Net-Zero Geosystems

Numerical Simulations for the Geosystems of the Energy Transition

WELL INTEGRITY

Well integrity refers to the unintended release of fluids along the structure wells across rock formations, aquifers and into the atmosphere. In the context of the energy transition, maintaining the integrity of wells has become critical for a number of applications. Storage of hydrogen and other fuel gas, oil & gas production and CCUS all rely on insulated wells to deliver performance and meet the regulations regarding the emission of greenhouse gases. Net-Zero Geosystems provides softwares and services for the prediction of well integrity loss in gas storage wells, oil & gas wells and CO₂ injector wells wether they are new built or legacy wells with a history production. The well integrity analysis we offer spans over the full life cycle of the well and from the reservoir scale to the well defect scale.

Well Screening

With our published analytical tool, we can detect major integrity issues in pre-existing legacy wells and assess their adequacy for storing and/or injecting CO₂, hydrogen and other fuel gas. For new built wells, we can test a wide range of configurations and materials and identify the most cost-effective and resilient wells. The basic version of the tool can be accessed here.

Reservoir-Scale Analysis

With reservoir-scale simulations (GEOS), we analyse the overall stress evolution in the well caused by the changes in injection pressure and reservoir pressure during:

Drilling and cementing
Oil & gas production and depletion of the reservoir
Injection of CO₂ and other fuel gas

In doing so we identify well sections where integrity is at risk and examine them further with defect-scale simulations.

Defect-Scale

After well zones at risk of well integrity loss have been identified, we perform fracture-scale simulations using specialised software developed with TotalEnergies and validated against data from proprietary well integrity experiments. With our software, debonding and fractures in the well are predicted along with their hydraulic aperture. This enables us to calculate the associated leakage potential of the well.

RESERVOIR ANALYSIS

with GEOS

Injectivity Analysis

We perform simulations of the injection of liquefied or supercritical gases (such as CO₂, H₂ and CH₄) in reservoirs such as saline aquifers or depleted oil & gas reservoirs. This enables us to calculate the maximum capacity of the reservoir, to determine the most cost-effective well configuration and injection schedule and to prevent leakage through faults and wells.

Fault Reactivation

Fluid injection is well-known for disrupting the stability of faults in the vicinity of the storage reservoir. In the oil & gas sector, injection of fluids has induced numerous low to medium magnitude earthquakes. In the context of gas storage, induced seismicity may have an unfavourable impact on the completion of the project by compromising wells or the infrastructure and driving negative public perception. Identifying the faults that may re-activate, calculating the energy they may release and locating brine water production wells that will minimise fault induced seismicity is critical to de-risk gas storage projects.

Caprock Stability

Because injected fluids are less dense that the resident brine, they rise to the top of the reservoir. Upwards fluid migration is prevented by the rock formation above the reservoir, the caprock. However, the integrity of the caprock may be affected by the stress changes caused by the injection. If the seal is compromised, drinking water aquifers may be contaminated and greenhouse gases may be released into the atmosphere.

Team

We are a team of geoscientists which formed at Imperial College London. We are passionate about the energy transition and committed to delivering cutting-edge software and services that will support the development of net-zero geosystems.