深层页岩气压裂用高黏高降阻一体化稠化剂的制备与性能评价

Preparation and Performance Evaluation of Integrated Thickener with High Viscosity and High Drag Reduction Used for Fracturing Deeper Shale Gas

魏娟明 贾文峰 陈昊 冯玉军

WEI Juanming JIAWenfeng CHEN Hao FENG Yujun

滑溜水水力压裂是高效开发页岩气的重要方法，但存在黏度低、淡水用量大和胶液不可自由转换等系列问题，限制了其在3500 m以深的深层页岩气中的应用。为解决上述问题，以丙烯酰胺、2-丙烯酰胺基-2-甲基丙磺酸等为原料，通过自由基聚合反应，室内合成了高黏高降阻一体化稠化剂（HVFR），考察了其溶解性、增黏性、降阻性、携砂性及耐温耐剪切性。结果表明，HVFR的相对分子质量为22.7×106。HVFR溶解速率快，1 min 增黏率达到93%，有利于实现压裂液的在线连续混配。HVFR的降阻性能良好。在150 L/min 流量下，作为低黏、高黏滑溜水时的降阻率均大于70%，作为胶液时的降阻率可达到68%。HVFR具有一剂多能特性，通过调整其浓度可实现低黏滑溜水、高黏滑溜水和胶液之间的自由转换。基于HVFR的交联压裂液具有良好的携砂能力及耐温耐剪切性能。在120 ℃、170 s-1下剪切120 min后，压裂液的保留黏度约为120 mPa·s，满足压裂施工的要求。

Slick water hydrofracking is an important method for the efficient development of shale gas，but there are a series of challenges such as low viscosity，large freshwater consumption and slick water-to-gel transition，which limit its application on the hydrofracking of deeper（>3500 m）shale gas reservoirs. In order to solve these problems，an integrated thickener（HVFR）with high viscosity and drag reduction was synthesized by free radical polymerization of acrylamide and 2-acrylamido-2- methylpropanesulphonic acid. The solubility，thickening ability，drag reduction，proppant carrying capability and temperature and shear resistance of HVFR were studied. The results showed that the relative molecular mass of HVFR was 22.7 × 106. HVFR thickener exhibited a rapid dissolution rate with thickening rate of 93% within 1 min，which was conducive to the online continuous mixing of fracturing fluid. HVFR thickener exhibited significant drag reduction performance. At a flow rate of 150 L/min，the drag reduction of slick water was higher than 70% for both low and high viscosity，and that was up to 68% for gel. HVFR thickener exhibited multifunctional properties and could be freely transited between slick water with low and high viscosity and gel by altering the concentration of HVFR. The cross-linked fracturing fluid based on HVFR displayed not only remarkable temperature and shear resistance，but also good proppant carrying capacity. The viscosity of cross-linked fracturing fluid could be maintained about 120 mPa·s after shearing 120 min at 120 ℃ and 170 s-1，which met the requirement of fracturing operation.

10.19346/j.cnki.1000-4092.2022.02.008