Zeolite Tracers Applied to Flow Through Production Well Connections

Abstract

Reported injection surveys in couplet Enhanced Geothermal System (EGS) injection wells show flow rate variations among several fracture-driven interactions (FDIs). Because the reported cases have all created hydraulic fractures in both injection and production wells, there may be production well fractures through which no flow is occurring. The placement of zeolites in production well fractures can serve to characterize the FDI between wells, thereby assessing how efficiently the system recovers heat and energy. The proposed approach involves employing commercially available zeolites with particle diameters ranging from 300 to 500 nm to evaluate both the passage and contact between the circulating fluid and the production well fractures. A doublet well configuration—comprising one injection well and one production well—serves as the assessment scenario. We propose to place zeolites in production well fractures in the expectation that flow through the fractures will carry zeolites to the surface. We propose to detect zeolites through X-ray diffraction (XRD) analysis of samples collected from the production well, leveraging the fact that zeolites are chemically stable and resistant to degradation under high temperature and pressure conditions. In summary, the proposed concept is to assess the contribution of productive fractures to the overall flow, which directly impacts the EGS heat recovery efficiency.