Abstract
Even where production is largely constrained by gas demand through fixed contracts, revenue from hyrdocarbon liquid recovery can be maximised through optimisation of well production and process efficiency.
Significant improvement in oil and condensate recovery has been achieved at Shell Todd Oil Services Ltd (STOS) using computer applications developed within the Operating Company, focussing on value enhancement as well as cost reduction. Installation of PI (Plant Information) has been fundamental in the development of these user-friendly PC based tools.
KAOS (Kapuni Apportioned Optimisation Spreadsheet) combines thermodynamic understanding of the process with well characteristic data to form a non-linear optimisation tool in MS Excel. It is used successfully by field operators to optimise production by prioritising wells and predicting optimal operating conditions. An extension of this tool quantifies condensate deferment and loss caused by sub-optimal operation, to highlight improvement opportunities. The KAOS model also forms the foundation for a Dynamic Production Forecasting tool, currently being developed for condensate shipping and maintenance scheduling.
Data from PI is used to advantage in another MS Excel based tool developed to monitor efficiency of an offshore gas compression system on a continuous basis. The model brings together all process information, including ambient conditions, so that operations and interactions can be conceived in a way that was not possible before PI. A more intimate knowledge of the process has enabled enhancement of oil recovery through rationalisation of maintenance, improvement in plant performance and assurance of integrity.
