基于岩性相单元和孔隙结构的低孔低渗储层有效性测井识别方法:以西湖凹陷NB1构造为例  

Logging Identification Method of Low Porosity and Low Permeability Reservoir Effectiveness Based on Lithofacies Units and Pore Structures:An Example from NB1 Structure in Xihu Depression

作　　者：崔维平[1] 杨玉卿[1] 刘建新 CUI Weiping;YANG Yuqing;LIU Jianxin(China Oilfield Services Limited,Beijing 101149,China;Shanghai Branch of CNOOC Ltd,Shanghai 200335,China)

机构地区：[1]中海油田服务股份有限公司,北京101149 [2]中海石油(中国)有限公司上海分公司,上海200335

出　　处：《现代地质》2022年第1期140-148,共9页Geoscience

基　　金：国家科技重大专项子课题“中深层储层测井新技术资料处理与解释”(CCL2017SHPSOO6EXP)。

摘　　要：东海西湖凹陷是近海最大的盆地之一,近些年在中深层花港组储层中获得重大发现。然而,由于储层具有厚度大、非均质性强、低孔低渗、孔隙结构复杂等特征,给精细评价和甜点储层的预测带来极大困难。利用高分辨率电成像资料,在岩性和层理构造识别的基础上,将研究区储层划分成槽状交错层理细中砂岩、板状交错层理细中砂岩、槽状交错层理细砂岩、板状交错层理细砂岩、块状层理砂岩及钙质胶结砂岩6种微尺度的岩性相单元,并利用核磁共振测井资料对不同岩性相单元的孔隙结构进行了精细表征。结果表明,槽状交错层理细中砂岩、板状交错层理细中砂岩、槽状交错层理细砂岩3种岩性相的排驱压力<0.5 MPa、平均孔喉半径>0.5μm,板状交错层理细砂岩岩性相的排驱压力为0.5~1.0 MPa、平均孔喉半径为0.25~0.50μm,这4种岩性相单元岩性较粗、交错层理发育、排驱压力较小、平均孔喉半径较大,为研究区甜点储层。在此基础上,建立了适用于研究区储层精细评价和甜点储层识别的分类方案,为研究区下一步勘探开发提供可靠依据。The Xihu Sag in the East China Sea is one of the largest offshore basins.In recent years,major oil and gas discoveries have been made in the reservoirs of the mid-deep Huagang Formation.However,due to the large thickness,strong heterogeneity,low porosity and low permeability,and complex pore structure of the reservoir,it brings great difficulties to fine evaluation and prediction of sweet spots.This paper classified 6 types of micro-scale lithofacies units for the reservoirs in the study area based on the identification of lithology and bedding structure by using high-resolution electrical imaging data,namely trough cross bedding fine-medium sandstone,plate cross bedding fine-medium sandstone,trough cross bedding fine sandstone,plate cross bedding fine sandstone,massive bedding sandstone and calcareous cemented sandstone.And furthermore,NMR logging data was used to finely characterize the pore structure of different lithofacies units.The results show that the three lithofacies of trough cross bedding fine-medium sandstone,plate cross bedding fine-medium sandstone,and trough cross bedding fine sandstone have a drainage pressure less than 0.5 MPa and an average pore throat radius greater than 0.5μm.The lithofacies of plate cross bedding fine sandstone has a displacement pressure between 0.5 MPa and 1.0 MPa,and an average pore throat radius between 0.25μm and 0.5μm.The above four types of lithofacies have coarser lithology,more developed cross bedding,lower displacement pressure,and larger average pore throat radius,which are favorable sweet spots in the study area.Based on the above studies,a classification scheme suitable for fine reservoir evaluation and sweet spots identification in the study area has been established,which provides a reliable basis for further exploration and development in the study area.

关 键 词：西湖凹陷 中深层储层 电成像 岩性相 孔隙结构 甜点储层 

分 类 号：P631.8[天文地球—地质矿产勘探] P618.13[天文地球—地质学]