Increasing Confidence in Production Forecasting Through Risk-Based Integrated Asset Modelling, Captain Field Case Study

Abstract

Abstract To assist in the probabilistic forecasting and decision making process for their Captain North Sea heavy oil asset, Chevron has developed an Integrated Asset Model (IAM). This model includes probabilistic predictions of facilities performance and production, enabling decision risk analysis for strategic and operational decisions. The IAM includes risk-based oil, gas and water production forecasts for the Captain Field and cash flows. These forecasts take full account of facilities constraints and uncertainties in reservoir and operational parameters through links to decision risk analysis software. This paper describes the novel approach used and model application. Given the presence of multiple reservoir models, multiple PVT descriptions, three-phase flow, and a variety of well types from infill to ‘new field’, the best source of reservoir performance profiles for each well was the in-house Eclipse™ reservoir simulation models. The production profiles for each well are represented by a rate versus cumulative production curve. A particular feature of the IAM is its ability to automatically capture the output of individual Eclipse™ data sets. The results of the simulation models are combined into a single spreadsheet model. This is of particular importance as it enables the effect of facility throughput limitations on gas and water production to be readily assessed. In particular it provides the ability to choke back individual wells on a priority basis from any of the wells in the separate simulations. A key feature of the model is the ability to investigate new scenarios without the need to run additional Eclipse™ simulations. Validation of this feature is demonstrated. An example of the model's application to a Captain development decision on whether to proceed with a well workover will be discussed.