疏松砂岩气藏低阻气层成因及识别研究——以柴达木盆地涩北气田为例  

Research on the genesis and identification of low resistivity gas reservoirs in unconsolidatedsandstone gas reservoirs:A case study of the Sebei gas field,Qaidam Basin

作　　者：顾端阳 窦文博 丁富寿 严力 吕浩 GU Duan-Yang;DOU Wen-Bo;DING Fu-Shou;YAN Li;LYU Hao(Exploration and Development Research Institute of Qinghai Oilfield Branch of CNPC,Dunhuang 736202,China;The 11 th Oil Production Plant of Changqing Oilfield Branch Petrochina,Qingyang 745000,China;No.3 Oil Production Plant of Qinghai Oilfield Branch Petrochina,Mangya 816400,China)

机构地区：[1]中国石油天然气股份有限公司青海油田分公司勘探开发研究院,甘肃敦煌736202 [2]中国石油天然气股份有限公司长庆油田分公司第十一采油厂,甘肃庆阳745000 [3]中国石油天然气股份有限公司青海油田分公司采油三厂,青海茫崖816400

出　　处：《物探与化探》2020年第3期649-655,共7页Geophysical and Geochemical Exploration

基　　金：国家科技重大专项“疏松砂岩气藏长期稳产技术”(2016ZX05015-004);中国石油天然气股份有限公司科技重大专项课题“柴达木盆地老气区控水稳气及新气区高效开发技术研究”(2016E-0106GF)。

摘　　要：涩北气田为第四系湖湘沉积的生物气藏,埋藏浅、成岩差,储集层存在“高孔隙度、高矿化度、高黏土含量、含(黄/磁)铁矿高电导”等“四高”背景,形成了低阻气层和特殊的特低阻气层。本文基于低阻气层测井曲线电性响应特征,研究其空间展布与对生产特征的影响,开展低阻气层成因与机理分析。研究表明:①高孔隙度、高矿化度、高黏土含量等地质背景,是导致涩北气田气层电阻率低的主要因素,砂泥岩薄互层也有一定程度影响;②特殊导电矿物的存在则是异常低阻气层的直接原因;③提出自然伽马—电阻率交会方法,有效识别地质背景、储层特性形成的低阻气层,而侧向、感应测井双电阻交会剖面提升了薄砂体的识别效果;④在测井精细解释的基础上加强研究铁矿质层平面展布,通过试气手段利用动态法形成平面监测,提高低阻气层解释的精度。The Sebei gas field is a Quaternary Huxiang sedimentary biogas reservoir with shallow burial and poor diagenesis.The reservoir has"four highs"background of"high porosity,high salinity,high clay content,and high conductivity of(yellow/magnetic)iron ore".A low gas barrier layer and a special ultra-low gas barrier layer were formed.Based on the electrical response characteristics of the low-resistance gas layer logging curve,the authors studied its spatial distribution and its influence on production characteristics,and made a mechanism analysis of the low-resistance gas layer.The results are as follows:First,geological backgrounds such as high porosity,high salinity,and high clay content are the main factors leading to the low resistivity of the gas layer in the Sebei gas field,and the thin interbeds of sand and mudstone also have a certain effect;Second,the existence of special conductive minerals is the direct factor responsible for the abnormal low-resistance gas layer;Third,the natural gamma-resistance intersection method can effectively identify the low-resistance gas layer formed by geological background and reservoir characteristics;as for lateral and induction logging,the double-resistance cross section improves the recognition effect of thin sand bodies;Fourth,on the basis of fine logging interpretation,it seems that strengthening the study of the planar distribution of iron ore layers and using dynamic methods to form plane monitoring by means of gas testing can improve the precision of the interpretation of low-resistance gas layers.

关 键 词：低阻气层 束缚水饱和度 泥质含量 磁铁矿 交会图 

分 类 号：P631.4[天文地球—地质矿产勘探]