海上X油田大位移CO_(2)回注井油管尺寸优选及井筒流态分析

Optimization of Tubing Size and Wellbore Flow State Analysis for Extended-Reach CO_(2)Injection Well in Offshore X Oilfield

对于海上X油田大位移CO_(2)回注井,采用412″油管即可满足工程压缩机对回注压力的限制。在不同注气量下,井筒流体的温度、压力及流态各异。首先,在高、中注气量下,井筒流体温度随井深增加而降低;在低注气量下,井筒流体温度在空气段和海水段迅速下降而后随井深增加而升高。其次,在高注气量下,井筒流体压力随井深增加而增大,直至接近水平段时开始随井深增加而降低;在中、低注气量下,井筒流体压力随井深增加而增大。此外,当处于温压超临界状态时,流体在高、中注气量下呈气态,在低注气量下呈不同流态依次转换。

For the extended-reach CO_(2)reinjection well in offshore X oilfield,412″tubing can meet the limit of the engineering compressor on the reinjection pressure.The temperature,pressure and flow pattern of wellbore fluid are different under different gas injection rates.At medium and high gas injection rates,the wellbore fluid temperature decreases with the increase of well depth,and at low gas injection rates the wellbore section and the seawater section decrease rapidly and then increase with the increase of the well depth.When the gas injection rate is high,the wellbore fluid pressure increases with the increase of the well depth,and after reaching the near horizontal section,the wellbore pressure decreases with the increase of the well depth.At medium and low gas injection rates,wellbore fluid pressure increases with the increase of well depth.When it is in the supercritical state of temperature and pressure,the fluid is in the gas state at medium and high gas injection rates,and in the different gas states at low gas injection rates.