PAN, RENFANG, and MEI Ll
Jianghan Petroleum University, Jiangzhou, Hubei, China

Abstract: Reservoir Characterization Using 3D Seismic Data on Qidong Field, Gulf of Bohai, China

Qidong, an offshore field in the Gulf of Bohai, was discovered in 1995 by two wells. The field contains four intervals in Minghuazheng Formation, depth from 1.3 to 2 km, in which stratigraphic traps developed due to its fluvial depositional system resulting from porous, permeable grainstones pinching out into muddy limestone and shale, and partially divided by west-east normal faults. Hydrocarbon, mainly occurs in the reservoirs along with the faults that cut into deep source structurally southwest to northeast. It is revealed that hydrocarbon occurrence is controlled by the deep source as well as its form is controlled by shallow structure.

Calibrating by core and logging data, seismic petrophysic inverse by DUPOR is applied to determine reservoir porosity and oil saturation, and by ANN algorithm the pay thickness is derived. The reservoirs are named with number 4, 10, 13, and 345. The most upper one is reservoir 4 with porosity 24-34%, oil saturation 50-75%, pay thickness 3-10m. Reservoir 10 is a typically channel sands, bird-foot like, with porosity 25-33%, oil saturation 45-60% pay thickness 2-6m. Reservoir 13 is a distributary-mouth bar met in two wells, with porosity 21-31%, oil saturation 51-95%, pay thickness 2-7m, it is very clear to see an oil/water contact boundary between two wells. Reservoir 345 is an upward pinchout sands with porosity 21-26%, oil saturation 45-61%, pay thickness 2-6m.

AAPG Search and Discovery Article #90928©1999 AAPG Annual Convention, San Antonio, Texas