海上注水开发油田单井经济极限含水率分析

经济极限含水率对注水开发油田具有重要的经济意义，目前行业标准笼统选取98%的含水率作为单井经济极限含水率，没有考虑经济因素，显然有失合理性。为合理确定不同经济条件下的单井经济极限含水率，评估单井生产是否具有经济效益，基于油价、油田实际产出、成本、税金等经济参数，运用投入产出平衡理论，首次推导出海上注水开发油田单井经济极限含水率计算模型。以渤海Q油田为例，计算了不同油价、不同采油速度下单井经济极限含水率，并绘制相应图版，评价了油井生产是否具有经济效益。结果表明：成本一定时，油价和采油速度对经济极限含水率影响较大，经济极限含水率随油价的升高而增大，随采油速度的增大而增大。对具有高采油速度的海上注水开发油田而言，高油价（$100/bbl，1 bbl=0.159 m³）下的经济极限含水率高达99.11%，远高于目前行业标准规定的98%的经济极限含水率数值，延长了油井高含水期效益生产的寿命，大幅度提高了单井经济效益，对海上注水开发油田单井生产策略具有重要的指导意义。

Economic limit water cut of single well in offshore waterflooding oilfield

Economic limit water cut has important economic significance for the development of oilfields with water injection. The industry standard selected 98% as the economic limit water cut of single well, without considering economic factors, which is obviously unreasonable. In order to reasonably determine the economic limit water cut of single well under different economic conditions and evaluate whether the production of single well has economic benefits, guided by the principle of input-output balance, a calculation model of economic limit water cut of single well in offshore waterflooding oilfield was derived for the first time based on the economic parameters such as oil price, actual output, cost and tax. Taking Bohai Q oilfield as an example, the economic limit water cut of single well was calculated under different oil prices and oil production rates, and the corresponding chart was drawn to evaluate whether the production of oil wells has economic benefits. The results show that when the cost is fixed, oil price and oil recovery rate have a great influence on the economic limit water cut, and the economic limit water cut increases with the increase of oil price and oil recovery rate. For offshore waterflooding oilfields with high oil recovery rate, the economic limit water cut is as high as 99.11% at high oil price ($100/bbl, 1 bbl=0.159 m³), which is much higher than 98% of the economic limit water cut value stipulated by the current industry standard. It prolongs the benefit production of oil wells in high water cut period, greatly improves the economic benefit of single well, and has important guiding significance for the production strategy of offshore waterflooding oilfields.