超临界CO2压裂液增黏剂设计及性能测试

Design of tackifier and performance test for supercritical CO2 fracturing fluid

张俊江 李涵宇 牟建业 张劲 陶少聃 曹宸瑜2

中国石化西北油田分公司工程技术研究院，新疆 乌鲁木齐 830011 中国石油大学（北京）石油工程学院，北京102200

Petroleum Engineering Research Institute, Northwest Oilfield Company, SINOPEC, Urumqi 830011, China College of Petroleum Engineering, China University of Petroleum, Beijing 102200, China

针对超临界CO2压裂液黏度低、携砂性能差等缺点，进行了CO2压裂液的增黏剂ZNJ分子设计和助溶剂优选及性能测试，对优选后的CO2压裂液体系的流变性、携砂性、摩阻进行了测试。结果表明：在-10~60 ℃，10~20 MPa条件下，加1.0%~2.0%增黏剂的CO2压裂液黏度是纯CO2压裂液的5~61倍；增黏剂质量分数对CO2压裂液黏度影响最大，其次是温度和压力；支撑剂在加有2.0%增黏剂的CO2压裂液中的沉降速度比在纯CO2压裂液中慢14.5%~37.4%，加增黏剂的CO2压裂液携砂性能较好；在40 ℃，20 MPa条件下，ZNJ可有效降低超临界CO2压裂液的摩阻；随着压裂液流速的增加，管柱摩阻急剧增加，故压裂时应选择合适的排量以降低摩阻。

Aiming at the disadvantages of low viscosity and poor sand carrying capacity of supercritical CO2 fracturing fluids, the supercritical CO2 fluid tackifier ZNJ molecular design and cosolvent were optimized, and the performance testing was carried out. The rheological property, sand carrying capacity and friction resistance of the optimized CO2 fracturing fluid system were tested. The results show that the viscosity of CO2 fracturing fluid added with 1.0%~2.0% tackifier system is 5~61 times higher than pure CO2 fracturing fluid at -10~60 °C and 10~20 MPa; the viscosity of CO2 fracturing fluid is affected most by the mass fraction of the tackifier, followed by temperature and pressure; the proppant settling rate in the CO2 fracturing fluid with 2.0% tackifier system is 14.5%~37.4% slower than that in the pure CO2 fracturing fluid, and the CO2 fracturing fluid with tackifier has better sand carrying capacity; at 40 °C and 20 MPa, ZNJ can effectively reduce the frictional resistance of the supercritical CO2 fracturing fluid; with the increase of fracturing fluid flow rate, the friction resistance of pipe string increases sharply, so the optimal displacement should be selected to reduce the friction resistance when fracturing.

10.6056/dkyqt201805029