Case 1 Descriptionof Problem New kudu pump 76K1200 wasinstalled in well on 11th May 2015 with pump setting depth at 928mbelow all perforations and ran continuously till 9th June , 2015despite increasing torque up to 115% limit.
While starting the pump at 100RPM, the water level was 18m and the torque was 11.3%. On 8th June2015, the water level had gone up to 412m, while torque had gone up to 54.2%,The TDS of water was 2250 ppm while temperature of water on surface was foundto be 53 oC. No sand production was reported during entire period. Inferencedrawn out The torque rise was seensuddenly during start-up of the well it may be due to elastomer swelling orstator choked with sand. As sand production was not reported so it can beruined out. The temperature of surface water was noted 53 o C so theelastomer swelling is possible due to high temperature.
Recommendations:- Ø Useunder sized rotor.Ø Changethe stator. Case 2 Description of Problem The 100 TP 1200 PCP was started after workover on 1st June, 2015 with initial torque 32% and water flow rate14 lpm. The variation in current and torque values started from the next dayand current variation from 25 to 31A, while torque variation from 36 to 54% dueto stick slip effect. Initially, sand production of around 1 kg/day wasobserved in this well for two days, but after that the sand production ceased.The pump ran continuously till 2nd October, 2015 with RPM ramped upto 140, while water level staying around 700m. There were no major changes incurrent and torque values.
On the well site visit on 2ndOctober, 2015, no water flow was observed with torque variation between 12-45%and current variation between 14 and 16A. The water level was recorded to be679m. The PCP was stopped and again started on the next day, while also rampingup the RPM till 300. The Current varied from 21 to 28A, while the torque variedfrom 15-40%. Water production was not observed on the surface. InferenceDrawn Out The pump was running normallyfrom 1st June till 1st October. Since the torquevariation observed during the site visit on 2nd October was low andno water production was reported, this could be due to tubing puncture in thetubing string.
Uncentralized rod string could be a root cause for the TubingPuncture. No water production was observed because as we produce water throughthe tubing string, the water being produced falls back into the annulus due tothe tubing puncture. Recommendations Ø Workover job in order to change the tubing Ø Centralizerscould be inserted in the rod string in order to minimize tubing- sucker rodcontact. Case 3 Descriptionof Problem The well was completed withnew 70K900 KUDU pump on 26th April, 2015 with pump intake depth at352m and run till 19th May, 2015. After that it was started on 10thJune, 2015 by self-flow.Before routine start up on 16thJuly, 2015 water level was 284m at 470 psi. When the PCP was started at 11:50hours at 100 RPM without opening the tubing valve, the torque was found to be9.8%, while current was 13.
4A. the torque increase was not observed through thetubing valve was not opened. At 12:15 hours, the RPM wasramped up to 150 with closed tubing valve and observed for 10 minutes but thetorque was only 10.
8% at 13.6A. at 12:20 hours, the RPM was ramped up furtherto 200 and observed for 10 minutes. But no increase in torque was observed- thetorque was 9.3% at current of 13.4A. InterferenceDrawn Out From the above case it can beinterpreted as the torque observed was very less and there was a negligiblerise in the torque values on ramping up the RPM.
This could be a reason ofsucker rod unscrewing or tubing unscrewing. The unscrewing of sucker rod ortubing was the main reason for low torque values at high RPM. RecommendationsØ Callfor a Work over job.
Conclusion:Based on the study ofChallenge and prospect of CBM the following solutions can be drawn:1. It is high time for the government to take CBMsincerely and commissioning a complete system for its exploitation andproduction in best possible way in India as other countries like USA, China,and Australia.2. Proper planning in this direction can lead tofruitful results such as proper monitoring of CBM wells and well siteoperations etc.
3. Technology plays an important role in thedevelopment of CBM resources. Thus R&D must be a priority for the time being.