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US 4,715,470 AGranted
Downhole electromagnetic seismic source
AssigneeChevron Research Company
InventorBjorn N. P. Paulsson
Life of this patent
Estimating the term…
Abstract
The present invention is a downhole seismic source capable of generating seismic forces in excess of 1000 newtons. The source produces seismic waves for seismic applications, particularly cross borehole measurements and vertical seismic profiling. Coupled with motion sensing devices, the present invention also performs as a seismic logging tool. The source is comprised of an outer housing, a means for clamping the source securely to the wellbore, and a linear electromagnetic actuator which utilizes permanent magnetic material having remanent magnetic field exceeding about 0.9 T such as rare earth permanent magnetics. The source has a diameter of about 12.5 cm to fit within a typical wellbore and the actuator has a length of about 1 meter.
Claims72
A downhole seismic source comprising:
- a housing;
- a clamping means for coupling said housing securely within a wellbore;
- and
- a linear electromagnetic actuator within said housing comprising;
- (a) a cylindrically shaped shell having an outer portion attached to said housing and an inner portion;
- (b) an armature winding attached to said inner portion of said shell;
- and
- (c) an inner core reaction mass slidably positioned inside said armature winding such that motion of said mass will impart substantially shear waves and presure waves on a surrounding formation, said reaction mass substantially constructed from a magnetically active material and moving along its lengthwise axis when said armature winding is energized.
5 more elements
A downhole seismic source comprising:
- a housing;
- a clamping means for coupling said housing securely within a wellbore;
- and
- a linear electromagnetic actuator within said housing, comprising;
- (a) an armature winding attached to said housing, said armature winding having a cylindrical shape around a center axis;
- and
- (b) a reaction mass within said housing comprising:
- (i) a center shaft coaxially positioned inside said armature winding and adapted to be slidably movable along its lengthwise axis;
- (ii) a cylindrically shaped inner core attached to said center shaft and coaxially positioned between said center shaft and said armature winding, said inner core being substantially constructed from a first magnetically active material;
- and
- (iii) a cylindrically shaped outer core attached to said center shaft and coaxially positioned outside said armature winding, said outer core being substantially constructed from a second magnetically active material;
- said reaction mass moving reiteratively from a first position to a second position when said armature winding is energized such that substantially shear waves and pressure waves are imparted on a surrounding formation.
9 more elements
The downhole seismic source according to calim 20 further comprising at least one motion sensing device, said motion sensing device being acoustically isolated from said actuator and capable of being independently coupled to the wellbore.
A downhole seismic source comprising:
- a housing;
- a reaction mass within said housing;
- a clamping means for coupling said housing securely within a wellbore;
- and
- an electromagnetic actuator means within said housing for moving said reaction mass to create substantially pressure waves and shear waves.
2 more elements
A downhole seismic source comprising:
- (a) a housing;
- (b) a clamping means for coupling said housing securely within a wellbore;
- (c) a linear eletromagnetic actuator within said housing;
- and
- (d) a reaction mass slidably positioned in said actuator such that motion of said mass will impart substantially shear waves and pressure waves on a surrounding formation.
2 more elements
A method of generating seismic waves comprising:
- lowering a seismic source into a borehole in an earthen formation said seismic source comprising a housing, a linear electromagnetic liner actuator a reaction mass slidably positioned within said actuator, and a clamping means;
- securing said seismic source in the formation with said clamping means;
- energizing said electromagnetic liner actuator to move said mass to generate substantially pressure waves and shear on said earthen formation.
A downhole seismic source comprising:
- a housing;
- a clamping means for coupling said housing securely within a wellbore;
- and
- a linear electromagnetic actuator within said housing comprising;
- (a) a cylindrically shaped shell having an outer portion attached to said housing and an inner portion;
- (b) an armature winding attached to said inner portion of said shell;
- and
- (c) an inner core reaction mass slidably positioned inside said armature winding, said reaction mass substantially constructed from a magnetically active material and moving linearly along its lengthwise axis when said armature winding is energized, said mass comprised of iron laminated with a rare earth permanent magnetic material.
5 more elements
A downhole seismic source comprising:
- a housing;
- a clamping means for coupling said housing securely within a wellbore;
- and
- a linear electromagnetic actuator within said housing, comprising;
- (a) an armature winding attached to said housing, said armature winding having a cylindrical shape around a center axis;
- and
- (b) a reaction mass comprising:
- (i) a center shaft coaxially positioned inside said armature winding and adapted to be slidably movable along its lengthwise axis;
- (iii) a cylindrically shaped inner core attached to said center shaft and coaxially positioned between said center shaft and said armature winding, said inner core being substantially constructed from a first magnetically active material;
- and
- (iii) a cylindrically shaped outer core attached to said center shaft and coaxially positioned outside said armature winding, said outer core being substantially constructed from a second magnetically active material, said second magnetically active material being a non-permanent magnetic material and said inner core comprised of:
- an inner portion constructed from non-permanent magnetic material and an outer portion constructed from a permanent magnetic material having a remanent magnetic field of at least about 0.9 T;
- said reaction mass moving reiteratively from a first position to a second position when said armature winding is energized.
10 more elements
A downhole seismic source comprising:
- a housing;
- a clamping means for coupling said housing securely within a wellbore;
- and
- a linear electromagnetic actuator within said housing, comprising;
- (a) an armature winding attached to said housing, said armature winding having a cylindrical shape around a center axis;
- and
- (b) a reaction mass comprising:
- (i) a center shaft coaxially positioned inside said armature winding and adapted to be slidably movable along its lengthwise axis;
- (ii) a cylindrically shaped inner core attached to said center shaft and coaxially positioned between said center shaft and said armature winding, said inner core being substantially constructed from a first magnetically active material;
- and
- (iii) a cylindrically shaped outer core attached to said center shaft and coaxially positioned outside said armature winding, said outer core being substantially constructed from a second magnetically active material, said second magnetically active material being a non-permanent magnetic material and said inner core comprised of:
- an inner portion constructed from non-permanent magnetic material and an outer portion contructed from rare earth permanent magnetic material;
- said reaction mass moving reiteratively from a first position to a second position when said armature winding is energized.
10 more elements
A downhole seismic source comprising:
- a housing;
- a clamping means for coupling said housing securely within a wellbore;
- and
- a linear electromagnetic actuator within said housing, comprising;
- (a) an armature winding attached to said housing, said armature winding having a cylindrical shape around a center axis;
- and
- (b) a reaction mass comprising:
- (i) a center shaft coaxially positioned inside said armature winding and adapted to be slidably movable along its lengthwise axis;
- (ii) a cylindrically shaped inner core attached to said center shaft and coaxially positioned between said center shaft and said armature winding, said inner core being substantially constructed from a first magnetically active material, said first magnetically active material being a non-permanent magnetic material and said outer core comprised of:
- an outer portion constructed from non-permanent magnetic material and an inner portion constructed from a permanent magnetic material having a remanent magnetic field of at least about 0.9 T;
- and
- (iii) a cylindrically shaped outer core attached to said center shaft and coaxially positioned outside said armature winding, said outer core being substantially constructed from a second magnetically active material;
- said reaction mass moving reiteratively from a first position to a said position when said armature winding is energized.
10 more elements
A downhole seismic source comprising:
- a housing;
- a clamping means for coupling said housing securely within a wellbore;
- and
- a linear electromagnetic actuator within said housing, comprising;
- (a) an armature winding attached to said housing, said armature winding having a cylinddrical shape around a center axis;
- and
- (b) a reaction mass comprising:
- (i) a center shaft coaxially positioned inside said armature winding and adapted to be slidably movable along its lengthwise axis;
- (ii) a cylindrically shaped inner core attached to said center shaft and coaxially positioned between said center shaft and said armature winding, said inner core being substantially constructed from a first magnetically active material, said first magnetically active material being a non-permanent magnetic material and said outer core comprised of:
- an outer portion constructed from non-permanent magnetic material and an inner portion constructed from rare earth permanent magnetic material;
- and
- (iii) a cylindrically shpaed outer core attached to said center shaft and coaxially positioned outside said armature winding, said outer core being substantially constructed from a second magnetically active material;
- said reaction mass moving reiteratively from a first position to a second position when said armature winding is energized.
10 more elements
Dependencies are inferred from the claim text.