阿姆河盆地中部卡洛夫阶—牛津阶储层特征及发育模式

Characteristics and development model of the Callovian-Oxfordian reservoir in the central part of the Amu Darya Basin

阿姆河盆地中部卡洛夫阶—牛津阶是重要的油气富集层。文中在29口典型井的钻测井、薄片鉴定、岩石物性及地震资料分析的基础上,开展了卡洛夫阶—牛津阶滩相储层特征与储层发育主控因素研究。结果表明:1)研究区卡洛夫阶—牛津阶礁滩复合体及生(砂)屑滩微相最有利于储层发育;2)生物骨架孔、生物体腔孔、残余粒间孔、粒间溶孔、粒内溶孔、铸模孔及晶间(溶)孔是主要的储集空间,主要发育孔隙型及裂缝-孔隙型储层,整体为中低孔中低渗特征;3)古地貌、沉积微相、层序界面及成岩作用等因素共同控制了储层的发育与分布,其中隐伏基底隆起直接控制有利沉积相带的发育与展布,礁滩复合体等有利沉积微相的继承性发育是储层发育的重要基础,高频层序界面附近发生的同生期溶蚀作用有助于孔隙型储层的形成,埋藏期构造及成岩改造则控制了优质储层的形成与保持,最终形成裂缝-孔隙型储层及部分缝洞型储层。

The Callovian-Oxfordian reservoir in the central part of the Amu Darya Basin is an important oil and gas enrichment layer.Based on the analysis of 29 typical wells of drilling,logging,thin section,physical properties of rock and seismic data,the research on the characteristics and the main controlling factors for the development of the Callovian-Oxfordian beach reservoir are carried out.The results show that:(1)the Callovian-Oxfordian reef and shoal complex,the bioclastic shoal and the sand-sized grain shoal are the most favorable for reservoir development;(2)biological skeleton pores,biological coelom pores,residual intergranular pores,intergranular dissolved pores,intragranular dissolved pores,mold pore and intergranular(dissolution)pores are the main reservoir spaces,which forming two types of reservoirs dominated by pore and fracture-pores,which mainly characterized by medium-low porosity and medium-low permeability;(3)the development and distribution of reservoirs are mainly controlled by factors such as palaeogeomorphology,sedimentary microfacies,sequence boundaries and diagenesis.Among them,the concealed basement uplift controls the development and distribution of favorable sedimentary facies belts.The inheritance development of favorable sedimentary microfacies such as the reef and shoal complex is an important basis for reservoir development.The contemporaneous dissolution occurred near the high frequency sequence boundary is conducive to the formation of pore-type reservoirs.Burial structure and diagenetic transformation control the formation and maintenance of high-quality reservoirs,which finally formed the fracture-pore type and the partial fracture-cavity type reservoirs.