Journal of Changchun, University of Earth Sciences, 1993
Hammer and Hammer-vibration
Mechanism for Liquidation of Sticking
(Abstract)
Kalinichenko
O.I., Karakozov A.A., Rusanov V.A.
(Donetsk Politechnical
Institute, Ukraine)
Sticking of the core barrel
and drilling string are One of the main problems, which
decreases technical-and-economic indices and efficiency of
exploration drilling. Its prevention and liquidation require 5-8
per cent of the work time. The forced completion of the wells,
which has not fulfiled the geological target first of all
depends On stickings of the drilling sting or core barrel
alot
of metal is spent, because well casing due to low casing pipes
damages by their stickings. Losses of stickings amounted to ten
million roubles one year (at the price Of January 1992) specific expenditure
on the liquidation of stickings practically
goes on.
Every expedition has One
drilling rig constantly engaged in failure learing. A hammer and
percussive machines are effective and economical for liquidation
of stickings. The department of Technology and Technique of
Geological Prospecting of Donetsk Politechnical Institute (DPI)
has developed series of submerible hydraulic hammer and hammer
units: drilling jar (DJ) and devices for liquidation Of sticking
(DLS).
DPI hydraulic hammer can be
included into the boring rig or be lower in sticking zone On
drilling string after failure.
The drilling jar is a
mechanism in which breaking of the locking assembly is the
result of pressure rise in the drilling string. This mechanism
can be included into the boring rig and is immediately put into
action after failure. Besides drilling jar can be lowered in
sticking zone. On the drilling string after its free part is
released and moved to the surface.
Joint action of the powerful
impact and natural oscillations of the drilling string on the
sticking zone provide high efficiency of the drilling jar.
The DPI had developed DJ
designs with external diameter 0,073 m,
0,089 m and even more.
The DPI has also produced the
device of repeated action in which energy of the hydrostatic
pressure of the fluid column in the borehole is used for
generation of the impact impulse. This device allows to realize
high energetic indices with small expenses of the input power.
Besides, drilling string does not take part in generation and
perception of the impact impulses. Therefore this device is
reliable and has the following advantages:
1. Utility of the mechanism;
2. Less difficulties in
clearing failures of stickings of pipes due to security of
abrupt local reduction of pressure in sticking zone;
3. The force of impact is
adjusted in broad range;
4. Simplicity of design,
mounting and repair;
5. Safety of the operation.
All the devices are evaluated
under laboratorial and industrial conditions and show
sufficiently high parameters of reliability.
