应力敏感性差异对天然裂缝储层直井产能的影响

Influence of stress sensitive differences on natural well productivity in fractured reservoirs

为了研究天然裂缝发育的低渗透油藏的产能特征,基于平面径向流理论,建立了考虑基质、天然裂缝的应力敏感性差异的天然裂缝储层产能预测模型,推导出考虑基质、天然裂缝应力敏感差异的天然裂缝储层产能方程。以低渗透油田基础数据为例,运用推导出的产能方程计算分析裂缝参数、基质应力敏感系数、裂缝应力敏感系数对产能的影响。结果表明,随着基质应力敏感系数增加,油井产能降低;裂缝宽度较小时,裂缝应力敏感对油井产能影响显著。因此,在天然裂缝发育的低渗透油藏,提高裂缝长度,勾通更多的微裂缝,对增产有利。

In order to study the productivity characteristics of low permeability reservoirs with natural fractures, we established a prediction model of natural fractured reservoir productivity considering stress sensitivity differences between matrix and natural fractures based on the theory of plane radial flow. After that, we derived the productivity equation of natural fracture reservoir con-sidering the difference of matrix and natural fracture stress sensitivity. Then taking the basic data of the low permeability oilfield as an example, we calculated and analyzed the influence of fracture parameters, matrix stress sensitivity coefficient and crack stress sensitivity coefficient on productivity by the productivity equation above. The results showed that with the increase of matrix stress sensitivity coefficient, the oil well productivity decreased. When the crack width was small, the stress sensitivity of fractures had a significant impact on the oil production. Therefore, in the low permeability reservoirs with natural fractures, increasing the length of the fractures and linking more microcracks would be beneficial to the increase of production.