哈萨克斯坦North Nuraly油田侏罗系多尚组储层特征及有利储层预测研究

哈萨克斯坦North Nuraly油田侏罗系多尚组发育一套扇三角洲沉积,为典型的低孔低渗储层。通过扫描电镜、岩石薄片、压汞、X衍射分析等资料首次对研究区储层的岩矿特征、物性以及孔隙结构特征进行了详细研究。研究表明该区储层主要岩石类型为砂砾岩、砂岩、细砂岩,岩石成分成熟度中等、结构成熟度较低;黏土矿物含量高,主要为高岭石和伊利石,对储层伤害较大;其孔隙类型主要为剩余粒间孔,其次为无效的粒内溶孔。进一步研究储层压汞参数和物性特征发现该区储层可细分为Ⅰ、Ⅱ、Ⅲ类,沉积微相控制了其有利储层的展布。通过储层特征及沉积微相之间的关系,预测其有利储层分布范围。结果表明优质储层都集中在水下分流河道、河口砂坝等沉积微相中、较差的储层都集中在远砂坝及碎屑流、浊流砂体中。同时通过最新试油成果,验证了该区有利储层预测的可靠性和可行性,为该地区低孔低渗储层勘探开发提供了扎实的地质理论基础。

Fig.5 Typical types of capillary pressure curves in DOSHAN FormationFig.6 Relationship between the Sedimentary micro-fades Testing distribution of DOSHAN formation

DOSHAN formation of North Nuraly Oilfield in Middle Jurassic of Turgay Basin developed a set of fan delta deposition, which deposited a typical lower porosity and peaneability reservoir. Based On the analysis of scanning electron microscope ,thin section ,X-ray diffraction, lahora- tory analysis and other comprehensive materials,the characteristics of reservoirs,Property and mode of pore evolution of this section were studied in detail. Observation from reservoirs studies indicate that the main type of sandstone were rudite , arenite, fine sandstone, which has a medium compositional maturity , lower texture maturity, and also the clay mineral contents of kaolinite and illite that destructed the reservoirs. The result shows that this section mainly include residual inter-granular pores and than is the inter-granular dissolution pores. Three kinds of reservoirs are identified by the mercury penetration parameters and physical properties of the reservoirs, whose distribution is controlled by sendimentary mirofacies. By analysising the sedimentary microfacies and reservoirs, we know that, reservoirs are subdivided into three categories, high quality reservoirs are concentrated in distributary channels and river mouth bars, poor reservoirs are in far sand dam , debris flow and turbudite dand body. Through the latest oil test result, the reliability and feasibility of the favorable reservoir prediction in this section are verified, which also provides a solid geological theoretical foundation for exploration and development of the area with low porosity and permeability reservoir.