CHARACTERISTICS OF IGNEOUS RESERVOIR AND CONTROLLING FACTORS OF RESERVOIR DEVELOPMENT IN THE PERMIAN OF THE SANTANGHU BASIN
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摘要: 三塘湖盆地二叠系为该区重要的油气勘查目的层段之一,其中火成岩特别是安山岩、玄武者及其过渡类型为主要的储集岩类,火成岩储层的储集空间主要为孔隙和裂缝,次为溶洞.孔隙类型较多,包括气孔、残余气孔、基质晶间孔、溶蚀孔、缝洞充填残余孔等,裂缝主要为构造缝,次为成岩裂缝和风化裂缝.该区火成岩储集空间曾经历过十分复杂的演化过程,主要有9个演化时期.从早至晚依次为原生孔隙形成期(气孔、收缩缝等)→岩浆期后热液矿物充填期→地表和近地表风比淋滤期→埋藏孔隙充填期→Ⅰ期构造裂缝形成期→溶洞发育期→溶洞充填期→Ⅱ期构造裂缝形成期→后期溶蚀充填期.根据储集物性及储集空间类型,可将本区二叠系人成岩储层分为3类,即Ⅰ类储层:岩石孔隙度10%~22%.渗透率大于10×10-3μm2,有的大于100×10-3μm2.属孔缝洞复合型储层及部分的孔缝性储层;Ⅱ类储层:孔隙度大干10%.渗透率为(1~10)×10-3μm2.属孔缝型储层和部分的裂缝型储层;Ⅲ类储层;孔隙度大于10%,渗透率小于1×10-3μm2,属孔隙型储层和部分裂缝型储层.控制本区火成岩储层发育的因素主要为火成岩相、构造破裂作用和溶解作用,另外,油气侵入对储集空间的保存亦十分重要.Abstract: The Permian of the Santanghu basin is one of key exploration systems of the region,in which igneous rocks,especially andesite,basalt and their transition types are main reservoir rock types,The storing space are mainly pores and fractures,and,then caves.The types of pores include air pores,residual air pores,in ter-crystal pores in matrix,dissolution pores and residual pore after cement of fractures and caves,etc.Fractures are mainly structural,and then diageneous and weathering in origin.The reservoir spaces experi enced very complex evolution processes,including nine stages:(1)primary pore(air pores and contraction fractures)development;(2)mineral filling up after igneous stage;(3)dissolution near surface;(4)burial filling up in pores;(5)first stage of structural fracture development;(6)cave development;(7)second stage of structural fracture development;(8)later filling up,and(9)dissolution stage.According to the storing space and petrophysical properties,igneous reservoir can be classified into the following three types:reservoir I,porosity 10%~22 %,permeability larger than 10×1O-3μm2,some up to 100×10-3μm2,belonging to pore-fracture-carve composite reservoir and partly pore-fractured reservoir,reservoir Ⅱ,porosity larger than 10%,permeability(1~10)×10-3μm2,belonging to pore-fractured reservoir and partly fractured reservoir,reservoirⅢ,porosity less than 10%,permeability less than 1×10-3μm2,belonging to pore-type reservoir and partly fractured reservoir.The controlling factors of reservoir development are mainly igneous facies,structure fracturing and dessolution.In addition,hydrocarbon invasion is very impor tant in reservation of storing space.
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[1] 管守锐,赵徽林.岩浆岩及变质岩简明教程.北京:石油大学出版社,1991
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