Mineral precipitation prediction and prevention during geothermal brine production in Clarke Lake field in British Columbia

Mineral precipitation is a common issue encountered in geothermal power facilities. Such scale formation is typically a result of variations in the geothermal fluid such as temperature, pressure, and ion composition. The precipitation of minerals can impede fluid flow leading to diminished plant efficiency and escalated maintenance expenses. The thesis aims to investigate brine production in the Clarke Lake field in British Columbia for geothermal purposes, focusing on studying scaling phenomena. Additionally, the study explores the integration of completion flowback water as a sustainable water resource for geothermal wells in the Clarke Lake field. The primary objective is to identify the types of scale that might form when flowback water is used in the geothermal system. Using a geochemical numerical tool PHREEQC (pH-REdox-EQuilibrium), the potential scale formation resulting from the mixing of formation water and two type of flowback waters are predicted. Through comprehensive laboratory experiments and analyses such as static bottle tests, scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS or EDX), X-Ray diffraction analysis (XRD), and inductively coupled plasma-optical emission spectrometry (ICP-OES), an in-depth insight into the scaling tendencies and behaviors of different minerals are gained. In the final stage of the thesis, the efficiency of a chemical inhibitor (Diethylene Triamine Penta) in preventing scaling was evaluated. Chemical inhibitors reduce the formation and growth of scaling deposits. Through rigorous testing, an assessment of the inhibitor's effectiveness in preventing scaling was conducted at both room temperature and elevated temperatures.