巴楚地区南闸组储集层特征及评价

Reservoir Characteristics Evaluation of Nanzha Formation of Bachu Area in Middle Part of Tarim Basin

二叠系是塔里木盆地塔西南地区勘探热点之一。应用层序地层学理论,划分了巴楚地区二叠系南闸组地层层序;在层序划分基础上,利用岩芯观测、岩石薄片鉴定、扫描电镜、铸体薄片等方法,综合研究分析了南闸组层序储集层特征、影响因素与储集层分布规律,提出了下一步有利勘探地区。结果表明,区内南闸组可划分为1个三级层序,包括低位体系域和海侵体系域,碳酸盐岩主要分布于海侵体系域中;海侵体系域储集层主要岩石类型为颗粒灰岩和白云岩,储集层类型为孔隙型、孔隙-裂缝型和裂缝型,颗粒灰岩是组成储集层的主要储集岩类;影响储集层物性的主要因素为沉积作用与成岩作用以及构造作用;最有利的储集层分布区和勘探地区位于巴楚西部,勘探潜力较大。今后勘探应突破传统的孔隙型油藏的束缚,坚持以寻找多类型油藏特别是孔隙-裂缝型与裂缝油藏为原则。

The Permian is one of the exploration hotspots in southwesthern Tarim Basin.Permian Nanzha Formation carbonate rock sequence of Bachu area in Tarim Basin was divided by using the theory of sequence stratigraphy;on the basis of sequence stratigraphy study,the reservoir characteristics and influential factors of Nanzha Formation carbonate rocks were studied by core,rock thin section,SEM,casting thin section method etc;the favorable reservoirs were evaluated by integrated approach.The results indicate that Nanzha Formation carbonate rocks belong to a third-order sequences,the sequence could be divided into lowstand system tract(LST)and trangressive system tract(TST)from lower to upper layer,and carbonate rocks are mostly situated in trangressive system tract;the main reservoir rock types of trangressive system tract are grainstone and dolomite.The reservoir types are pore,pore-fracture and fracture.The grainstone belongs to favorable reservoirs.The main factors influencing the reservoir ability are sediment,diagenesis and structure.The best reservoirs are located in the westhern Bachu Area in Tarim Basin.The next exploration Prospect in Bachu Area is pore-fracture and fracture reservoirs.