p.943
p.950
p.957
p.965
p.971
p.977
p.984
p.993
p.1000
Analysis of N80 Tubing Failure for CBM Well Drainage
Abstract:
Aimed at the serious problem of N80 tubing failure in the drainage of CBM (Coal bed methane) well, it can define the failure into two types: eccentric failure wear and the corrosion failure, through analyzing the well space structure, the stress and the chemical reaction on the tube in the coal bed water. The main reason is well deviation, instability of rod string and rod vibration. It makes sucker rod contacts with the N80 tube, when the sucker rod is up and down, the friction exists between the sucker rod and the tube, which leads to the tube wear out. Corrosion failure may happened in the condition that there are some acid anions in the coal seam water, such as HS-, S2-, Cl-, HCO3-, SO42-, CO32-, etc. These ions react with N80 tubing that corrodes and destroys the N80 tube. In this paper, we suggest to replace the N80 tube with the UHMWPE (ultra-high molecular weight polyethylene) liner tube. This is capable to reduce the wear and corrosion rate effectively. The field tests show that it is still useful over 600 days, which means that the serving life of UHMWPE liner tube can be increased over 50 percent than others. Therefore, it has a significant meaning to popularize UHMWPE liner tube in the CBM well.
Info:
Periodical:
Pages:
971-976
Citation:
Online since:
March 2016
Authors:
Keywords:
Price:
Сopyright:
© 2016 Trans Tech Publications Ltd. All Rights Reserved
Share:
Citation: