新型二氧化碳干法压裂增稠减阻剂理化性质评价

Physicochemical Properties Evaluation of New Carbon Dioxide Dry Fracturing Thickening and Resistance Reducing Agent

摘要: 针对二氧化碳干法加砂压裂中二氧化碳黏度低、携砂困难、易砂堵、注入过程井筒摩阻大、施工压力高、铺砂浓度低、常规支撑剂无法满足低温高压状态压裂施工等问题，系统表征所研制二氧化碳干法压裂增稠减阻剂的理化性质和微观结构，评价研制二氧化碳干法压裂增稠减阻剂的性能，包括溶解度、耐温、滤失，优化参数。为我国二氧化碳干法压裂以及非常规油气资源开采提供实验数据和方法支撑。采用红外光谱、紫外光谱、核磁共振等表征方法，分析增稠减阻剂XZ-CTR的组成、结构特征，评价其微观组构，对其二氧化碳干法压裂增稠减阻剂的性能进行评价。通过实验建立了以温度和黏度作为评价指标，综合评价增稠减阻剂XZ-CTR的评价方法，在温度35℃时，压力18.6 MPa的条件下，增稠减阻剂与CO₂的最大溶解度为0.3%。实验结果表明，二氧化碳干法压裂增稠减阻剂适合低温高压状态下压裂施工。

Abstract: Aiming at the problems of carbon dioxide dry sand fracturing, such as low viscosity of carbon dioxide, difficulty in carrying sand, easy to be plugged by sand, high friction of wellbore in the injection process, high pressure in the construction, low concentration of sand spreading, and inability of conventional proppant to satisfy the low-temperature and high-pressure state of fracturing construction, the physicochemical properties and microstructure of the developed carbon dioxide dry fracturing thickening and drag reducing agent were systematically characterized, the performance of the developed carbon dioxide dry fracturing thickening and drag reducing agent was evaluated, including solubility, temperature resistance, filtration loss, and optimized parameters, providing experimental data and methodological support for carbon dioxide dry fracturing as well as unconventional oil and gas resource extraction in China. The composition and structural features of the thickening and drag reducing agent XZ-CTR were analysed by infrared spectroscopy, ultraviolet spectroscopy, nuclear magnetic resonance and other characterization methods, and its microstructure was evaluated to evaluate its performance as a thickening and drag reducing agent for carbon dioxide dry fracturing. A comprehensive evaluation method of thickening and drag reducing agent XZ-CTR was established through experiments using temperature and viscosity as evaluation indexes. Maximum solubility of thickening and drag reducing agent with CO₂ is 0.3% at a temperature of 35°C and a pressure of 18.6 MPa. The experimental results show that the CO₂ dry fracturing thickening and drag reducing agent is suitable for fracturing construction under low temperature and high pressure.