塔河油田岩溶型碳酸盐岩缝洞单元综合评价

Comprehensive evaluation of fracture-cave units in karst carbonates in Tahe Oilfield,Tarim Basin

岩溶型碳酸盐岩缝洞储集空间非常复杂,如何识别和评价相互连通具有一个油藏特征的缝洞单元,是该类油藏基础性储层地质工作的难题。通过岩溶地质分带、不同岩溶带缝洞成因结构和岩溶缝洞充填物成因规律研究,提出了四步法识别缝洞单元的方法,即确定缝洞成因结构及缝洞单元边界、查明缝洞充填物类型和分布、静态分析缝洞充填物和洞缘储集物性、动态分析缝洞单元内井间连通性。这个四步法识别缝洞单元本身就是对其进行的综合评价,然后还要对缝洞单元进行产油潜力等方面的评价。通过对塔河油田主体区若干缝洞单元的应用,取得了重新认识缝洞形成和充填过程、动静态相结合的综合评价结果。

Karstified carbonate is a complicated reservoir rock. Some fracture-cave units are connected and occur as oil reservoirs. Based on the studies of karst zones in the weathered crust of Ordovician carbonates, the genetic construction of fracture-caves and the filling materials in fracture-caves, a four-step method to identify and evaluate the fracture-cave units in karstified Ordovician carbonates in the Tahe Oilfield was pro genetic construction and boundaries of fracture-cave units were defined. Secondly, the distribution of fillings in the caves were identified. Thirdly, the porosity and permeability of posed. Firstly, the genetic types and the fillings in the caves and the carbonates of cave walls were predicted. Finally, the connectivity between wells in the fracture-cave units were dynamically estimated. The four-step identification of fracture-cave units is a comprehensive evaluation. In addition, oil production potential is predicted for the fracture-cave units. This method was applied to several fracture-cave units in the Tahe Oilfield, which resulted in the re-recognition of reservoir rocks with karst fracture-caves and their contents.