川西地区上三叠统水化学场、水动力场与油气富集关系研究

CHEMICAL FIELDS,HYDRODYNAMICAL FIELDS AND GAS ENRICHMENT IN THE LATE TRIASSIC OF WESTERN SICHUAN BASIN

为探讨川西地下水对油气富集规律的影响 ,作者对川西上三叠统须二段、须四下段水化学场、水动力场分别进行了系统研究。通过把水化学场、水动力场与沉积环境有机地结合起来 ,作者提出地下水地球化学动力带的概念 ,并进一步把须二段和须四下段地下水系统划分为还原环境溶质迁移聚集的卸压带、溶质迁移聚集的稳压带和强还原环境溶质分异纯化的水压形成带 3个带。文中指出 ,已发现的气田主要分布在稳压带和卸压带内 ,而含气构造主要分布于水压形成带内。最后 ,作者从水文地质的解度对川西地区有利勘探区带进行了预测。

The ingredient and movement features of the groundwater are important for the enrichment of oil and gas in gas bearing basins.The features of the groundwater in the second and forth menbers of the Xujiahe Formation in the Late Triassic of the Western Sichuan Basin was discussed.By integrating chemical fields and dynamical fields of the groundwater and the around geochemical environment,the concept of geochemical dynamical belt of groundwater was proposed,and three belts,i.e.,hydro-pressure forming belt,backwater belt and discharge belt,were indicated in the members of the formation.In the discharge belt and backwater belt,the solute is in the state of transplanting and congregating with deoxidizing environment,and the known gas fields are mainly distributed in the belts.Nevertheless,in the hydro-pressure forming belt,solute diverse and become pure,and most of the gas bearing traps are distrbuted in the belt.Based on above characteristics,the promising exploration belts in the Western Sichuan Basin was pointed out.