超低渗储层混合水体积压裂重复改造技术研究与现场试验

Re-fracturing technology research and field application of mixing water volume fracturing in ultra-low permeability reservoir

关键词:  重复压裂  体积压裂  混合水压裂  增产机理  多级暂堵 

Key words:  re-fracturing  volume fracturing  mixing water fracturing  increase production mechanism

摘要:

以华庆油田为代表的超低渗透油藏定向井单井产量低,日产量小于1.0 t的低产低效井占56.2%。常规重复压裂压裂后的油井增产效果不理想,具体表现在压裂后增产幅度小、产量递减速度快、有效期短。针对长庆油田华庆区块超低渗透储层油井的重复改造,将混合水体积压裂技术应用于老井重复压裂中,形成了老井混合水体积压裂配套工艺技术,并在考虑井网和注水条件下,进行体积压裂理论与多级暂堵多缝压裂理论的结合研究。室内工艺优化结果和9口井的现场试验表明,措施后油井的平均单井日增油量2.81 t。截至目前,平均单井有效生产天数达252天,增产效果显著。该技术的成功实施运用,为超低渗透油藏重复压裂效果的提高提供了有力的依据。 

Abstract:

Single well has low yield in Huaqing low permeability oilfield. The wells with daily output less than 1 tons account for a larger proportion of total wells, reaching 56.2% in Huaqing Oilfield. Re-fracturing is an important measure to improve the production of fractured wells in Changqing ultra-low permeability reservoirs. Currently, the re-fracturing well stimulation is not ideal by using the conventional technologies. The performances such as small yield increase, water cut rising, production decline suddenly, short increasing period are appeared after re-fracturing. In this paper, the hybrid slick water SRV and multi-stage temporary blocking fracturing are combined to work for old production wells in ultra-low permeability reservoirs. Considering the well pattern and injection well conditions, the theories of volumetric fracturing and multi-stage temporary blocking are combined. After the parameters optimization in the laboratory and application of nine wells in the field, the average single well daily output increased 2.81 t, the effective production period for average single well is up to 252 days, and the effect of increasing yield is significant. The successful application of this technique also provides a strong basis for the re-fracturing in ultra-low permeability reservoir.