Study On Reservoir Characteristics And Water Flow Dominant Channel Of The Lower Karamay Formation Reservoir In T Wellblock Of Baijiantan Area

In this paper,the Lower Karamay Formation of the Triassic in T wellblock of Baijiantan area in the northwestern margin of the Junggar Basin is studied.Based on the core characteristics,well logging and related analytical data,the reservoir characteristics and water flow dominant channels in this area are studied.The lower Karamay group developed two sets of mudstone marking layers,R5 and R6,which were divided into two sand layers:S₆ and S₇.Among them,S₇ is divided into 9 small layer units such as S₇^4-2,S₇^4-1,S₇^3-3,S₇^3-2,S₇^3-1,S₇^2-3,S₇^2-2,S₇^2-1,and S₇¹;S₆is divided into 3small layer units such as S₆³,S₆² and S₆¹.The sedimentary facies mainly include the sedimentation of gravel bodies(S₇^4-2,S₇^4-1,S₇^3-3)and the deposition of turbulent channels in the fan(S₇^3-2,S₇^3-1,S₇^2-3,S₇^2-2,S₇^2-1),fan-edge runoff sedimentation(S₇¹,S₆³,S₆²,S₆¹).The compositional maturity and structural maturity of the Lower Karamay Formation are poor.From bottom to top,the lithology transitions from conglomerate and glutenite to coarse sandstone and medium-fine sandstone,and the overall performance is upwardly tapered.The S₇⁴ layer mainly develops conglomerate reservoirs,the S₇³ layer develops glutenite reservoirs,the upper S₇³ layer and the S₇² layer develop pebbled sandstone reservoirs,and the S₇¹ layer develops medium-fine sandstone reservoirs.There are significant differences in the pore structure characteristics of reservoirs in different small layers.The pore throat types are diverse and unevenly distributed.The primary pores and secondary pores coexist.The throat types are neck-shaped throat,sheet throat and curved throat.Mainly.The permeability of the reservoir is positively correlated with the maximum pore throat radius,the average pore throat radius,the pore throat median radius and the average throat radius.The reservoirs in the study area are classified into I,II,III according to the K-means reservoir classification.IV four types of reservoirs.The main controlling factors of the dominant flow channel include the sedimentary facies belt,the physical properties of the reservoir,the heterogeneity of the reservoir the volume of the injection and production of the well group and artificial fracturing fracture.Through the comprehensive identification of geological identification,coring analysis and well logging water layer interpretation and identification,production and absorption profile analysis,typical well group dynamic analysis and Rdos grid numerical simulation,the main types of water flow dominant channel in the study area are determined as hole seam type,high permeability strip type and dominant phase belt type.The dominant channel of water flow is mainly distributed in the high structure.The thicker the glutenite is,the easier it is to develop high-permeability channels,which are easy to be distributed in the middle to high porosity and middle to high permeability zones.The wells with high connectivity of sand-conglomerate and the corresponding rate of injection-production are easy to form water flow.Advantage channel.The dominant channel of the dominant sedimentary facies type is located in the sedimentary facies belts such as braided channels and schist gravel bodies.Through the blocking and adjustment of the dominant channel of the water flow in the reservoir,it will have a certain effect on the oilfield production increase,and at the same time adjust the water blocking measures and the injection and production flow lines accordingly.