强挤压型盆地最大埋深期泥岩压实重建及其油气地质意义——以库车前陆盆地为例  

Reconstruction of mudstone compaction in the maximum burial depth period of strongly compressional basin and its petroleum geological implications:Take the Kuqa foreland basin as an example

作　　者：王刚 范昌育[1,2] 李子龙 吴双 张随随 WANG Gang;FAN Changyu;LI Zilong;WU Shuang;ZHANG Suisui(Department of Geology,Northwest University,Xi'an,Shaanxi 710069,China;State Key Laboratory of Continental Dynamics,Xi'an,Shaanxi 710069,China;Yingqian Oil Production Area of Yingmai Oil and Gas Development Department,PetroChina Tarim Oilfield Company,Aksu,Xinjiang 842000,China)

机构地区：[1]西北大学地质学系 [2]大陆动力学国家重点实验室 [3]中国石油塔里木油田公司英买油气开发部英潜采油作业区

出　　处：《天然气工业》2021年第10期29-38,共10页Natural Gas Industry

基　　金：国家自然科学基金项目“压性断裂主滑动面薄膜的形成机制及其侧向封闭性研究——以川西北、库车前陆盆地冲断带为例”(编号:41972133);国家科技重大专项“典型盆地深层—超深层流体动力场与输导层地质模型研究”(编号:2017ZX05008-004-004)。

摘　　要：最大埋深期泥岩压实研究是超压成因判别、地层压力预测、剥蚀厚度恢复及油气运聚研究的基础。强挤压型盆地后期经历的强挤压和强剥蚀强烈地改造了最大埋深期泥岩压实规律,重建最大埋深期泥岩压实对于认识和预测超压气藏的形成具有重要的意义。为了揭示最大埋深期泥岩的压实规律,以典型强挤压型盆地——库车前陆盆地为例,根据库车前陆盆地内克拉苏冲断带和南部斜坡带新近系物源相同、泥岩类型相似以及构造变形强弱不同的典型地质特征,重建强挤压型盆地最大埋深期泥岩压实模型,恢复强挤压区克拉苏冲断带最大埋深期泥岩压实过程,并探讨泥岩压实重建对流体压力定量评价、超压成因判别的意义。研究结果表明:(1)强挤压型盆地中弱挤压区/弱剥蚀区(山前坳陷、斜坡带)沉积的与强挤压区相似的泥岩可以作为重建最大埋深期泥岩压实模型;(2)利用弱挤压区/弱剥蚀区泥岩重建的最大埋深期泥岩压实曲线评价强挤压盆地最大埋深期流体压力更精确,误差更小;(3)强挤压盆地中,重建的最大埋深期加载曲线能够较准确地判别超压成因,反映真实的超压演化与油气成藏过程,体现了多成因超压机制相互作用的结果。Study on the mudstone compaction during the maximum burial depth period is the foundation for overpressure origin determination,formation pressure prediction,denudation thickness restoration and hydrocarbon migration and accumulation research.Strong compression and denudation applied on the strongly compressional basin in the later stage changes greatly the mudstone compaction law during the maximum burial depth period,so the reconstruction of mudstone compaction during the maximum burial depth period has great implications for understanding and predicting the formation of overpressured gas reservoirs.This paper takes a typical strongly compressional basin,i.e.,the Kuqa foreland basin,as an example to reveal the mudstone compaction law during the maximum burial depth period.Based on the same Neogene provenance,similar mudstone type and typical geological characteristics of different tectonic deformation in the Kelasu thrust belt of the Kuqa foreland basin and the southern slope belt,a mudstone compaction model is established,and the mudstone compaction in the maximum burial depth period of Kelasu thrust belt in the strongly compressional area is restored.In addition,the implications of mudstone compaction reconstruction for quantitative evaluation of fluid pressure and determination of overpressure origin are discussed.And the following research results are obtained.First,the mudstone deposited in the weakly compressional or denuded areas(piedmont depression and slope belt)of the strongly compressional basin and similar to that in the strongly compressional area can be used to reconstruct the mudstone compaction model.Second,the mudstone compaction curve which is reconstructed on the basis of the mudstone in the weakly compressional or denuded areas can evaluate the fluid pressure more accurately with smaller errors.Third,as for a strongly compressional basin,the reconstructed loading curves can determine the overpressure origin more accurately,reflect overpressure evolution process and hydrocarbon accumulation p

关 键 词：强挤压型盆地 最大埋深期 泥岩压实 重建 超压成因 加载曲线 超压气藏 库车前陆盆地 

分 类 号：P618.13[天文地球—矿床学]