海上稠油油田热水化学驱油技术研究

Study on hot water chemical flooding technology in offshore heavy oil field

热水化学驱技术通过热水与化学药剂有机结合,可在吞吐热采的基础上进一步提高采收率。基于渤海N油田实际地质油藏参数,将提高采收率值和经济指标作为目标函数,开展了驱油体系评价实验和数值模拟研究,优化设计影响热水化学驱增油效果的热水温度、药剂浓度、药剂用量等注入参数,并对比分析了多元热流体吞吐和热水化学驱两种热采技术的开发特征和效果。结果表明:随着温度的升高,化学药剂改善水油流度比和降低原油黏度的作用被削弱,热对提高采收率起着主导作用,但温度高于115℃后,提高采收率值增幅减缓,经济指标快速下降;随着化学药剂浓度的增加,提高采收率值单调递增,浓度在1500 mg/L时经济指标达到峰值,之后出现下降的趋势,药剂效率降低;化学剂总体用量控制在0.25~0.30 PV。实例计算表明,热水化学驱将受效半径从80 m扩大到400 m,更能有效动用注采井间的储量,采收率提高4.8个百分点,吨剂增油量31.7 m^(3)/t,建议渤海N油田在多元热流体吞吐后转换为热水化学驱方式,以持续保障油田产量。

Through the organic combination of hot water and chemicals,hot water chemical flooding technology can further improve oil recovery on the basis of huff and puff thermal recovery.Based on the actual geological reservoir parameters of Bohai N oilfield,taking the enhanced oil recovery value and economic index as the objective function,the evaluation experiment and numerical simulation of oil displacement system are carried out,the injection parameters such as hot water temperature,chemical concentration and chemical dosage that affect the oil incremental effect of hot water chemical flooding are optimized,and the development characteristics and effects of multi-component thermal fluid huff and puff and hot water chemical flooding are compared and analyzed.The results show that with the increase of temperature,the effect of chemicals on improving water/oil mobility ratio and reducing crude oil viscosity is weakened,and heat plays a leading role in improving hydrocarbon recovery.However,when the temperature is higher than 115℃,the increase of EOR value slows down and the economic index decreases rapidly.With the increase of chemical concentration,the EOR value increases monotonously,and the economic index reaches its peak when the concentration is 1500 mg/L,but then there is a downward trend,and the chemical efficiency decreases.The overall dosage of chemicals is controlled at 0.25-0.30 PV.The actual example calculation shows that by expanding the response radius from 80 m to 400 m,hot water chemical flooding can produce the reserves between injection and production wells more effectively by increasing 4.8%oil recovery and 31.7 m^(3)/t oil increment per ton of chemical.Therefore,it is suggested that Bohai N oilfield should be converted to hot water chemical flooding after multi-component thermal fluid huff and puff so as to ensure oilfield production.