塔河油田多井缝洞单元注水开发试验研究

Pilot study on waterflooding development in multi-well fracture-cavity units of Tahe Oilfield

塔河油田奥陶系油藏为碳酸盐岩缝洞型油藏,为了控制由于油藏能量不足造成的较大的自然递减,改善油藏开发效果,从2005年开始在多井缝洞单元进行注水开发试验。根据油藏储集体发育特点、油藏能量状况和水体特征,选择不同开发特征的缝洞单元、不同部位、不同的注水方式以及不同注入速度进行注水,对比分析影响注水效果的主要因素。试验结果表明,注水井与生产井之间剩余油丰富、储集体相对均质、注水部位位于缝洞单元低部位时,注水效果好;为了防止注入水快速突进,宜进行温和注水,注水初期注采比应控制在0.8～1.0之间。注水开发的成功试验为后期合理高效开发此类油藏提供了技术支撑和理论依据。

Ordovician reservoirs in Tahe Oilfield are carbonate fracture-cavity reservoirs. In order to control the quick natural decline caused by the shortage of reservoir energy, Tahe Oilfield explored to test waterflooding development in multi-well fracturecavity units in 2005. According to the reservoir development characteristics, reservoir energy, and water body features, water injection was performed in different fracture-cavity units and position with different injection mode and rate. Main factors affecting injection effect were analyzed. The results prove that waterflooding effect is good when surplus oil is rich between the injection and production well, reservoir is relatively homologous, and water injection lies in the low position of fracture-cavity unit. Moderate injection should be conducted to prevent the injection water from dashing fast, with the initial injection-production ratio at 0.8-1.0.Successful test provides technological support and theoretical basis for efficient and rational development of similar reservoirs.