胜坨油田抽油机井沉没度的优化分析

Optimal Analysis of Submergence Depth of Rod-pumped Wells in Shengtuo Oilfield

抽油机井的沉没度是影响泵效和系统效率的重要因素。一定的沉没度能够使产出液具有一定的能量,从而平衡掉压头损失,打开泵阀,进入泵内,在活塞的往复运动下举升到地面。沉没度的大小不仅影响到泵效大小,更影响到整个机采系统效率的大小。沉没度过小,自由气可能脱离而吸入泵中,影响抽油泵的排量系数,从而影响泵效和系统效率;沉没度过大,下泵深度就增大,杆管增长,造成冲程损失增加,系统总的举升负荷增大,这又会使抽油泵的排量系数降低,影响泵效。另外,增大沉没度就增加了原油中溶解的气量,溶解气在地面脱出后将引起原油的体积收缩,严重影响抽油机系统效率,使地面产量减小。所以,需要确定一个合理的沉没度值,实现泵效和系统效率最优。结合生产实际,合理优化不同作业类型下的抽油机井沉没度设计标准,为油田生产提供设计依据。

Submergence depth of the rod-pumped wells is the key factor that influences pump efficiency and system efficiency.The energy of the produced fluid makes it balance headloss,unclose pump valve,run into the pump and be lifted to the ground by means of plunger ′ s reciprocate at definite submergence depth.The submergence depth may influence pump efficiency and even system efficiency of the whole mechanical pro-duction.Much low submergence depth,free gas may be separated and sucked into the pump,and the pump efficiency and system efficiency may be influenced through the changed discharge factor of the oil pump.Much high submergence depth,stroke loss and total lift load of the system will increase for the increase of pumping depth and rod,which will influence the pump efficiency through lower discharge factor of the oil pump.The increase of the submergence depth will increase dissolved gas in the crude oil.And the dissolved gas removed on the ground will result in volume shrinkage of the crude oil and even the change of the system efficiency and decrease of the surface production.A reasonable submergence depth needs for realizing the optimal pump efficiency and system efficiency.Combined with actual production,design criteria of the submergence depth of the rod-pumped wells should be optimized for various operation types,which will provide design foundation for oilfield production.