水平井开发的无夹层底水稠油油藏波及系数计算新方法  

A new method for calculating the sweep efficiency in viscous oil reservoirs with bottom water and without interlayer during horizontal-well development

作　　者：孙一丹 刘凡 周文胜[1,2] Sun Yidan;Liu Fan;Zhou Wensheng(State Key Laboratory of Offshore Oil Exploitation,Beijing 100028,China;CNOOC Research Institute Co.,Ltd.,Beijing 100028,China)

机构地区：[1]海洋石油高效开发国家重点实验室 [2]中海油研究总院有限责任公司

出　　处：《天然气勘探与开发》2022年第1期74-79,共6页Natural Gas Exploration and Development

基　　金：“十三五”国家科技重大专项“海上稠油油田开发模式研究”(编号:2016ZX05025-001)。

摘　　要：对于应用水平井开发的无夹层底水稠油油藏,波及系数是评价开发效果、进行开发调整的基础参数,也是指导进一步挖潜、从而提高采收率的重要依据。而目前常用的波及系数计算方法,未考虑水平井开发时水脊的动态变化,计算结果误差较大,不适用于水平井开发的无夹层底水稠油油藏。针对这一现状,研究寻求波及系数计算新方法。①利用地质建模与数值模拟技术,分析底水稠油油藏水平井水脊的三维形态,并推导建立了水脊体积计算模型;②采用灰色系统关联分析法,从单井和油组两个层面的实际生产动态开展研究,确定了波及系数的主控影响因素,综合考虑水脊体积计算公式后最终选择井距、平均渗透率、避水高度、产液能力和含水率这5个参数为影响水脊形态特征参数的显著因素;③将上述5个参数作为试验因素,应用Box-Behnken响应面法设计数值模拟的试验模型,并对数值模拟的试验结果进行回归,通过多元非线性回归法得到水脊体积计算公式中3个水脊形态几何特征参数的表达式,即建立了水脊形态参数与气藏静、动态参数的关系式;④在上述研究基础上,推导得出波及系数的计算公式,即建立了适用于水平井开发的无夹层底水稠油油藏波及系数计算方法。实际油藏的应用表明,新方法的计算结果比常规方法更为准确合理,更能反映水平井开发过程中底水的波及状况,可为无夹层底水稠油油藏的挖潜对策提供技术支持。For most viscous oil reservoirs with bottom water and without interlayer via horizontal-well development,sweep efficiency is important to production evaluation,development adjustment,and enhanced oil recovery.Common approaches for its calculation are not generally available for such reservoirs because of their larger error for not considering the dynamic change of water crest during horizontal-well development.So,a new method was presented to calculate the sweep efficiency.Firstly,both geological modeling and numerical simulation were conducted to examine the 3D geometry of water crest occurred in these bottom-water viscous oil reservoirs,and one model was built for calculating the water-crest volume.And then,major controls of sweep efficiency were found out by investigating the production performance of individual wells and oil layer groups through grey correlation analysis.In accordance with the formula of water-crest volume,5 parameters,i.e.well spacing,average permeability,height of water exclusion,liquid productivity,and water cut,were set to be the dominant controls of water-crest geometric parameters.Thirdly,the model for numerical simulation was designed using the Box-Behnken response surface method for the test on the above 5 parameters,and multiple non-linear regression was made on the numerical simulation to obtain not only an expression of three water-crest geometric parameters in the formula of water-crest volume,but also one relation between the water-crest geometric parameters and the static and dynamic reservoir parameters.Finally,the equation of sweep efficiency was derived for the viscous oil reservoirs with bottom water and without interlayer.Field application shows that this new method is more accurate and rational than conventional ones to characterize the bottom-water coverage during horizontal-well development and can provide technical support for enhanced oil recovery in these reservoirs with bottom water and without interlayer.

关 键 词：底水稠油油藏 波及系数 水平井 水脊体积 

分 类 号：TE345[石油与天然气工程—油气田开发工程]