Bhagyam field is an onshore, shallow field containing light sweet oil (27° API) with low Gas Oil Ratio (GOR) (~100 scf/stb). The crude has ~30% wax content with moderate insitu oil viscosity of ~ 50–250 centipoise (cP) with wax appearance temperature (WAT) ~2° C lower than the reservoir temperature of 53° C. With water production, it was initially expected that viscosity of production fluid will rise upto 3000 cP due to emulsification.

Rod driven Progressing Cavity Pump (PCP) system was selected as artificial lift for the field development considering low GOR and relatively high fluid viscosity. To ensure flow assurance of the high WAT crude, various methods such as annular hot water circulation, heater cable, vacuum insulated tubing (VIT) etc were considered. Based on the analogue Mangala field, which is located in the same license area, it was decided to utilize annular hot water circulation as the downhole heating methodology as it provided a significant completion design similarity with previous installation and operational experience. This completion involves running Colied Tubing (CT) clamped to the main production tubing as a secondary string. The main production tubing with PCP stator is stabbed in a production packer for downhole isolation.Hot water is circulated at 85° C down the coil taking returns through the annulus. This arrangement ensures temperature of the fluid inside the main production tubing is maintained higher than the WAT at all times.

In the 1st phase of field development, wells completed with PCP and have been successfully operating for ~ 2 years meeting requirement of flow assurance & PCP run life. However, PCP efficiency was lower in high GOR wells, as downhole gas separation was not possible. For the 2nd phase of development, alternate completion designs which can mitigate the downhole flow assurance challenges and at the same time open up the annulus similar to a conventional PCP application were considered and finally hollow rod driven PCP design was selected as the most suitable method.

The paper details PCP application in Bhagyam field during the first two phases of development, installation & operating practices, lessons learnt & overall system performance.

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