RU2733865C1 - Method and device for well shaft cleaning from plugs - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: group of inventions relates to oil and gas industry, namely to methods and devices for cleaning of the well shaft, including horizontal ones. Proposed method comprises lowering of case with destructing head with downhole motor to the well on the non-rotating string, which provides, during pumping of flushing liquid through drilling pipes with creation of definite pressure drop rotation of destructing head at breakage of plug. Crushing head is equipped with a central water jet channel. Pressure drop for engine pulse rotation is due to reciprocal movement of downhole motor in the form of striker, which is created at thrust of destructing head on destructed rock and partial overlapping of jetting channel. Housing from above is equipped with annular chamber interconnected with external space. Crushing head is inserted inside the housing with possibility of rotation and from above on end along perimeter is equipped with inclined on one side sampling. Thrust is pressed from above by the spring inserted into the annular chamber to the end face of the cutting head of the hollow striker. Stop upper part is tightly inserted into the annular chamber. At the lower end of the hammer there are ledges for cutting head slots inclined on one side along the perimeter. To move up the striker between the inner annular narrowing of the body and the above annular shoulder of the striker, there is an annular hydraulic chamber communicated with the inner cavity of the striker. Housing above the chamber is equipped with radial holes made with possibility to communicate with the chamber when the striker is moving upwards. On external surface of annular ledge of hammer there is an annular shaped groove made of symmetric upper and lower alternating grooves connected in series by inclined grooves through its side wall. In opposite upper grooves are inserted paired symmetrical supports of housing with possibility of successive movement.

EFFECT: enabling passage of loose plugs due to jetting action, and dense sections of plugs by means of mechanical action, without wasting energy during erosion of plug on rotation of destructing head, and in case of mechanical destruction for waterjet exposure, and in automatic mode.

1 cl, 2 dwg

Description

The invention relates to the oil and gas industry, and in particular to methods and devices for cleaning a wellbore, including horizontal.

A known method for cleaning horizontal and inclined wells (patent RU No. 2524228, IPC E21B 21/08, publ. 07/27/2014 Bull. No. 21), including the creation of circulation of drilling mud by pumping it through the drill string with a sub installed at the beginning of the horizontal section, and the drilling fluid flow is divided when passing through the sub, containing a hollow body with radial channels made in the body at an angle of 30-60 ° to its axis, into two parts, while one part of the drilling fluid is thrown out through the radial channels in the form of a turbulent flow, providing removal cuttings particles into the vertical section of the well, and the other part of the drilling fluid is directed in the form of a laminar flow into the horizontal section of the well.

The method is implemented using a sub, including a body with a central channel and radial channels, made in the body at an angle of 30-60 ° to its axis, for dividing the flow of drilling fluid into central laminar and turbulent, ejected through the radial channels and ensuring the removal of cuttings particles into the vertical well section.

The disadvantages of this method and device are a narrow area of application due to the possibility of flushing only loose and non-extended plugs due to the absence of their mechanical destruction, the spread of the fluid pressure in several directions sharply reduces the effectiveness of plug destruction, and is not intended to work directly in horizontal shafts.

There is also known a method for cleaning a wellbore from cuttings (patent RU No. 2176017, IPC Е21В 21/00, publ. 20.11.2001 Bull. No. 32), including its removal by flushing fluid along the annulus, and in the annular space in the interval of the horizontal section of the wellbore wells in the process of drilling create a radial movement of the drilling fluid flow to ensure the removal of cuttings particles into the upper part of the radial section of the annular space corresponding to the movement of the main part of the drilling fluid flow.

The disadvantages of this method are a narrow area of application due to the possibility of using only during the drilling of hard rocks, since there is no possibility of a jetting effect (high-speed fluid pressure) on the plug, and the presence of a constantly rotating eccentric driven by a special engine (turbine) requires high energy consumption for pumping liquid through the pipe string.

The closest in technical essence and the achieved result is a device for cleaning wells from cuttings (patent RU No. 2160818, IPC Е21В 21/00, publ. 20.12.2000 Bull. No. 35), including non-rotating drill pipes, a bit, downhole motor and centralizers with blades located at an acute angle to the axis of the drill pipes, and it is equipped with turbines installed behind the centralizers with the ability to rotate around their longitudinal axes under the action of the flow of flushing fluid, and the outer diameter of the turbines is less than the outer diameter of the centralizers, and the direction of the blades of the centralizers in the direction of movement of the flushing fluid coincides with the direction of rotation of the bit.

This device implements a method for cleaning a well, including lowering into the well on a string of non-rotating drill pipes with a casing with a bit and a downhole motor and centralizers located above with blades delighted by turbines, which are installed behind the centralizers with the possibility of rotation around their longitudinal axes under the action of a flow of drilling fluid, moreover, the outer diameter of the turbines is less than the outer diameter of the centralizers, and the direction of the blades of the centralizers in the direction of the drilling fluid movement coincides with the direction of rotation of the bit, intensive pumping of the drilling fluid through the drill pipes to ensure rotation by the downhole motor of the bit when the rock is destroyed at the bottom hole and rotation of the turbines to obtain a swirling flow with giving it a rotational-translational motion.

The disadvantages of this device are a narrow field of application and high energy costs, since for the constant rotation of the downhole motor and turbines when driving plugs, high energy costs are required for pumping fluid, which is especially not cost-effective (and therefore not used) when driving sand plugs and / or proppant plugs after completion of hydraulic fracturing (hydraulic fracturing).

The technical objective of the proposed invention is to create a method and a device for cleaning the wellbore from plugs, allowing loose plugs to pass through due to the jetting action, and dense plugs by means of mechanical action, without wasting energy when the plug is washed out on the rotation of the breaking head, and in case of mechanical destruction on the jetting impact, and in automatic mode.

The technical problem is solved by a method for cleaning the wellbore from plugs, including lowering a body with a destructive head with a downhole motor into the well on a string of non-rotating pipes, which ensures the rotation of the destructive head when the plug is destroyed while pumping the drilling fluid through the drill pipes with the creation of a certain pressure drop ...

What is new is that the collapsing head is equipped with a central jetting channel, and the pressure difference sufficient for the impulsive rotation of the engine is due to the reciprocating movement of the striker, which is created when the breaking head rests on the rock to be destroyed and the jet channel is partially blocked, while the speed of lowering the drilling pipes are reduced until they stop to stabilize the frequency of pressure surges at the wellhead, and after the pressure surges stop, the descent rate is gradually restored.

The technical problem is also solved by a device for cleaning the wellbore from plugs, which includes non-rotating pipes, a housing, a destructive head and a downhole motor.

What is new is that the body is equipped from above with an annular chamber communicated with the outer space, the collapsing head is equipped with a central jetting channel for blurring the plug, inserted into the body with the possibility of rotation and at the top at the end along the perimeter is equipped with samples inclined on one side, the downhole motor is made in the form pressed from above by a spring inserted into the annular chamber, to the end of the cutting head of a hollow striker, hermetically inserted into the annular chamber by the upper part, and on the lower end of the striker there are projections inclined on one side for the cutter head recesses along the perimeter, while for moving up the striker between the inner with an annular narrowing of the body and an annular protrusion of the striker located above, an annular hydraulic chamber is located, communicated with the inner cavity of the striker, above the chamber, the case is equipped with radial holes designed to communicate with the chamber when the striker moves upward, on the outer surface the width of the annular protrusion of which an annular shaped groove is made, consisting of symmetrical upper and lower alternating grooves connected in series by inclined grooves so that the top of each lower groove is connected to the next upper groove through the side wall, and the bottom of each upper groove is connected to the next lower groove through it the side wall, and in the opposite upper grooves are inserted paired symmetric body stops made with the possibility of sequential movement along the entire figured groove during the reciprocating movement of the striker, the spring force is selected so that the striker is kept in the lower position when the jetting channel of the destruction head is open, and the number of protrusions striker and, accordingly, cutting head samples should not be a multiple of two.

FIG. 1 shows a device for cleaning a wellbore from plugs with a partial longitudinal section.

FIG. 2 shows the striker in isometric view.

A device for cleaning a wellbore from plugs (not shown) includes non-rotating pipes 1 (Fig. 1, schematically shown), a housing 2, a destructive head 3 and a downhole motor in the form of a striker 4 (Figs. 1 and 2). The body 2 (Fig. 1) is equipped from above with an annular chamber 5 communicated with the outer space with openings 6. The breaking head 3 is equipped with a central hydromonitor channel 7 for blurring the plug, inserted into the body 2 for rotation, for example, due to the outer annular recess 8, in which is inserted into the inner projection 9 of the body 2, or the inner annular recess of the body 2, into which the outer projection of the cutting head 3 is inserted (not shown in Fig. 1), or the like. At the top of the perimeter end, the cutting head 3 is equipped with recesses 10 with a slope 11 on one side. The striker 4 is pressed from above by the spring 12 inserted into the annular chamber 5 to the end of the cutting head 3. The striker 4 is hermetically inserted into the annular chamber 5. At the lower end of the striker 4 (Fig. 2), projections 13 are located along the perimeter with an inclination 14 with one side for the recess 10 (Fig. 1) of the cutting head 3. To move up the striker 4 between the inner annular constriction 15 of the housing 2 and the annular protrusion 16 of the striker 4 located above, there is an annular hydraulic chamber 17 communicated with the holes 18 (Figs. 1 and 2) with the inner cavity of the striker 4. Above the chamber 17 (Fig. 1), the body 2 is equipped with radial holes 19 made with the possibility of communicating with the chamber 17 when the striker moves upward. On the outer surface of the annular protrusion 16 (Fig. 2) of the striker 4 there is an annular shaped groove 20, consisting of symmetrical upper 21 and lower 22 alternating grooves connected in series by inclined grooves 23 and 24 so that the top of each lower groove 22 is connected with the next upper groove 21 through the side wall, and the bottom of each upper groove 21 with the next lower groove 22 through its side wall. In the opposite upper grooves 21 (Fig. 1) of the shaped groove 20, paired symmetric stops 25 are inserted (usually 2 pieces for duplication, less often 4), for example, removable screws, cylindrical protrusions, pressed-in pins, or the like) of the body 2, made with the possibility of sequential movement along the entire figured groove 20 (Fig. 2) with the reciprocating movement of the striker 4. The force of the spring 12 (Fig. 2) is selected so as to hold the striker 4 in the lower position when the jetting channel 7 of the destructive head 3 is open to ensure retention striker 4 in the lower position during the jetting destruction of the plug. The number of protrusions 13 (Fig. 2) of the striker 4 and, accordingly, the recesses 10 (Fig. 1) of the cutting head 3 should not be a multiple of two, so that when the striker 4 is turned (Fig. 2) with the help of a shaped groove 20 with an even number of upper 21 and of the lower 22 grooves, the projections 13 of the striker 4 with displacement interacted with the recesses 10 (Fig. 1) of the cutting head 3, creating each time the striker 4 is lowered under the action of the spring 12 by means of the corresponding slopes 14 (Fig. 2) of the protrusions 13 and inclinations 11 (Fig. 1) sampling 10 the torque of the cutting head 3 relative to the body 2.

The destructive head 3 can be equipped with cutting teeth 26 of any design (the authors do not pretend to be).

Structural elements, process connections and seals that do not affect the performance of the method and device are not shown in Figures 1 and 2, or are shown conditionally.

The method for cleaning the wellbore from plugs is implemented in the following sequence.

Often after technological work to stimulate the reservoir (for example, hydraulic fracturing, acidizing, sedimentation, etc.) plugs are formed in the wellbore table (especially in horizontal and sub-horizontal wellbores). To clean the wellbore, the assembled device with the help of the housing 2 is connected to the string of non-rotating pipes 1, on which the interval where the plug is located is lowered into the well. Flushing fluid is pumped through the pipe string from the wellhead (not shown). The liquid, passing through the body 2 and the cavity of the striker 4, using the central jetting channel 7 of the destructive head 3, creating a high-speed pressure that destroys the weakly bonded plug particles, which is on the surface along the annular space (between the pipe string 1 and the walls of the well). In this case, the string of pipes 1 is lowered into the well to move the device towards the bottom of the well, and the spring 12 holds the striker 4 in the lower position with support on the collapsing head 3. When approaching a denser section of the plug, for the destruction of which one high-speed liquid pressure from the jet channel 7 is not enough, the breaking head 3 rests on the plug, partially or completely blocking the jetting channel 7. As a result, the pressure inside the pipe string 1 and the striker 4 begins to build up pressure relative to the annular space communicated with the annular chamber 5 by holes 6. The pressure in the hydraulic chamber 17 also begins to rise communicated by holes 18 (Fig. 1 and 2) with the inner cavity of the striker 4 and located between the inner annular constriction 15 (Fig. 1) of the body 2 and the annular protrusion 16 of the striker 4. Under the action of excess pressure in the chamber 17, the striker 4 moves upward, overcoming spring force 12. In this case, the stops 5, moving along the figured groove 20 (Fig. 2) from the upper part of the upper groove 21 along the inclined groove 24 to the lower part of the lower groove 22, rotate the striker 4 relative to the body 2 (Fig. 1) and the destructive head 3. After lifting the striker 4 and communicating the chamber 17 with the radial holes 19 of the body 2, the pressure in the chamber 17 is dropped through them into the annular space and is aligned with the pressure in the annular chamber 5. As a result, under the action of the expanding spring 12, the striker 4 is interspersed with a downward slope 14 (Fig. 2) of the projection 13 interacts with the slope 11 (Fig. 1) of the destructive recess 10 head 3, transmitting the longitudinal and rotational shock load relative to the body 2. In this case, the stops 5, moving along the figured groove 20 (Fig. 2) from the lower part of the lower groove 22 along the inclined groove 23 to the upper part of the upper groove 21, again rotate the striker 4 relative to body 2 (Fig. 1) and destructive head 3. Upon impact and rotation of the destructive head 3 (for example, thanks to the annular recess 8 and the internal protrusion 9 of the body whisker 2) cutting teeth 26 destroy the dense rock of the plug, which is washed out through the jetting channel 7 along the annular space to the surface of the well. If the channel 7 has not completely opened, then the striker 4 continues reciprocating movements, transferring the shock and rotational forces to the breaking head 3 in impulse. The more the channel 7 is blocked (the denser the plug rock, the more the channel 7 is blocked), the faster the pressure in the chamber 17 grows and the higher the frequency of shock pulses. This is recorded by a decrease in the weight of the pipe string 1 on the wellhead weight indicator (not shown) and pressure surges (pulses) on the wellhead pressure indicator (not shown) inside the pipe string 1. To eliminate a large load on the breaking head 3, the running speed of the pipe string 1 is reduced so that not to increase the frequency of pressure pulses, which is fixed by stabilizing the frequency of pressure surges at the wellhead. If the frequency of pressure pulses continues to increase, then the descent is stopped until the pressure surges stop and stabilize, which indicates the mechanical destruction of the plug by the cutting teeth 26. After that, the descent rate is gradually restored. With further interaction with dense sections of the plug, the method is implemented in the same sequence, taking into account the frequency of pressure surges at the wellhead.

Combining the passage with the help of a water jet and mechanical destruction of 26 plugs with cutting teeth, the entire wellbore is cleaned to the bottom in one pass. When testing the method and device at the fields of the Republic of Tatarstan, not a single emergency situation occurred, all plugs in the horizontal and vertical wellbores were drilled in one pass.

The proposed method and device for cleaning the wellbore from plugs allows loose plugs to pass through due to the jetting action, and dense sections of plugs with the help of mechanical action, without wasting energy when the plug is washed out on the rotation of the breaking head, and in case of mechanical destruction on the jetting action, and in automatic mode due to partial or complete blocking of the jetting channel plug by the rock.

Claims (2)

1. A method for cleaning a wellbore from plugs, including lowering a casing with a destructive head with a downhole motor into the well on a string of non-rotating pipes, which ensures rotation of the destructive head during pumping of the drilling fluid through the drill pipes with the creation of a certain pressure drop when the plug is destroyed, characterized by that the breaking head is equipped with a central jetting channel, and the pressure drop sufficient for the impulse rotation of the engine occurs due to the reciprocating movement of the downhole motor in the form of a striker, which is created when the breaking head rests on the rock to be destroyed and the jetting channel is partially blocked, while the descent rate drill pipes are reduced until they stop to stabilize the frequency of pressure surges at the wellhead, and after the pressure surges stop, the lowering speed is gradually restored. 2. A device for cleaning the wellbore from plugs, including non-rotating pipes, a body, a destructive head and a downhole motor, characterized in that the body is equipped with an annular chamber from above, communicated with the outer space, the destructive head is equipped with a central jetting channel to erode the plug, inserted into the body with the possibility of rotation and from above at the end along the perimeter it is equipped with recesses inclined on one side, the downhole motor is made in the form of a hollow striker pressed from above by a spring inserted into the annular chamber, to the end of the cutting head of a hollow striker, hermetically inserted into the annular chamber by the upper part, and at the lower end of the striker located along the perimeter, inclined on one side of the protrusions for the recesses of the cutting head, while for moving up the striker between the inner annular constriction of the body and the annular protrusion of the striker located above the annular protrusion of the striker, there is an annular hydraulic chamber communicated with the inner cavity of the striker, above the core chamber The pus is equipped with radial holes designed to communicate with the camera when the striker moves upwards, on the outer surface of the annular protrusion of which an annular shaped groove is made, consisting of symmetrical upper and lower alternating grooves connected in series with inclined grooves so that the top of each lower groove is connected to the next the upper groove through the side wall, and the bottom of each upper groove - with the next lower groove through its side wall, and in the opposite upper grooves there are paired symmetrical body stops made with the possibility of sequential movement along the entire figured groove during the reciprocating movement of the striker, the spring force are selected so as to keep the striker in the lower position when the jetting channel of the destruction head is open, and the number of protrusions of the striker and, accordingly, of the cutting head samples should not be a multiple of two.

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