US 2018/0003009 A1Published application

Adaptive Stimulation System

OwnerDennis W. Gilstad, Barbara C. Gilstadinventors

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Abstract

Adaptive stimulation systems combine impulse-generated swept-frequency stimulation vibration with cyclically-varying hydraulic pressure to provide adaptive down-hole stimulation. Swept-frequency stimulation vibration arises from cyclical shifts of the power spectral density (PSD) of each stimulator's fluid interface vibration (via closed-loop control of the rebound cycle time and/or the fluid interface's effective elastic modulus). PSD's are adjusted for resonance excitation and fracturing of geologic materials at varying distances from a wellbore, closed-loop control incorporating backscatter vibration from stimulated geologic material. One or more stimulators generate vibration in bursts comprising a plurality of vibration frequencies. Timed signals from a programmable controller affect directional propagation of combined vibration wave fronts from a stimulator array. As fracturing proceeds to smaller (e.g., proppant-sized) fragments having higher resonant frequencies, PSD's are up-shifted, increasing relative stimulation vibration power in higher frequencies. Progressive stimulation is thereby optimized, facilitating plain-water (or liquefied propane) fracs with self-generated proppant.

Claims20

Dependent claims

An adaptive stimulation system comprising

a frac pump for creating cyclically-varying down-hole hydraulic pressure in response to a timed pressure signal;
a plurality of down-hole hydraulic stimulators connected in a spatial array, each said down-hole hydraulic stimulator hydraulically transmitting, in response to a timed stimulator transmission signal, vibration having an adjustable power spectral density, and
a programmable controller for periodically transmitting one said timed pressure signal for said frac pump, one said timed stimulator transmission signal for each said down-hole hydraulic stimulator, and one timed stimulator shift signal for each said down-hole hydraulic stimulator, each said timed pressure signal being in-phase with at least one said timed stimulator transmission signal;
wherein each said down-hole hydraulic stimulator comprises
a hollow cylindrical housing having a longitudinal axis, a first end, and a second end, said first end being closed by a fluid interface for transmitting and receiving vibration, and said fluid interface comprising at least one accelerometer for producing an accelerometer feedback signal representing vibration transmitted and received by said fluid interface;
a driver element reversibly sealing said second end;
and
a hammer element longitudinally movable within said housing between said driver element and said fluid interface, said hammer element being responsive to said driver element for striking said fluid interface and rebounding therefrom during an adjustable rebound cycle time to hydraulically transmit a vibration burst comprising a plurality of transmitted frequencies;
a transverse coil peripheral to and surrounding said fluid interface, said transverse coil for generating a step-wise adjustable steady-state longitudinal magnetic field intersecting said fluid interface, and said fluid interface being magnetostrictively responsive to said longitudinal magnetic field for altering its effective elastic modulus;
wherein each said driver element comprises an electromagnet/controller having cyclical magnetic polarity reversal characterized by a variable polarity reversal frequency;
wherein longitudinal movement of each said hammer element is responsive to said cyclical magnetic polarity reversal;
wherein longitudinal movement of each said hammer element striking, and rebounding from, one said fluid interface is in-phase with one said variable polarity reversal frequency;
wherein said adjustable power spectral density is responsive to said adjustable rebound cycle time and to said step-wise adjustable steady-state longitudinal magnetic field;
and
wherein said adjustable rebound cycle time is responsive to one said timed stimulator shift signal.

12 more elements

An adaptive stimulation system comprising

a frac pump for creating cyclically-varying down-hole hydraulic pressure in response to a timed pressure signal;
a plurality of down-hole hydraulic stimulators connected in a linear stimulation array, each said down-hole hydraulic stimulator hydraulically transmitting a vibration burst in response to a timed stimulator transmission signal, and
a programmable controller for periodically transmitting one said timed pressure signal for said frac pump, and a plurality of timed stimulator signals as a signal group, each said signal group including one said timed stimulator transmission signal for each said down-hole hydraulic stimulator and one timed stimulator shift signal for each said down-hole hydraulic stimulator, each said timed pressure signal being in-phase with one said timed stimulator transmission signal;
wherein each said down-hole hydraulic stimulator comprises
a hollow cylindrical housing having a longitudinal axis, a first end, and a second end, said first end being closed by a fluid interface for transmitting and receiving vibration, and said fluid interface comprising at least one accelerometer for producing an accelerometer feedback signal representing vibration transmitted and received by said fluid interface;
a driver element reversibly sealing said second end;
and
a hammer element longitudinally movable within said housing between said driver element and said fluid interface, said hammer element being responsive to said driver element for striking said fluid interface and rebounding therefrom during an adjustable rebound cycle time to hydraulically transmit one said vibration burst comprising a plurality of transmitted frequencies as part of a directionally propagated array vibration wave front;
a transverse coil peripheral to and surrounding said fluid interface, said transverse coil for generating a step-wise adjustable steady-state longitudinal magnetic field intersecting said fluid interface, and said fluid interface being magnetostrictively responsive to said longitudinal magnetic field for altering its effective elastic modulus;
wherein each said driver element comprises an electromagnet/controller having cyclical magnetic polarity reversal characterized by a variable polarity reversal frequency;
wherein longitudinal movement of each said hammer element is responsive to said cyclical magnetic polarity reversal;
wherein longitudinal movement of each said hammer element striking, and rebounding from, one said fluid interface is in-phase with one said variable polarity reversal frequency;
wherein said timed stimulator transmission signals within each said signal group are simultaneous signals;
wherein said directionally propagated array vibration wave front is responsive to said simultaneous signals;
wherein each said variable polarity reversal frequency is responsive to one said timed stimulator transmission signal;
wherein each said step-wise adjustable steady-state longitudinal magnetic field is responsive to one said timed stimulator shift signal;
wherein each said adjustable rebound cycle time is responsive to one said timed stimulator shift signal;
and
wherein each said timed stimulator shift signal is responsive to one said accelerometer feedback signal.

16 more elements

An adaptive stimulation system comprising

a frac pump for creating cyclically-varying down-hole hydraulic pressure in response to a timed pressure signal;
a plurality of down-hole hydraulic stimulators connected in a linear stimulation array, each said down-hole hydraulic stimulator comprising an impulse vibration generator responsive to a timed stimulator transmission signal and a timed stimulator shift signal, each said impulse vibration generator being tuned via an adjustable rebound cycle time and an adjustable effective elastic modulus to periodically hydraulically transmit, in response to a timed stimulator transmission signal, a vibration burst comprising a plurality of vibration frequencies as part of a directionally propagated array vibration wave front;
and
a programmable controller for periodically transmitting one said timed pressure signal, a plurality of said timed stimulator transmission signals, and a plurality of said timed stimulator shift signals as a signal group, each said signal group including one said timed stimulator transmission signal and one said timed stimulator shift signal for each said down-hole hydraulic stimulator, each said timed pressure signal being in-phase with one said timed stimulator transmission signal;
wherein each said vibration burst comprising a plurality of vibration frequencies has an adjustable power spectral density that is responsive to one said adjustable rebound cycle time and one said adjustable effective elastic modulus;
wherein said timed stimulator transmission signals within each said signal group are sequential signals;
wherein said directionally propagated array vibration wave front is responsive to said sequential signals;
wherein each said down-hole hydraulic stimulator comprises at least one accelerometer for sensing vibration and transmitting an accelerometer feedback signal derived therefrom;
wherein each said timed stimulator shift signal is responsive to one said accelerometer feedback signal;
wherein each said adjustable effective elastic modulus is responsive to one said timed stimulator shift signal and;
wherein each said adjustable rebound cycle time is responsive to one said timed stimulator shift signal.

8 more elements

Dependencies are inferred from the claim text.

Facts

Application: 15/686,334Filed 25 Aug 2017
Priority: 22 Oct 2015
Published: 4 Jan 2018
Term ends: Not estimatedThe source records don’t support an estimate.

Classification11 codes

E21B 43/003
Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells: vibrating earth formations
E21B 28/00
Vibration generating arrangements for boreholes or wells
E21B 43/2607
By forming crevices or fractures: surface equipment specially adapted for fracturing operations
E21B 47/12
Survey of boreholes or wells: means for transmitting measuring-signals or control signals from the well to the surface, or from the surface to the…

Family

Application14/919,848Continuation in part · filed 22 Oct 2015
Application15/686,334Continuation in part
US 2017/0114620 A1Published application
US 9,777,556 B2Related patent
US 9,879,507 B2Related patent
US 2018/0003009 A1This patent

From the US filing history. Foreign family members aren’t listed.