摘要
在低渗透复杂构造油藏水平井开发中,当地层倾角较大且最大主应力方向与地层倾向垂直时,受构造约束的水平井轨迹易演变为大斜度井拟水平井。此时,地层倾角对油井产能的调控作用已不可忽略。因此,为实现此类井压裂后产能的快速精准预测,本文基于等效虚拟井径理论,融合地层倾角效应,建立了大斜度拟水平井分段压裂产能预测模型。通过与数值模拟结果对比,验证了模型的可靠性,并对大斜度拟水平井分段压裂产能影响因素进行了分析。研究结果表明:水平段越长,大斜度拟水平井产能越高;地层厚度与倾角对油井产能影响显著,随着地层厚度的增加,油井产能及其增幅均逐渐增大;而随着地层倾角的增大,油井产能降低,且降幅逐渐加大;裂缝半长和裂缝条数均对产能存在显著影响,油井产能随着参数的增大而提高,但增幅呈减缓趋势,存在最优取值范围;地层各向异性越小,大斜度拟水平井产能越高,且产能增幅随各向异性系数减小而增大。通过苏北某油田大斜度井现场实际应用,验证了本文所建立的大斜度拟水平井分段压裂产能模型计算结果与油井实际产能相近,相对误差小于5%,满足现场精度要求。该模型适用于地层倾角10°~40°的油藏条件,能为低渗透复杂构造油藏合理生产制度的制定提供依据,且模型形式简洁,计算效率高,实用性强,便于现场推广应用。
In the development of horizontal wells in low-permeability reservoirs with complex structures,when the formation dip angle is large and the direction of the maximum principal stress is perpendicular to the formation dip,the horizontal well trajectory tends to become a high-inclination pseudo-horizontal well due to structural constraints.At this point,the regulatory effects of formation dip angle on well productivity can no longer be neglected.To achieve rapid and accurate prediction of post-fracturing productivity for such wells,this study established a productivity prediction model for staged fracturing in high-inclination pseudo-horizontal wells based on the equivalent virtual wellbore radius theory,incorporating the effect of formation dip angle.By comparing with numerical simulation results,the reliability of the model was verified,and the influencing factors of the productivity of staged fracturing in high-inclination pseudo-horizontal wells were analyzed.The results showed that the longer the horizontal section,the higher the productivity of the high-inclination pseudo-horizontal well.Formation thickness and dip angle significantly influenced well productivity.As formation thickness increased,both the productivity and its growth rate gradually increased.As the formation dip angle increased,well productivity decreased,and the rate of decline gradually accelerated.Both fracture half-length and the number of fractures significantly affected productivity.Oil well productivity increased with the increase of these parameters,but the rate of increase showed a slowing trend,indicating an optimal value range.The smaller the formation anisotropy,the higher the productivity of the high-inclination pseudo-horizontal well.Moreover,the increase rate of productivity grew as the anisotropy coefficient decreased.Through field application in a high-inclination well in the Subei oilfield,it was verified that the calculation results of the productivity model for staged fracturing in high-inclination pseudo-horizontal well established in this study were close to the actual productivity of well CD101X,with a relative error of less than 5%,meeting the accuracy requirements for field applications.This model is applicable to reservoir conditions with formation dip angles of 10°~40°.It can provide a basis for formulating a reasonable production system for low-permeability reservoirs with complex structures.Moreover,the model features a concise form,high computational efficiency,and strong practicality,making it easy for field promotion and application.
作者
郑永旺
王伟
任建华
倪振玉
卢比
胡春锋
ZHENG Yongwang;WANG Wei;REN Jianhua;NI Zhenyu;LU Bi;HU Chunfeng(Research Institute of Exploration and Development,Sinopec East China Oil&Gas Company,Nanjing,Jiangsu 210019,China)
出处
《油气藏评价与开发》
北大核心
2026年第2期374-382,共9页
Petroleum Reservoir Evaluation and Development
基金
中国石化科技部“溱潼凹陷低TOC陆相页岩油勘探开发关键技术”(P23190)。
关键词
大斜度地层
拟水平井
分段压裂
产能模型
影响因素
high-inclination formation
pseudo-horizontal well
staged fracturing
productivity model
influencing factors
