Gamma-Ray Detectors For Downhole Applications

摘要

Methods and related systems are described for gamma-ray detection. A gamma-ray detector is made depending on its properties and how those properties are affected by the data analysis. Desirable properties for a downhole detector include; high temperature operation, reliable/robust packaging, good resolution, high countrate capability, high density, high Z, low radioactive background, low neutron cross-section, high light output, single decay time, efficiency, linearity, size availability, etc. Since no single detector has the optimum of all these properties, a downhole tool design preferably picks the best combination of these in existing detectors, which will optimize the performance of the measurement in the required environment and live with the remaining non-optimum properties. A preferable detector choice is one where the required measurement precision (logging speed) is obtained for all of the required inelastic elements and/or minimization of unwanted background signals that complicate the data analysis.

主权项

1. A system for detecting gamma-rays downhole comprising:
a tool housing adapted and dimensioned to be deployed in a borehole within a subterranean formation; and a scintillator material mounted within the tool housing, and emitting light when gamma-rays are absorbed, the scintillator material having an associated decay time of less than about 100 ns and an associated resonance integral of less than about 100 barns.