Characters Of Structure Controlled Reservoirs And Direction Of Oil-gas Exploration Of Tangyuan Fault Depression In Daqing Peripheral Basins

Tangyuan Fault depression is located in Tangyuan , Luobei and Huachuan County, Hegang City, Heilongjiang Province, which is south to Zhengyang Forest and Lixin Village, north to Baoquanling Farm, west to Helihe Farm and Shijiaochang area, east to the coast of Songhua River. The width from north to south is about 120km, and 5-24km from east to west, generally 18-20km. The total area is about 3320km2. In regional, Tangyuan Fault depression is the northernmost sub-tectonic units of Yishu graben which is north-east spreading. The north of the fault is Hegang basin and the south is Jiamusi basin. Its borders are controlled by two deep faults which extent parallel from north-east. Generally, the fault is dustpan fault depression, fault at east and overlap at west, which is controlled by the big fault at eastern border.In east to west direction, Tangyuan Fault depression is controlled by deep faults that are north-east trend, and can divide into five zones which are the northern strike-slip thrust belt, the eastern depression belt, the central salient belt, western depression belt, and western slop belt. In south to north direction, Tangyuan Fault depression is controlled by north-western faults F1, F2, F3 and F4 which divide the Tangyuan Fault depression into five. By observing the structure, sedimentary characteristics and evolution history of Yishu Graben, according to the characteristics of the faulted filling strata, the basement and the cover, combined with development history analysis of the tectonic and sedimentation, we think that Tangyuan Fault depression experienced the earlier, the developmental and the post fault period. We further divide tectonic evolution into mesozoic fault stage, cenozoic strong fault stage, sustainable fault stage, fault transformation stage, fault atrophy stage and fault extinction stage. Nature and size of tectonic movement in each stage are different.In this paper, drilling and logging data were used to calibrate seismic horizons, build up seismic horizon systems, interpret structure, and find traps. Based on fine structure interpretation, combined with drilling, seismic, borehole, logging, measurement, examination, regional geology data, lateral change of main reservoirs are predicted and reservoir development region is pointed out. According to structure interpretation, lateral prediction of reservoirs, drilling results and hydrocarbon accumulation analysis, we figure out favorable exploration areas. In longitudinal direction, oil&gas in Tangyuan Fault depression mainly distribute in Dalianhe Group, Xinancun Group and Wuyunzu Group. In the plane, hydrocarbon show wells, industrial gas flow wells and industrial gas reservoirs mainly distribute in the central salient belt and the eastern depression belt, which are at the east of central axis of Tangyuan Fault depression, and adjacent to Dongxing and Dongfa sub-depression. The recent exploration target of Tangyuan Fault depression should be lower tertiary in Dongxing sub-depression.