渤海湾盆地黄骅坳陷二叠系致密砂岩储层特征、主控因素及发育模式

Characteristics, control factors and development models of Permian tight sandstone reservoirs in Huanghua depression, Bohai Bay Basin

为了研究黄骅坳陷二叠系优势储层的形成与分布规律,以实物钻井取心、井壁取心为基础,综合分析钻井、录井、测井、地震等地质资料,对二叠系致密砂岩储层特征、主控因素进行分析,提出印支期古构造控制二叠系优势储层的形成与分布。研究认为黄骅坳陷二叠系岩石以长石砂岩和石英砂岩为主,致密砂岩储层储集空间以次生的粒间溶孔、粒内溶孔、铸模孔及裂缝为主,属于低孔—特低渗透储层。二叠系致密砂岩储层主要发育孔隙型储层及裂缝型储层,其中印支期古构造对两类储层的分布具有决定性影响,歧口凹陷潜山地处印支期古隆起区,古隆起区及其斜坡区溶蚀作用强烈,易于形成孔隙型优势储层;沧东凹陷潜山印支期逆冲推覆构造活动强烈,造成储层裂缝发育,易于形成裂缝型优势储层。

In order to study the formation and distribution of the dominant Permian reservoirs in Huanghua depression,geological data(including drilling,geological logging,well logging and seismic)were investigated based on actual drilled cores and sidewall cores,and the characteristics and controlling factors of the tight Permian reservoirs were analyzed in the study.It is concluded that the formation and distribution of the dominant Permian reservoirs are controlled by Indo-Chinese palaeo-structures;the Permian rocks are mainly arkose and quartz sandstone;and the reservoir space is composed of secondary intergranular and intragranular dissolution pores,moldic pores and fractures.The low-porosity and extra-low-permeability reservoirs can be classified into porous and fractured reservoirs,and their distribution depends on the Indo-Chinese palaeo-structures.The buried hill in the Qikou sag is located in the Indo-Chinese palaeo-uplift area where the palaeo-uplift and its slope have been denuded intensively,so that it is easy to develop porous reservoirs.The buried hill in the Cangdong sag had been influenced by strong Indo-Chinese thrust nappe activities,so that fractures are developed,and it is possible to form fractured reservoirs.