鄂尔多斯盆地中部气田水化学条件与天然气聚集  

HYDROCHEMICAL CONDITIONS AND NATURAL GAS ACCUMULATION IN THE MIDDLE PART GASFIELD OF THE ORDOS BASIN

作　　者：徐国盛[1] 宋焕荣[1] 周文[1] 

机构地区：[1]成都理工学院"油气藏地质及开发工程"国家重点实验室,四川成都610059

出　　处：《石油实验地质》2000年第4期330-335,共6页Petroleum Geology & Experiment

摘　　要：该文旨在通过现代水文地质特征和形迹的研究 ,判明储层所处的地球化学环境 ,指明储层的含油气性 ,并建立油气判识指标。鄂尔多斯盆地中部气田奥陶系马家沟组地层水具有浓度高、正变质程度深、均为CaCl2 型水的特点 ,表明其进入水文完全交替停止带 ,封闭条件好。它经过了从碳酸盐岩同沉积海水到风化剥蚀期的淋滤水 ,再经埋藏期的高矿化度的浓缩变质水到成藏期的气田伴生水的水化学场演变过程。与海水室内蒸发浓缩曲线相比较 ,马五1 气田水富集Cl- 、Ca2 + ,消耗Na+ 、Mg2 + ,反映完全封闭的还原环境有利于天然气的聚集与保存。文中还讨论了水化学特征参数与天然气富集的关系 ,并建立了马五1 储层利用现今水化学特征判别含气性的指标体系。This paper aims at ascertaining the geoche mical environment of reservoirs, calculating the oil/gas prospects of reservoirs and establishing the identification indexes of hydrocarbon by the research of m odern hydrogeologic characteristics and trackways. The Ordovician Majiagou forma tion water in the middle part gasfield of the Ordos Basin has high concentration and deep orthometamorphic degree, and is all CaCl 2-typed. This indicates th at it enters into the complete hydrologic exchanging-stagnant zone and has good sealing conditions. It experienced the evolutionary process of the hydrochemical field, from carbonate rock synsedimentary sea-water to the leached water in th e weathering and denuding period, and from the condensed metamorphic water with high mineralization degree in the burial period to the gasfield associated water in the pool-forming period. Compared with sea-water in -house evaporating an d condensing curves, M5 1 gasfield water enriches Cl - and Ca 2+ and e xpends Na + and Mg 2+, showing that the completely isolated setting of reduction is favorable to the accumulation and preservation of natural gas. In t his paper, the relationship between hydrochemical characteristic parameters and natural gas accumulation is discussed, and the index system to identify gas pros pects by modern hydrochemical characteristics in M5 1 reservoir is set up.

关 键 词：天然气聚集 水文地质 鄂尔多斯盆地 气田 

分 类 号：P618.130.2[天文地球—矿床学]