一种计算有限导流裂缝压裂水平井产能的新方法

A new productivity calculating method of fractured horizontal wells with finite conductivity fractures

基于偏心直井的产能公式,引入当量井径,将带有N条垂直裂缝的压裂水平井等效为井径为当量井径的N口偏心直井,运用势的叠加原理,建立更接近于实际情况的压裂水平井产能计算公式。分析了裂缝导流能力、裂缝半长、裂缝间距、偏心距离等因素对压裂水平井产能的影响。研究结果表明,随着导流能力的增大,考虑偏心距影响的水平井产能公式计算结果与常规公式计算结果的差距逐渐增大;综合考虑裂缝导流能力对产量和产量增幅的影响,最佳无因次裂缝导流能力为1~10;采用"中间短缝、两端长缝"的布缝模式,合理优化裂缝间距,可提高压裂水平井产能。

Based on productivity formula of eccentric vertical wells, this paper introduces equivalent radius, and employs N eccen- tric vertical wells with equivalent wellbore radius to describe the fractured horizontal wells with N vertical fractures. In addition, the potential superposition principle is used to establish productivity calculating method of fractured horizontal wells, which is more close to actual situation. What＇s more, the effects of fracture conductivity, fracture half-length, fracture interval, eccentric dis- tance on productivity of fractured horizontal wells are analyzed. The results show that, as the increase of flow conductivity, the dif- ference of the solutions between the common method and new method also increases when the eccentricity is taken into consider- ation. Furthermore, by the comprehensive considering the effects of fracture flow conductivity on production and production growth rate, it concludes that the optimal dimensionless flow conductivity of the fracture is 1 - 10. Moreover, the fracture distribution pat- tern that the short fractures in the middle and the long fractures in the edges should be adopted, and the productivity of the frac- tured horizontal well can be improved reasonably with the suitable fracture distance.