Publication Date:
2009-11-01
Description:
A field-specific geomechanical model serves as a platform for greatly reducing costs and increasing production over the life of a field. The information contained in a geomechanical model makes it possible to reduce drilling costs and production losses through fieldwide well planning that can optimize production and minimize risk. A significant value of the geomechanical model is its application to the efficient exploitation of fractured reservoirs. The essential contribution of wellbore image technologies to this exploration and production challenge is illustrated through a case study of a compartmentalized fractured gas reservoir located in Hokkaido, Japan. A growing body of evidence reveals that, in many fractured reservoirs, the most productive fractures are those that are optimally aligned in the current stress field to fail in shear. Thus, it is necessary to obtain knowledge of both the stress magnitudes and orientations and the distribution of natural fractures to determine the optimal orientations for wells to maximize their productivity. The best well intersects the maximum number of stress sensitive fractures. Applying geomechanics and the reservoir fracture distributions to model shear-enhanced permeability as the mechanism for reservoir production appears to be a promising improvement to existing reservoir flow models. Using quantitative risk assessment and realistic uncertainties in the critical parameters, it is possible to estimate the uncertainty in predictions of optimal well trajectories and of stimulation pressures to enhance natural fractures. The results indicate that the critical parameters are not always those with the most uncertainty, and that the most effective way to reduce prediction uncertainties is to calibrate against the productivity of a preexisting well. Colleen Barton is a cofounder and senior technical advisor of GeoMechanics International (GMI). She received her Ph.D. from Stanford University in 1988 in reservoir geomechanics. Prior to cofounding GMI in 1996, she spent 10 years as a research scientist at Stanford developing techniques in in-situ stress measurement and enhanced recovery from fractured reservoirs. She is an industry expert in wellbore image analysis technologies. Daniel Moos is a cofounder and chief scientist of GeoMechanics International. He received his Ph.D. from Stanford University in 1983, cofounded the Borehole Geophysics group at Lamont-Doherty Earth Observatory, which developed and managed well logging services for the Ocean Drilling Program, and subsequently spent 10 years as a research scientist at Stanford University before GMI was founded in 1996. Kazuhiko Tezuka is a senior manager of the reservoir characterization laboratory in Japan Petroleum Exploration Co. (JAPEX) Research Center. He joined JAPEX after he graduated from Tohoku University in 1984 with a B.S. degree in geophysics. He worked as a visiting scientist at Earth Resources Laboratory at Massachusetts Institute of Technology in 1993–1994. He received his Ph.D. from Tohoku University in 1997 in earth resources engineering.
Print ISSN:
0149-1423
Electronic ISSN:
1943-2674
Topics:
Geosciences
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