川东地区大斜度水平井排水采气技术优化

OPTIMIZATION OF WATER DRAINAGE&GAS PRODUCTION IN HORIZONTAL AND HIGHLY DEVIATED WELLS OF CARBONIFEROUS PERIOD IN EAST SICHUAN

川东地区大斜度、水平井井身结构复杂,普遍带封隔器及节流工作筒,油管存在变径,部分排水采气工艺技术及设备应用受制。借鉴直井排水采气经验,泡排和气举虽在该类气井中进行了先导性试验,取得了一定效果,但却存在泡排剂适应差、固体泡排投注遇阻,泡排效果不明显;气举阀下入深度受限,影响气举效果,而打孔气举又存在启动压力与连续注气压力差值过大的问题。通过研究,优化泡排加注方式、优选液体泡排剂,显著提高泡排效果;气举设计方法上,引入适合川东地区该类气井的地层吸液指数,增加注气深度,最大化利用地面注气设备,使气水井快速复产或提高举升效率;改进柱塞气举工具结构,解决油管变径及井斜过大对工艺的限制,使柱塞气举成为川东地区大斜度、水平井又一经济有效的排水采气手段。

Carboniferous gas reservoirs are widely distributed in the east port of Sichuan Basin and mainly developed by highly deviated wells and horizontal wells.At present,East Sichuan carboniferous reservoir development has entered into the mid-later period.The gas wells show high temperature,low pressure and low liquid level.Some of the existing gas production technology and equipment have some limitation in highly deviated wells and horizontal wells.In terms of these problems,through experimental research,a kind of high-efficiency nano-particle foam drainage agent for high temperature,high salinity and high acid gas has been developed,which can significantly improve the drainage effect.At the same time,the gas lift design method is optimized,and the formation fluid absorption index suitable for such gas wells in Eastern Sichuan is introduced to increase the gas injection depth,maximize the use of surface gas injection equipment,and enable the gas wells to quickly resume production or improve the lifting efficiency.