Methods and systems for determining mud flow velocity from measurement of an amplitude of an artificially induced radiation
AssigneeSchlumberger Technology Corporation
InventorBenjamin Jeffryes
Life of this patent
Estimating the term…
Abstract
Embodiments of the present invention relate in general to methods and apparatus for determining downhole mud flow rates and other downhole parameters. More specifically, but not by way of limitation, an embodiment of the present invention may provide a method for determining a downhole parameter that includes operating a pulsed neutron generator, detecting the activated drilling fluid at-least one known distance (d) from the pulsed neutron generator, and determining a time-of-flight (t) for the activated drilling fluid slug to travel from the pulsed neutron generator to a detection point, or between detection points
Claims25
A method for determining a downhole parameter in a drilling environment, comprising:
- activating, by an activation device, drilling fluid flowing past the activation device;
- measuring the activity levels of the activated drilling fluid at two locations separated by a known distance;
- and
- determining a time-of-flight t from the ratio of the activity levels.
A method for determining a downhole parameter in a drilling environment, comprising:
- activating, by an activation device, drilling fluid flowing past the activation device;
- measuring the activity level of the activated drilling fluid at a known distance d from the activation device;
- comparing the activity level to the activity level at a time t0 when the time-of-flight for the fluid between the activation device and the measurement point is known;
- and
- deriving from the comparison a measurement of the time-of-flight at the time of the activity measurement.
A tool for determining a downhole parameter in a drilling environment, comprising:
- the tool, wherein the tool is adapted to be placed in a drill string and wherein the tool comprises an activation device and at least one gamma ray detector separated along a drill string axis thereof by a distance d;
- and
- processing means coupled with the at least one gamma ray detector and configured to determine the amplitude of gamma radiation received at the detector.
A method for determining a downhole parameter in a drilling environment, comprising:
- activating, by an activation device, drilling fluid flowing past the activation device;
- measuring the activity level of the activated drilling fluid at a multiplicity of locations with known separations and distances from the activation device;
- comparing the activity levels to the activity level at a time t0 when the time-of-flight for the fluid between the activation device and the measurement point is known, and to one another;
- and
- deriving from the comparison a measurement of the time-of-flight at the time of the activity measurement.
Dependencies are inferred from the claim text.