Exploring the Use of Bullheading for Steam Kick Management in Super-Hot Geothermal Drilling: A Numerical and Full-Scale Experimental Investigation

Document Type

Conference Proceeding

Publication Date

1-1-2025

Abstract

Managing steam kicks during super-hot geothermal drilling presents significant challenges that conventional well control methods struggle to address. This paper investigates bullheading-a technique involving downward fluid displacement-as an intervention strategy for these events. This study integrates findings from full-scale experiments at Louisiana State University's PERTT Laboratory with comprehensive numerical simulations using a validated RELAP5-3D model. In the experiments, steam kicks were simulated using nitrogen gas injection in a 5,163-ft wellbore, and the bullheading process was monitored using high-resolution Distributed Temperature Sensing (DTS). The numerical model, validated against this experimental data, was then used to simulate bullheading in a 3,000-meter super-hot geothermal well. The results demonstrate that while bullheading effectively suppresses the steam kick, it induces a sequence of complex thermohydraulic phenomena. Key findings include the observation of a localized temperature spike caused by the release of latent heat during steam condensation and the generation of a significant water hammer effect. Furthermore, a parametric study revealed that the overall time to collapse the steam is not highly sensitive to the injection rate or fluid temperature, suggesting the process is robust and primarily driven by hydraulic pressure. This work provides critical insights and quantitative guidelines for applying bullheading, highlighting that while the method is effective, the management of secondary risks like water hammer is paramount for ensuring wellbore integrity.

Publication Source (Journal or Book title)

Transactions Geothermal Resources Council

First Page

576

Last Page

594

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