Research On Regularity Of Hydrocarbon Enrichment In F, Y Oil Layers In Shangjia Oil Field

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 nosing structure and the development and evolution features of faults in Shangjia area, the main active periods and development types of faults in Shangjia area were summarized and the types and distribution regularity of reservoirs were analyzed. By using geochemical indicator, the sources of oil and gas and supply ablity of sourcrock were determined. According to the relation of steric position between reservoir and sourcerock, the driving force of hydrocarbon migration and transporting passage was studied and the migration and accumulation mode of oil and gas in F, Y oil layers in Shangjia area was analyzed. Based on well dissection, the main controlling factor of hydrocarbon accumulation was analyzed.According to homogenization temperature of reservoir fluid inclusion, combining with burial history, thermal history and the history of faults activity, the main accumulation period of oil and gas of F, Y oil layers in Shangjia area was determined. In the light of the main controlling factor and mode of hydrocarbon accumulation, the favorable distribution areas of oil and gas in F, Y oil layers in Shangjia area were optimized. Through the research it was considered that Shangjia nosing structure was a long-term inherited palaeostructure. There are mainly four types of faults: faults that formed in rift period and continued their activities in downwarping period, faults that formed in downwarping period, faults that formed in rift period and continued their activities in downwarping period and structure reverse period, faults that formed in downwarping period and continued their activities in structure reverse period. There are mainly three kinds of reservoir in F, Y oil layers in Shangjia oil field: fault block reservoir, fault screened reservoir and fault-lithological reservoir. The most are fault-lithological reservoir, followed by fault screened reservoir, fault block reservoir the least. Oil and gas on plane is mainly distributed in the tip of Shangjia nosing structure or near it. The distribution relation between oil and water is complex,which is mainly controlled by the connectivity of sand and fault and the continuity of sand distribution, and is characterized as oil above and water below, complex distribution of the bottom of oil, larger difference of oil and water distribution of fault blocks, and no unified oil/water interface in the same block. Oil in F, Y oil layers in Shangjia area is mainly from K1qn1 sourcerocks in Sanzhao depression, secondly from K1qn2+3 sourcrocks. Supply ability of K1qn sourcerocks in Sanzhao depression is better, whose supply amount to Shangjia area is about 1.1×108t. Hydrocarbon accumulation mode of F, Y oil layers in Shangjia area is that oil and gas from K1qn sourcerocks in Sanzhao depression migrated downward into underlying F, Y oil layers through T2～T22 faults under the action of overpressure. Then oil and gas migrated laterally through sand bodies which connected by faults under the action of buoyancy, and accumulated in fault block traps, fault screened traps and fault-lithological traps in Shangjia nosing structure. The accumulation of oil and gas in F, Y oil layers in Shangjia oil field was mainly controlled by three factors: whether the traps being well developed, whether the traps being in the paths of hydrocarbon migration, whether the sand bodies in traps being well developed. The homogenization temperature of fluid inclusion of reservoir samples mainly ranges from 115℃to 120℃. Combining with its burial history, thermal history, history of hydrocarbon generation and expulsion of sourcerock and faults activity, it was considered that the oil and gas in F, Y oil layers in Shangjia area mainly accumulated in the end of K2m deposition period. There are three favorable areas that belong toⅠclass in F, Y oil layers in Shangjia area, whose area is 52.2km2 and resource amount is 1507×104t, and four favorable areas that belong toⅡclass whose area is 13.3km2 and resource amount is 267×104t.