塔河地区深层碳酸盐岩断溶体圈闭类型及特征

Classifications and characteristics of deep carbonate fault-karst trap in Tahe area

塔里木盆地塔河地区深层碳酸盐岩断溶体圈闭作为一种新型的圈闭类型,在油气勘探开发实践中已被业界广泛认可,但尚需细致划分。基于断溶体圈闭的形成条件,根据断裂的级别、构造样式、破碎程度和岩溶强度等控制因素分析,塔河地区奥陶系碳酸盐岩断溶体的圈闭类型可划分为主干断溶带圈闭、分支断溶带圈闭和内幕断溶带圈闭3大类,以及纺锤状圈闭、板状圈闭、"X"或"Y"字形圈闭、"卜"字形圈闭、夹心饼状圈闭、菱格状圈闭和团块状圈闭7个亚类。圈闭的成因机制、发育特征以及相应的生产特征表明:主干断溶带圈闭受深大断裂控制,岩溶作用强,储集空间以溶洞为主,圈闭规模大;分支断溶带圈闭受分支断裂控制,岩溶相对较弱,储集空间以缝-洞为主,圈闭规模较大;内幕断溶带圈闭受内幕断裂控制,岩溶相对较弱,储集空间以裂缝为主,圈闭规模较小。断溶体圈闭的细致划分可进一步丰富深层碳酸盐岩油气圈闭理论,深化塔里木盆地碳酸盐岩岩溶圈闭及其他类型圈闭的研究,为油气圈闭的勘探与开发提供可靠的地质依据。

As a new type of trap, the deep carbonate fault-karst trap in Tahe area of Tarim Basin has been widely recognized by the industry during oil and gas exploration and development, but it needs to be divided in detail. Based on forming conditions of the fault-karst trap, and analyses of control factors such as the grade, structural style, fragmentation, and karstification of faults, the fault-karst trap of the Ordovician carbonate rocks in Tahe area can be divided into 3 major types of the main fault-karst zone trap, the branch fault-karst zone trap and the inner fault-karst zone trap, as well as 7 subclasses of spindle-shaped trap, slab-shaped trap, X or Y-shaped trap, "卜"-shaped trap, sandwich-shaped trap, rhombus-shaped trap and block-shaped trap. The genesis, development and production characteristics of trap indicate that the main fault-karst zone trap is controlled by deep faults with strong karstification, cavity reservoir space and large trap scale, that the branch fault-karst zone trap is controlled by branch faults with relatively weak karstification, fracture-cavity reservoir space and large trap scale, and that the inner fault-karst zone trap is controlled by internal faults with relatively weak karstification, fracture reservoir space and small trap scale. The detailed division of fault-karst trap can further enrich the hydrocarbon trap theory of deep carbonate rocks, deepen the study of carbonate karst trap and other trap types in Tarim Basin, and provide a reliable geological basis for the exploration and development of oil and gas traps.