Tectonic stress field and the development of low permeability oil fields.
Zeng, Lianbo; et al. (Petroleum University, Beijing 102200, P. R. China).
Paleo tectonic stress field is the main factor controlling the development and the distribution of the natural fracture systems, while modern tectonic stress field affects the retention of thesefracture systems. The effects of modern tectonic stress field will be: ①The opening of fractures is maximum in the direction parallel to the major stress and their interconnection is best, while the opening will be minimum and the interconnection will be least in the direction nearly perpendicular to the maximum stress; ②The declining in the fluid pressure and the opening of the fractures will be faster (may become closed fracture systems finally) in the direction parallel to the maximum stress under constant confining pressure as development proceeds, while both the opening and fluid pressures in fracture systems in the direction nearly perpendicular to the major stress decrease at a much slower rate (may become major permeable fracture system at a certain development phase); ③Low permeable reservoirs can be classified into 3 types of double porosity, porosity, or purely fractured, their fracture systems play a different role in each type of reservoir; thus modern tectonic stress field plays a different role controlling the distribution of remaining oil in each type of reservoirs stated above; ④In a porosity type reservoir the direction of fracture extension by artificially hydrofracturing depends upon both the minimum formation pressure and the directions of natural fracture systems previously existed. On the basis of studying the distribution of natural fracture systems controlled by paleo tectonic stress field, a study of the distribution of modern tectonic stress field can give a guide to make a development program, management of water injection, design of horizontal wells in the development of a low permeability reservoir effectively and can prevent the casing distortion of production and/or injection wells.
【CateGory Index】： TE348,P553