川东石炭系碳酸盐岩储层孔隙演化中的古岩溶和埋藏溶解作用

PALAEOKARST AND BURIAL CORRASION IN POROUS EVOLUTION OF CARBONATE ROCK RESERVOIRS OF CARBONIFEROUS IN EAST SICHUAN

川东石炭系天然气储层孔隙成因与古岩溶和埋藏溶解作用关系密切。海西期古岩溶斜坡带和古岩溶高地是岩溶空隙发育的有利区。岩溶空隙系统虽然在形成后又被充填，但为埋藏溶解孔隙的发育提供了条件。石炭系储层中的埋藏溶解孔隙是天然气的主要储集空间，其形成过程与志留系烃源岩的成熟过程及烃类在储层中的演化、运聚等有关。石炭系印支期的古构造高部位是埋藏溶解孔发育的有利地区。石炭系的沉积相、白云石化作用和去云化作用、晚期方解石的充填作用等对储层孔隙的发育也有程度不同的影响。古—今构造复合圈闭和不整合一构造复合圈闭与石炭系天然气储层的形成过程有关。

he pore genesis of Carboniferous gas reservoirs in East Sichuan is closely related to palaeokarst and burial corrasion.Hercynian palaeokarst slope and palaeokarst upland are favourable to the development of karst pores.Although karst pore system was packed again after forming,it provides conditions for the development of burial corrasion pores. The burial corrasion pores of Carboniferous reservoirs are the main storage and accumulation spaces of which formation are relative to the muturation of Silurian source rock,hydrocarbon evloution,migration and accumulation.The palaeostructure high part of Carboniferous in Indosinian epoch is favourable to the development of burial corrasion pores.Carboniferous sedimentary facies,dolomitizatiom,dedolomitization,paulopost calcite packing etc.have influences on the development of reservoir pores in different degree.Palaeo-present structure combination trap and unconformity-structure combination trap arerelative to the formation of Carbonlferous gas reservoirs