液体胍胶制备方法及其耐高温体系性能

Preparation Method of Liquid Guar Gum and High Temperature Resistant Performance of Hydraulic Fracturing Fluid

张大年 张锁兵 赵梦云 苏长明 郑成刚

ZHANG Da-Nian ZHANG Suo-Bing ZHAO Meng-Yun SU Chang-Ming ZHENG Cheng-Gang

针对干粉羟丙基胍胶在配液过程中出现的问题，制备以白油、表面润湿剂（甲醇与水）和乳化剂（烷基酚聚氧乙烯醚）为主的液体胍胶增稠剂（LGC），具有配制简单、分散速度快、溶胀时间短的特点。室温下，在自来水和人工海水中加入1.0%液体胍胶和0.15%甲醛，低速搅拌30 min后的黏度分别为110.11和112.40 mPa·s，与有效物含量相同的干粉羟丙基胍胶基液黏度相近。液体胍胶配制基液受水源pH值和矿化度的影响较小，用海水或矿化水配制可达到淡水配制效果，降低海上施工成本。液体胍胶和干粉胍胶配制的压裂液（羟丙基胍胶含量0.4%）在95oC破胶4 h后，破胶液黏度分别为3.542和2.243 mPa·s，破胶残渣分别为476和432 mg/L，差别较小。1.0%液体胍胶（有效物含量40%）压裂液在120oC下的初始滤失量为1.907′10-4 m3/m2、滤失系数为0.997′10-4 m/min?、平均滤失量为0.366′10-4 m3/(m3·min）。0.6%干粉羟丙基胍胶经过24 h溶胀后加入自制交联剂CYS-1及其他助剂，在160 oC、170 s-1下剪切120 min后的黏度约180 mPa·s；CYS-1交联剂与液体胍胶在30 min内完成配制，在160oC、170 s-1剪切120 min后的黏度约190 mPa·s；在170oC、1000 s-1高速剪切3 min后，再在170 s-1下剪切90 min的黏度大于122 mPa·s，实现快速配制、溶胀充分、耐高温耐剪切要求。

In order to promote the hydration process of traditional hydroxypropyl guar gum (HPG), a liquid guar gum thickening agent (LGC) was fabricated, which mainly consists of white oil, surfactant and emulgator, with simpler preparation, better dispersion ability and faster swelling. The viscosity of tap water and sea water with 1.0% LGC and 0.15% methanal was 110.11 and 112.40 mPa·s separately under low-speed mixing for half an hour at room temperature, which was the same as standard base solution with the same effective amount of HPG. Base fluid prepared with LGC was not sensitive to pH value and salinity of any water source. Both of sea water and fresh water could be used, which could dramatically reduce the construction cost in off shore oil production. Base fluid of LGC or HPG (0.4% effective content HPG) with organic borate-zirconate cross-linker CYS-1 could be completely broken with final viscosity 3.542 and 2.243 mPa·s and glue residue 476 and 432 mg/L by using 0.08% ammonium persulfate (APS) at 95 oC for 4 hrs. The base fluid with 1.0% LGC (40% effective content) and CYS-1 had initial filtration Vsp of 1.907′10-4 m3/m2, filtration coefficient Cw of 0.997′10-4 m/min? and average filtration Vcm of 0.366′10-4 m3/(m2·min) at 120oC. For powder HPG, the swelling time of base fluid with 0.6% HPG, CYS-1 and other additives was up to 24 hrs, and the viscosity was 180 mPa·s under the shear rate of 170 s-1 at 160oC. However, for the LGC sample, under the same experiment condition as above, the swelling time was only less than 30 min, and the viscosity of base fluid could be 190 mPa·s which kept above 122 mPa·s even under high shear rate of 1000 s-1 for 3 min at 170oC. LGC met the high requirement of rapid preparation, fast swelling and high temperature resistance under high shear rate.