考虑摩阻损失的水平井长度优化

OPTIMIZATION OF THE HORIZONTAL WELL LENGTH CONSIDERING THE FRICTION LOSS

井筒压降会影响水平井的产能,传统的水平井产能公式不考虑井筒压降。为了得到井筒的压降方程,把水平井水平段看作水平管路,并且假设地层流体均匀流入井筒,利用伯努利方程得到管路任意两个断面之间的摩阻损失,进而得到层流和紊流条件下井筒中的压力梯度,经过积分得到水平井跟部和趾部之间的摩阻损失。根据Joshi公式得到水平井在水平面和垂直面上的摩阻,再结合井筒中的摩阻,利用等值渗流阻力法便可得到水平井在层流和紊流条件下的产能公式,最后优选出水平段的长度。

Wellbore pressure drop will affect the productivity of the horizontal well,the conventional productivity formula of the well does not consider the wellbore pressure drop. In order to obtain the wellbore pressure drop equation,taking the level of the horizontal section as horizontal pipeline,and moreover assuming the formation fluids uniformly flow into the wellbore,the pipeline friction losses between any two cross-sections were achieved from Bernoulli equation,and then the pressure gradients were got under the conditions of the laminar and turbulent flows,and furthermore with the help of the integration,the friction loss between the heel and the toe of the horizontal well was obtained. According to the formula of Joshi,the frictions on the horizontal and vertical planes of the well were gotten,and moreover combing with the wellbore frictions,the productivity formulas of the well under the conditions were achieved by means of the equivalent flow resistance method,finally the length of the horizontal section was optimized.