Rapid Derivation of in-place Hydrocarbon Volumes in Large, Complex Field Settings

Abstract

Proposal South West Ampa Field in Brunei is a large, structurally complex oil and gas field offshore Belait, Brunei Darussalam. Starting with seismic interpretation in the time domain, this paper describes a modeling workflow culminating in the derivation of initial in-place volumes for oil, associated gas, and non-associated gas. At the centre of the process is an integrated full-field reservoir model. The initial phases of the workflow are summarised only; these are described in more detail in Reference 1. In this paper emphasis is placed on the derivation of the hydrocarbon volumes, and is based on work carried out over the last year. Deriving volumetrics from an integrated full-field reservoir model has several advantages over more traditional methodologies: Graphically auditableForced consistency with the live reservoir modelRapidly re-run through pre-existing user-defined workflowsOutput format facilitates further analysis using spreadsheets or relational databases This paper also discusses areas for possible improvement: The method is more susceptible to gridding artifactsCurrently the volumes are largely deterministic in nature; probabilistic modeling is feasible, but at the detailed reservoir level is likely to require a much more hands-on approachAdditional software enhancements are required to further streamline the process To date the emphasis has been on designing a suitable workflow. This has now been achieved, and the study will move forward to a phase of comparison with the existing corporate volumetrics database. This may generate additional opportunities for infill drilling. There are many additional benefits of the full-field model. These include: Rapid output of maps and cross-sections for reports and well proposalsWell planning in a collaborative three-dimensional environmentEase of integration of diverse datasets (for example well paths, seismic data, formation tops)Live model updating with results of ongoing activitiesThe ability to use the full field model as the basis of detailed models for dynamic simulation The model is already playing an important role in the drive to maximise hydrocarbon recovery from this large but highly mature field.