Gas supply security plays a vital role in ensuring the continuity of the power generation and distribution for one of Malaysian State. Unplanned deferments at offshore facilities creates enormous impacts on gas quantity leading to loss/lowering of power generation. Such occurrences lead to value leakage and hinders the expansion strategies by non-firming of investment decisions. It therefore becomes imperative as prudent operator to sustain upstream gas supply by ensuring the security by appropriate strategies in occurrence of such events. Also, for complex facilities it is decisive to have comprehensive understanding of network characteristic, offshore supplies distributions and topology in terms of hydraulics & flow regimes from multiple fields to ensure security of gas supply to customers.

This paper proposes an approach to endorse the security of gas supply during normal and ad hoc situations by aligning the relevant feeders to respective demand centers thru comprehensible network modeling and ensure the optimized system response operating envelope for such events. An innovative process was commenced to design, develop, validate, and deploy the network simulation model to cater for the technical characteristics in terms of ullage, hydraulic first principles, blending aspects and safety features during aligning of the respective feeders. The landscape includes around 100+ feeders, multiple export pipelines, several gas highways, and many demand centers with each of its specific requirement. The inline equipment such as pressure boosters with performance curves (compressors/pumps), pressure manipulators (control valves) also formed the integral portion of the model for resilient outputs. Also, the equation of state (for thermodynamic behavior) and appropriate flow co-relation (for pressure drop estimations) were embedded in the model for representative results. The model was validated thoroughly with the plant data by identifying critical junction points to have realistic consequences. Input to the model were classified as engineering input (static such as design capacity, pressure limits, maximum allowable operating pressure (MAOP)) and operational inputs (flow allocations, priority of supply, precedence in operation of demand centers). The process was looped to reallocate the feeders till the required intent is met for the supply as well as on technical aspects.

The simulation model could decipher the pain points across the various intensity of the networks such as pressure choking, unintended flow distribution, violations of the resultant specifications and potential breach in the safety limitations. Several iterations could be accomplished in terms of permutations and combinations to align appropriate feeders. The scenarios could be also optimized for the optimal value ranking of the fields to be evacuated for designated demand centers. The simulation model could suggest amendments in the operating strategy such as clustering of sweet/sour fields, integrated contaminant management system, and addition of loop lines to ensure the hydrocarbon molecule travels the intended path. Also, model assisted in generating the heat maps in terms of pressure concentration, flow dispersal and other aspects to have the big picture of the asset which can be probed as required. Network Modeling could recommend the relevant swing fields or alteration in the configuration in case of unforeseen circumstances if it occurs to ensure the security of supply of gas is intact to cater necessities.

The approach could recommend that the upstream security of gas supply could be enhanced or endorsed via usage of Network Modeling by either by apposite changes in the operating philosophy and/or configuration. It also resulted into nurture trust of the stakeholder to empower the power generation using gas as fuel and business continuity is ensured for upstream.

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