塔里木溢流玄武岩火山通道的三维反射地震解释

It is of great significance to accurately identify the shape and structure of the volcanic channel in the large igneous province, to understand the role of volcanic rock at the “inside” area of oil and gas basin on hydrocarbon migration and accumulation, to recognize the effect of volcanic thermal disturbance on hydrocarbon source rock and reservoir maturity, and the exploration capacity of oil and gas at volcanic basin..A three-dimensional seismic exploration cube with a total area of 3000 km2, which is located in the Yingmai 2 and Tazhong 47 block in Tarim Basin and has plenty of overflow basaltic volcanic mechanism, is used to do the interpretation of the volcanic channel. .Using the drilling and logging data to calibrate the location of the volcanic channel in the seismic data volume, the characteristics of the seismic faces of the volcanic channel are summarized, and the three-dimensional geological interpretation model of the volcanic channel is established. .The accuracy and resolution of this 3-D interpretation model can be optimized by seismic wave field forward and iterative correction method, and its maximum resolution can reach to 10m..Under the constraint of drilling and logging data, it is possible to use the optimized 3-D interpretation model to explain the two-dimensional and three-dimensional seismic data of the basaltic volcanic channel in the basin, and the morphological and structural characteristics of the Tarim overflow basalt volcanic channel. At the same time, this model also gives good supplement to calculation and discussion of "thermogenic gas release" and "oil and gas system impact" and other issues.

大陆溢流玄武岩火山通道研究在火山学、全球环境变化、油气勘探等领域都具有重要意义。本项目拟选择塔里木盆地英买2区块和塔中47区块两个溢流玄武岩火山机构集中分布，面积共计3000km2的三维地震勘探工区，对地震数据体中的火山通道进行解释刻画。利用钻井、测井资料标定火山通道在地震数据体中的位置，总结火山通道的地震相特征，建立火山通道的三维地震解释模型。利用地震波场正演和迭代修正法，对解释模型的准确度和分辨率进行优化，获得最大分辨能力为10m级的优化解释模型。通过解释模型对盆地内溢流玄武岩火山通道进行系统的二维和三维地震数据解释，得到塔里木溢流玄武岩火山通道形态和结构特征，进而对全塔里木盆地溢流玄武岩分布区的“热成因气体释放”及“油气系统影响”等问题进行计算和讨论。

大陆溢流玄武岩火山通道研究在火山学、全球环境变化、油气勘探等领域都具有重要意义。本项目选择了塔里木盆地英买2区块和塔中47区块两个溢流玄武岩火山机构集中分布，面积共计3000km2的三维地震勘探工区，对地震数据体中的火山通道进行解释刻画。利用17口探井的钻井、测井资料标定火山通道在地震数据体中的位置，总结出塔里木溢流玄武岩火山通道以单个或多个相互联结的强反射、低角度穿层的碟状岩床为主的地震相特征，建立了火山通道的三维地震解释模型。利用地震波场正演和迭代修正法，对解释模型的准确度和分辨率进行优化，在选择频率为80Hz子波频率时，可获得最大分辨能力为10m级的优化解释模型。通过解释模型对盆地内溢流玄武岩火山通道进行系统的三维地震数据解释，得到塔里木溢流玄武岩火山通道形态和结构特征，进而对全塔里木盆地溢流玄武岩分布区的“热成因气体释放”及“油气系统影响”问题进行计算，确定英买2区块热成因甲烷释放量达11.3Gt（即113亿吨）。假设整个塔里木溢流玄武岩省具有与英买2地区相同的释放强度，则塔里木溢流玄武岩省活动期间释放的甲烷总量达7062.5Gt，会导致非常显著的环境效应。同时，玄武岩火山通道岩浆引起的热接触变质作用对已存在的油藏具有明显的破坏作用，塔里木盆地古生界总量约8~10Gt的油藏破坏和大量沥青的形成可能与此有关。