清洁压裂液返排液渗吸驱油效果影响因素评价

Evaluation of influencing factors on imbibition displacement effect of clean fracturing flowback fluids

刘煜 杨建民 王丹 廖庆星 杜光辉 谢岩

长江大学地球科学学院，湖北 武汉 430100 中国石油长庆油田分公司第七采油厂，陕西 西安 710000 中国石油青海油田分公司采油三厂，青海 茫崖 816400

School of Geosciences, Yangtze University, Wuhan 430100, China No.7 Oil Production Plant, Changqing Oilfield Company, PetroChina, Xi’an 710000, China No.3 Oil Production Plant, Qinghai Oilfield Company, PetroChina, Mangya 816400, China

致密砂岩油藏通常需要采用水力压裂进行开采，压裂液返排液的处理及回收利用成为制约此类油藏开发的重要因素，而渗吸驱油是致密砂岩油藏开发的一种重要技术手段。清洁压裂液返排液中通常含有较多的表面活性剂，具备渗吸驱油的有利条件。因此，室内以致密砂岩油藏天然岩心和现场清洁压裂液返排液为研究对象，开展了清洁压裂液返排液渗吸驱油效果影响因素研究。结果表明：随着压裂液返排液界面张力的下降、岩心渗透率的升高，渗吸采收率呈现出先上升后下降的趋势，存在一个最佳的界面张力值和渗透率范围，使得渗吸采收率达到最大；而随着岩石表面亲水性的增强、温度的升高以及原油黏度的降低，渗吸采收率逐渐增大。矿场试验结果表明，实施清洁压裂液返排液渗吸驱油措施后，油井的产油量得到明显提高，含水率明显下降，取得了显著的增油效果。

Hydraulic fracturing is usually used in tight sandstone reservoirs, the treatment and reuse of fracturing flowback fluids are important factors that restrict the development of such reservoirs. Imbibition displacement is an important technical means for the development of tight sandstone reservoirs, and clean fracturing flowback fluids usually contains more surfactants and has favorable conditions for imbibition displacement. Therefore, taking natural cores of tight sandstone reservoirs and field clean fracturing flowback fluids as the research objects, the influencing factors on imbibition displacement effect of clean fracturing flowback fluids are studied. The results show that with the decrease of interfacial tension of fracturing flowback fluids and the increase of core permeability, the imbibition recovery shows a trend of first rising and then declining. There is an optimum interfacial tension value and permeability range to maximize the imbibition recovery. With the enhancement of hydrophilicity of rock surface, the increase of temperature and the decrease of crude oil viscosity, the imbibition recovery increases gradually. Field test results show that after the implementation of imbibition displacement measures of clean fracturing flowback fluids, oil production of oil wells has been increased obviously, water cut has been reduced obviously, and remarkable oil increase effect has been achieved.

10.6056/dkyqt202005024