| Ordos Basin is the second largest sedimentary basin in China,which is rich in mineral resources and transporting large amounts of oil and natural gas resources for Changqing oilfield every year.The study area is located in west of Yan Wu,where is the west of Ma Ling,east of Pengyang,south of Huanxian,north of Zhenyuan.Reservoir type concludes anticline reservoir and subtle reservoir,which is one of the main reservoirs in Mesozoic in Erdos basin Jurassic reservoir.However,many problems are encountered in Jurassic reservoir exploration.As the study area in Tianhuan syncline,Late Triassic Indosinian movement,Yanchang Formation suffered erosion,preservation is not complete.Part of Yanchang formation is erosion or more.Geological stratification is not unified and Fuxian formation and Yan 10 formation and Yan 9 formation sedimentary strata distribution changed,because of the Yanwu highland.At the same time,lots of extrusion anticline and fault nose low amplitude structure developed in this area under the background of the extrusion,which characterized by complex structures,resulting in reservoir control factors is not clear.Therefore,it is necessary to strengthen the reservoir forming characteristics and distribution law for the exploration work.This study is guided by modern sedimentary geology and petroleum geology theory,based on the previous research results,integrated the dynamic data of logging and logging,combined macro and micro analysis,using modern testing techniques.This paper analyzes the reservoir forming characteristics of the Yan'an formation in the west of YanWu;analysis of hydrocarbon inclusions and time of hydrocarbon generation,the paper comprehensively analysis hydrocarbon accumulation period and reservoir forming process,draw reservoir forming pattern,through the analysis and synthesis of the reservoir forming process of the two types of reservoirs,we can fully understand the characteristics of reservoir migration and accumulation.Combining sedimentary and tectonic setting,and anatomizing many reservoirs,this paper studies the reservoir forming rules and main controlling factors of reservoirs.Based on the above conclusions,the following conclusions are drawn:(1)The Jurassic crude oil mainly comes from Yanchang Formation of the 7 oil-bearing formations,which has the characteristics of low density,low viscosity,light oil and good quality;(2)The formation water in Yanan formation is mainly NaHCO3 type and Na2SO4 type water.(3)The oil and gas migration channels of Yanan formation in the study area are mainly unconformities,fractures,connected pore sand bodies and faults.(4)Oil and gas began filling in the Middle Jurassic,late Jurassic early Middle Jurassic to late;filling occurred in the late Jurassic to the early Cretaceous.(5)The study area mainly includes two types of reservoirs:Lithologic reservoir and low amplitude structural reservoir,most of low amplitude structural reservoir as the principal thing.The study area mainly includes four types of reservoir forming models:the slope type oil reservoir,the inverted hill type reservoir,the low amplitude structural reservoir and the fault related 'reservoir.(6)The direct control of hydrocarbon source rock distance to the west of Shandong Province is less.The paleo landform plays a key role in the formation of the Yanan formation,in which the low amplitude structure is the most favorable area for oil and gas accumulation.The origin of the paleo highland channel is the main direction of oil and gas accumulation in the reservoir of Yanchang Formation in the west of Jurassic in the western part of the Cambrian in 9.The boundary of low amplitude micro structure control reservoir.The yield of single well is closely related to sedimentary microfacies,and the main distributaries channel in delta plain is the most favorable.facies belt.The fractures in this area play an important role in the vertical migration of oil and gas,which is of great significance to the reservoir. |
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