Researchers Launch Free Calculators for Carbon Capture & Sequestration Projects 

University of Houston researchers recently made public three calculators to measure carbon dioxide (CO₂), hydrocarbon minimum miscibility pressure (MMP), and dead oil viscosity. The tools target engineers and technical professionals working on carbon capture and sequestration projects, in which they must determine the MMP—feasibility and displacement efficiency—of gas injection processes for carbon sequestration or enhanced oil recovery. 

 

Located in the North Sea, the Sleipner natural gas field hosts the world’s first offshore carbon capture and storage plant, which began operations in 1996. Image used courtesy of Equinor

 

The web-based apps provide useful inputs for measuring CO₂ and hydrocarbon MMPs to save engineers time and resources through faster calculations and screenings. Both gasses are commonly used for gas injection but exhibit different oil phase behaviors. As such, the researchers developed a toolset with a range of capabilities with different methods to measure MMP. 

Carbon capture, utilization, and storage (CCUS) is a relatively new field in the renewable energy space. CO₂ emitted from coal-fired power stations and other fossil fuel-based resources is captured, isolated, and stored for future energy generation. While many CCUS projects have been demonstrated worldwide, high costs are a barrier to widespread commercialization. 

 

Three New Calculators

The University of Houston researchers will collect user feedback to improve the calculators and develop new ones. They’re working on another tool to measure CO2 solubility in brines with mixed salts, targeting sequestration in deep saline aquifers–a point of growing interest in carbon capture and storage. A few demonstration projects serve as case studies for injecting CO2 into saline aquifers, such as the In Salah Project, which pumped millions of tons of CO2 into a saline formation near a gas field in Algeria. 

The researchers used various machine learning models to develop more accurate calculators than existing technologies. 

• Viscosity App: Calculates the thickness of crude oil in its natural form (also known as dead oil). The researchers published a study on this viscosity model in the Journal of Petroleum Science and Engineering in 2020. 

• Carbon Dioxide MMP Calculator: Using oil composition and temperature inputs, this hybrid model performs better than other correlations and machine learning methods. A related study was published in a 2021 issue of the SPE Journal. 

• Hydrocarbon Gas MMP Calculator: This app estimates the MMP for hydrocarbon gas injection via a Light Gradient Boosting framework. It also determines the minimum amount of heavy hydrocarbon gas to reach the target MMP. A study about the model was published last month in Geoenergy Science and Engineering. 

 

What is Carbon Capture and Storage?

According to the Center for Climate and Energy Solutions, CCUS technologies can capture over 90% of CO₂ emissions from power and industrial facilities. Carbon capture and sequestration processes are already used at fossil fuel-fired power plants worldwide. 

Outside the power industry, there are some cases where CO₂ generated by burning hydrocarbons isn't always easy to capture, such as in oil used in transportation, according to the Society of Petroleum Engineers. Storage entails injecting CO₂ into depleting oil reservoirs via enhanced oil recovery processes. 

 

This infographic shows the various CO₂ sources and end-users in the carbon capture value chain. Image used courtesy of the U.S. Department of Energy

 

Some notable case studies include Norway’s offshore Sleipner CCUS site in the North Sea and Canada’s Weyburn-Midale Project, each storing over 1 million metric tons of CO₂ annually. 

According to the International Energy Agency, 35 commercial facilities operate CCUS technologies worldwide across power generation, industrial processes, and fuel transformation. Around 300 CCUS projects are in various development stages, with 200 facilities expected to begin storing over 220 metric tons of CO₂ annually by 2030. 

 

Operating and planned carbon capture facilities by region (left) and application (right) as of 2022. Image used courtesy of the International Energy Agency

 

Most facilities already in operation are natural gas processing, followed by hydrogen and industrial categories. The mix is expected to be more diverse by 2030, with a growing share of power/heat, direct air capture, and other fuel supply projects.