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US 8,299,420 B2Granted
Neutron shielding for downhole tool
AssigneeSchlumberger Technology Corporation
InventorChristian Stoller
Life of this patent
Estimating the term…
Abstract
A downhole tool for performing measurement of a formation. The tool comprising a housing surrounding a source for generating neutrons and a detector for detecting the neutrons. A shield is located outside of, or embedded in, the housing and focuses the neutrons.
Claims20
A downhole tool for performing measurement of a formation, the tool comprising:
- a housing having a source for generating neutrons and a detector for detecting the neutrons;
- and
- a shield for focusing the neutrons and located outside of, or embedded in, the housing, wherein said shield comprises a neutron absorber, and wherein the housing includes an area of nonzero reduced thickness under the shield.
A method for focusing neutrons of a downhole tool measuring a formation, the method comprising:
- generating neutrons with a source located in a housing of the tool;
- detecting neutrons with a detector in the housing;
- and
- focusing the neutrons with a shield, wherein the shield is located outside of, or embedded in, the housing, said shield having an opening therein for focusing the neutrons to flow in a direction,
- wherein said shield comprises at least one neutron absorber selected from the group consisting of Boron, enriched 10 Boron, lithium, enriched 6Li, cadmium, gadolinium and mixtures thereof, and
- wherein the housing includes an area of nonzero reduced thickness under the opening.
3 more elements
A downhole tool for performing measurement of a formation, the tool comprising:
- a housing having a source for generating neutrons and a detector for detecting the neutrons;
- and
- an outer shield wherein said shield comprising at least one neutron absorber selected from the group consisting of Boron, enriched 10Boron, lithium, enriched 6Li, cadmium, gadolinium and mixtures thereof, said shield located outside of, or embedded in, the housing and around the source, the outer shield having an opening for focusing neutron flow in an azimuthal direction, and the housing including an area of nonzero reduced thickness under the opening.
A downhole tool for performing measurement of a formation, the tool comprising:
- a housing having a source for generating neutrons and a detector for detecting the gamma-rays induced by the neutrons interacting in the formation;
- and
- a shield located outside of, or embedded in, the housing and around the source, the outer shield having an opening for focusing neutron flow in an azimuthal direction, wherein said shield comprises at least one neutron absorber selected from the group consisting of Boron, enriched 10Boron, lithium, enriched 6Li, cadmium, gadolinium and mixtures thereof, and wherein the housing includes an area of nonzero reduced thickness under the opening.
Dependencies are inferred from the claim text.