页岩气排水采气技术研究及应用

页岩气井长期经济有效的生产是页岩气开发的基本要求。页岩气井积液严重影响采气生产，需要长期实施排水采气工艺。通过定制实验及现场测试发现：页岩气井后期带液生产，水平段以层流为主，斜井段为段塞流，是井筒积液开始发生的位置，斜井段积液后，液体回流导致水平段液量聚集；关井油管内的积液退回到储集能力强的长水平段，井筒液面低；油管下入水平段将限制气井产能；斜井段偏心漏失导致柱塞气举效率降低。根据页岩气井长期低压小产特征及井筒气液流动特点，提出了充分利用页岩气井能量、实现经济高效排水采气的开采对策。选定优选管柱、泡沫、柱塞作为页岩气井排水采气3项主体工艺，优化各项主体工艺的技术方案和做法，实现通过工艺辅助页岩气井自喷排水采气。页岩气排水采气技术在川南地区长宁区块推广实施后，气举助排及复产工作量降低，水淹井次减少，有效维护了老井产能。

Study and Application of Shale Gas Well Deliquification Technology

Long-term and economically-efficient production of shale gas is one of the basic requirements for shale gas development. The accumulated liquid of a shale gas well seriously affects gas production. The gas well deliquification tecnology is needed on a long-term basis. According to the tailored laboratory experiment and on-site test, shale gas production is accompanied with liquid in the later period. The liquid in the horizontal segment is mainly the formation flow while the liquid in the inclined segment is the plug flow. They are the locations for accumulation of liquid to take place in the wellbore. When liquid is accumulated in the inclined segment, the back-flow of liquid leads to accumulation of liquid in the horizontal segment. The liquid accumulated in the shut-in tube returns to the long horizontal segment where the liquid can be easily accumulated while the liquid surface of the wellbore drops. The productivity of the gas well will be limited when the tube is lowered into the horizontal segment. The eccentric leakage in the inclined segment reduces efficiency of plunger gas lift. Based on the characteristics of long-term low-pressure low production and wellbore gas-liquid flow of the shale gas well, this paper proposes the countermeasure of making full use of the shale gas well energy for economic and high-efficiency deliquification and gas production, optimizes pipe string, foam and plunger as three main technical processes for shale gas well deliquification, optimizes the technological plans and practices of various main processes, and helps the shale gas well flow by means of the auxiliary technical processes. When the shale gas well deliquification technology was used in the Changning Block in South Sichuan, gas-lift production and resumption of production needed less manpower and work while the water-flooded wells were reduced, effectively maintaining the productivity of old wells.