新疆三塘湖盆地牛圈湖区块异常低压成因及压力演化定量分析  

The Quantitative Analysis of Causes of Low Pressure and the Pressure Evolution in the Niujuanhu Area of Santanghu Basin,Xinjiang

作　　者：康媛[1,2] 孙卫[1,2] 盛军[1,2] 时建超[3] 刘艳妮[3] 赵婷 

机构地区：[1]西北大学大陆动力学国家重点实验室,西安710069 [2]西北大学地质学系,西安710069 [3]中国石油长庆油田分公司勘探开发研究院,西安710018 [4]中国石油青海油田分公司涩北作业公司,青海格尔木816000

出　　处：《地质论评》2016年第1期103-110,共8页Geological Review

基　　金：国家科技重大专项大型油气田及煤层气开发(编号:2011ZX05044)项目的成果~~

摘　　要：三塘湖盆地牛圈湖区块中生界侏罗系西山窑组储层具有典型的异常低压油藏特征，晚白垩末期储层达到最大埋深，此时下部芦草沟组烃源岩演化程度达到最大，随着油气持续向储层充注，此时地层压力达到最大，可达30．33—50．74MPa。本文从引起油藏异常低压的主要因素入手，定量分析了构造抬升与地层剥蚀、地层温度降低、成岩作用中的“耗水作用”以及矿物蚀变引起的自生体积缩小等因素对地层压力的影响。这些因素共同作用导致了地层压力降低，其中溶蚀作用中矿物蚀变所形成的“耗水作用”，使地层压力下降24．4％-37．1％，是造成储层异常低压的首要因素，同时矿物蚀变导致自身体积缩小并导致储层压力下降16．5％～24．8％，地层温度降低和构造运动对储层压力降低影响相对较弱，降低幅度分别为7．9％～8．6％和4．8％～8．1％。以上种种因素的共同作用，使得地层压力下降17．45～37．85MPa，最终形成现今异常低压的分布格局。Objectives ： The Mesozoic Jurassic reservoir of Xishanyao formation in the Niujuanhu area of Santanghu basin has typical abnormal low pressure reservoir characteristics, reservoir reaches a maximum depth during late of Late Cretaceous, at this point the lower Lucaogou source rocks evolution reached the maximum extent, with the oil and gas continued to fill the reservoir, when the formation pressure reaches the maximum, up 30.33 -50.74MPa. Methods： In this paper, start with the main factors that cause abnormal low pressure reservoir, quantitative analysis impact of the tectonic uplift and denudation, formation temperature decreases, the ＂ water effect＂ in diagenesis, the own volume reduction of mineral alteration and other factors on the formation pressure. Results： These factors together led to a lower formation pressure, dissolution of mineral alteration which form the ＂water effect＂ makes the formation pressure drop 24.4% - 37.1% , it is the primary factor causing abnormal low pressure reservoir, meanwhile its volume is reduced leading to mineral alteration, it leading to the reservoir pressure drops 16.5% -24.8% , the impact of the reduce of formation temperature and the tectonic movement for reservoir pressure is relatively weak, reduce the rate were7.9% -8.6% and 4.8% -8.1%. Conclusions： All these factors that mentioned above work together, making the formation pressure decreased by 17.45 -37.85MPa, eventually formed the current distribution pattern of abnormal low pressure.

关 键 词：三塘湖盆地 牛圈湖区块 西山窑组 异常低压 压力演化 

分 类 号：P618.13[天文地球—矿床学]