基于偏心井反演理论的压裂水平井产能计算方法

Productivity calculation of fractured horizontal well based on equivalent eccentric well inverse theory

何军 范子菲 赵伦 宋珩 李孔绸 吴学林

中国石油勘探开发研究院，北京 100083

Research Institute of Petroleum Exploration & Development, PetroChina, Beijing 100083, China

基于垂直裂缝稳态渗流等效井径模型、圆形供给边界偏心井反演理论和压降叠加原理，建立了考虑油藏及裂缝渗流的耦合模型，推导了圆形供给边界压裂水平井产能计算新公式，分析了裂缝半长、裂缝条数、裂缝导流能力、裂缝布缝方式对压裂水平井产能的影响。结果表明：压裂水平井裂缝产量是非均匀的，具有边部裂缝产量高，中间裂缝产量低的特点；压裂水平井裂缝存在最优条数，当裂缝条数大于最优条数，水平井产量增加缓慢；裂缝半长增加，水平井产量增加，其中边部裂缝产量增加最显著，中间裂缝产量略有增加；裂缝无因次导流能力增加，水平井产量增加，且很快趋于平稳，在压裂设计中，应避免裂缝导流能力小于曲线的拐点值，引起压裂水平井产能快速下降。最后，通过分析4种布缝方式发现，压裂水平井宜采用交错布缝，同时延长边部裂缝的缝长，适当减小中间裂缝缝长，降低裂缝间的干扰，提高水平井产量。

Based on equivalent wellbore radius model of vertical fracture in steady state flow, eccentric well inverse theory of circular supply boundary and the principle of pressure-drop superposition, a coupling model of reservoir and fracture flow was developed and a new productivity formula of fractured horizontal well was derived. The influence of fracture half length, fracture numbers, fracture flow conductivity and fracture distributions on the productivity of fractured horizontal well was analyzed. The results show that the distribution of fracture productivity is not uniform with high production in outer fractures and low productivity in inner fractures; there is an optimal fracture numbers, the productivity of horizontal well increases slowly when the fracture numbers exceeds the optimal fracture numbers; with the increase of fracture half length, the productivity of horizontal well increases, the increase of outer fracture productivity is remarkable and the inner fracture productivity rises slightly; with the increase of fracture dimensionless flow conductivity, the productivity of horizontal well increases and tends to be steady quickly; the productivity of horizontal well decreases quickly if the fracture flow conductivity is less than the value of inflection point; finally, analyzing four types of fracture distribution, it is better to adopt interlaced fracture distribution pattern, prolong the length of outer fractures, and reduce the length of inner fractures appropriately to reduce fracture interference and improve the productivity of horizontal well.

10.6056/dkyqt201601013