Calculating method on static horsehead load of water drainage and gas production equipment about beam pump for CBM wells

The horsehead load of water drainage and gas production equipment about beam pump is one of the im-portant parameters which mark its work ability.Static horsehead load plays a major role in horsehead load.Static horsehead load is the important basis of selecting and using correctly the water drainage and gas production equipments.Based on studying actual mining in Chinese CBM wells,the horsehead load of water drainage and gas production equipment was analyzed,the calculating method of horsehead load and its variation were set up,and the algorithm was verified based on the data of field measurement.The verification results show that the weight of rod string and liquid column plays a major role in static horsehead load,but pressure on the piston imposed by liquid column in outside of tubing cannot be neglected.Static deformation in up and down stroke is relatively small.The calculating method has simple steps,its results conform to reality,and it can meet the need of statistical data cal-culation for CBM wells.This will help to lay a theoretical foundation of studying the horsehead load of water drainage and gas production equipment in CBM wells.Also it has important directive significance and application value for designning calculating and selecting water drainage and gas production equipment in CBM wells.