摘要
探讨了塔河油田奥陶系碳酸盐岩油藏三重介质储渗系统的识别、划分和与之相对应的水驱油机理,具有高孔低渗特征的岩块系统主要靠自吸排油方式水驱油,在驱替压力和重力作用下,高孔高渗特征的洞穴系统水驱油近乎均匀推进,低孔高渗特征的裂缝系统水驱油易发生指进和突进.
A new concept of triple medium permeable-storage system for Ordovician carbonates in Tahe oil field is presented, and the criteria is defined differentiating cave system, fracture system and rock block system. Rock block system is described by analysis of physical properties of core and core plug. Cave system is easily recognized but difficultly described. Various indicators include drilling bleak and karst breccias, subsurface fluvial deposition and large calcite crystals, abnormal widening of drilling radius, drastically low in density and resistivity. The fracture system is often characterized by invisible drilling bleak, a decline in drilling speed as well as lower core recovery, fractures in cores etc. The lower density and resistivity with positive amplitude contrast as well as higher sonic logging also respond well to fracture system. Water-driving mechanism of oil under triple medium conditions is also studied. The results indicate that water-driving process of cave system with higher porosity and higher permeability is completed under driving pressure and gravitational drainage, and that of fracture system with lower porosity and higher permeability includes crossflow from fracture system to cave system and flow within fracture system, and that of rock block system with high porosity and low permeability include absorption-type drainage under capillary pressure and additional pressure gradient.
出处
《新疆地质》
CAS
CSCD
2002年第1期80-82,共3页
Xinjiang Geology
