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US 8,895,914 B2Granted
Ruggedized neutron shields
AssigneeSchlumberger Technology Corporation
InventorJoshua Wayne Gibson
Life of this patent
Estimating the term…
Abstract
A shield for a well logging instrument includes an outer layer including a reinforcing fiber disposed in a matrix and an inner layer including a thermal neutron absorbing material disposed in a matrix. The thermal neutron absorbing material is selected to emit capture gamma rays having energy outside a selected energy range.
Claims15
A shield for a well logging instrument disposed in a formation, comprising:
- an outer layer including a reinforcing fiber disposed in a matrix, the reinforcing fiber comprising a carbon fiber;
- an inner layer including a thermal neutron absorbing material disposed in a matrix in a graduated manner with a greater concentration of thermal neutron absorbing material disposed in a direction away from the outer layer, the thermal neutron absorbing material selected to emit capture gamma rays having energy outside a selected energy range of gamma rays of interest resulting from neutron interaction with the formation;
- and
- a structural layer disposed between the inner layer and the outer layer.
1 more element
A well logging tool, comprising:
- a tool mandrel configured to be moved along an interior of a wellbore drilled through subsurface formations;
- at least one radiation detector disposed in an interior chamber defined by the tool mandrel;
- a radiation shield disposed on an exterior surface of the tool mandrel proximate a position therein of the radiation detector, the shield including an outer layer including a reinforcing fiber, comprising a carbon fiber, disposed in a matrix, and an inner layer including a thermal neutron absorbing material disposed in a matrix in a graduated manner with a greater concentration of thermal neutron absorbing material disposed in a direction away from the outer layer, the thermal neutron absorbing material selected to emit capture gamma rays having energy outside an energy range of gamma rays of interest resulting from neutron interaction with the subsurface formations, and a structural layer disposed between the inner layer and the outer layer.
Dependencies are inferred from the claim text.