高速砾岩下伏构造目标落实技术与应用

Application and technology of determining structural targets under high-velocity conglomerate

在我国含油气盆地的边缘地带,冲积扇体内部高速砾岩的存在,严重制约着下伏构造目标的落实精度,增大了油气勘探的风险.充分考虑砾岩的分布特征,选取合理的速度建场方法,准确落实下伏构造目标,是解决这一问题的基本途径.本文系统建立了"高速"背景下的构造目标落实技术流程,其实现过程可概括为几大步骤:首先,综合利用测井、地震、地质及非地震资料,明确高速砾岩的响应特征,准确识别高速砾岩;然后,通过地质规律分析与地震综合解释,精细预测高速砾岩的分布特征;其次,全面考虑浅层砾岩的分布及下伏构造目标的发育特征,建立相应的地质模型,初步定性判断高速砾岩对下伏构造目标的影响程度;最后,根据研究区实际占有的资料及地质条件,选取合理的速度建场方法,落实下伏构造圈闭的形态.在鄂尔多斯盆地西南缘彭阳地区和库车坳陷北部大北地区的高速砾岩发育区域,该技术取得了良好的应用效果,为有利区带的综合评价及新一轮的井位部署提供了重要依据.

At the edge of most hydrocarbon basins in China,the existence of high-velocity conglomerate inside the alluvial fan seriously restricts the implementation accuracy of the underlying tectonic targets and increases the risk of oil and gas exploration.The basic approach to solve this problem is to take full account of the distribution characteristics of conglomerate,select a reasonable method for establishing velocity field and accurately implement the underlying tectonic targets.In this paper,the technical process of tectonic target implementation under the background of'high velocity'is systematically established,which can be summarized as several steps.Firstly,the response characteristics of high-velocity conglomerate are clarified by comprehensive utilization of logging,seismic,geological and non-seismic data,and the high-velocity conglomerate is accurately identified.Secondly,through the analysis of geological law and comprehensive seismic data interpretation,the distribution characteristics of high-velocity conglomerate can be accurately predicted.Thirdly,the distribution of the shallow conglomerate and the development characteristics of the underlying tectonic target were considered comprehensively,and the corresponding geological model was established to preliminarily determine the influence degree of the high-velocity conglomerate on the underlying tectonic target.Finally,according to survey data and geological conditions of the study area,the reasonable method for establishing velocity field is selected to implement the shape of the underlying tectonic traps.This technology has achieved good application effect in the development area of high-velocity conglomerate,such as Pengyang region in the southwest edge of Ordos basin and Dabei region in the northern area of Kuqa depression.The obtained results and understanding provide important basis for comprehensive evaluation of favorable zone and well location deployment of the new round.