Hydrocarbon Accumulation Law Research In The South Of Chepaizi Aera

Conducted by modern theory of petroleum accumulation, on the base of clearing the source of oil and gas, we applicate the geological,geophysical, geochemical and other technical means to carry out the hydrocarbon accumulation potential. We summarized hydrocarbon accumulation law and forecasted the favorable area.In the south part of Chepaizi area, we discovered Su-1 well light oil reservoirs. There are Chun-23 well and Chun-29 well light oil reservoirs in the neighborhood. Studies have shown that these light oil mainly come from southern Sikeshu depression and Lower Jurassic source rocks Anjihaihe. It is a multi-phase reservoir. It is known that skeleton sand, unconformity and faults constitute a double conduit system Chepaizi region. We applicate the seismic data to extract attributes and predict sand distribution, and combine with logging, logging data to study the transporting performance of sand skeleton. We find that some sand of Shawan and thick sand of Jurassic bottom is developed.They are beneficial to the lateral migration of oil and gas. Relying on logging data, we identify the type and distribution of the unconformity between Shawan and Paleogene(N1s/E), Paleogene and Cretaceous(E/K), Cretaceous and Jurassic(K/J). Use its properties to analyze the lithology changes of the unconformity. Combine impedance section to analysis the conducting properties of the unconformity. The unconformity between Shawan and Paleogene(N1s/E) distributes widely and the range of the conducting effectiveness is large.It provides a good long-distance transport channel. The fault in the regional is less and opens largerly, so it provides a good channel of vertical migration.Some oil and gas provided by he four trees Jurassic source rocks migrates along the inner part of the sand and the bottom of the unconformity of Cretaceous. They gather in the favorable reservoirs of Jurassic.Some transport into the Cretaceous reservoir and aggregate through open faults. The other transport into Shawan along the Duan fracture and Gathere in the Pinch point of sand. The oil and gas provided by the source rocks of Anjihaihe transport into the sand bodies of Shawan and gathere along the bottom unconformity of Shawan and the small faults.The configuration relationship of the sources of the oil and gas and tectonic setting determines the hydrocarbon migration trends, while the reservoir-cap combination determines the type of traps and the possibility of accumulation. The configuration relationship of transporting system and the sources of the oil and gas determines the migration and accumulation of oil and gas. According to the location and characteristics of the reservoir,we establish an accumulation mode of the southern slopes background of Chepaizi. The pinch-out end and the high structural site is the beneficial Tibetan.