Abstract
Asset development teams have the responsibility of identifying, evaluating and executing infill well opportunities. In maturing these projects, realistic forecasts are needed. An intrinsic part of these forecasts is the initial rate of production, which influences the economic viability of the opportunity and the producing life of subsequent facilities. It is every team's desire to come up with a range of producible rates given reservoir, wellbore and surface constraints. This would serve as the basis for the decisions regarding rates of production. Inflow-outflow modelling (nodal analysis) is generally the accepted method for rate prediction. However, data and time constraints such as unreliable well tests, BHP surveys and questionable PVT data can make rate determination very challenging.
This paper details a methodology to overcome these obstacles through the application of a two-dimensional approach to deriving a range of production rates using both integrated modelling and analog comparisons. The 2-step approach involves building an integrated production model that includes wellbore models connected to a surface production network (could be built to varying levels of complexity). The results from the network model are tuned using an acceptable set of well test data from analog reservoirs. The end result is a more realistic range of IP rates that are representative of the opportunity under evaluation.
The workflows detailed in this paper were used to derive forecasts for infill oil wells in the offshore Niger Delta. A few of these have been drilled and many are currently being evaluated, some of the challenges, lessons learned and results are also shared in this paper.
