Real Time Optimisation in Gas Constrained System Results in Production Gain
Authors: Choudhary Manish Kumar , Lai Suan-Loong , Sahu Sambit Kumar , Arfie Mezlul 
Published: October 2017

Brunei Shell Petroleum (BSP) encompasses multiple offshore and onshore oil and gas field. The study asset produces more than 50% of company's hydrocarbon production. Currently, gas production from the asset is at maximum system limit governed by downstream gas demand and surface-facility constraints. Producing the wells at right configuration can help in maximising condensate production while honouring gas demand thereby maximising revenue for the asset.

The analysis of data from past few months indicated that actual condensate production was quite lower than asset-wide Integrated Production System Model (IPSM) estimates. Frequently, wells were operated in wrong configuration which had resulted in system/wells operating outside Operating Envelopes (OE's), excessing choke wears, system trips and higher production deferment. A production optimisation study using LEAN approach was initiated to maximise condensate production and to increase process safety compliance.

Multiple brainstorming sessions were organized to map data flow from well-testing to production optimization to offshore operations. The process map highlighted that scheduled activities, operational requirement and communication issues often resulted in well configuration different than IPSM suggested configuration. The LEAN approach helped in identifying system wastes, viz. absence of real-time feedback to operators, different tools/software used by different team, reaction time to new testing data, misunderstanding of well OEs etc. which were resulting in lower condensate production.

A fit-for-purpose Real Time Optimization (RTO) tool was developed which used pressure and flow data from wellhead sensors and from real-time production estimation tool (viz. Production Universe) to generate best configuration of wells for maximising revenue. The optimum configuration accounted for well and facilities OE ensuring better process safety compliance. The tool output could be compared against real-time measures (e.g. Tubing head pressures) and providing continuous feedback to operators.

The RTO tool was implemented in Q2 2016 with full support of asset leadership. Multiple offshore trips were made to explain the tool to frontline operation staff, operation supervisors and production leads. The project helped in increasing condensate production by over 20% and created a reliable and sustainable process for continuous optimization directly by operations staff. It also ensured that wells always produced within OEs thereby increasing process safety compliance. Operating the wells and chokes optimally also led to cost savings from reduced choke replacements and lower production deferment. The tool served as a common reference for all teams thus eliminating communication waste.

The use of real-time sensors and Production Universe and RTO can help in reducing reaction time to system changes and help in maximising revenue. A sustained and integrated effort is needed to drive the process in the organisation and achieve production gain. The LEAN process can be useful to in root cause identification of problems and for drafting mitigation measures.