Coal Powder Suspending Agent Used In Coal-Bed Fracturing

There is much coal powder generated during coal-bed fracturing。The small specific gravity but strong hydrophobicity make coal powder easy gathered, which will block off coal-bed fractures, be harmful to the expansion of cracks, and cause permanent damage to the permeability of coal seam.Coal powder suspending ability of different common surfactants is investigated, and the The mechanism of action is discussed.Infrared spectral analysis showed that aliphatic hydrocarbons, aromatic hydrocarbons and oxygen containing functional are the main three groups on the coal powder, and the great number of aliphatic hydrocarbons, aromatic hydrocarbons direct cause coal powder surface strong hydrophobic.The coal powder suspending ability is influenced by the concentration of suspending agent, but influence of the majority of suspending agent is not obvious within certain range of concentration.Compound studies have shown that when the1831, SDS, LAS compound with AEO-9respectively, the suspension of pulverized coal capacity has increased to some extent. Especially when LAS compound with the AEO-9,the suspension rate reached37.72%while the concentration is0.2g/LThe wettability of the surface of coal can be improve effectively as the suspending agent adsorbed on the surface of coal, and the surface tension of working fluid is reduced greatly also, then the coal powder can be suspended in working fluid.There is no unfavorable effect on viscosity and shear resistance of the system which coal suspending agents added to guar gum, hydroxypropyl guar gum, carboxymethyl guar gum, and the breaksurface tension and viscosity of glue reduced. These shows the suspending agent can be added to fracturing fluid.There are50.53%,46.71%of the coal can be washed out from the cracks by1831、OP-40separately, which show that coal powder can be dispersed in the working fluid, then the harm caused by coal powder in coal seam fracturing will reduced.