卡拉库里区块异常高速层对勘探的影响及解决方案

Influence of abnormal high-speed layer in Kalakuli block on exploration of the block and its solution

卡拉库里区块具有良好的生储盖组合,上侏罗统启莫里-齐顿阶膏盐层是良好的盖层。在该区的油气勘探中发现,膏盐层异常高速对下伏构造形态的精细落实和目的层埋深的精确预测影响很大,使得传统的构造成图方法误差较大。针对卡拉库里区块膏盐岩构造区构造成图的难点,从膏盐层的地质、地震特征对构造成图的影响入手,分析了不同岩层的层速度及其对构造成图的影响,改变以往构造成图的思想,采用平均速度场进行时空转换,再利用钻井计算硬石膏层厚度图和盐岩层厚度图,然后将三者相加进行目的层的时深转化,最后进行校正的方法。实钻效果验证该方法实用可靠,对膏盐岩高速异常层发育的类似区块油气勘探具有借鉴作用。

There are good source- reservoir- caprock associations in Kalakuli block,north-central Amu Darya Basin,The Republic of Uzbekistan,and the gypsum-salt layer in upper Jurassic Qimoli-Qidun Order is good caprock. In the oil and gas exploration of the block,it is found that the abnormal high speed of the gypsum-salt layer has great influence on the accurate determination of underlying structure and the accurate prediction of objective layer depth,and it makes the error of traditional structural mapping method increase.In view of the difficulty in the structural mapping of the gypsum-salt layer in Kalakuli block,the speed of different rock layers and its influence on structural mapping are analyzed based on the influences of the geological and seismic characteristics of the gypsum-salt layer on structural mapping,which changes the traditional structural mapping idea: firstly,the average velocity field is used for time-to-space conversion,and secondly the thickness mappings of anhydrite layer and gypsum layer are made based on drilling data,thirdly the sum of the three is used for the time-to-depth conversion of the objective layer,and finally the time-to-depth conversion result is corrected.Drilling result verifies that the structural mapping method is reliable,which can be provide reference for the oil and gas exploration and development of similar blocks developing abnormal high-speed gypsum-salt layers.