A general modelling framework for optimization of multiphase flow networks with discrete decision variables is presented. The framework is expressed with the graph, and special attention is given to the convexity properties of the resulting programming formulation. Nonlinear pressure and temperature relations are modelled using multivariate splines and a special mixed-integer nonlinear programming (MINLP) formulation with spline constraints results. A global solution method is devised by combining the framework with a spline-compatible MINLP solver, recently presented in the literature. The solver is able to globally solve the nonconvex optimization problem. The new solution method is benchmarked with several local optimization methods on a set of three realistic subsea production optimization cases provided by the oil company BP.

At the SPE conference in 2006 BP announced the Field of the Future Integrated Surveillance Information System (ISIS) project. Since then the ISIS system has been developed, delivered, tested and verified. Deployment to BP assets has been at the scale and pace proposed in the conference papers published at that time. This paper describes a core module, the Rate&Phase virtual flow meter, and also gives reasons why deployment has been achieved so successfully.BP's Rate&Phase system automatically estimates production rates from individual wells and other well performance and reservoir information at least once per hour. The approach has been to automate a proven Petroleum Engineering methodology using models of well hydraulics and flow though chokes. The system takes advantage of the instrumentation typically installed on new wells and the transmission of those data for analysis at technical centres often remote from the production sites. Rate&Phase is integrated in ISIS along with routines to automatically reconcile production across entire fields, monitor issues of erosion and sand production and estimate reservoir pressure at shut-ins.The Rate&Phase system has been deployed widely across BP-operated assets including many major oil and gas fields. Benefits have been realised from the ability to efficiently monitor well stock, manage fields better and allocate production more accurately. The effort to determine monthly production allocation is significantly reduced. Production gains have been realised through assets operating closer to constraints because of the assurance of flow rates in critical pipework. Developments are being introduced to reduce maintenance effort through tools to assist model re-calibration and to complement the hydraulic models with models derived entirely from measured data.Rate&Phase exploits commonly-used modelling tools and is designed to be easy to deploy/configure. Acceptance of the system has been hastened because it is not regarded as a black box and all results can be reproduced manually offline. Current production and performance information is readily available and changes over time can be trended though existing data interfaces.

This paper describes the current use of continuous live data feeds to estimate reservoir pressure automatically from build-up analysis -in real time -and to evaluate well performance from well testing automatically -also in real time.Since 2002 much work has been done to create the Field of the Future TM Integrated Surveillance Information System (ISIS) -a universally deployable, global software application that can process continuous data feeds from remote sites, perform calculations on the data in real-time (such as virtual flow-metering of wells) and visualise the results for the user on a web browser. With these underlying calculations already complete and extending to phase rates down-hole and at surface, the current well flowing status (which wells flow through which facility components, production reconciliation, and more) there was already a mature and solid foundation on which to build a pressure analysis engine and a flow-test module.This original pressure transient analysis (PTA) concept was to provide permeability, skin and reservoir pressure estimates using traditional build-up/fall-off techniques but with no engineer intervention required other than to approve the results. The outcome was a technology has been deployed globally and has now been in service since 2009. Using this system data is collected every time there is a shut-in event on every well for which the tool is enabled. Smart scheduling is adopted during a complete field shut-in so that all wells can be interpreted together.The technology was built in parallel with a tool for recording production flow tests using flow-meter or separator data. Using smart systems to estimate the quality of flow tests, and combining the results with sampling and other data, a powerful system now exists to provide consistent, and fully auditable, results that can be used by reservoir modelling tools and other systems. It was deployed in 2007.Examples are given describing use of the technology and where business has been impacted by it.Field of the Future is a registered trademark of BP.The following text is a manuscript for an e-poster and should be considered in conjunction with the electronic presentation that accompany it. Graphic material resides within the presentation. IntroductionThe estimation of reservoir pressure and some other dynamic reservoir properties are customarily obtained through pressuretransient analysis (PTA). Pressure management is the most fundamental element of reservoir performance and ongoing knowledge of reservoir pressure is a key to field depletion strategy. With modern technology and monitoring it is possible to receive continuous data from field sensors to office desk-top. Marshalling the tidal-wave of data to yield useful information is a problem in itself but it is recognised that much valuable pressure data can be overlooked if processing it manually is time-consuming. The challenge addressed was to use conventional techniques of PTA but doing it in Real Time, using the Live Data feeds and doing Automatically, in the back-...