Development of integrated software for running the multiphase simulator Ledaflow with the reservoir simulator GEM for simulating multiphase CO₂ injection flow between well and reservoir

Development of integrated software for the coupling of the dynamic multiphase flow simulator LedaFlow® and the reservoir simulator GEM, for simulating multiphase CO₂ injection into depleted reservoirs

Scope of the Project

The project aim is to create a commercially available integrated wellbore and reservoir modelling system that can capture the detailed interaction between the well and near well reservoir region for CO₂ injection projects. This will allow a substantial improvement in the ability to de-risk the operation of these CO₂ injection wells compared to current capabilities that use a simple fixed table to represent the reservoir response.

CCS projects looking to store CO₂ in depleted gas reservoirs will experience large pressure and temperature changes in the near well region which will have a significant impact on injectivity (rates and pressures that the well can operate at) and well integrity (with localized fracturing due to large thermal changes). These effects on injectivity are critical to the economic viability of such projects and are not captured by existing available tools.

The main deliverable and outcome of this project is to create a suitable controller program, with an user friendly interface, to link together and manage the interaction between, the currently separate, well and reservoir systems. This controller will be a newly developed system to link together 2 existing commercial solutions: CMG’s GEM reservoir simulator; and Kongsberg Digital’s LedaFlow® transient well and pipeline simulator.

Challenges faced:

1. The first challenge is to address the differing time and length scales, since the wellbore transient time scale is in seconds and minutes, while the reservoir simulator time scale is typically in hours, days, or years. The reservoir simulator needs to understand how and when to interact with the wellbore model to adequately capture the near wellbore feedback into the wellbore system.

2. A second challenge will be to accurately capture the fluid information passed between the two modelling systems to accurately capture the phase behavior of CO₂ as it transitions between vapor, liquid and super-critical phases, particularly as it leaves the wellbore and enters the reservoir. The different amounts of impurities in the CO₂ fluid also add another level of complexity to the computation and can lead to numerical instability.

3. Other challenges faced will relate to handling and passing of temperature information, dealing with near critical CO₂, and potential water encroachment into the well.

A secondary deliverable of this project will be to develop numerical methods to adequately capture these phase behaviour effects to remove the potential for numerical instability.