--> Abstract: A High Resolution 3D Seismic Survey Using 55 x 55 Feet Bin Size in Osage County, OK to Delineate Details of of Structure, Stratigraphy and Subtle Lithologic Variations, by B. Sharma, T. K. Reeves, W. I. Johnson, S. Banerjee, S. George, and R. Lindsey; #90937 (1998).

Datapages, Inc.Print this page

Abstract: A High Resolution 3D Seismic Survey Using 55 x 55 Feet Bin Size in Osage County, OK to Delineate Details of of Structure, Stratigraphy and Subtle Lithologic Variations

SHARMA, B., T.K. REEVES, W.I. JOHNSON, S. BANERJEE, and S. GEORGE, BDM Petroleum Technologies; and R. LINDSEY, NPTO, Department of Energy, Tulsa OK.

A high resolution 3D seismic survey was recently concluded with carefully selected data acquisition parameters in a 16.75 sq mile area in Osage county, Oklahoma to investigate the reserves growth potential of the platform deposits which have produced oil and gas from the area for over 100 Years. The effectiveness of closer scanning of the subsurface with a smaller bin size was investigated by acquiring seismic data from six sq miles out of the total area with a bin size of 55 ft x 55 ft and the rest with the more conventional 110 ft x 110 ft bin configuration.

Data acquired with the two bin configurations in the same area indicate that due to averaging over a larger area, the small individual faults (throw around 30-40 ft) could not be resolved as effectively in the 110 ft bin data as in the 55 ft data. The higher frequency content in the 55 ft bin data (80-90 Hz from the deepest reflectors) have contributed to the sharpness of the fault plane images. This enables precise mapping of these faults in the entire sedimentary section down to the basement which occurs at a depth of around 4000 ft. The distribution of oil and gas production in Osage county indicates that some of the small faults mapped act as barriers to fluid migration.

Detailed correlation with wireline logs indicates that amplitude and wave shape variations of the reflected wavelet are mainly affected by changes in thickness, lithology, porosity and fluid saturations of the reservoir rocks. The shallow Pennsylvanian Layton gas sand (at a depth of around 1100 ft) gives a large negative reflection when the reservoir porosity and gas saturations are high in one part of the field but the amplitude diminishes as the reservoir becomes less porous due to an increase in the clay content and the gas saturation also decreases. A significant increase in clay content is indicated by a change in the reflected wave shape due to dampening of the pulse. Preliminary studies indicate that lithologic variations may be approximately quantified from the frequency content of the reflected pulse. The porosity development in thin, tight Arbuckle carbonates of Ordovician age is seen as a local zone of amplitude reduction in the high resolution seismic sections.

The superior imaging capabilities of seismic data acquired with 55 ft bin configuration has significantly improved our capabilities to conduct detailed investigation of structure, stratigraphy and fluid saturation distributions.

AAPG Search and Discovery Article #90937©1998 AAPG Annual Convention and Exhibition, Salt Lake City, Utah