空心杆中管掺热液体闭式循环井筒流体温度计算模型

Calculation model of wellbore fluid temperature for mixing hot liquid closed-cycle within inner pipe and hollow rod in rod pumping wells

针对稠油井井筒流体流动条件和举升效果差的问题,研究了抽油机井空心杆中管掺热液体闭式循环举升工艺,建立了抽油机井空心杆中管掺热液体闭式正循环和闭式反循环的井筒流体温度计算模型,并分析了掺入热液体的温度和质量流率对井筒中地层产出流体的温度分布和抽油机井的悬点载荷的影响。结果表明,提高掺入热液体的温度和质量流率,井筒中地层产出流体的温度升高;正循环和反循环方式分别有利于提高热交换井段下部和上部的地层产出流体的温度;反循环方式时地层产出流体在井口温度较高,更有利于地面集输;抽油机井的最大悬点载荷减小,最小悬点载荷增加,载荷差降低,举升效果得到改善,且正循环方式的举升效果优于反循环方式。

The closed-cycle lifting techniques of the pumped well with the mixing hot liquid in the inner pipe of hollow rod are studied, and the temperature calculation models of the wellbore fluid for both the normal closed-cycle and the reverse closed-cycle are developed with respect to heavy oil well's low wellbore flow condition and poor lifting efficiency. The impacts of injection temperature and injection rate on the producing fluid's temperature distribution and the polished rod load of the pumped well are analyzed. The results show that with the increment of injection temperature and injection rate, the temperature of the producing fluid in the wellbore increases; the normal cycle and the reverse cycle are respectively beneficial to increase the producing fluid's temperature in the deeper part and the lower part of the heat interacting section in the wellbore; the reverse cycle leads to higher producing fluid temperature of the wellhead and therefore is favorable for producing liquids' surface transportation; both the normal cycle and the reverse cycle can reduce the load difference, as well as improve the lifting efficiency by reducing the maximum polished rod load and increasing the minimum polished rod load while the normal cycle has a higher lifting efficiency.