Oil & Gas Geology ›› 2005, Vol. 26 ›› Issue (1): 9-15.doi: 10.11743/ogg20050102

Previous Articles     Next Articles

Yanshanian tectonic features in west-central China and their petroleum geological significance

Jia Chengzao1, Wei Guoqi2, Li Benliang 2   

  1. 1. PetroChina Company Limited, Beijing;
    2. Langfang Branch of Petroleum Exploration and Development Research Institute, PetroChina, Langfang, Hebei
  • Received:2004-12-17 Online:2005-02-25 Published:2012-01-16

Abstract:

Yanshanian tectonic movement was very common in west-central China. Firstly, it appears as the unconformity between Cretaceous and Jurassic,and even the Tertiary directly and unconformably contact with Jurassic. Secondly, Yanshanian palaeostructures occur in every basin in west-central China. Thirdly, Lasha and Qiangtang terrains collided along Bangonghu-Nujiang suture zone, leading to the uplift of earth crust, a set of red molasse formation was deposited both in Qiangtang basin and Lasha terrain. As a result, an apparent angular unconformity occurs between Cretaceous and Jurassic. Yanshanian tectonic movement is characterized by the followings:regional tectonic elevation led to the shrinkage of sedimentary basin and relatively weak tectonic deformation; large set of coarse glutenite deposits were commonly developed in the front-edge of orogenic belt; magmatic activity occurred in local area within the orogenic belt. The significances of Yanshanian tectonic movement to hydrocarbon accumulation include:(1) Speed up of the thermal evolution of source rocks made the two major coal measure source rocks, Upper Paleozoic and Upper Triassic-Lower and Middle Jurassic, in west-central China entering the peaks of hydrocarbon generation and expulsion or began to generate hydrocarbons respectively in Late Yanshanian; (2) The timing of Yanshanian palaeostructures and hydrocarbon generation and expulsion of source rocks would be favorable for early accumulation of hydrocarbons; (3) Readjustment of oil and gas by Himalayanian tectonic movement would be favorable for the formation of secondary oil and gas pools in new traps near the Yanshanian fossil oil and gas reservoirs; (4) Yanshanian tectonic elevation led to the development of good reservoirs of coarse clastic rocks deposited in low water level system tract, thus they would be favorable for reservoiring of oil and gas.

Key words: Yanshanian movement, hydrocarbon generation period, reservoir, reservoiring of oil and gas

CLC Number: