濮阳凹陷白庙气田沙河街组三段下亚段扇三角洲沉积模拟研究

STUDY ON SEDIMENTARY SIMULATION OF FAN DELTA IN LOWERSUB-MEMBER ES OF BAIMIAO GAS FIELD IN PUYANG DEPRESSION

夏长淮 张春生 周海彬 施斌全 刘忠保 李力

Xia Changhuai Zhang Chunsheng Zhou Haibin Shi Bingquan Liu Zhongbao Li Li

根据白庙地区砂体沉积特征设计的沙三下砂体形成过程模拟实验表明,沙三下扇三角洲主要是碎屑流和牵引流交替作用的结果,洪水期以碎屑流作用为主,平水期以牵引流作用为主,扇三角洲存在叠置与展开两种结合形式,前者厚度大而面积小,后者厚度小而面积大。它的发育和演变主要受上游水流强度、泥砂搬运、水流分汊变迁、湖水位升降及活动底板下降速率等因素的影响。模拟认为,沙三下扇三角洲在形成过程中,在白5井、白3井和白28井之间及白 7井一带主要发育3条主辫状河道,最宽达 750m,最窄为 300m;辫状河道在杜寨断层处,砂岩质纯、厚度大、物性好,在兰聊断层与杜寨断层之间,砂岩厚度大且分布普遍,而在靠近兰聊断层处则砂岩厚度减薄,物性变差。

Simulation of genetic process of sand body in sub-member Es 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 Es 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.

10.11743/ogg20020304