Research And Application Of Ultra-light Weight Cementing Technology For Coalbed Methane Wells

Coalbed methane is a new source of efficient secure energy,which has a very important value of exploitation.Seam is a low-pressure and low penetration reservoir.So leakage,collapse and poor cementation are easy to occur during cementing.To solve the above problems,it has a very important significance to come up with a ultra-light weight cement slurry system,in order to achieve low damage and efficient development of coalbed methane wells.This paper systematically analysis the microstructure and particle size distribution of float beads,hollow beads and hollow glass beads and compares shear capability of various lightening materials.Finally hollow glass bead S3 8 was selected as the optimal lightening material for the ultra-light weight cement slurry system.Development of active filler material is based on the particle size distribution of oil well cement and lightening materials.The closely packed granular materials is achieved by using theoretical analysis and calculation of the characteristic equation of powder grain group.Combination of theoretical calculation and experimental validation,evaluated by cement slurry time,static gel strength,compressive strength and volume change rate of cement paste,ultra-light density cement slurry system is eventually developed,whose density is 0.82-1.20g/cm3.Also,supporting admixtures are optimized in the process,such as dispersant,fluid loss additives,early strength agent and so on.The rheological performance and sedimentation stability of ultra-light weight cement slurry system are very good,which can fully meet good demand in the field test of coalbed methane wells.