A tool, system and a method for determining barrier and material quality behind multiple tubulars in a hydrocarbon wellbore

Abstract

A tool and method for determining material quality of hydrocarbon wellbore cross sections comprising tubular elements and filling materials, the tool comprising: a body; moveable assemblies having arms configured to be in contact with an inner wall of a downhole tubular element, wherein the plurality of the moveable assemblies are configured to move between a retracted position where the arms are within a housing located in the body of the tool and an extended position where the arms protrude from the housing and are in contact with the inner wall of the downhole tubular element, wherein at least one of the plurality of moveable assemblies comprises an acoustic broad band source array operating in the frequency range of 0-100 kHz and at least one of the plurality of moveable assemblies comprises an acoustic broad band receiver array comprising one or more radially spaced acoustic broad band receivers.

Description

CROSS REFERENCE TO RELATED APPLICATION[0001]This application is a national stage application, filed under 35 U.S.C. § 371, of International Patent Application No. PCT / NO2019 / 050019, filed Jan. 25, 2019, which claims priority to Norwegian Patent Application No. 20180117, filed Jan. 25, 2018, both of which are incorporated by reference herein in their entirety for all purposes.FIELD OF THE INVENTION[0002]The invention concerns the field of well logging. More specifically, the invention concerns a tool, system and a method for determining material quality of a hydrocarbon wellbore, as set out by the independent claims 1, 21 and 24.BACKGROUND OF THE INVENTION[0003]Hydrocarbon fluids such as oil and natural gas are obtained from a subterranean geologic formation, referred to as a reservoir, by drilling a well that penetrates the hydrocarbon bearing formation. Once a wellbore has been drilled, the well must be completed before hydrocarbons can be produced from the well. A completion invol...

AI Technical Summary

Benefits of technology

The invention is a tool for determining the material quality of a hydrocarbon wellbore cross section. The tool comprises a body with a plurality of moveable assemblies with multiple arms that can be extended to make contact with the inner wall of the downhole tubular element. The moveable assemblies have acoustic broad band sources and receivers that can trigger wave modes on the inner wall of the tubular element to enable eigenfrequencies in sonic and ultrasonic spectrum. The acoustic broad band sources and receivers can operate in different frequencies to obtain information about the material quality of the cross section. The tool can also have instrumentation means for telemetries, motor drivers, controllers, signal amplifiers, CPUs or memories to control and process the signals obtained from the acoustic broad band sources. The method involves conveying the tool in the downhole tubular and activating the acoustic sources to trigger wave modes on the inner wall of the tubular element to enable eigenfrequencies in sonic and ultrasonic spectrum. The recorded wave modes are then compared with pre-stored models in a computer to determine the material quality of the cross section.

Problems solved by technology

Poor cement bonding between the cement and the casing, or the formation, channels, or fractures through the cement, may lead to hydrocarbon leakage to the surface and cause a blowout with severe damages to people, equipment and the environment.

In addition, some wells also experience subsidence of the formation in which they are located.

These elements are some of the most obvious features that can cause changes to the cement properties and result in leakage of fluids through the cement or disconnection (de-bonding) from the steel casing or the formation.

If the gate opening is too large, there may be interference between early and late arriving signals.

Ultrasonic tools are superior to the acoustic CBLs, although they remain adversely affected by highly attenuating muds.

Today's existing cement evaluation tools and technology for cement evaluation are limited to characterize cement behind only one casing wall.

Existing cement evaluation tools also rely on a large degree of interpretation and calibration, often leading to contradicting results depending on the analyst, irrespective of the actual cement quality.

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