川西新场蓬莱镇组层序地层研究与储层横向预测

STUDY ON SEQUENCE STRATIGRAPHY OF PENGLAIZHEN FORMATION IN XINCHANG,WEST SICHUAN AND RESERVOIR LATERAL PREDICTION

魏力民 柳梅青

Wei Limin Liu Meiqing

通过钻井、测井和地震资料的综合分析,运用基准面旋回为参照格架的高分辨率层序地层分析原理和对比方法,依据地层冲刷现象、滞留物沉积、短期旋回叠加样式、地震反射终止类型及反射特征重大变化等标志,在蓬莱镇组中识别出5个钻井中期基准面旋回以及与之对应的5个地震层序,建立了高分辨率层序地层对比格架。指出蓬莱镇组主体沉积处在中期基准面下降晚期和上升早期的三角洲水下平原及向河口坝过渡的部位,且大都位于层序界面的上、下两侧。利用含气砂体的地震响应特征,对储层进行横向预测,认为长期基准面缓慢上升或下降过程中形成的三角洲沉积体系有利储层发育,使有利储集砂体的时空展布预测精度及小层砂体描述精度大大提高。

Based on drilling,logging and seismic data,principles of high resolution sequence stratigraphy and correlation method using datum cycle as reference framework are used in this paper.Five drilling datum mid-term cycles and five corresponding seismic sequences are recognized and the framework of high resolution sequence stratigraphy correlation is established in Penglaizhen Formation of Upper Jurassic in Xinchang of West Sichuan Depression according to formation denudation phenomena,remained deposits,short-term cycle superimposed pattern,seismic reflection end type and important variation of reflective character.It is pointed out that the main body of Penglaizhen Formation deposited in the position of transititional part from deltaic subwater-plain to river mouth bar during the process of late descending-early rising of the mid-term datum and mostly occurred in both sides of sequence boundary.Seismic response of the gas-bearing sand bodies was used for lateral prediction.Consequently,the accuracy of predicting time-space distribution of the favorable sand bodies and description of smaller sand bodies is significantly increased.

10.11743/ogg20000307