临兴气田井筒堵塞机理及现场解堵工艺研究

Research on Wellbore Blocking Mechanism andField Unblocking Process in Linxing Gas Field

临兴区块自投产以来,井筒堵塞问题日益严重,导致气井生产测试、措施作业等无法正常开展。文章结合区块堵塞物的粒径分析、无机成分XRD、红外等分析结果,明确了堵塞物成分主要包括石英、石盐、难溶盐垢(以硅铝酸盐垢为主)及少量的铁垢和固体砂砾等,主要堵塞类型为砂堵、腐蚀结垢及结盐堵塞等。通过解堵实验,优选出HYJD-10和CAWF两种解堵剂体系,静态溶蚀实验最高溶解率分别可达25.3%及18.3%,驱替实验最优渗透率的提高率分别可达105.9%及91.3%。现场结合注解堵剂、气举及泡沫流体等方式进行解堵作业,单井平均增产不小于9 000 m3/d,最高增产25 000 m3/d。本研究为致密气井井筒解堵试验提供了参考。

Since Linxing area has been put into production,the problem of wellbore blocking has become increasingly serious,leads to the failure of gas well production test and stimulation operation.Combined with the results of particle size analysis,inorganic composition XRD and infrared analysis,it is clear that the composition of the blocking mainly includes quartz,stone salt,insoluble salt scale(mainly aluminate silicate scale),a small amount of iron scale and solid sand gravel,etc.,the main types of blocking are sand blocking,corrosion scale and salt blocking.Two kinds of unblocking agent systems,HYJD-10 and CAWF,were optimized to solve the problem through unblocking test.The highest dissolution rate of static dissolution experiment could reach 25.3%and 18.3%respectively,and the optimal permeability improvement rate of replacement experiment could reach 105.9%and 91.3%respectively.Combined with the injection of unblocking agent,gas lift and foam fluid,the average production increase of single well is not less than 9000 m 3/d,and the highest increase is 25000 m 3/d.This study provides a reference for the tight gas wellbore unblocking test.