SU987069A1 - Percussive hole-bottom mechanism - Google Patents

Description

(54) WATCH SHOCK MECHANISM

one

The invention relates to a technique for the drilling of exploration wells, namely to downhole percussion drilling mechanisms.

A well-known downhole hydraulic percussion drilling machine (m) is a direct action, comprising a housing, a spring-loaded valve and a piston head, a cylinder and an anvil, which provides effective drilling of exploration wells using process water 1 as a washing liquid.

However, its use with gas-liquid flushing agents is practically impossible because of the high flow rates of the agent during off-cycle periods (free and reverse strokes), due to which the hydrodynamic pressure on the valve and pressure point drastically increases, at the end of the working stroke, a significant increase in the tension and stiffness of the springs is required, which in turn leads to a significant decrease in the power and efficiency of the impact mechanism.

Known downhole percussion mechanism, comprising a housing, a spring-loaded head.

valve box, valve and lower flow rate with spring loaded valve | 2.

The disadvantage of this hydraulic hammer when using it with foam is the impossibility of ensuring its stable operation, since the use of a gas-liquid flushing agent practically eliminates the occurrence of hydraulic shocks necessary for the operation of the reducer, and the presence in the saddle of the valve 10 of the reducer of through holes causes the flushing agent flow during free and idle striker strikes.

The purpose of the invention is to increase the impact power and reliability of the downhole impact mechanism.

15

The goal is achieved by the fact that in a downhole percussion mechanism comprising a housing, a spring-loaded striker, a valve box, a valve and a flow reducer with a spring-loaded valve, the valve is connected 20 with the possibility of limited axial movement with a spring-loaded valve of the flow attenuator, in addition, the mechanism is equipped with a spring-loaded non-return valve installed in the valve box with the ability to interact with the valve.

FIG. 1 shows the mechanism, a general view; in fig. 2 shows a valve assembly with a spring loaded check valve.

The device comprises a housing 1 of a mechanism that is connected to an anvil assembly 2 and a cylinder 3, and the latter is connected to a nozzle 4.

Inside cylinder 3, there is a striker 5 supported on a power spring 6. A valve assembly, including a valve box 7, a spring 8, a lower valve 9 and a valve 10 in the flow reducer, rests on top of the cylinder. The valves 9 and 10 have the possibility of limited longitudinal movement relative to each other, which is provided by the splines 11 and the lid 12: the cavities A and B inside the valve box 7 and the valve 9 communicate with each other. Valve 9 interacts with the brisk psi 5.

In the upper part of the valve box 7 there is a seat 13 of the valve 10 interacting with the housing 7; at the moment of interaction, the cavity of the pressure line B is isolated from the cavities A, B.

FIG. 2 shows an embodiment of the device with an additional spring-loaded ball valve 14 installed in the channel of the valve box connecting the internal cavity A of the valve box 7 and the cavity B of the pressure line. Under the valve 14 is located the pusher 15.

The device works as follows.

Before the start of drilling, the spline connector of the anvil 2 of the mechanism is opened, the face 5 is in the lower position, the valves 9 and 10 are moved to the extreme upper position by the spring 8 and the flushing agent (gas-liquid mixture) flows freely through the valve assembly and the head 5 to the bottomhole, having cleaned the well from schlama

When the mechanism is set on the bottom, the slot connector of the anvil 2 closes, the head 5 moves upwards to meet with the valve 9 and the flow of the agent overlaps, in zones L and B above the valve 9 pressure rises and the head 5 moves together with valves 9 and 10 working stroke. After the valve 10 of the reducer, with its conical part, connects the seat 13 to the separation of zone B, where the high pressure is maintained, from zones A and B, where the pressure drops, as at this moment the firing pin 5 detaches from valve 9 and moves further down inertia (free running). After completing the free stroke and striking the anvil 2, the firing pin 5 under the action of the force spring 6 moves upward (reverse); on this way, he picks up the valve 9, with which he mixes up to the stop at the lower end of the valve 10 of the flow reducer and strikes the latter. As a result, a gap is formed between the seat 13 and the valve 10, into which the flushing agent rushes; the pressure in zones A to B rises, the valve 9 is pressed against the striker biv as a result of equalizing the pressures in zones A, B c C in the same sequence.

Possible constructive performance

a pair of composite valves 9 and 10 with hydraulic, rather than mechanical interaction at the end of the valve 9 lift with the striker 5. If for ensuring maximum power of the percussion mechanism in the pressure head

the line is maintained at a high pressure and for tearing the valve 10 away from the seat 13, at the end of the return stroke, considerable force is needed, it is advisable to use a variant of the device with an additional ball valve 14 shown in

FIG. 2. The device operates as follows.

The initial stages of the operating cycle are the same as for valves with mechanical interaction.

At the end of the return stroke of the striker 5 with the valve 9, the latter rests on the pushing rod 15 with its lid 12, which in turn will move the spring-loaded ball up from its saddle

0 valve 14. Due to this, the zones S and L are communicated, the pressure in them is equalized and the valve 10 is moved by the spring 8 to the upper position, and the valve 9 is pressed by the increased pressure to the striker 5 and moves downwards with it (working ).

The presence of a composite two-stage valve that ensures the separation of the pressure line from the working chamber of the mechanism during periods of free and reverse strokes allows the use of gas-liquid mixtures (including a liquefied zone in the lower part of the drill string) as a flushing agent, which in turn allows achieve a high downhole power of the percussion mechanism as a result of the improvement of its working cycle (constant pressure in the valve valve nadklapannogo zone during the entire period of acceleration of the piston –block) awns increasing stroke length while maintaining constant acceleration force capabilities of the device operation at high pressure in the pressure line.

All this allows to increase the energy of a single blow of the mechanism, which leads to an increase in the speed of drilling.

Claims (2)

1. A downhole impactor comprising a housing, a spring-loaded striker, a valve box, a valve and a flow reducer with a spring-loaded valve, characterized in that, in order to increase the impact power when drilling using a gas-liquid flushing agent, the valve is connected with the possibility of limited axial movement with spring loaded flow control valve. 2. The mechanism according to claim 1, characterized in that it is provided with a spring-loaded reverse valve installed in the valve box with the ability to interact with the valve. Sources of information taken into account in the examination 1. Graf L. E. and others. Hydraulic impact machines and tools, M., “Nedra, 1972, p. 53. 2. Graf L. E. and others. Hydraulic impact machines and tools. M., “Nedra, 1972, p. 63 (prototype).