塔中北斜坡奥陶系鹰山组三、四段碳酸盐岩优质储层形成机制及分布规律

Formation mechanism and distribution of carbonate reservoirs in the 3rd-4th members of Ordovician Yingshan Formation on the northern slope of Tazhong Uplift

奥陶系深层(鹰山组三、四段-蓬莱坝组)碳酸盐岩是塔里木台盆区重要勘探领域之一。2018年,塔中北斜坡G70井在奥陶系鹰四段测试获高产工业气流,塔中北斜坡奥陶系深层展示出广阔的勘探潜力。但目前对制约奥陶系深层勘探选区和目标优选的关键问题--深层优质储层特征尚不清楚,成储机制与储层分布也不明确。采用塔中北斜坡单井录井、测井、试油试井动态资料,综合利用地震资料开展塔中北斜坡鹰山组三、四段储层主控因素与优质储层分布。研究发现塔中北斜坡鹰山组三、四段岩石类型多样,包括石灰岩类、云灰过渡岩类、白云岩类,储集空间类型为洞穴、孔洞、裂缝,洞穴型、裂缝-孔洞型储层是研究区主要的储集类型;溶蚀组构选择性、岩溶地貌和走滑断裂作用共同控制了优质储层分布,并据此建立了层间岩溶叠加走滑断裂控储模式。依据优质储层地震反射特征,指出研究区鹰山组三、四段最有利储层发育区主要集中在塔中10号带以北岩溶斜坡叠加走滑断裂羽状破碎带发育区,为下步勘探优选区带。

The deep layer carbonate rock of Ordovician(the 3rd-4th members of Yingshan Formation and Penglai⁃ba Formation)is one of the important exploration fields in Tarim Basin.In 2018,Well G70 in the north slope of Tazhong obtained high-yield industrial gas flow in the test of the fourth member of Yingshan Formation of Low⁃er Ordovician,and the deep layer of Ordovician in the northern slope of Tazhong Uplift showed broad explora⁃tion potential.The key problem restricting the selection and target optimization of the deep exploration of Ordo⁃vician System is the poor knowledge about the reservoir characteristics,forming mechanism and reservoir distri⁃bution.Based on the analysis of single well logging,well logging,well testing and well testing dynamic data and comprehensive utilization of seismic data,the main controlling factors and high-quality reservoir distribution of the 3rd and 4th members of Yingshan Formation of Tazhong Uplift are developed in this paper.It is found that there are various types of rocks in the 3rd and 4th members of Yingshan Formation on the northern slope of the Tazhong Uplift,including limestone,dolomite transition rock and dolostone.The reservoir space type is cave,vug-pore and fracture.Cave type and fracture type reservoirs are the main reservoir types in the study area.The dissolution fabric selectivity,karst landform and feather strike slip fault control the high-quality reservoir compo⁃nents.In addition,the reservoir control model of interlayer karst superimposition strike slip fault is established.According to the seismic reflection characteristics of high-quality reservoir,it is pointed out that the most favor⁃able reservoir development area of the third and fourth members of Yingshan Formation in the study area is mainly concentrated in the development area of pinnate fracture zone of karst slope superimposed strike slip fault in the north of Tazhong No.10 belt,which is the next exploration preferred area.