“多井联合气举+环空激动降压”组合复产工艺在水淹井中的应用及评价

Reproduction Combining Multiple-well Compound Gas Lift and Annular Surge Pressure Drop to Water-flooded Wells

随着大牛地气田开发步入中后期,气井产能不断降低、携液能力逐渐变差,水淹井日趋增多、严重影响气田的长期稳产。目前,现场最常用的单一排液复产工艺有液氮气举、多井联合气举、井口排液气举、环空激动降压、套管充压气举。这些成熟的工艺技术以其各不相同的特点在积液停产气井的排液复产中发挥着重要作用。但对于套压低于8 MPa、液气比高于5 m^3/10~4m^3的积液严重水淹井,采用单一复产方法效果不佳。为此,选取两口积液严重水淹井开展了"多井联合气举+环空激动降压"组合复产试验,并进行了经济效果评价。现场应用表明,两口水淹井均复产成功,成功率为100%。经济评价显示,两口水淹井复产后日增产量12 617 m^3、累计增产量837.572×10~4m^3,累计创效971.59万元,投入产出比为1∶810,经济效益显著。

In Daniudi gasfield, with moving into middle to late development stages, the deliverability and liquid-carrying capability are getting worse, and water-flooded wells become more and more,seriously affecting a long-term and stable production. At present,there are common-used reproduction technologies including liquid nitrogen gas lift, multiple-well compound gas lift, wellhead liquid discharge and gas lift, annular surge pressure drop, and casing boosting gas lift. These mature technologies with different features are important to water drainage and reproduction for many shut-in gas wells due to liquid accumulation. However, their application to those water-flooded wells, which are characterized by more serious accumulation, casing pressure of less than 8 MPa and liquid-gas-ratio of more than 5 m3/10~4 m^3, are often fruitless. So, taking two water-flooded wells with serious accumulation as examples, we implemented an experimental reproduction combining multiple-well compound gas lift and annular surge pressure drop, and evaluated its economic effect. Results show that the two wells obtain a success ratio of 100 %, illustrating this reproduction has a better effect. In addition, our evaluation also reveals that, its application also gains obvious benefits, such as the daily and cumulative incremental production of both 12 617 m^3 and 837.572 × 10~4 m^3, the created benefits of RMB 9,715,900, and the input-output ratio of 1∶810, respectively. In general, it shows a good prospect in the middle to late development stages for Daniudi gasfield.