一种气井泡沫排水采气效果模糊定量评价方法

A fuzzy method to quantitatively evaluate the effect of foam deliquification in gas wells

排水采气是出水气田稳产和提高采收率的主体技术,泡沫排水采气是天然气开发降本增效的重点攻关方向,而现有泡沫排水采气效果却没有系统评价方法,并且无法对不同井况的气井泡沫排水采气效果进行对比。针对上述问题,提出了一种气井泡沫排水采气效果模糊定量评价新方法。该方法确定了气井日产气变化率、日产水变化率、油套压差变化率、日注量成本变化率4个评价指标,采用线性分析方法、层次分析方法和模糊关系合成算子等计算得出评价结果。将该方法应用于苏里格气田、重庆气矿共30口泡沫排水采气井,计算出了气井泡沫排水采气效果的综合评价指数。该方法的优势在于全面考虑了影响泡沫排水采气效果和效益的技术和经济因素,以及各个评价指标之间的隶属度关系和各指标的权重系数,可对不同井况气井的泡沫排水采气效果进行综合评价和定量对比,辅助泡沫排水采气工艺措施前气井的选择,指导进行气田泡排剂的选型。

Deliquification is the primary technique for stabilizing gas production and improving gas recovery in the gas field with water produced, and foam deliquification is the key subject of research for purpose of enhancing natural gas production and reducing cost. However, there is no systematic method to evaluate and compare the effects of foam deliquification in gas wells with different working conditions. This paper introduces a fimzy quantitative evaluation method which provides evaluation results based on four indicators （i.e. daily gas production, daily water production, tubing-casing pressure difference, and daily cost of foam injection） and using the linear analysis method, the analytic hierarchy process and a fuzzy synthetic operator. Applied to a total of 30 gas wells producing by foam deliquiflcaton in Sulige Gas Field and Chongqing Division of PetroChina Southwest Oil and Gas Field Company, the method delivered comprehensive evaluation indicators for measuring the effect of foam deliquification in gas wells. Since this method incorporates all technical and economic factors that influence the results and benefits of foam deliquification, and considers the membership relation between evaluation indicators and the weight coefficient of every indicator, it can be used to comprehensively and quantitatively evaluate the effect of foam deliquificaton in gas wells with different conditions, and it is helpful to the selection of target wells and the best foam agent before deliquificaton.