George R. Kear

Use of Log-Derived High-Resolution Mineral-Based Lithofacies from Borehole Spectroscopy Logs and Microresistivity Images for enhanced Formation Pressure Sampling and Vertical Interference Tests

from Borehole Spectroscopy Logs and Microresistivity Images for Enhanced Formation Pressure Sampling and Vertical Interference Tests Elshahawi, Hani1, Eileen Donaghy1, Christina Guillory1, George Kear2, Anish Kumar2, Mario Ardilla3, David Williamson4, Wesley Cantwell4, Brian Briscoe4 (1) Shell International E&P Inc, Houston, TX (2) Schlumberger Oilfield Services, Houston, TX (3) Schlumberger Oilfield Services, Lagos, Nigeria (4) Schlumberger Oilfield Services, New Orleans, LA

Application of integrated technology for improved reservoir characterization at Texaco's Vermilion Bay Field, Louisiana

Summary Traditionally conventional well logs such as gamma ray, spontaneous potential, resistivity, and porosity are used to evaluate development wells in mature fields. This paper will show the positive impact of integrated applied technology; borehole seismic, micro-resistivity imaging, and extended well testing, to improve reservoir characterization. Based on a recently acquired 3-D seismic survey over a mature salt dome play in southern Louisiana, a well location was proposed in close proximity to the salt face and updip of a thick sand found wet in a previous well. Structural mapping places a large fault 200 feet to the west of the wellbore. A Formation Micro Imager log was acquired across the reservoir section. From handpicked bedding planes, the interpreter was able to determine that the suspected fault was in fact an unconformity. An extended well test was designed to detect the presence of reservoir sealing boundaries. Well test interpretation indicated the presence of two sealing boundaries at about 760 ft. and one boundary at about 1900 ft. away from the wellbore. A 3D salt proximity survey was acquired to locate the face of the salt that would delineate the updip extent of the reservoir. The 3D Salt Proximity results independently confirmed the salt flank location as interpreted from the Pressure Transient testing. Integration of the 3D Salt Proximity, Pressure Transient data and Formation Micro Imager has resulted in the remapping of the objective segment. This significantly increased the size of the reservoir and more than tripled the estimated recoverable reserves. Salt Dome Visualization, which utilizes 3D imaging and interpretation techniques to aid in salt-flank delineation, is being employed in further development drilling. Based on the results obtained by these techniques, one successful offset has been drilled and two additional wells are planned for 2000.