Abstract:

Fissures are primary types of reservoir space in Shuguang buried hills. The formation, reconstruction and distribution law of reservoir fissures are related to area stress field. Fissure characteristic and its origin analysis indicate that Early-Middle Jurassic and Early Paleogene are the main period for the formation and reconstruction of reservoir fissures in Shuguang buried hills, and the former shows a  counter clockwise compression area stress field in 125°-305°; the latter shows a clockwise extension area stress field in 80°-260°. The results of core fissures statistics and area-stress-field simulation indicate a nice linearity relation between fissure density and strain energy, by which reservoir fissures of different bed set in Shuguang buried hills were predicted. The fissure density chorograms reveal that the fissure density in Archaeozoic migmatitic granite and Proterozoic quartzose sandstone near the area along the wells of S103, S107, S109 and Sg92, slate and dolostone is correspondingly big (more than 196 items per meter and become much more and more towards northeast); so is it in Paleozoic limestone near the area between well S109 and Sg92, and the southwest area of well S103 (the fissure density is more than 200 items per meter). Fissure types include shearing macrofissures and extension microfissures. The macrofissures distribute obviously in the directions of 10°-30°, 50°-85° and 320°-345°among which the 50°-85° is the most upgrowth ones.

Key words: tectonic evolution, stress field, fissure prediction, lower Shuguang buried hill, Liaohe rift