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Apparatus For Pressure Transducer Calibration

IP.com Disclosure Number: IPCOM000169624D
Publication Date: 2008-Apr-24
Document File: 6 page(s) / 183K

Publishing Venue

The IP.com Prior Art Database

Abstract

Pressure transducer assemblies (PTAs) used primarily in petroleum service work such as cementing, stimulation, and drilling require calibration. A method for “one button” cali-bration of pressure transducers is described. The calibration system includes a pressure generating source, associated plumbing, a reference transducer, and a data acquisition and processing unit. Improvements involving the technique of comparing the output of a transducer under test to a reference transducer are also described. The entire system and process is automated, the results standardized and acceptability limits are clearly defined. The calibration system may be placed in every field location for the purpose of regular, NIST-traceable pressure transducer calibration and performance validation. Improved service quality and safety benefits may be realized including 1) fewer on-location trans-ducer failures (marginal units are identified in testing), 2) fewer pump kick-outs and associated treatment failures, 3) better customer perception, 4) less chance of wellhead damage, 5) better fracturing analysis, and 6) safer on-location work environment. An em-bodiment targets the use of Weco® union, high-pressure transducers.

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APPARATUS FOR PRESSURE TRANSDUCER CALIBRATION

ABSTACT

Pressure transducer assemblies (PTAs) used primarily in petroleum service work such as cementing, stimulation, and drilling require calibration. A method for "one button" cali- bration of pressure transducers is described. The calibration system includes a pressure generating source, associated plumbing, a reference transducer, and a data acquisition and processing unit. Improvements involving the technique of comparing the output of a transducer under test to a reference transducer are also described. The entire system and process is automated, the results standardized and acceptability limits are clearly defined. The calibration system may be placed in every field location for the purpose of regular, NIST-traceable pressure transducer calibration and performance validation. Improved service quality and safety benefits may be realized including 1) fewer on-location trans- ducer failures (marginal units are identified in testing), 2) fewer pump kick-outs and associated treatment failures, 3) better customer perception, 4) less chance of wellhead damage, 5) better fracturing analysis, and 6) safer on-location work environment. An em- bodiment targets the use of Weco® union, high-pressure transducers.

BACKGROUND

Commercial pressure calibrators typically include a pressure source (gas, pumped liquid, or stacked plates), a processing unit with a calibration algorithm and reporting capabili- ties, and some means of determining the output of the PTA under test usually by a third- party instrument with a digital output compatible with the processing unit. Available commercial pressure calibrators lack cost-effective, fit-for-purpose design such that there is no commercially available device to do what is disclosed here. Fabricating one using the commercial calibrators as a building block can be done at significant cost and com- plexity. Described herein is a device, the size of a small workbench, that is a single-piece, stand alone unit for the purpose of calibrating and/or performance verification of high- pressure, Weco union transducers. See DH Instruments and Ruska for commercial pres- sure calibration equipment.

DESCRIPTION

Oilfield high-pressure transducers typically have process fittings that follow FMC's We- co union design. These are typically Weco wing union figures 1502, 2002, and 2202, although there are others. These fittings have a male threaded portion and female threaded portion. The female portion is typically part of the pressure transducer assembly in the form of a three-lobed wing or a nut (see Figures 1 and 2). The calibration system may have one or more male fittings to accept one or more PTAs. The calibration system may include other fitting types such as Autoclave F250C, F375C, F562C, F750C, F1000C, SF250CX, SF375CX, SF562CX, SF750CX, SF1000...