Prudent and Integrated Production Planning to Maintain Excellent Operations in Angsi Field, Peninsular Malaysia Operations

Abstract

Angsi Field is an offshore field located in offshore Peninsular Malaysia, developed with an integrated oil and gas processing plant, water injection facilities and gas lift infrastructure. The field was brought to oil production at an initial rate about 30 Mstb/d in end 2001. In early 2002, it started gas production at an initial rate of about 300 MMscf/d of gas which is currently maintained at about 300–400 MMscf/d. Crude oil production peaked in 2005 and was followed by a moderate decline over the next three years. Besides crude oil and gas production, the field also produces condensate while producing gas. It was recognized that a proactive field management strategy was required in order to minimize any further production decline and maintain excellent production operations as the field production forecast showed a declining trend. Four key levers for sustaining Angsi's production were identified, namely:prudent reservoir management and reliable water injection;continuous production improvement and unfailing well integrity;facility optimization and operational improvement; andmaintenance of high equipment uptime and infrastructure integrity. On top of those four levers, prudent and integrated production planning was very important in managing the integration of sub-surface and surface aspects. Various sub-surface and surface technologies were sourced with a target of sustaining production and maximizing oil and gas recovery. The look-back analysis presented here describes the use of an integrated approach in production planning and creativity in resolving problems involving reservoir management & well integrity and production operations through teamwork building. Introduction The Angsi Field is located 165 kilometers east of the Kertih coast line in water depth of 70m. The field is developed under the terms set forth in the Gas Production Sharing Contract ("GPSC") between PETRONAS Carigali Sdn Bhd ("Carigali"), ExxonMobil Exploration and Production Malaysia Incorporation ("EMEPMI") and Petroliam Nasional Berhad ("PETRONAS"), the national oil corporation of Malaysia. The field was discovered by drilling Angsi-1, a wildcat well offshore Terengganu, Peninsular Malaysia in 1974, followed by the first three appraisal wells drilled in 1995 and the second two appraisal wells drilled in 1997. The oil is produced from Sand Group I while the gas is produced from Sand Groups I and K. Water injection was identified as the suitable method for reservoir pressure maintenance from the first day of production with a voidage replacement ratio (VRR) target of one. Wells at the Angsi field typically have dual completions and multiple packers to allow sequential or commingled production from multiple zones. This strategy has been implemented to reduce the number of wells while maintaining a high number of drainage points. Prior to mid-2006, the Asset Base management approach was applied where production planning of the Angsi Field, was taking role in managing the exploration and production of Angsi Field and three other blocks in the region. To sustain competitiveness and resilience against the changing business landscape, the Asset Base approach was subsequently replaced by the Functional Base management method. Since then, some changes were made to suit the new functional base.