Abstract
This paper provides an insight into the mechanism of gas injection process in reducing gas-well productivity losses due to condensate blockage in the near wellbore region. A technique is proposed to predict performance of gas-condensate reservoirs where cycling is employed.
Toual gas condensate field with its two reservoirs, TAGS & TAGI, was used as a case study in this paper. Comparison between the primary depletion and gas recycling was studied and the economic feasibility of the project was evaluated.
An equation of state (EOS) with 6 pseudo components was used to characterize the complexity of the hydrocarbon column. The model used consists of a grid of 2600 and 1875 cells (25×15××07) and (25×15×05) for TAGS & TAGI respectively. After a successful history match, MER (maximum efficiency rate) of 9% and 8% were used to optimise the primary depletion of TAGS & TAGI reservoirs respectively.
After running many cases, it was found that the injection of 100% produced gas for 20 years is the optimum case for the development of the Toual Field. It was observed that the condensate recovery increased as the duration and the volume of the injection gas increased. Prediction runs indicated that the injection of 100% of gas, starting in 2005 will result in a total recovery of 973.38 MSTCM and 777.53 MSTCM (22.2%, 30.5%) for both the reservoirs respectively over a life span of 20 years.
