Abstract

Abu field's production was declining due to the increasing water cut from its major producers. With water cut ranging from 50–90%, these wells needed gas lift to flow at their optimized conditions. The gas lift compressor (GLC) had been experiencing uptime problem since beginning of field production stage, which prevented it to be able to provide continuous support of gas lift supply for the field. Engine knocking problem and lube oil contamination are among the problems faced. This scenario had greatly impacted the gas lift optimization (GLOP) plan on high water cut (HWC) wells, hence affecting the field production.

Due to lack of gas lift supply, it was proposed to convert Abu-X well from oil producer into gas producer by perforating the new C-Sand reservoir. This well would be used as gas source for well-to-well gas lift, in view of the rectification of the compressor issue will be prolonged. Abu-X was originally perforated at A-Sand and B-Sand, however it was able to produce only from A-Sand. It was then idle due HWC at 94% and required gas lift to flow.

During the initial study, several identified wells would be utilizing this Abu-X gas, and the nodal analysis done showed an instantaneous incremental of 637 barrels of oil per day, which would help to boost Abu field's production. At required rate of 4 MMSCF/D and tubing head pressure (THP) of 1500 psia, this well would be able to sustain its supply for at least 1 year and recover 54% of the reserves i.e. almost 2.0 BSCF. Assuming the GLC will be able to back online and maintain its continuous operation; this well also can be used as future gas source for the GLC.

The re-completion job of Abu-X to gas well was successfully conducted in April 2013. The intervention work, which utilized coiled tubing unit was deemed to be a challenging operation due to the massive scope of work and risk it imposed i.e. highly deviated well, top to bottom isolation-perforation target zone and thru-tubing gravel pack application. Nevertheless, a prudent and integrated approach involving all disciplines, had assisted in ensuring the viability of the project.

The application of new technology like Double Ended Distributed Temperature Survey (DE-DTS) utilizing Real-Time Downhole Monitoring Coiled Tubing (1st such application in Asia) had helped to improve and optimize the well profiling. It eliminated the need for cementing job for B-Sand, hence the cost, and ensured a precision depth correlation in high deviation of Abu-X well. In addition, Thru Tubing Gravel Pack (TTGP) application would ensure the integrity of the wellbore from sand production, while at the same time contributed a huge cost saving of estimated RM 14 million, compared to conventional gravel pack done by the rigged operation.

The well has been flowing the gas required for the gas lift for Abu field. With the current gas lift optimization is on-going, it is expected gas lifted well will boost and sustain Abu field production.

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