Arrangement and method for monitoring of annulus volume
AssigneeThe Subsea Company
InventorsTorbjørn Amundsen, Carl Olav Wickmann, Henrik Tvedt
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Abstract
The present description is related to integrity monitoring of an annulus volume in a pipe. More specifically, the present disclosure is related to an arrangement and a method for determination of annulus free volume of a pipe. The monitoring can as an example be performed by use of a logical unit which controls the annulus testing by use of diffusion or gas feed, and also give input to calculation of the pipe's remaining lifetime. Further, the arrangement can as an example save and present results, allow for user specified settings and set off alarms it critical values are detected.
Claims27
An arrangement for determination of an annulus free volume in a pipe, the arrangement comprising:
- a reference volume,
- at least one first valve connected to the annulus free volume in the pipe and the reference volume for depressurization of the annulus free volume in the pipe to the reference volume,
- at least one second valve connected to the reference volume and at least one outlet for depressurization of the reference volume, and
- at least one first pressure instrument for pressure measurement of the annulus free volume in the pipe and at least one second pressure instrument for pressure measurement in the reference volume, wherein
- the at least one first and second valve and the at least one first and second pressure instrument are arranged to read off and control pressurization and depressurization, and where the pressure measurement in the reference volume and in the annulus free volume in the pipe prior to and after depressurization, together with a dimension of the reference volume are used for calculation of the annulus free volume in the pipe.
A method for determination of an annulus free volume in a pipe, characterized by acts comprising:
- establishing a pressure difference between the annulus free volume in the pipe and a reference volume,
- performing a number of depressurizations from the annulus free volume in the pipe to the reference volume, where the number of depressurizations is one or more,
- measuring pressure in the reference volume prior to and after each of the number of depressurizations,
- measuring pressure in the annulus free volume in the pipe prior to and after the total number of depressurizations, and
- calculating the annulus free volume in the pipe based on the measured pressure in the annulus free volume in the pipe prior to and after the total number of depressurizations, the measured pressure in the reference volume prior to and after each of the number of depressurizations and a dimension of the reference volume.
Dependencies are inferred from the claim text.