白云岩储层特征与渗透率评价方法——以伊拉克美索不达米亚盆地古近系为例  

Dolomite reservoir characteristics and permeability evaluation methods:An example from the Paleogene,Mesopotamian basin,Iraq

作　　者：李雄炎 秦瑞宝 曹景记 汪鹏 叶信宇 尹中旭 LI Xiongyan;QIN Ruibao;CAO Jingj;WANG Peng;YE Xinyu;YIN Zhongxu(CNOOC Research Institute Lid.,Beijing 100028.China;National Eng ineering Research Center of Offshore Oil and Gas Ex ploration,Beijing 100028,China)

机构地区：[1]中海油研究总院有限责任公司,北京100028 [2]海洋油气勘探国家工程研究中心,北京100028

出　　处：《中国海上油气》2024年第3期81-94,共14页China Offshore Oil and Gas

基　　金：“十三五”国家科技重大专项“海外重点区勘探开发关键技术”课题3“海外重点盆地地球物理勘探关键技术攻关与应用(编号:2017ZX05032-003)”部分研究成果。

摘　　要：伊拉克美索不达米亚盆地古近系白云岩储层储集空间多样,渗透率测井定量评价非常困难。针对这一难题,首先,基于铸体薄片、CT扫描等实验数据,分析白云岩储层的储集空间;其次,结合阵列声波和电成像测井表征微裂缝,划分孔隙型和微裂缝-孔隙型白云岩储层类型;最后,耦合“数据驱动”和“知识驱动”计算白云岩储层的静态渗透率,并分别建立孔隙型和微裂缝-孔隙型白云岩储层动静态渗透率之间的转换关系。结果表明,研究区白云岩储层所发育裂缝的平均宽度为50μm,属于微裂缝级别,微裂缝孔隙度基本小于1.5%;当白云岩储层各向异性小于3.1%时,为孔隙型储层;当白云岩储层各向异性大于或等于3.1%时,为微裂缝-孔隙型储层;从“数据驱动”角度出发,可以将静态渗透率的计算逐步转化为复杂的、高维的、非线性的分类问题,并引入“知识驱动”,弥补“数据驱动”的盲目性和无效性,最终针对研究区白云岩储层所建立决策树分类模型的深度为16层、准确率为84.06%,从而准确计算白云岩储层的静态渗透率,静态渗透率的评价精度提高约70%;孔隙型和微裂缝-孔隙型白云岩储层动静态渗透率转换的相关系数R2分别为0.86和0.90,动静态渗透率之间准确转换关系的建立将为白云岩储层的产能预测奠定重要基础。In the Paleogene,Mesopotamian basin,Iraq,the diversity of dolomite reservoir space makes it very difficult to quantitatively evaluate the permeability.In order to solve this problem,firstly,based on cast thin sections and CT scans,the reservoir spaces of dolomite reservoirs are analyzed.Secondly,based on the array acoustic logging and electrical image logging,microfractures can be accurately characterized and pore reservoirs as well as microfracture-pore reservoirs can be classified.Finally,combined data-driven with knowledge-driven,the static permeability of dolomite reservoirs can be accurately calculated,and the conversion relationship between dynamic and static permeability of pore dolomite reservoirs and microfracture-pore dolomite reservoirs can be established respectively.The research results show that the average width of fractures of dolomite reservoirs in the study area is 50μm,which belongs to the level of microfractures,and the microfracture porosity is basically less than 1.5%.When the anisotropy of the dolomite reservoir is less than 3.1%,it is the pore reservoir;when the anisotropy of the dolomite reservoir is greater than or equal to 3.1%,it is the microfracture-pore reservoir.The static permeability evaluation can be gradually transformed into complex,high-dimensional,non-linear classification problem from the perspective of data-driven.Additionally,the introduction of knowledge-driven can make up for the blindness and inefficiency of data-driven.Finally,the depth of the established classification model of decision tree for dolomite reservoirs in the study area is 16 layers and the accuracy is 84.06%,so that the static permeability of dolomite reservoirs can be accurately calculated,and the evaluation accuracy of the static permeability is improved by about 70%.The correlation coefficients R?between static and dynamic permeability of pore dolomite reservoirs and microfracture-pore dolomite reservoirs are 0.86 and 0.90,respectively.The establishment of an accurate conversion relationship between

关 键 词：白云岩 储层特征 微裂缝 储层参数 渗透率 测井评价 美索不达米亚盆地 

分 类 号：TE132.1*4[石油与天然气工程—油气勘探]