Tectonic evolution of Chegu 201 buried hill and its relation to oil-gas reservoir forming

Chegu 201 buried hill is a typical fault block buried hill in Jiyang Depression. The deep study of its evolution process has not only importance of understanding oil and gas reservoir forming, but also of recognizing the genesis of fault block buried hill. According to the study of geologic background and formation characteristics, the evolution process of Chegu 201 buried hill is divided into four phases. The first phase is the forming of buried hill rudiment in Paleozic, and it takes on anticline structure during this time. The second phase is the appearance of reverse fault. The reverse fault controls the sedimentation and denudation of formation. The third phase is upthrow fault block forming period. In this time, Jiyang Depression is under the background of extension, but because of the formation of Chengnan Fault and the influence of Chengning Upthrow, the Chegu 201 buried hill is heaved strongly. In late Cenozoic, the buried hill finally forms. This is the last phase. Because Chegu 201 buried hill forms in several phases, each of its four reservoirs has itself independent oil water system. They stratifies vertically and overlaps each other on plane.