Abstract
In the recovery of low permeability reservoir, the capillary pressure has an important effect, which may reduce gas production. Due to the capillary end effect, there are two flow patterns in the vicinity of the production well: both water and gas phases can flow into the production well and only gas phase can enter the production well. Based on the analytical equations of one-dimensional radial flow considering the capillary end effect, an alternative numerical well model for low permeability gas reservoir is constructed. Numerical examples show that the proposed model can reflect the dramatic change for saturation and gas-phase pressure in the vicinity of the production well both for two flow patterns, and therefore can predict the gas and water productions accurately at different grid scales. In contrast, the original Peaceman well model for multi-phase flow, which is directly extended from that for single-phase flow, only can provide good prediction under the condition of that the grid size is enough small. Especially, for the original Peaceman well model, this problem is out of control since it is difficult to estimate a suitable grid size.
Highlights
The water have phase is trapped in the reservoir and only the gas phase can flow into the wellbore
When pressure difference between the formation pressure and the well bottom-hole pressure is not large enough to overcome the capillary end effect, only the gas phase can flow into the wellbore and cause the gas production significantly reduced
When the pressure drop is enough to overcome the capillary end effect, both water and gas phases can flow into the wellbore
Summary
Peaceman’s finite difference well model was for the well located at the center of square grid for single phase flow (Peaceman, 1978) It was extended into various applications, including horizontal wells, anisotropic reservoirs, and multiphase flow, etc. It has already been shown that the capillary end effect in water-wet reservoir creates a water layer near the wellbore with residual saturation of gas or oil. This layer will cause the hydraulic resistance for gas or oil flow (Barenblatt et al, 1989; Bedrikovetsky, 2013).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
