The First Subsea Completion by an Operator in KN Field, Offshore Malaysia

Abstract

The KN field in KM cluster is located approximately 200km offshore, at water depths ranging from 59–102m. The field is part of the KM Cluster Integrated Development Plan, where the primary objective for KN field development is to recover the reserve from fringing pinnacle reef carbonate reservoir, expected to be achieved through two deviated 7-inch open-hole monobore subsea wells. KN field is expected to deliver around 200 to 300 MMSCF/day to the LNG plant to help relieve an anticipated gas shortage, as such failure to deliver the target would definitely upset the gas supply. Besides cost savings, the shallow water subsea development concept is part of the company's long-term vision to train its staff with new technologies and prepare them with basic guidelines for future development especially in deepwater. Although this is already considered a norm in other parts of the world, subsea completion is relatively a new experience in the company operation. The open-hole sections were drilled using Potassium/Sodium formate fluids with calcium carbonate as weighting and bridging agent and later the wells were completed with Cessium formate. Based on extensive laboratory test, it was found that this formate fluids allow for thin mud filter cake that can be remove effectively with differential pressure alone, excluding the need for filter cake breaker. High rate acidizing was planned as contingency should the wells failed to deliver the targeted well deliverabilities. Based on transient simulation using OLGA, high rate clean-up were planned to ensure effective filter cake break-up, removing debris and confirming the technical potential of the wells. With high rate, the duration of well clean-up is shorter and effective thus saving rig time. This paper details the planning and execution towards achieving the successful project of KN field, the 1st subsea development in the company

Experience with Formate Fluids for Managed Pressure Drilling and Completion of Subsea Carbonate Gas Development Wells

“…The results of the MRT measurements on well SS-1 are shown in Table 6 [Mahadi et al, 2013]. The test results confirmed that both wells could produce over 150 MMscfd of gas, giving a total production rate potential of greater than 300…”

“…The aim was to achieve a production rate of 60 MMscfd within 2 hours, increasing to 100 MMscfd within 4 hours [Mahadi et al, 2013]. OLGA multiphase flow transient simulations predicted that full well clean-up would be achieved within 6 hours from start-up prior to conducting well deliverability tests.…”

“…Although both wells showed excellent productivity after natural clean-up by drawdown, it was decided to subject the well SS-1 to a high rate acidising treatment using 15% HCl and a gelled diverter system [Mahadi et al, 2013]. A total of 331 barrels (bbl) of 15% HCl and 83 barrels of gelled diverter were pumped into the open hole at 16-36 barrels per minute.…”

“…A 7" pre-drilled liner was to be installed across the deviated (26-30 degrees) 100-200 metre open-hole sections. Target gas production was 100 MMscfd from each well [Mahadi et al, 2013]. The plan required the use of low-solids well construction fluids to minimise formation damage and ensure maximum rates of gas production from the reservoir.…”