Acoustics – Geophysical or subsurface exploration – Well logging
Reexamination Certificate
1999-12-14
2001-01-16
Dang, Khanh (Department: 2837)
Acoustics
Geophysical or subsurface exploration
Well logging
C073S152170, C166S250110
Reexamination Certificate
active
06173804
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a system intended for permanent installation of measuring sondes against the inner wall of pipes.
The installation system according to the invention can find application in many industries. It is notably useful for positioning various measuring sondes useful for longtime monitoring of underground zones, such as hydrocarbon reservoirs during exploration and/or production stages, or storage or burial reservoirs. The system can be used for example for installing seismic pickups (geophones, hydrophones, etc) coupled with the wall of a well for monitoring operations, whether active monitoring using a seismic source placed at the surface, in another well or possibly in the same well, or passive monitoring for detecting reactions of the zone in response to production operations carried out therein.
BACKGROUND OF THE INVENTION
It is well-known to lower seismic receivers into a well by means of a support such as a tube lowered in the well to a working depth. The receivers are placed in sondes, mobile boxes or pads secured to anchor systems suited to move on demand the receivers until they are coupled with the well wall, directly or by means of a casing pipe. The anchor systems can comprise mobile arms that can be shifted by hydraulic jacks or springs. Moving to a stretched position is performed by electric or hydraulic triggering means controlled by an operator from the surface, once the depth of installation is reached. They can also be secured to flexible blades such as tube off-centering blades and pressed against the well wall thereby.
Patent FR-A-2,656,034 (U.S. Pat. No. 5,181,565) describes a system for permanent installation, in a well, of a sonde for seismic or acoustic pickups by means of a tubular string such as a production tubing for example. The sonde (or each one of them) is associated with a system externally fastened to the string. At the operator's request, each sonde can be moved from a set back position where it is coupled with the string to a position of coupling with the well wall (or a well casing pipe) and acoustically decoupled from the string.
SUMMARY OF THE INVENTION
The system according to the invention allows installation of at least one measuring sonde against the wall of a pipe (a tube or a wellbore drilled through an underground formation for example).
The system comprises an elongate support element (a rod, a tube or a specialized tubing suited for fluid circulation for example), at least one device for coupling each sonde, comprising at least one flexible element to which the measuring sonde is fastened, this flexible element being suited, in a stretched position, to press said sonde against the wall of the pipe, and means for locking the flexible element in a set back position at a distance from the wall of the pipe, these locking means being actuated by establishing (by pumping means for example) an overpressure in the pipe.
Each coupling device comprises for example a tubular sleeve supporting each elastic element, the cross-section of this tubular sleeve being larger than that of the elongate element, the locking means comprising a lock suited to engage into a part secured to the flexible element, in a set back position thereof, and means for releasing the lock through breaking of a finger under the effect of a determined overpressure applied in the pipe.
The system can comprise means for transverse positioning of the elongate element in the pipe, so dimensioned that, in a stretched position of each elastic element, each coupling device is mechanically decoupled from the elongate element.
Each coupling device can comprise elastic damping means placed between the sleeve and the elongate element, for mechanically decoupling each measuring sonde from the elongate element when the flexible element is in a stretched position.
According to an embodiment, the unblocking means include a hydraulic jack comprising a cylinder that communicates with the inside of the pipe at a first end, the cylinder being secured to the elongate element, a mobile piston secured to the lock, sliding in the cylinder and a calibrated blocking finger that gives way when the differential pressure applied to the piston of the jack is higher than a threshold value.
The system can be used for example for installing a series of seismic sondes against the wall of a wellbore drilled through an underground zone, and it comprises in this case means for transmitting, to a surface recording station, signals picked up by the various seismic sondes. The elongate element used to lower the various coupling devices to their working depth can either be a tubing that remains in place in the well where it is used for carrying fluids (hydrocarbon production, injection of scavenging fluids, gas, substances to be stored, etc.), or a simple tube that is withdrawn once the seismic sondes are coupled with the well wall.
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patent: 4578785 (1986-03-01), Gelfand
patent: 4616703 (1986-10-01), Laurent
patent: 4686653 (1987-08-01), Staron
patent: 5092423 (1992-03-01), Petermann
patent: 5111903 (1992-05-01), Meynier
patent: 5212354 (1993-05-01), Miller et al.
patent: 5801642 (1998-09-01), Meynier
patent: 5810080 (1998-09-01), Meynier
patent: 5864099 (1999-01-01), Wittrisch et al.
patent: 1169871 (1959-01-01), None
patent: 2656034 (1991-06-01), None
Antonelli Terry Stout & Kraus LLP
Dang Khanh
Institute Francais du Petrole
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