Abstract:

Simulation of genetic process of sand body in sub-member Es³ which is designed on the basis of sedimentation characteristics of the sandbody in Baimiao region indicates that the development of delta in sub-member E s3 fan is the result and caused chiefly by the intersected process of clastic current and traction current. The clastic current played a main rule in the flooding period while the traction current played a chief rule in the period of normal water level year; Two types of combinations(stack and spread)exist in the fan delta, the former with small size but in great thickness, and the later in small thickness but with big size. The development and evolution of sub-member E s3 fan delta is largely effected by several factors of upper reaches current intensity, migration of muddy sand, braiding and migration of water current, uplift and subsidence of lake water level as well as subsidence rate of the mobile bottom bed etc.. It is believed by simulating that the width of three braided channels between Bai No.5,and No.3 and No.28, and No.7 well which mainly developed in the process of the development of the delta in sub-member Es³ fan are 750m at maximum and 300m at minimum; In Duzai fault where purified sandstones are found in the braided channels with great thickness and good physical property, between Lanqing fault and Duzai fault sandstones are with great thickness and widely spread while sandstones near Lanqing fault become thinner and thinner and with poor property.

Key words: fan delta, simulation, develop process, controlling factor, distribution, Baimiao region