钻井泥浆泵失控/重载引发的波动压力

泥浆泵失控/重载引发的不稳定流动对泥浆泵设备损害较严重,容易给钻井作业带来安全隐患.考虑钻井液压缩性、管道弹性,结合井口泥浆泵及其管路的特殊结构,建立了钻井中泥浆泵失控/重载等事故引发的泵入口管线的波动压力模型.以一个具体的工程实例为背景,借助计算机编程对其求解.计算结果表明,当立管压力为18 MPa时,双泥浆泵失控引发的波动压力高达6.77 MPa,双泥浆泵重载引发的波动压力高达11.59 MPa;随泥浆泵数量增多/立压增大,增大了泥浆泵高速运转的惯性,从而泥浆泵入口管线所受波动压力增大;随泥浆泵入口管线长度增大,增大了波动压力的摩擦阻力做功,减小了波动压力动能及压力势能的转换,从而泥浆泵入口管线所受波动压力减小,波动压力叠加时间滞后.

Fluctuating pressure caused by runaway/overload of mud pump in drilling operations

Unsteady flow caused by runaway/overload of mud pump can seriously damage the equipment, easily raising security risks in drilling operations. This study constructs a mathematical model for predicting surge pressure in pump suction line caused by accidents such as runaway/overload of mud pump in drilling operations. Model construction is based on considerations of drilling mud compressibility and drill string elasticity, combined with special structures of wellhead mud pump and its pipeline. The proposed model is solved using computer programming through an example study. Under standpipe pressure of 18 MPa, surge pressures caused by runaway and overload of dual mud pumps are up to 6.77 and 11.59 MPa, respectively. With increasing number of mud pumps, the inertia in high-speed operation of mud pumps is increased, thereby elevating surge pressure in the pipeline. With increasing length of the pipeline, the frictional resistance of fluctuating pressure is increased, while its conversion from kinetic to pressure energy is reduced. These changes ultimately result in a reduction in fluctuating pressure and a time lag in fluctuating pressure super imposition in the pipeline.