SUCCESSFUL OBSTRUCTION REMOVAL IN HIGH-TEMPERATURE GAS WELL

Background

A client in Indonesia needed to perforate a gas reservoir to increase production. The well was flowing at around 0.2 MMscfd, and the reservoir had estimated reserves of around 0.5 Bcf.

After a 3.5” gauge cutter hung up at 4860m, a 2.3” pump bailer was run to remove debris. Only 12 liters of debris was recovered from a total of four runs.

Because the amount of debris to remove in order to reach the target depth of 4921m was expected to be substantial, the client was hesitant to continue with slickline bailers and sought alternative solutions.

Welltec® proposed the Well Cleaner® with the Well Miller® available as a contingency in case hard, or compact, debris was encountered.

OPERATION

The Well Cleaner® recovered 12.6 liters with three bailers and progressed four meters during the first run. However, recovery averaged only two liters of sand per run over the next four runs with no depth progress. Moreover, the recovered sand was contaminated with pieces of metal, likely gun debris. It was suspected that a hard restriction was blocking the Well Cleaner® progress.

The Well Miller®, equipped with a 3.5″ tapered scale bit, was then run in hole. Milling commenced at the point where the Well Cleaner® had hung up on the previous run. The Well Miller® completed four milling cycles of three-meter intervals, before being pulled out of the hole and swapped for the Well Cleaner®.

After the milling run, the recovery efficiency of the Well Cleaner® increased significantly. Recovery over the next five runs averaged between 16 and 17 liters per run. The final tag depth was 4934.7m, deeper that the target depth of 4921m.

ACHIEVEMENTS

Welltec® achieved the client’s objective. The combination of the Well Cleaner® and Well Miller® allowed the client to regain access to the reservoir for additional perforation, leading to increased production. Using Welltec’s eline interventions resulted in a faster, and more cost effective, solution than alternatives, such as coiled tubing.