基于测井曲线互相关分析定量识别顺直型水下分流河道内部构型要素方法研究

Reservoir architecture research is a hot and difficult problem in the field of international sedimentology study, and also is the key technology of each big oilfield to predict remaining oil and to improve the ultimate recovery of oil and gas. Taking the meandering river delta front underwater distributary channel of K1q4 in J19 block, Fuyu oilfield as an example, Based on establishing progradation architecture model and identifying foreset and foreset sand body, dissection architectural elements of coring wells, grading to establish the key well architecture elements in typical logging facies model library; Introducing the cross-correlation analysis theory, use fixed length of vertical comparison method and optimal cycle comparison method, researching single well logging cross-correlation algorithm and multi-well logging cross-correlation algorithm based on the curve reconstruction, analyze the distribution of single well logging correlation coefficient and multi-well logging correlation coefficient, to identify foreset and foreset sand body. This research has important theoretical and practical significance of exploring architectural elements of quantitative identification method, establishing fine 3-D architecture model and improving oil recovery factor.

储层构型研究是国际沉积学研究领域的热点和难点问题，也是各大老油田剩余油挖潜、提高油气最终采收率的关键技术。本申请以扶余油田J19井区泉四段曲流河三角洲前缘顺直型水下分流河道为解剖对象，在前积型构型模式建立和前积体、前积层构型要素划分的基础上，对取心井进行单井精细构型解剖，分级次建立关键井构型要素的典型测井相模式库；引入互相关分析理论，采用固定长度纵向对比法和择优循环对比法的对比原则，研发单曲线互相关算法和基于曲线重构的多曲线组合互相关算法，对比分析前积体和前积层的单曲线相关系数和多曲线组合相关系数的分布规律，达到定量识别前积体和前积层的目的。这对探讨构型要素的定量表征方法、建立精细的剩余油分布模型、提高油气最终采收率具有重要的理论和现实意义。

本项目以鄂尔多斯盆地西杏子河侏罗系延安组延6三角洲前缘水下分流河道为解剖对象，定量解剖水下分流河道的外部几何形态及内部结构，总结了该露头剖面水下分流河道的岩相类型、岩相组合、构型界面级次及构型要素特征，建立了基于露头解剖的三角洲前缘水下分流河道储层构型的原型模型。在此基础上，综合应用钻井、岩心、测井、生产动态等资料，对扶余油田J19井区泉四段水下分流河道地下储层内部构型进行了精细解剖，在单井构型要素识别的基础上，总结了水下分流河道4级构型要素的4种垂向叠置样式、5种横向接触样式及其测井相模式，前积层3级构型要素的3种类型及测井相模式和前积体3级构型要素的3种类型及测井相模式，建立了水下分流河道内部不同级次构型要素的典型测井相模式库。.在构型要素测井相模式库建立的基础上，研发了单曲线互相关算法和多曲线组合互相关算法，分析表明随着夹层厚度增大，相关系数减小；夹层个数增多，相关系数减小；测井曲线回返程度越大，相关系数减小速率越快；透镜体、顶平底凸、底平顶凸型三类地质体的箱型模型的相关程度较高；箱型、漏斗型、钟型模型标准曲线与输入对比曲线砂体厚度差异越大，相关系数越小。以鄂尔多斯盆地水下分流河道露头解剖的构型原型模型为指导，结合水下分流河道内部构型要素定量解剖的成果，建立了基于露头原型模型约束的水下分流河道构型模式。剖析了单砂体垂向叠置样式、横向接触样式、前积层分布及前积体叠置类型对剩余油分布的控制作用；在对水下分流河道5级构型要素测井相分类分析的基础上，依据不同类型测井相的RILD与RILM曲线值差异分布的特征，重构新的差值参数△RT，结合产能统计数据，提出了基于曲线重构及产能统计的低阻油层快速定量识别方法。.