渤中13-1油田沙一段生屑云岩储层特征及控制因素

Bioclastic Dolomite Reservoir Characteristics and Controlling Factors in S_1 Formation of BZ 13-1 Oilfield in Bohai Bay

针对渤中13-1油田在埋深超过3 900 m的沙一段储层仍发育高孔中渗储层现象,利用有关录井、岩心、薄片、常规物性、全岩资料,分析储层基本特征和古地貌,探讨优质储层形成的控制因素。研究发现,该区沙一段优质储层主要以生屑云岩为主,平均厚度约3 m,具有中高孔、中渗透的特点;储集空间类型主要为生物体腔孔等原生孔隙,其次为粒间溶蚀孔和颗粒溶蚀孔。宏观上,古地貌控制了优质储层的平面分布,古水深控制了优质储层纵向上的厚度。微观上,螺类的含量及碳酸盐胶结物、长石、酸性火山岩岩屑的溶解作用和方解石等胶结物的白云石化作用,是形成优质储层的主要原因。勘探实践表明,生屑云岩是该区油气富集的主要场所。

Reservoir with high porosity and medium permeability is still developed in the reservoir of member 1 of Shahejie formation of BZ13 - 1 oilfield in Bohai Bay which is buffed more than 3900m depth. Based on the basic characteristics of reservoir and palaeogeomorphology analysis, the controlling factors for the formation of high - quality reservoirs are discussed, according to the data of logging, core, thin section, conventional physical properties and bulk composition. Study shows that bioelastie dolomite is the high quality reservoir of member 1 of Shahejie fomlation in the oilfield, with the characteristics of average thickness of about 3m with high porosity and medium permeability. And reservoir space types are mainly biological body cavity hole of primary pore, while intergranular dissolution pore and grain dissolution pore is secondary. Generally speaking, the main controlling factor of the planar distribution of the high quality reservoirs is palaeogeomorphology, and the thickness of the high quality reservoirs vertically is influenced by ancient water depth. On the microscopic level, the content of snails and the dissolution of carbonate cement, feldspar, acidic volcanic rock cuttings, and dolomitization are the main causes of forming high quality reservoirs. Exploration practice shows that bioelastie dolomite reservoir is the main place for oil and gas enrichment