沁水盆地晋城地区煤层气田固井实践

分析了晋城地区煤层气井的地质特点及固井现状,从5个方面指出了影响该地区固井质量的原因。针对这种情况,在固井中,采用低密度水泥浆,严格控制水泥浆的失水量,提高水泥浆的粘度和切力,并采用低返速顶替技术,使得固井质量优质。

CEMENTING PRACTICES IN COALBED GAS WELLS IN JINCHENG AREA OF QINSHUI BASIN

Cementing quality in the coalbed gas wells in south Qinshui Basin is very poor. This paper investigates the causes that influence the cementing quality in this area, e.g., inefficient mud displacement caused by high fluid column pressure in annular and "U" tube effect; excessive fluid loss of cement slurry because of high differential; changes of slurry density, and improper field cementing operation, etc. Based on the analysis and in combination with the characteristics of coalbed gas reservoir, some measures are taken in the following cementing jobs. Such as use lightweight cement slurry, control fluid loss, raise viscosity and shear force, displace with low flow rate in slow return velocity, and maintain even density distribution. Cementing quality is highly improved in this area.