渤中34构造古近系受玄武岩控制砂岩储层成岩相展布特征及发育模式

摘要

采用铸体薄片、扫描电镜、电子背散射等手段,结合测井数据、物性资料等对渤海海域黄河口凹陷渤中34构造BZ34-9区古近系储层基本特征、成岩相类型、展布特征及演化等进行了研究,结果表明:沙-二段发育钾长石钠长石化、白云石包壳、长石溶蚀等成岩作用,以三角洲前缘中细砂-白云石包壳-溶孔相为主;东三段发育钾长石钠长石化、石英溶蚀、沸石充填、长石溶蚀等成岩作用,以溶蚀-溶孔相为主,包括三角洲前缘中细砂-沸石、方解石溶蚀-溶孔相和三角洲前缘-长石溶蚀-高岭石充填-溶孔相;东一二段以沸石的充填与溶蚀为主,发育三角洲前缘中细砂-沸石溶蚀-溶孔相.沙一二段—东三段一东一二段玄武岩喷发强度呈弱—无—强过程,与玄武岩相关成岩矿物沸石含量呈低—低—高特征,与玄武岩相关成岩相展布范围呈宽 窄宽的特征.物源方向上玄武岩展布区下游玄武岩水解产生的沸石等矿物对于储层孔隙的保存与次生孔隙的形成具有重要作用,是有利勘探区带;溢流相远端砂岩储层富凝灰质,胶结致密、物性较差.本文研究成果可为渤海海域及其他类似地区的油气勘探提供地质依据.%Combining well logging and physical property data with thin sections,scan electron microscope and back scattering,the basic characteristics,types,distribution and evolution of diagenetic facies of the Palaeogene reservoir in BZ34-9 area of BZ34 structure in Huanghekou depression,the Bohai sea,are analyzed.Results indicate that Es1-2 reservoir develops potassium feldspar albitization,ctenoid dolomite and feldspar dissolution,and the diagenetic facies are mainly delta front medium-fine sand-ctenoid dolomite-dissolved pore;Ed3 develops potassium feldspar albitization,quartz dissolution,zeolite filling and feldspar dissolution,and the diagenetic facies are mainly dissolution-dissolved pore,including delta front medium-fine sandstone-zeolite,carbonate dissolution-dissolved pore and delta front-feldspar dissolution-kaolinite filling-dissolved pore;Ed1-2 mainly develops zeolite filling and dissolution,and the diagenetic facies are mainly delta front medium-fine sandstone-zeolite dissolution-dissolved pore.Basalt eruption strength of Es1-2-Ed3-Ed1-2 is weak-none strong,content of zeolite related to basalt is low-low-high,and distribution range of diagenetic facies related to basalt is wide-narrow-wide.In downstream of distribution area of basalt along provenance direction,zeolite from basalt dissolution has an important effect on preservation of reservoir pore and formation of secondary pore,which is favorable exploration zone.The sandstone distributed distally from effusion facies contains tuffaceous rock,with compact cementation and poor physical property.The research can provide geological basis for oil and gas exploration in the Bohai sea and other similar areas.