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WELL ABANDONMENT
Blast Perforating & Casing Destruction
EXPLOSIVE TECHNOLOGY
Explosives & Blast Perforating for Well Abandonment
Explosive charges with projectiles penetrate and blast holes through the casing, then high velocity detonating cord rips seams, joints and enlarges the holes created by the projectiles.
These charges are placed in the well, then the well is filled with cement.
The cement above the charge works as stemming that stops upward movement
and directs the energy out to the casing walls and into the formation.
The advantage of using this system is; as soon as the casing is perforated
and ripped the explosive energy and the weight of the cement forces
the cement into voids, cavities and gravel that surrounds the well.
MATERIALS USED
Initiating Device: A non electrical firing mechanism used to initiate the shock tube.
Shock Tube: Noiseless trunk line coated on the inside with HMX mixed with aluminum - sends energy to fire the detonator.
Detonator: Non-electric blasting cap- uses 12 grains
PETN as a base charge.
Detonating Cord: Round flexible non-electric cord
- uses a core load of 50 to 100 grains of PETN per foot and has detonation
velocity of approximately 22,000 fps.
Boosters: Plasticized rubbery tubes of 8 gms PETN
with a detonation velocity of approximately 24,000 fps.
Projectiles: Round bullets 3/8" to 1/2" balls made out of AISI 52100 chrome alloy steel.
Stemming: Cement mix from neat (27 sack per yard)
to 9 sack per yard.
Blast Perforating & Casing Destruction
for Well Abandonment
The primary purpose of abandoning wells is to eliminate the risk of contamination from:
- Surface water seeping into the well.
- One aquifer traveling into another aquifer
Ideal Method for Abandoning: Remove Steel Casing then place sealing material in well.
~Problems with Removing Steel Casing~
- Time consuming. It can take several days (depending on the depth of the well) to remove the casing.
- It is difficult and, in most cases, almost impossible to remove the casing.
- Even if you get the casing out, then the well may collapse before you get the sealing material in the well.
Common Method for Abandoning: Puncher
Casing by Hydraulic or Mechanical Perforating then place sealing material
in well.
~Problems with Hydraulic or Mechanical Perforating~
- Time consuming. Perforating adds an additional step to the abandonment process. It can take a few days depending on the depth of the well.
- Never sure if the casing actually gets penetrated (the only way to ensure that the casing gets penetrated is to camera the well before the sealing material is added).
- The brittle, old, and deteriorated casing may be weakened to the point where the well collapses.
The Best way for Abandoning: Destroy Casing using our most
powerful tool "explosives" to blast perforate and shatter casing
and at the same time pushing sealing material into the formation to insure
proper sealing. When an explosive detonates, tremendous pressure is released
instantaneously in a shock wave. This sudden pressure will shatter rather
then displace objects (casing) then compression energy pushes objects
(cement) at great pressure out from the center.
Description of Service:
Charges are placed in the well and then the well is filled
with cement. Next, the charges are detonated. The explosive charges and
projectiles penetrate and blast holes through the casing. Then, high velocity
detonating cord rips and busts the seams, joints, and enlarges the holes
created by the projectiles. The cement, which is twice the weight of water,
above the charge stems the blast (absorbs the upward blast and pushes
the blast sideways through the casing). In addition, the cement is thrust
through the shattered casing out into any voids, cavities, and gravel
that surrounds the well.
SAFETY FEATURES
Non Electrical: Power lines, Radio frequency and other extraneous electricity are safe to work around.
No Air Blast or Flying Debris: The weight of the
cement makes a excellent stemming and keeps debris confined in the well.
Low Noise Level: The viscosity of the cement dampens, keeping the noise from reaching the surface.
Low Vibration Level: The small amount of explosive charges used kept vibrations confined to the area immediately surround the well.
Benefits of Service:
1. Saves time. This process is completed at the same time
as the cement is added to the well.
2. The casing is not only penetrated, it is also shattered.
3. The explosive energy and weight of the cement forces the cement into
voids, cavities, and gravel that surrounds the well.
4. Never have to worry about the well collapsing before the sealing
material is placed into the well.
5. This is a non-electrical process. Thus, power lines, radio transmission
equipment, and other extraneous electricity are safe to work around.
6. No air blast or flying debris. The cement confines the upward blast
and keeps debris in the well.
7. Low noise level. The viscosity of the cement dampens the blast noise
and prevents the noise from reaching the surface.
8. Low vibration level. By using a small and appropriate amount of explosive,
the vibration is confined to the area immediately surrounding the well.
9. Process completely eliminates the risk of contamination from ground
water seeping into the well or contamination moving from one aquifer
to another.