Cementing technology of foam cement slurry for coalbed methane well and its application

Aimed at the characteristics of CBM wells in south part of Qinshui basin, such as low pressure, easy leakage and easy collapse, high performance foam cement(HPFC) system of ultralow density and temporary plugging prepad fluid system were developed and cementing technology with foam cement slurry for coalbed methane well was formed. The density of HPFC system is 1.10~1.20 g/cm³, it has many advantages, such as good flowing properties, no free liquid, stable sedimentation, small API filtration loss (≤ 50 mL/30 min), reasonable thickening time and high strength of set cement. The temporary plugging fluid system has good rheological properties, good leaking stoppage capacity for seam.3. The paper summarizes technological matching measures of foam slurry cementing techniques from the amount of cementing slurry and displacement fluid on the basis of the leakage situation, returning situation of drilling fluid and hole wall stabilization condition. This cementing technology has been applied in 4 wells for field test at the southern Qinshui basin, and good effect is obtained.