硼交联N_2伴注泡沫压裂液的阻力特性研究

Study on the frictional pressure drop of borate-crosslinked N_2 foam fracturing fluid

液氮泡沫伴注压裂液的阻力性能对于有效实施压裂工艺、选择合理的压裂参数、进行更为准确的裂缝预测、评估压裂效果都至关重要．利用高参数泡沫压裂液实验回路详细研究了模拟实际压裂条件下N2泡沫压裂液的阻力特性．研究表明：N2泡沫压裂液的摩擦压降梯度随着流速的增大而增大，随着温度的升高而减小，随着压力的增大而增大；摩擦阻力系数随着流速增大而增大，随着温度的升高而减小，而其随着压力的变化特别复杂．通过实验研究得出了N2泡沫压裂液在15～45MPa范围内摩擦阻力系数和广义雷诺数之间的计算关联式，其在本文实验工况下的平均计算误差为10．2％．

Borate-crosslinked N_2 foam fracturing fluid presents the property of non-Newtonian fluid,and the characteristics of its frictional pressure drop in vertical oil pipe under the conditions of actual fracturing operation directly affects the accurate estimations of fracturing pressure and fracturing result.The characteristics of the frictional pressure drop of borate-crosslinked N_2 foam fracturing fluid in vertical pipe are experimentally studied under the condition of the simulated practical fracturing operation of 15～45 MPa and 50～110 ℃.It is shown that,the frictional pressure drop gradient of the fracturing fluid increases with the increase of its flow velocity,decreases with the increase of temperature and increases with the increase of pressure.The frictional resistance factor increases with the increase of the flow velocity,decreases with the increase of temperature and its variation law with the pressure is complicated.The relational expression between the frictional resistance factor and generalized Reynolds number is obtained by the experiments,and whose average calculation error is 10.2% under the experimental condition.