Reduced-Order Model for Leakage Through an Open Wellbore from the Reservoir due to Carbon Dioxide Injection

Technical Report · Wed Jul 26 04:00:00 EDT 2017

DOI:https://doi.org/10.2172/1372675· OSTI ID:1372675

Pan, Lehua ^[1]; Oldenburg, Curtis M. ^[1]

---

1. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Potential CO₂ leakage through existing open wellbores is one of the most significant hazards that need to be addressed in geologic carbon sequestration (GCS) projects. In the framework of the National Risk Assessment Partnership (NRAP) which requires fast computations for uncertainty analysis, rigorous simulation of the coupled wellbore-reservoir system is not practical. We have developed a 7,200-point look-up table reduced-order model (ROM) for estimating the potential leakage rate up open wellbores in response to CO₂ injection nearby. The ROM is based on coupled simulations using T2Well/ECO2H which was run repeatedly for representative conditions relevant to NRAP to create a look-up table response-surface ROM. The ROM applies to a wellbore that fully penetrates a 20-m thick reservoir that is used for CO₂ storage. The radially symmetric reservoir is assumed to have initially uniform pressure, temperature, gas saturation, and brine salinity, and it is assumed these conditions are held constant at the far-field boundary (100 m away from the wellbore). In such a system, the leakage can quickly reach quasi-steady state. The ROM table can be used to estimate both the free-phase CO₂ and brine leakage rates through an open well as a function of wellbore and reservoir conditions. Results show that injection-induced pressure and reservoir gas saturation play important roles in controlling leakage. Caution must be used in the application of this ROM because well leakage is formally transient and the ROM lookup table was populated using quasi-steady simulation output after 1000 time steps which may correspond to different physical times for the various parameter combinations of the coupled wellbore-reservoir system.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE
• OSTI ID: 1372675
• Report Number(s): LBNL--1006122; ir:1006122
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES