注水开发底水油藏水平井预警产量计算新方法

A Calculation Method of Warning Production of Horizontal Well in Water-Flooding Bottom Water Reservoir

摘要: 底水油藏水平井的预警产量是延缓甚至避免底水脊进的重要指导参数，目前的方法仅适用于单相流，尚无注水开发底水油藏水平井预警产量的计算方法。为此，将水平井的三维渗流场近似分解为平面和纵向两个平面渗流场，根据平面径向流理论分别计算各渗流场的预警产量，进而根据等值渗流理论叠加计算得到水平井的预警产量，最终结合相渗曲线建立不同含水阶段注水开发底水油藏水平井预警产量计算新方法。实例计算结果表明：原油粘度较小时，预警产量随着含水率的增大先减小后增大，为避免底水脊进注入水突破后要对应调整工作制度；原油粘度较大时，预警产量随着含水率的增大不断增大，故注入水突破后可适当开展提液。在海上某油田进行了应用，计算结果与数值模拟结果基本一致，验证了方法的可行性，建议X井含水率超过15%后调低日产量。

Abstract: The warning production of the horizontal well in the bottom water reservoir is an important pa-rameter to postpone or avoid the bottom water coning. The present method is only suitable for single phase flow. And there is no calculation method for warning output of horizontal well in bottom water reservoir with water injection. Therefore, the 3D percolation field of horizontal well is approximately divided into two parts including internal and external percolation fields. According to the theory of plane radial flow, the warning output of each seepage field is calculated respectively. Then the warning output of the horizontal well is obtained by the superposition of the theory of equal value seepage. In the end, a new method for calculating the warning output of horizontal wells at different water content stages is established by combining with the phase seepage curve. The calculation results show that when the crude oil viscosity is relatively small, the warning yield decreases first and then increases with the increase of water content. When the viscosity of crude oil is larger, the warning output increases with the increase of water content, so the liquid can be properly carried out after the injection of water. It is applied in an offshore oilfield. The calculated results are basically the same with the numerical simulation results. The feasibility of the method is verified. It is recommended that the daily production of X well be cut down when the water content is over 15%.