Abstract:

The λ-type structure is one of shear-form.The authors,proceeding from astudy of some oil-bearing λ-type structures such as Zhongba,Sichuan,elucidate the characteristics of oil and gas distribution in the λ-type structure,analysethe tectonic stress field of the λ-type structure in connection with photo-elastic experiments,discuss the effects of the stress activity on the migration and accumulation of oil and gas and the inner cause of controls,analyse the fundamental geological conditions for the formation of the oil-bearing λ-typestructure,and approach the controlling effects of the λ-type structure onthe distribution of oil and gas.In this paper an attempt is made to furtherre flect the major features of the control on oil and gas by the shear structure from such an aspect as the λ-type structure.