Discovery of Yanting-Tongnan Trough of Late Permian in Sichuan Basin and Its Significance

• Published in: Journal of earth science (Wuhan, China) Vol. 23; no. 4; pp. 582 - 596
• Main Author: 李秋芬 汪泽成 李军 江青春 王铜山 殷积峰 谢芬 苗顺德
• Format: Journal Article
• Language: English
• Published: China University of Geosciences China University of Geosciences 01.08.2012; Springer Nature B.V
• Subjects: Basins; Belts; Biogeosciences; Comparative studies; Coral reefs; Earth and Environmental Science; Earth science; Earth Sciences; Exploration; Geochemistry; Geology; Geotechnical Engineering & Applied Earth Sciences; Hydrocarbons; Lithosphere; Natural gas; Oil and gas fields; Permian; Platforms; Reefs; Reservoirs; Sedimentology; Seismic phenomena; 动力学分析; 勘探领域; 发展中国家; 四川盆地; 断裂活动; 晚二叠世; 网页翻译; 西部盆地; China; Sichuan China; Yanting-Tongnan trough; migration of reef-bank body; lithofacies paleogeography; Sichuan basin
• ISSN: 1674-487X; 1867-111X
• DOI: 10.1007/s12583-012-0276-z

ABSTRACT： Reef-bank of Sichuan （四川） basin have been explored along the platform margin belt on both sides of the Kaijiang （开江）-Liangping （梁平） trough for a long time. Correspondingly, a series of major breakthroughs have been obtained and a number of large oil and gas fields have been found. After the breakthroughs of Kaijiang-Liangping trough, how reef-bank exploration will proceed？ Is there another ＂Kaijiang-Liangping trough＂ in Sichuan basin？ Previous research shows that Sichuan basin underwent intracratonic rift and basement fault activities in Late Permian, developing a paleogeography framework of ＂three uplifts and three depressions＂ under the background of the regional large ramp, including Exi （鄂西）-Chengkou （城口） trough, Kaijiang-Liangping trough and Yanting （盐亭）-Tongnan （潼南） trough. Based on sedimentology and tectonics dynamics analysis, data of drillings, outcrops and seismic, Yanting-Tongnan trough has been discovered in central Sichuan basin in our study which distributes from Mianzhu （绵竹）, Jiangyou （江油） in western Sichuan basin through Nan-chong （南充） to Guang＇an （广安）, as long as about 210 km, extending in NW-SE nearly paralleling to Kaijiang-Liangping trough, opening to the sea north-westward, and gradually pinchout to the east platform. Similar to Kaijiang-Liangping trough, another platform margin reef belt distributes along a U-shape belt around Yanting-Tongnan trough, which is expected to become another natural gas accumulation zone after the platform margin around Kaijiang-Liangping trough. The discovery of Yanting-Tongnan trough expands favorable reef exploration area from original 2x 10^4 km2 on both sides of Kaijiang-Liangping trough to more than 6x10^4 km2 in Yanting-lbngnan trough platform margin belt and Kaijiang-Liangping platform margin belt, greatly enlarging the reef exploration field. But com-pared to Kaijiang-Liangping trough, YantingTongnan trough is relatively shallower and smaller, and the scale and quality of reef-bank reservoirs in its margin belt is a little poor relatively. Therefore, much research should be done timely such as comparative study of two troughs, detailed research of formation and evolution of the trough, regularity of reef migration, meticulous depiction of reef-bank reservoir size andDiscovery of Yanting-Tongnan Trough of Late Permian in Sichuan Basin and Its Significancedistribution in order to obtain major breakthroughs around the Yanting-Tongnan trough.