致密砂泥岩地层中裂隙性气藏的预测

PREDICTION OF GAS RESERVOIR FROM FRACTURED ZONES IN COMPACT SAND-MUDSTONE FORMATION

四川盆地的致密砂泥岩地层中,天然气的运移、储集与裂隙的发育程度密切相关。在局部构造上,储集层和含气的富集程度往往在横、纵向上会有变化。为了提高钻井的成功率,我们开展了地震地层学研究工作,划出了有利的相带和构造层位;并利用地震波的特征圈出油、气向上运移的通道及可能的裂隙发育带,以利于次生气藏的开发。 本文以地震资料的速度参数为基础,尽量利用其它可用的参数和波的特征,分析了凹陷东坡的一个局部构造。根据构造上第一口深钻井的气显示和地震资料的综合分析,进行了构造含气远景、特征及层位的宏观预测。应当指出,这种预测是建立在中间成果资料不断补充的动态过程之中,在推论中存在不够完善和不够严格的地方。本文的主要目的是强调普查勘探过程中,把地震成果和油、气直接挂钩,及时反馈信息,以便抓住战机,这应是当前地震勘探工作提倡和努力的方向。

It is thought to be the case that the migration, accumulation of natural gas must be closely related to the development of fracture in the compact sand-mudstone formation of some depression in Sichuan basin. In local structure, there always tends to be a transversal and longitudinal variations between reservoir beds and enriched gas-bearing zones. For the sole purpose of increasing the probability of hitting in drilling, research of seismic stratigraphy is conducted. The facies zone and tectonic level of interest are marked off. The channel for hydrocarbon migrating upward and potential well-developed fractured zone are delineated using the characteristics of seismic wave so that it may help exploit the oil/gas reservoir. This paper is based on the velocity parameters of seismic data and is trying to make full use of those available parameters and characteristics of wave, which come from other than seismic information so as to be able to make an analysis of the local structure at eastern slope of the depression. On the basis of gas indication from the 1st deep well and comprehensive analysis of seismic data, a macro-prediction with respect to the gas-bearing prospect, its characteristics and horizon is made. However, it should be pointed out that such a prediction is built up on the information subject to substantiation, so possibly there might be some inferences imperfectly interpreted or not rigorously approached in some areas. The major purpose of writing this paper is to lay stress on the fact that while conducting the reconnaissance survey, its result turned out ought to be always aimed at oil/gas discovery attempts and prompt feedback about the information in this regard should be energetically encouraged so that we'll be able to seize every possible opportunity. These are something we strongly recommend and also it is what we are striving for in terms of the objective of current seismic prospecting.