Research Of Sedimentary Facies Of Member1of Shuangyang Formation In The Moliqing Area

Moliqing Depressions second-order tectonic unit of Yitong Basin with a total area of290km2,is located in the southernmost end of Yitong Basin,including block52,block47and Yi6well area. Yitong Garben, which is in the central of Jilin province, throughout Changchun and Jilin,is situated in southern Yilan-Yitong basin,close to the western Song Liao Basin.Its formation is influenced by Yilan-Yitong deep fracture tectonic activities,which is the eastern China Tancheng-Lujiang deep fault to the northeast extension. It formed on the base of Yanshan stage early Tertiary Strike-slip Fault Basins,the vertical length is around160km,the lateral range is of10-20km and the whole basin covering an ares of about2400km.Moliqing Basin is rich in oil and gas resources and it has huge exploration potential.But over the years, the exploration and development mainly concentrated in Member2of Shuangyang Formation,research on Member1of Shuangyang Formation is relatively low.lt cannot satisfy the demand of the reservoir and reservoir research.By analyzing cores,utilizing the well logging data,the oil logging data and the seismic data, established Member1of Shuangyang Formation isochronous stratigraphic framework over the study area and realize the geological system layer of Member1of Shuangyang Formation. On the basis of the combination of single well sedimentary facies, well profile and plane distribution of sand body, Member1of Shuangyang Formation sedimentary facies types and characteristics, plane phase distribution and evolution laws of different geological period are studied. And its aim is to provide geological basis for the study of favorable hydrocarbon accumulation and distribution of reservoir rule.Through collecting,collating and analysing the previous research and analysing the present seismic,drilling and logging data,we can summarize that Moliqing Fault Depression is a slip-extensional basin controlled by the northwestern fault.The basin has a complex evolutionary history,including initial rift stage, stable settlement stage, differential settlement stage,tectonic inversion phases,atrophy and loss phase.The strata can be divided from the bottom upwards into Member1of Shuangyang Formation,Member2of Shuangyang Formation,Member3of Shuangyang Formation,Member1of Sheling Formation,Member2of Sheling Formation,Member1of Yongji Formation,Member2of Yongji Formation,Member3of Yongji Formation,Member4of Yongji Formation of early Tertiary Eocene and Member1of Wang chang Formation,Member2of Wang chang Formation,Member3of Wang chang Formation,Member1of Qijia Formation,Member2of Qijia Formation of Oligocene and Chaluhe Formation of late Tertiary.Southwest,southeastern,and northeastern of the study area mainly developed secondary fracture in fault depression.The fault properties are mainly extension and tenso shear true faults,the aligement of which are nainly northeast and northwest.However,the northwest of the study area developed basin controlling faults.This paper identifies the top and bottom boundary interface of Member1of Shuangyang Formation by using logging,seismic,logging data.And member1of Shuangyang Formation can be divided into I sand group and II Sand group. II Sand group will be further subdivided into E2S1II-1sublayer’s ill-2sublayer,E2SiII-3sublayer.On the basis of core observation,combining the single well-phase,cross-sectional phase,sandstone distribution,the distribution of sand than flat studies in this area for some two-sedimentary facies types and characteristics were analyzed,summarized the sedimentary facies patterns and spatial evolution of the area.Development of the region’s total fan delta,Sublacustrine fan and lake three kinds of fan facies types,and further identified eight kinds of facies,16kinds of micro-phase.Fan delta system which mainly developed in the work area southwest,southeast of moderate terrain area,the outer edge of the basin eroded and supply provenance,plus traction and terrain slope flow together, forming a near-source rapid accumulation of fan-delta system. Sedimentary system mainly along the northwest border rift work area with steep distribution,high-angle faults resulting in steep dense development along the deep basement,ample supply and transport provenance slope and a short distance from the larger fan for a wide range of developmental lake provided the necessary conditions.In addition,in the southwest side of the basin and the southeast portion of the shaft,there turbidite fan delta front collapse due to the formation and turbidites southeast and northwest body often form handling foreign provenance lake fan overlapping each other to form a composite fan body.Lacustrine depositional system developed in other regions.Comprehensive Moliqing double faulted sedimentary layers or some of the small group of sand facies distribution,during the deposition of two-period,the lake level rose gradually deepening water,fan lanes shrinking trend.E2Si II group of three small layer of sand,sand as a whole showed a decreasing trend. To sand when E2S1I sedimentary basins have been more open,the lake level is high,only partially developed fan deposition,the other at the lake are shallow,semi-deep lacustrine sediments,forming a large set of relatively pure dark mudstone. According to the statistical analysis of testing data from oil and gas,the correlation between sedimentary facies and oil and gas are discussed. An delta is the phase region where most oil and gas are found at present in the work area, and the wells with high yield of oil and gas are mainly distributed in fan delta-front facies in the basin.The Outside fan of sublacustrine fan, fan delta plain and frontal fan delta facies may not be favorable zones for oil and gas gathering.The sublacustrine fan braided channel and fan delta-front underwater distributary channel have higher capacity of oil and gas and more oil and gas shows. River mouth bar and sheet sand microfacies of fan delta front have relatively low production capacity of oil and gas and less oil and gas shows than those of sublacustrine fan channel and fan delta underwater distributary channel.In addition,lateral margin of sublacustrine fan channel and sand of coastal shallow lake also have less oil and gas shows.