicly sponsored R and D is used, and as much as 2 to 8 Tcf could be delivered per year by 1990. This volume comprises three parts discussing the public policy issues, proposed research strategy in enhanced gas recovery, and methodology. 14 figures. (DLC