川西中浅层气井速度管柱排采工艺经济评价

Economic Evaluation for Application of Velocity String to Enhance Gas Production of Middle-Shallow Gas Wells in Western Sichuan Gas Field

川西中浅层气井普遍产水,对气井稳产影响较大,为提升气井携液能力,川西气田于2012年开始引入速度管柱排采工艺。大部分井实施该工艺后带液稳定,有效控制了气井产量递减速度,但有部分井存在实施后效果较差,经济效益不佳的现象。在统计川西中浅层气井的速度管柱作业各项费用基础上对速度管柱排采工艺成本进行了合理测算,并对不同产量下介入速度管柱以及介入后递减率降低值不同时的工艺经济性进行了评价分析。结果表明,速度管柱排采工艺在中浅层气井具有一定的经济效益,但由于部分井介入前产量过低使总体收益有限,为保障较好的经济效益,需尽可能选择日均产气量大于1×104 m 3的气井进行作业。同时开展了天然气价格等影响因素波动时的敏感性分析,为川西中浅层气井速度管柱排采工艺的投资选择提供了经济上的决策依据。

Water breakthrough has significant impact on stable gas production of gas wells.This phenomenon is common in mid zone and shallow gas wells in Western Sichuan Province gas field.Installation of velocity string was introduced in 2012 to improve liquid loading of these gas wells,to increase gas production.Most of the wells have stable liquid loading after installation of velocity string,effectively mitigating the gas production decline.However,there are still some wells that do not benefit much from velocity string installation,resulting in poor economic return of the investment.This paper presents the economic evaluation of velocity string installation based on the statistics of various cost items,and assess the cost and economics of velocity string installation in gas wells under different stages of gas production decline.The results show that velocity string installation has economics advantage in most gas wells producing from mid and shallow reservoir zones.However,the effectiveness of velocity string is dependent on intervention timing.It is found that velocity string is most effective if installed before the gas production of the well falls below 10000 m 3/day.Sensitivity analysis was also carried out on factors including natural gas price fluctuation.This economic analysis provides sound basis for decision making on investment in velocity string for middle-shallow gas wells in Western Sichuan province gas field.