Increase gas production at shallow zone reservoir in PSU Area, North Sumatera

Abstract

PSU Area is known as one of gas producer field in North Sumatera. One of the fields which supports in producing gas in PSU Area is DRO. DRO is an oil and gas field that is included in the North Sumatra Province managed by PT. Pertamina EP Asset 1. The surface location of DRO field is in the form of tidal swamp areas with mangrove plants. Gas production in PSU had decreased about 0.54 mmscfd in September 2016. Since October 2016, DRO Field has already contributed in increasing gas production in PSU area by producing gas in shallow zone reservoir. The reservoir is developed in some of the gas wells, for example, DRO-51, DRO-38, DRO-45, DRO-48, DRO-36. Gas production cumulative of the reservoir until the end of January 2019 is about 620.5 MMSCF. The problem encountered in developing this reservoir consists of liquid loading that restrains gas production of the well. The root causes of this problem are the matter of potential layer selection and bad cement bonding behind the production casing. The matter of layer selection occurred at well DRO-45, DRO-36, DRO-38 and bad cement bonding at well DRO-51, DRO-36, DRO-48, that result in wells-shut in. There are two solutions that given to the problem, the first one by doing remedial cementing to the bad cement bond layer that close to aquifer zone based on Cement Bond Log reading and the second one by perforating the selective potential reservoir based on high resistivity log and appropriate neutron porosity-density log reading. By doing these solutions, gas production is sustainable, and the lifetime of the wells increased.