HAMMER AND HAMMER-VIBRATION MECHANISM FOR LIQUIDATION OF STICKING

O.I. Kalichenko
A.A. Karakozov
V.A. Rusanov
Donetsk Politechnical Institute
Ukraine

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Source of information: Журнал Changchum University of Earth Sciences, Geology Committee of Jilin Province, P.R.C.

ABSTRACT

    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 string or core barrel,a lot 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 tearing. 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 0.073m, 0.089m and even more.

Brief Performance data of hydraulic hammer

Parameter
Diameter of hydraulic hammer (m)
0.057 0.073 0.089 0.108 0.146
Rate of discharge (m/s) 0.0015 0.002 0.003 0.005 0.066
Average differential pressure (MPa) 2.94 2.46 2.75 3.5 4
Impact frecuency (s) 30 32 35 35 30
Impact energy (J) 50 80 120 330 350
Mass (kg) 38 55 85 145 170


    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.
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