Acoustic source using a shaftless electrical hammer
AssigneeSchlumberger Technology Corporation
InventorChung Chang
Life of this patent
Estimating the term…
Abstract
A shaftless acoustic source is disclosed having a solenoid, a bullet and driving electronics. The bullet, which is positioned inside the solenoid's coil, can be accelerated by a magnetic force generated when a current pulse is applied to the coil. Acoustic energies are generated upon the impact of the bullet with an object, such as a borehole wall. This impact force can be described by the Hertzian Contact Theory (also referred to herein as Hertzian Theory) as a point of normal force with a time function similar to a half period sine function. A retraction device may be used to retract the bullet back into the solenoid after firing.
Claims10
An acoustic system for determining properties of a borehole formation comprised of:
- a. a borehole apparatus equipped with an acoustic energy source, wherein said acoustic energy source is comprised of a solenoid having a bullet positioned within its coil;
- b. driving electronics to control said solenoid to accelerate said bullet and thereby impart acoustic energy into said borehole formation;
- and
- c. one or more receivers for receiving said acoustic energy, wherein at least a portion of said acoustic energy has traveled through said borehole formation.
A method of sensing properties of a borehole formation, comprising the steps of:
- a. providing a borehole apparatus equipped with an acoustic energy source, wherein said acoustic energy source is comprised of a solenoid having a bullet positioned within its coil and wherein said borehole apparatus is further equipped with one or more receivers;
- b. applying a current pulse to said solenoid thereby generating a magnetic force to accelerate said bullet;
- c. impacting acoustic energy into said borehole formation using said accelerated bullet;
- and
- d. receiving said acoustic energy, wherein at least a portion of said acoustic energy has traveled through said formation.
Dependencies are inferred from the claim text.