Reservoir Characteristics and Main Controlling Factors of the 1st Sub-Member of the 1st Member in Middle Triassic Leikoupo Formation of the Moxi Gas Field,Central Sichuan Basin
This work attempts to further determine the reservoir spatial characteristics of the 1st sub-member of the 1st member in Middle Triassic Leikoupo Formation(Lei11)of the Moxi gas field in the central Sichuan Basin,and thus to support stable production and potential tapping,and the delineation of favorable target areas.A total of core samples from 65 coring wells,648 lithification analyses from 11 wells,physical property testing of 282 core samples,416 casting thin sections,368 electron microscopy scans,and 82 high-pressure mercury injection data were utilized to explore the reservoir characteristics and control factors in the Lei11 Formation of the Moxi gas field.Results show that the reservoir of Lei11 Formation is developed in dolomite,calcareous dolomite,sandstone dolomite,and dolomite limestone,and the reservoir is mainly distributed in the middle of the upper sub-member of the Lei11,and the bottom and top of the middle sub-member of the Lei11.The diverse reservoir space is dominated by dissolution pores due to dissolution.The reservoir is a porous type with middle porosity and low permeability,and displays coarse pore and fine throat,mesoporous and micro-throat,and microporous micro-throat,with mesoporous micro-throat and microporous micro-throat being dominant.The development of reservoirs is mainly controlled by sedimentation,diagenesis,and tectonic processes.The physical properties of the coarse-grained lithology formed during the sedimentation are better than those of the fine-grained lithology.The cementation effect reduces the porosity formed in the early stage by 5%～95%,and the dissolution effect increases the pore space formed in the early stage by 3%～20%.The higher the degree of dolomitization is,the better the physical properties are.The number of low-angle cracks formed by tectonic activity is dominant,with more unfilled or partially filled cracks than fully filled cracks.Unfilled or partially filled fractures contribute significantly to reservoir development and greatly help to improve reservoir performance.
Lei11 gas reservoirreservoir characteristicsmain controlling factorsMiddle TriassicMoxi gas fieldSichuan Basin
万方数据
维普
