Abstract

The current oil and gas market is characterized by low prices, high uncertainties and a subsequent reduction in new investments. This leads to an ever-increasing attention towards more efficient asset management. An off-spec event is one of the main scenarios that drastically affects process reliability and throughput of an upstream production facility. This paper illustrates the application of Advanced Process Control techniques to beyond-standard targets of process parameters and product specifications.

The early identification of potential process upsets is nowadays mandatory in the day-by-day management of a process plant. APC applications proved to introduce significant advantages to process stabilization and overall plant optimization, as it allows the single equipment to be pushed and kept at the maximum performance inside its optimal operating window.

In this work is described how a multi-variable, real time, optimization engine is deployed to the gas-oil separation section of an upstream production asset, from slug catcher to stabilizer column. The main intent is to automatically take advantage of inlet vessels buffer volume to manage the intrinsically unstable flowrate and composition of raw reservoir fluid. The selected objective functions are able to efficiently manage levels in the upstream separators to avoid upsets inside the stabilizer, reducing steam consumption at the reboiler. Positive drawback is to keep the control room operator free from manage this target functions by his own expertise, focusing on other more demanding loops.

Results show that in an industry where process optimization by design changes are not always feasible or cost-effective, a well-tuned APC controller could increase asset performance being deployed without any interference with production with a minimum investment. Moreover, significant results in term of energy efficiency, operations efficiency and stabilization/standardization of the plant management can be achieved.

Introduction

Advanced Process Control is a multiple input — multiple output (MIMO) digital tool that nowadays has never been systematically implemented in upstream facilities. Main reasons are the high volatility of reservoir fluids flowrates and product overspecification that assures safe operations and production continuity.

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