新疆西克尔地区下奥陶统鹰山组岩溶分带性研究

The Study of Karst Zonation in Yingshan Formation of Lower Ordovician in Xikeer,Xinjiang

塔里木盆地岩溶缝洞型储层作为重要的油气储层备受关注,而目前预测此类型储层的方法较有限。在新疆伽什县西克尔野外露头区地表岩溶现象丰富,志留系地层以填平补齐的方式充填在一系列的溶沟和溶槽中,部分洼地中还有志留系地层残留,表明该区发育加里东中期岩溶。在本区岩溶古地貌的基础上,基于排泄基准面的分析,划分出3级岩溶台面并对应发育3期岩溶。据现代地貌学和岩溶学理论,按照水动力条件的不同并结合本区岩溶发育特征,运用岩溶旋回的观点将第二期岩溶剖面分为表层岩溶带、垂直渗滤带和水平潜流带,认识到西克尔地区古岩溶地下水发育规律及洞穴发育程度。构造运动是垂向岩溶分带性的主控因素;因此,在大的构造背景的前提下,可以有效地预测巴楚地区的缝洞型储层。

Recently,people pay more and more attention to karst fractured/caverned reservoir that has been thought as an important oil and gas reservoir in Tarim basin,but the means to predict this kind of reservoir are limited at present.The epi-karst is rich in Xikeer outcrop in Jiashi County,Xinjiang.A series of lapis were filled with Silurian by filling and levelling up,and some Silurian formation still remained in part of karst depression.All these characters express that this area develop karst of Middle Caledonian.In the light of modern geomorphology and karst theory and according to different hydrodynamic conditions,we can divide the second period karst profile into epi-karst zone,vertically filtering zone and horizontally potential flow zone.Developmental law of palaeo-karst-subterranean river and developmental extent of cavern in this area are identified.Owing to the master control element of tectonic movement to vertical karst zonation,effectively fractured/caverned reservoir in Bachu area can be predicted on condition of the tectonic background.