Features Of Geological Structure And Potential Prediction Of Oil And Gas In The Taohe Syncline Of Western Qinling

Taohe syncline lies in the central of Western Qinling tectonic belt, and the north of which is Zhong Qinling uplift together with Bailongjiang uplift in its south. The western Qinling tectonic zone locates in the central belt of China. It is an important part of central orogenic belt in China. The North is Qilian tectonic belt, and the south-west for the Songpan-Graze tectonic belt and the south-east is contiguous to motioning structure belt. Western Qinling has always been the focus of attention of Chinese and foreign geologists for its rich mineral resources. This paper is based on the analysis of basic geological structure characteristics about the western Qinling Taohe syncline, and research in the fold belt in the complex syncline structure in search of a favorable oil-gas accumulation area.This article is based on elaborate field investigation and the geological structure profile. And collected all kinds of data widely, and did many analyses of test samples. The paper takes structural geology, petroleum geology as the theoretical guidance and researches the relationship between characteristics of tectonic evolution and the basic conditions of the petroleum geology in Taohe syncline, and makes a favorable exploration area for selection and evaluation.From the Structural characteristics, Taohe syncline is widen duplex syncline structure, which south limb is relative integrity, and from south to north there are Late Paleozoic-Triassic strata. Taohe syncline is mainly controlled by two major faults, that is, the northern part of Minxian-Dangchang fault zone as well as the southern Dieshan-Zhouqu fault. Taohe syncline comes under the two powerful squeezing pressures from the north and the south, and comes under weaker force in Taohe syncline, and forms a relatively stable region of the syncline, which is advantage for preservation of oil and gas.The study area developed passive continental margin in the north of Songpan-Aba depression in the Early Paleozoic, and disposed a shelf slope-carbon basin mudstone, siliceous rocks, clastic rock and limestone. Late Paleozoic to Early Triassic had similar structures-sedimentary environment in the Yangtze region and for a broad carbonate platform, which developed platform-platform margin carbonate rock sedimentary rocks. Middle Triassic-Late Triassic carbonate developed turbidite deposition and terrigenous clastic turbidite deposition.Study area possesses favorable oil and gas exploration foreground , and hydrocarbon source rock and reservoir have well develop, and at wholly look into inside profile become know clearly Triassic mantle. According to stratigraphic analyses, the profile characteristics of geological structures, as well as the situation of sample test, we consider that the main source rocks developed in the early Paleozoic and Precambrian belt of Silurian Period, the reservoir developed in the late Paleozoic belt and made a set of carbonate rocks, and the cover developed in the Triassic. This area is divided into two sets of bottom-up potential reservoir-seal combination. That is the Lower Paleozoic reservoir-seal combination and the Late Paleozoic-Triassic-reser voir-cap portfolio. Ultimately determine the region of favorable target areas.