Production Enhancement for Tight-Gas Condensate Reservoirs: A Compositional Dual-Porosity Model for Sabriyah Field, Kuwait

Al-Qahtani, Misfera Misfer (Kuwait Oil Company) | Uzun, Ilkay (Colorado School of Mines) | Kazemi, Hossein (Colorado School of Mines)

OnePetro 

Abstract

A significant fraction of the world gas needs is supplied from gas-condensate reservoirs. The well productivity of these reservoirs is compromised because of liquid condensation in the matrix and fracture. The Sabriyah field is the first successful exploration in the North of Kuwait which led to the discovery of six extensive, deep, tight gas-condensate reservoirs. A purely fracture-dominated unconventional resource play, Najmah-Sarelu formation, is considered the source for most of the reservoirs in the Sabriyah field. In this paper, a compositional, multi-phase, dual-porosity model was used to analyze an existing horizontal well performance, and to evaluate potential enhancements to the future production.

The Sabriyah gas-condensate field in North of Kuwait is an abnormally high-pressure tight reservoir, which has very low matrix permeability and porosity. In this study, the geological system of Sabriyah field was studied using a static model to decipher the complexity of the reservoir—especially, the Najmah-Sarelu formation. A well's performance was analyzed using history-matching of the production data using a multi-component compositional dual-porosity model. To assess potential enhancement of the future production, eight different scenarios were studied. Specifically, we extended the current horizontal well length and added several multi-stage hydraulic fractures to increase production.

To assess the flow behavior of gas-condensate in Sabriyah field, we began with a study that tied the reservoir geology to the performance of a typical well using both static and dynamic simulation models. Both pressure build up and production data were analyzed using pressure and rate transient techniques which yielded an effective formation permeability of 0.5 to 0.6 mD. The numerical modeling parameters achieved a successful history match for one year of production, and the sensitivity analysis demonstrated that producing at a pressure of slightly below the dew point yielded the largest amount of condensate production. In particular, the additional condensate production was twenty-two percent for this case. Also, we observed that the existing horizontal well performed as effectively as having three-stage hydraulically fractured well in a matrix-dominated situation because of the presence of existing natural fractures replace the effect of the multi-stage fracturing.