Study On Main Controlling Factors And Reservoir Enrichment Regularity Of Chang 2 Reservoir In Jiyuan Oilfield

Jiyuan oilfield is located in the midwest of the northern Ordos Basin in northern Shanxi,located in Dingbian County,Shanxi Province,Ningxia Yanchi County.It is a combination of multiple oil reservoirs enrichment area which obtained the industrial oil flow at Yan 9,Chang 2,Chang 4+5.From the exploration and development history,Chang 2 reservoir is the main reservoir of the area.It has the characteristics of large resource potential,many oil wells and single well production.But with the scale of production and construction has been expanding,has basically completed the rolling around the oil point built,because the reservoir is small in scale,in follow-up exploration appraisal wells of a new discovery,also need to use deep development wells in Chang 2 oil,combined with logging information,discovery and screening of new Chang 2 favorable target area.In this paper,based on previous research results,according to the main tasks and problems of the area,on the basis of the stratigraphic contrast,starting from the structure,stratum thickness,sandstone,sedimentary facies and reservoir in the study area,sedimentary facies,reservoir,controlling factors of hydrocarbon accumulation and enrichment regularity of oil reservoirs in systematically.The main factors controlling the reservoir Chang 2 enrichment,provide the basis for further optimization of the target prediction.The research shows that the Chang 2 belongs to the delta plain distributary channel sedimentary environment,The lithology is mainly composed of gray,grayish green,medium grained feldspar sandstone and lithic feldspathic sandstone,and the sandstone has low mineral maturity and better structural maturity.Because of the difference of sedimentary microfacies and diagenesis,the Chang 2 reservoir has strong macroscopic heterogeneity.The sand bodies on the plane are northeast-southwest.The study of Chang 2 oil and gas accumulation regularity shows that the Chang 2 reservoir is mainly tectonic-lithologic reservoir,and the reservoir is located in the most developed part of distributary channel sand body and is distributed along the low-amplitude nasal uplift along the west.The plane has the characteristics of small distribution area and poor continuity of the oil sand body,but the overlapping of the multi-stage channel sand bodies in the local area of the area leads to the overlapping distribution of the reservoir.Sedimentary facies and tectonics have common control characteristics for oil and gas.According to the classification and evaluation criteria of Chang 2 reservoir,there are five ?type favorable construction regions,six ? type favorable construction regions and twelve ? type favorable construction regions.