Characterization of the mud displacement in an enlarged wellbore: An integrated rock-fluid model

Journal Article · 10 February 2022 · Journal of Natural Gas Science and Engineering

DOI: https://doi.org/10.1016/j.jngse.2022.104471 · OSTI ID:1977361

Wu, Yuxing  ^[1]; Salehi, Saeed ^[2]; Khalifeh, Mahmoud  ^[3]

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1. Univ. of Oklahoma, Norman, OK (United States); OSTI
2. Univ. of Oklahoma, Norman, OK (United States)
3. University of Stavanger (Norway)

Cement-mud displacement plays a crucial role in the sealability of cement sheaths. Irregular geometric features of a wellbore due to washout can have a negative impact on mud and cement mobilization. An unstable interface between two fluids always leads to mud channeling, interfluid mixing, and cement contamination, degrading the cement quality. Many factors, such as mechanical and rheological properties of fluids, annulus geometry, flow pattern, and flow rate, significantly influence the displacement efficiency. This study investigates the characterization of the mud displacement in an irregular horizontal well using a 3D computational fluid dynamics (CFD) model. Mud is displaced in an enlarged wellbore by geopolymer and neat class G cement. The wellbore geometry is developed based on the caliper log data from an unconventional shale well in the Tuscaloosa Marine Shale (TMS) lithology. The effects of pump rate, density difference, and mud contamination are evaluated by numerical simulations. The results present those residual muds mainly exist in the upper annulus of the enlarged section. Geopolymer has a better sealing performance and can resist more water-based mud (WBM) contaminations than neat class G cement. The scenario with a low mud-cement density difference and high cement injection rate results in a high cement volume fraction, mitigating the gas migration.

• Research Organization: Univ. of Louisiana, Lafayette, LA (United States)
• Sponsoring Organization: USDOE Office of Fossil Energy (FE)
• Grant/Contract Number: FE0031575
• OSTI ID: 1977361
• Journal Information: Journal of Natural Gas Science and Engineering, Journal Name: Journal of Natural Gas Science and Engineering Journal Issue: C Vol. 100; ISSN 1875-5100
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English