| Base on source-reservoir-cap rocks, divide low and high tectonic framework, and focus on Alar tectonic zone, discussion the tectonic evolution of the continuous development type depression-uplift area in Western Qaidam Basin. Discussion on geological conditions of hydrocarbon accumulation with characteristics of hydrocarbon source rock, reservoir and cap rock in Western Qaidam Basin. With the distribution characteristics of oil and gas fields have been discovered, to summarize tyle of oil and gas reservoirs. On this basis, to analyze process and distribution of petroleum transportation, migration, enrichment with fault fractures opening and closing in the process of tectonic evolution during each sedimentary period. The main conclusion as follows:(1) According to low and high tectonic framework, present tectonic can be divided into: Qigequan depression-uplift area, Hongliuquan depression-uplift area, Alar depression-uplift area, Youyuangou-Shizigou depression-uplift area, Yingdong-Youshashan depression-uplift area, Kunbei depression-uplift area, Wunan depression-uplift area, Youquanzi-Kaitemilike depression-uplift area, Xianshuiquan depression-uplift area, Xiaoliangshan-Jiandingshan depression-uplift area, Dongping depression-uplift area and Nanyishan depression-uplift area.(2) North of Alar depression-uplift area is Hongliuquan depression-uplift area and Yingdong-Youshashan depression-uplift area. Sorth is Kunbei depression-uplift area. East is Wunan depression-uplift area. West is Altun Mountain and East Kunlun Mountains. Alar depression-uplift area extends NW. Central of this area is relatively high, and low in northern and sorthern. The deepest area is Zhahaquan area.(3) Alar fault has a controlling effect on Alar depression-uplift area.Alar fault can be divided into western, middle and Eastern. Geometric features of Alar fault are different in every section. Continuity of Alar fault activity lead to continuity of depression-uplift area and Alar structural ridge. Alar fault has interactive nappe-uplift kinematic characteristics, and it was activity in each period.(4) In the Alar tectonic belt has been found in five with industrial value of oil and gas fields, Yuexi oil field, Yuejinerhao oil field, Tuezhong- Yuedong oil field, Yuejinsihao oil field and Zhahaquan oil field. Yuexi oil field and Yuejinerhao oil field are anticline oil field. Yuejinsihao oil field is monoclinal structure. These oil fields are located in the hanging wall of the Alar fault, and Yuexi oil field, Yuejinerhao oil field are near the tectonic ridge of Alar depression-uplift area. Tuezhong- Yuedong oil field is located in the hanging wall of the Alar fault, it is nose-like structure. Zhahaquan oil field is located in the eastern Alar tectonic belt, it is saddle structure. These oil fields are located in low position of the structure of Alar depression-uplift area. Yuexi oil field, Yuejinerhao oil field and Yuejinsihao oil field have a close relationship between the imbalance of oil and gas migration along the direction of the Alar fault. Tuezhong- Yuedong oil field and Zhahaquan oil field have a close relation with the ancient depression-uplift area under the background of oil and gas migration. The change of the tectonic pattern has a certain effect on the formation of oil and gas under the background of the ancient tectonic framework. |
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