Determination of the Time of Accumulation of a Liquid in Periodic Gas-Lift Wells

Abstract

Introduction. The problem of increasing the effi ciency of the periodic gas-lift production of oil is of great practical importance. It should be noted that, all things being equal, the effi ciency of a periodic gas-lift hoist depends in many respects on the rate of pumping-out of the liquid accumulated in a well. Therefore, the period of accumulation of the liquid fl owing into the well from a pool should be regulated such that the amount of the liquid pumped out from the well during a day be maximum. To attain this level of oil production, it is necessary to know the dependences of the discharge of a periodic gas lift on the parameters of the pool–well system and the regime of pumping-out of the liquid. The indicated problem was investigated in [1, 2]. However, in these works, the infl uence of the seam pressure on the fi ltration of a pool was considered in the simplifi ed form, which can lead to a large disagreement with practice. Therefore, the determination of the period of accumulation of a liquid in a well, during which a maximum discharge of the well is attained is of great practical and scientifi c importance. Formulation of the Problem and Methods of Its Solution. We will consider a periodic gas-lift well (Fig. 1), in which a gas-lift valve is positioned at a depth l. A simplifi ed variant of the problem being considered will be solved in a fi rst approximation. It is assumed that the amount of the liquid fl owing from a pool into the well in a unit time is directly proportional to the difference between the contour Pc and seam Ps pressures. In this case [2] Q