Abstract
Abstract
The reservoir A is a gas recycle reservoir which has been in production since 2000 with a cumulative VRR (voidage replacement ratio) of 95%, aiming at maximizing condensate recovery through pressure maintenance above dew point. As market demand for lean gas increases, lower operating VRR is expected. Historically, the reservoir A operated at near full recycle mode with injection gas distributed equally among available injectors. An assessment has been done aiming to maximize condensate recovery with available gas to reinject. From the exercise, it was found that sectorial based prioritization alone is not enough due to presence of inefficient injectors which affect the injection efficiency for that particular sector.
Well operation priority for injectors is not as straight forward as it would be for producers, which can be ranked based on CGR (condensate gas ratio) to achieve maximum condensate production from time to time, because the effect of injection cannot be seen immediately, particularly in a large reservoir. On the other hand, there are limited studies on gas recycle reservoir injection optimization in the literature.
To tackle this challenge, the reservoir team developed a workflow methodology with wider applicability of injection prioritization in gas line drive injection patterns. This paper will describe how to utilize the reservoir simulation model to come up with optimum injection rate range per well through setting up an assisted optimizer.