Research On Regularity Of Hydrocarbon Accumulation Of F, Y Oil Layers In Chang 10 Block Of Songliao Basin

By taking full advantage of available data of research area, recovring the palaeostructure on the top surface of F, Y oil layers, studing the evolution history of Bohe tai nosing structure and the development and evolution features of faults in Chaoyang gou terrace, the main active periods and development types of faults in chang 10 block of Songliao basin were summarized. By using existing drilling and seismic data, studying sediment types and distributing feature of sandstone and the types and distribution regularity of reservoirs were analyzed. Determining the sources of oil and gas, and supply ablity of sourcrock was calculateed. Studying hydrocarbon migration mechanism, hydrocarbon accumulation pattern of F,Y oil layers in chang 10 block of Songliao basin.Based on well dissection,the main controlling factor and the main period of hydrocarbon accumulation were analyzed. Finally the favorable distribution areas of oil and gas were optimized.Through the research it was considered that Bohe tai nosing structure in Chaoyang gou terrace was a long-term inherited palaeostructure, and the F, Y oil layers of this structure were mainly the downwarping period faults. There are mainly four kinds of reservoirs in F,Y oil layers of Songliao basin: fault-lithological reservoirs, fault screened reservoirs, fault block reservoirs and lithological reservoirs. The most are fault-lithological reservoirs and fault block reservoirs .In profile, oil of F,Y oil layers in chang 10 block mainly located in the FI oil layers group,few located in the FII oil layers group, the oil layers varied less from low structure position to high structure position, the distribution relation is firstly characterized as oil above and water below; secondly characterized as water above, oil middle and water below; thirdly characterized as water above, gas and oil middle and water below. In the plane, the oil mainly located in constructure slope, few located in high structure position; The oil mainly located in fault-condensed belts; The distribution relation of oil above and water below mainly located in the north of fault-condensed belts, the distribution relation of water above, oil middle and water below; water above, gas and oil middle and water below in the south of fault-condensed belts.Oil of F,Y oil layers in chang 10 block is mainly from K1qn1 sourcerocks in Sanzhao depression, and their hydrocarbon generation ability are better, whose overall hydrocarbon generation amount are about 171.19×108t .Hydrocarbon accumulation mode of F,Y oil layers in chang 10 block is that oil and gas from K1qn sourcerocks in Sanzhao depression migrated downward into underlying F,Y oil layers through source faults under the action of overpressure. Then oil and gas migrated laterally through sand bodies which connected by fault-condensed belt under the action of buoyancy,and accumulated in fault-lithological traps, fault block traps,fault screened traps and lithological traps of high structure position.The accumulation of oil and gas in F,Y oil layers of chang 10 block were mainly controlled by four factors: regional structure pattern, fault-condensed belts, transporting pathways that formed by faults combing with sand bodies and high fault blocks. Combining with history of hydrocarbon generation and expulsion of K1qn1 sourcerock,faults activity and traps conformation,it was considered that the main period of hydrocarbon accumulation of F,Y oil layers in chang 10 block mainly accumulated in the end of K2m deposition period.The traped target area which are superimposed by favorable channel sand body has eight place in chang 10 block of research area,but the oil sources are limited, the southern target areaⅥ,Ⅵ,Ⅵstill have greater risk.