Lifting the depth of rod pump with deepening tail pipe and its influencing factors

The Tahe reservoir is a fractured-vuggy carbonate reservoir about 5 350-6 600 m deep with complicated fluid properties. The highest viscosity is 245 000 mPa·s (55℃), that is, crude oil in wellbore over 3 000 m deep could not flow. Therefore, we mixed light oil into pipes to reduce viscosity. As more heavy oil reserves have been employed, the difficulty of mechanical lifting increased. We lifted the depth of rod pump and deepened tail pipe in view of different sucker-rod pump types in heavy oil blocks in the Tahe oil field, and discussed their influencing factors. By guarantee the quality of mixed oil, we reasonably lifted pump depth in order to reduce rod load, and to improve rod pump working condition.