Research On Bedrock Buried-hill Oil Reservoir In Damintun Depression

Based on the study of rock characteristics, core structural fracture parameter characterization, comprehensive interpretation of fracture repose on strata dip, imaging and other logging data, core description, seismic coherent body analysis and seismic attribution analysis, the lithology of Biantai bedrock buried hill, fracture characteristics and distribution, and the reservoir physical property in Damintun Depression was researched. The factors that caused poor effect in North Block development and South Block water flooding was discussed.The rock in Biantai bedrock buried hill mainly are migmatitic granite, biotitegneiss and other metamorphic rock. Through the rock restoring, the original metamorphic rocks are mainly a set of sand-mud sedimentary rock with bedded formation. The analysis of microscopic characteristics of buried hill fracture showed that there are many micro-fractures in the block. With lower development degree and poor reservoir physical property; single well lithology and fracture characteristics were difficult to identify and analyze. The spatial distribution of buried-hill lithology were combined to establish the buried-hill lithology distribution model in different depth. Metamorphic reservoir fractures in Biantai buried hill were predicted, it's showed that the development of fractures in the south of the buried hill is superior to the north, the fractures near the top of the buried hill and fault zones are well developed. The bad performance in the north of buried hill due to the low level of fracture development, a large number of micro-fractures and poor physical property. Because the reservoir at the bottom part of the south block has layered characteristics, barrier affect flood effectiveness. Based on the research of the reservoir, fishbone horizontal wells were designed to enhance the rate of encountering micro-fractures, increase the drainable area, improve individual well production, and the effect is obvious in the exploitation of trouble reserve in the north of buried hill. According to layered reservoir characteristics, the separate injection technique of input wells in the same formation was proposed, the preliminary effect is good.