可酸溶固化堵漏材料的封堵及储层保护性能

Plugging and Formation Damage Control Performance of a Lost Circulation Material

张 浩 佘继平 杨 洋 倪建军 韩 凯

ZHANG Hao SHE Jiping YANG Yang NI Jianjun HAN Kai

为了解决恶性漏失及储层段漏失控制难题，制备了一种新型可酸溶固化堵漏材料，基于室内评价手段研究了该堵漏材料的密度、粒径分布、流变性、高温高压固化性能、封堵承压性能和储层保护性能，并提出了现场应用方案。研究表明，可酸溶固化堵漏材料基浆密度为1.32 g/cm3，通过添加密度调节剂可使密度在0.8-2.4 g/cm3之间可调；材料粒径D50和D90值分别15.0 μm和50.8 μm，可以进入地层微米及以上宽度裂缝进行封堵；室温下基浆表观黏度为60 mPa·s，终切值约为初切值的2-3倍，且具有良好的稳定性。材料基浆初始稠度小于10 Bc，且可实现直角稠化，稠化时间可根据实际施工时间设定。材料抗钻井液污染能力强，10%侵入量下稠化时间延长约30 min，固结体强度未发生明显下降。8 mm裂缝封堵带承压可达18 MPa以上，可有效解决恶性漏失问题。固结体渗透率可达0.81×10-3 μm2，且在15%盐酸溶液中酸溶率为100%，可以有效保护储层裂缝渗透率。可酸溶固化材料不仅可以有效封堵恶性漏失地层，还可用于储层段漏失控制以达到保护储层的目的。

A novel acid-soluble solidified plugging material was developed to solve the difficult drilling problems in control of severe losses and lost circulation in reservoir. The properties of the acid-soluble solidified plugging material，such as the density， particle size distribution，theological property，solidification performance in high temperature and high pressure，plugging efficiency and pressure bearing ability，as well as the reservoir protection performance，were characterized by conducing comprehensive experiments，and the field application scheme was proposed. Experimental results showed that the base slurry of acid-soluble solidified plugging material had a density of 1.32 g/cm3，which could be adjusted in the range of 0.8—2.47 g/cm3 by adding density regulator. The D50 and D90 of the material were 15.0 μm and 50.8 μm，respectively，which could meet the requirements of entering and plugging the fractures with micron width and above. The apparent viscosity of the base slurry was 60 mPa·s at room temperature，the final shear value was about 2—3 times of the initial shear value. The initial consistency of the slurry was less than 10 Bc，and the right-angle thickening could be realized. The thickening time of the slurry could be adjusted according to the requirement of filed operation. The slurry was highly resistant to drilling fluid contamination，when 10% volume of drilling fluid invasion，the thickening time extended by about 30 min，while the compression strength of the consolidating body changed little. The plugging material could bear pressure up to 18 MPa in fracture with 8 mm width，curing the severe losses efficiently. The permeability of the consolidating body was 0.81 × 10-3 μm2，and the consolidating body could be completely dissolved in 15% hydrochloric acid solution，which indicated that the plugging materials could protect the conductivity of fractures in reservoirs. The acid-soluble solidification material could not only effectively seal severe thief zone，but also be applied in the reservoir because of it’s removability.