内嵌经济条件的采收率预测图版

Study on new recovery forecast chart with embedded economic factors

鉴于在固定极限含水率下得到的传统童氏图版难以确保特殊油藏采收率预测精度,从甲型水驱曲线入手推导了采收率预测图版的基本公式,并考虑油田经济参数、单井平均日产液量、年递减率等因素推导出了经济极限含水率的计算公式,结合海上某油田的具体情况分别建立了经济极限含水率和采收率的预测图版。研究结果表明,经济极限含水率随油价上升而上升,且低油价时上升较快,随着油价的升高其变化渐趋于平缓;经济极限含水率随单井日产液量和递减率的增大而增大,且其影响在低油价下较为显著,随着油价升高相应经济极限含水率的差别减小。通过与传统童氏图版的预测结果对比,油价为4000元/t时,应用新图版预测海上某油田采收率的精度提高了2.1%;油价为2000元/t时,预测精度提高了6.7%。新图版的建立为快速准确预测不同油藏的采收率奠定了基础。

The recovery ratio of particular reservoir is hard to be predicted accurately using the traditional Tong's chart because it was derived under the condition of fixed economic limit water cut. The basic formula of recovery forecast chart is deduced first by water-drive characteristic curve and combined with the economic limit water cut function considering the economic parameters, the average well daily liquid production, annual decline rate. The forecast chart is applied to an offshore field. The results show that the economic limit water cut increases with the oil price rising and increases quickly with low oil price and gradually slowly with the oil price rising; The economic limit water cut increases with well daily liquid production and decline rate increasing, and the effect is significant when oil price is low. Compared with the forecast result of traditional Tong's chart, the recovery ratio of the offshore field using the new chart is 2.1% higher, when oil price is 4 000 Yuan/t, and 6.7% higher when oil price at 2 000 Yuan/t. The recovery ratio of different reservoir can be predicted quickly and accurately by the forecast chart.