基于决策树对致密储层流体识别的方法研究——以盐池地区长8储层为例  

Study on Fluid Identification Method of Tight Reservoir--A Case Study of Chang 8 Reservoir in Yanchi Area

作　　者：郑晓梅 何桂平 王子龙 ZHENG Xiaomei;HE Guiping;WANG Zilong(School of Geosciences and Engineering,Xi'an Shiyou University,Xi'an 710065,China;Changqing Industrial Group Co.,LTD.,Changqing Oilfield,Xi'an 710018,China)

机构地区：[1]西安石油大学地球科学与工程学院,陕西西安710065 [2]长庆油田长庆实业集团有限公司,陕西西安710018 [3]延长油田股份有限公司勘探开发技术研究中心,陕西延安717199

出　　处：《北京石油化工学院学报》2023年第3期21-27,49,共8页Journal of Beijing Institute of Petrochemical Technology

基　　金：油气藏地质及开发工程国家重点实验室(西南石油大学)开放基金课题资助项目(PLN2022-25)。

摘　　要：致密砂岩储层由于受到储层岩性和孔隙结构等多种因素影响,利用传统复杂的流体识别方法对油水层识别困难、识别效率低。基于传统的图版法、重叠法和测井法等识别方法综合测井响应特征,能够充分利用基础地质数据、测井资料以及油水关系识别流体性质。但是,致密砂岩储层性质不稳定且储层非均质性强,加之孔隙结构和油水关系复杂,导致识别效率低、人为主观性强,限制了识别效果。以盐池地区长8致密储层为研究对象,提出了基于决策树对致密储层流体识别的方法。该方法通过研究区测井响应特征以及储层流体特征,结合电阻率、声波时差、中子和密度等测井数据计算出研究区孔隙度、渗透率和含油饱和度等参数作为决策树的特征值,最后根据决策树原理计算出基尼指数,依据基尼指数越小准确度越高的原则建立决策树模型,对储层流体性质进行预测。结果表明,决策树预测结果准确率达到90%,与试油结果基本一致,验证了该方法对致密储层预测具有效性和可靠性。Due to the influence of many factors such as reservoir lithology and pore structure,it is difficult to identify oil and water layers with traditional complex fluid identification methods,and the identification efficiency is low.Based on the traditional identification methods such as map method,overlap method and logging method,the logging response characteristics can be integrated,and the basic geological data,logging data and oil-water relationship can be fully used to identify the fluid properties.However,the unstable properties and strong heterogeneity of tight sandstone reservoirs,coupled with the complex relationship between pore structure and oil and water,lead to low identification efficiency and strong subjectivity,which limits the identification effect.Taking the Chang 8 tight reservoir in Yanchi area as the research object,this paper proposes a method for fluid identification of tight reservoir based on decision tree.In this method,parameters such as porosity,permeability and oil saturation are calculated as the characteristic values of the decision tree through logging response characteristics and reservoir fluid characteristics of the study area,combined with logging data such as resistivity,sonic time difference,neutron and density,etc.Finally,the Gini index is calculated according to the principle of decision tree.The smaller the Gini index is,the higher the accuracy is,the decision tree model is established.The characteristics of reservoir flow are predicted.The test results show that the accuracy of the decision tree prediction results is 90%,which is basically consistent with the oil test results,which verifies the effectiveness and reliability of this method for tight reservoir prediction.

关 键 词：储层流体识别 测井解释 决策树 致密储层 

分 类 号：P618.13[天文地球—矿床学]