CN111305759A - Double-speed double-core drilling speed increasing system for increasing drilling speed of oil and gas well - Google Patents

Abstract

The invention provides a double-speed double-center drilling speed-up system for improving the drilling speed of an oil-gas well, which comprises an outer cylinder, a downhole power device, a large cutting head and a small cutting head, wherein the large cutting head is provided with a first central line, a connecting piece, an inner volume cavity and a cutting part with a first diameter; the outer cylinder body is sleeved outside the underground power device and directly or indirectly connects the upper drill column with the large cutting head, so that the large cutting head and the underground power device can rotate together with the upper drill column; the underground power device is provided with a power generating part capable of generating power and a rotary output part for providing independent power for the small cutting head, so that the small cutting head can revolve around a first central line under the driving of an upper drill string while rotating under the driving of the small cutting head. The invention can avoid the problem that the linear velocity of the central point of the large cutting head is zero, and is beneficial to improving the drilling speed.

Description

Double-speed double-core drilling speed increasing system for increasing drilling speed of oil and gas well

Technical Field

The invention belongs to the technical field of oil and gas drilling speed acceleration, and particularly relates to a double-speed double-center drilling speed acceleration system capable of improving the drilling speed of an oil and gas well.

Background

In the oil and gas well drilling engineering, how to increase the drilling speed is an important subject of research. Although the drilling speed is improved to some extent by optimizing the design of the drill bit structure, for example, developing new drill bit tooth materials, higher performance teeth, etc., the problem that the linear speed of the central point of the drill bit is zero and the linear speed near the central point affects the drilling speed during drilling is still not solved.

Moreover, the inventors have found that this effect is particularly pronounced in PDC bits which are currently in large use. The bit that is pulled out of service is also difficult to find, and this problem is one of the key problems affecting the speed increase of the well.

Disclosure of Invention

The present invention aims to address at least one of the above-mentioned deficiencies of the prior art. For example, one of the objectives of the present invention is to solve the technical problem of zero linear velocity of the center point of the drill bit during drilling.

In order to achieve the above objects, one aspect of the present invention provides a dual speed dual center drilling acceleration system for increasing the drilling speed of an oil and gas well. The well acceleration system comprises an outer cylinder, a downhole power unit, a large cutting head and a small cutting head, wherein the large cutting head has a first centerline, a receiving coupling fixedly coupled to each other along the first centerline, and a hollow cutting portion having a first diameter, the small cutting head has a second centerline and a second diameter, the receiving coupling has a coupling member and an inner volume disposed along the first centerline, the inner volume being capable of receiving the small cutting head, the second centerline being parallel to but not coincident with the first centerline, the second diameter being smaller than the first diameter; the outer cylinder is sleeved outside the underground power device and forms an annular space, the left end of the outer cylinder is directly connected with the upper drill string, and the right end of the outer cylinder is directly connected with the connecting piece of the large cutting head for accommodating the connecting part, so that the large cutting head can drill under the driving of the upper drill string, and the underground power device rotates under the driving of the upper drill string; the downhole power device is provided with a power generation part and a rotation output part, wherein the power generation part can generate power and rotate the rotation output part, and the right end of the rotation output part enters the inner volume cavity of the accommodating connection part of the large cutting head to be connected with the small cutting head and can drive the small cutting head to rotate.

In an exemplary embodiment of an aspect of the present invention, the distance between the first centerline and the second centerline may be 1/50-1/10 of the first diameter.

In an exemplary embodiment of an aspect of the present invention, a ratio of an angular velocity of the small cutting head to an angular velocity of the large cutting head may be 4 to 7: 1.

in an exemplary embodiment of an aspect of the invention, the outer cylinder may further comprise a quincunx-like cavity fixedly arranged in the right end, the quincunx-like cavity being capable of centering the power generating portion or the rotational output portion, or of centering a portion of the cutting bit coupled with the rotational output portion.

In an exemplary embodiment of an aspect of the invention, the outer cylinder may further comprise a water diversion member disposed in the left end between the upper drill string and the power generation section, wherein the water diversion member has a central bore and a plurality of water diversion bores disposed thereon, the plurality of water diversion bores being capable of communicating drilling fluid in the upper drill string with the annulus and forming a first flow, the central bore being capable of communicating drilling fluid of the upper drill string with the power generation section and forming a second flow, the first flow being capable of lubricating the large cutting head, the second flow being capable of powering the power generation section.

In one exemplary embodiment of an aspect of the present invention, the cutting portion may have an outer wall provided with an outer cutting surface and an inner wall provided with a plurality of inner cutting surfaces, and a flow channel groove may be formed between any two adjacent inner cutting surfaces of the plurality of inner cutting surfaces, and the flow channel groove may communicate with the inner volume chamber.

The invention also aims to provide a drilling speed-up system which can effectively solve the problem that the linear velocity of the central point of a drill bit is zero during drilling, has good stability and service life, and realizes power driving by using the shunted drilling fluid.

In order to achieve the object, another aspect of the invention provides a drilling acceleration system comprising a flow diversion device, an outer cylinder, a downhole power device, a centralizer, a large cutting head and a small cutting head, wherein the large cutting head has a first centerline, a receiving coupling fixedly coupled to each other along the first centerline, and a hollow cutting portion having a first diameter, the small cutting head has a second centerline and a second diameter, the receiving coupling has a coupling and an inner volume disposed along the first centerline, the inner volume is capable of receiving the small cutting head, the second centerline is parallel to but not coincident with the first centerline, and the second diameter is smaller than the first diameter; the outer cylinder is sleeved outside the underground power device and forms an annular space, the left end of the outer cylinder is connected with an upper drill string through the flow dividing device, and the right end of the outer cylinder is connected with the connecting piece, containing the connecting portion, of the large cutting head through the righting device, so that the large cutting head can drill under the driving of the upper drill string, and meanwhile, the underground power device rotates under the driving of the upper drill string; the downhole power device is provided with a power generation part and a rotation output part, wherein the power generation part can generate power and rotate the rotation output part, and the right end of the rotation output part enters the inner volume cavity of the accommodating connection part of the large cutting head to be connected with the small cutting head and can drive the small cutting head to rotate; the righting device is configured to right the power generation portion, the rotary output portion, or the small cutting head; the flow divider is configured to separate drilling fluid in the upper drill string into a first flow that enters the annulus and lubricates the large cutting head and a second flow that enters the power generation portion of the downhole power plant.

In an exemplary embodiment of another aspect of the present invention, the distance between the first centerline and the second centerline may be 1/50-1/10 of the first diameter.

In an exemplary embodiment of the invention, the ratio of the angular velocity of the small cutting head to the angular velocity of the large cutting head may be 4 to 7: 1.

in an exemplary embodiment of another aspect of the invention, the cutting head may have a jet channel with a decreasing radial cross-sectional area, one end of the jet channel receiving the second fluid flow through the power generation portion and emitting from the other end of the jet channel.

In an exemplary embodiment of another aspect of the invention, the righting means may have a quincunx-like cavity capable of righting the power generating portion or the rotary output portion, or capable of righting the portion of the cutting bit coupled with the rotary output portion.

In an exemplary embodiment of another aspect of the invention, the flow diversion device may have a water diversion member, wherein the water diversion member has a central bore and a plurality of water diversion bores disposed therein, the plurality of water diversion bores being capable of communicating drilling fluid in an upper drill string with the annulus and forming the first flow, the central bore being capable of communicating drilling fluid of an upper drill string with the power generation section and forming the second flow.

In an exemplary embodiment of another aspect of the invention, the outer cylinder may further comprise a quincunx-like cavity fixedly arranged in the right end, the quincunx-like cavity being capable of centering the power generating portion or the rotational output, or a portion of the cutting bit coupled to the rotational output.

In an exemplary embodiment of another aspect of the invention, the outer cylinder may further comprise a water diversion member disposed in the left end between the upper drill string and the power generation section, wherein the water diversion member has a central bore and a plurality of water diversion bores disposed thereon, the plurality of water diversion bores being capable of communicating drilling fluid in the upper drill string with the annulus and forming a first flow, the central bore being capable of communicating drilling fluid of the upper drill string with the power generation section and forming a second flow, the first flow being capable of lubricating the large cutting head, the second flow being capable of powering the power generation section.

In an exemplary embodiment of another aspect of the present invention, the cutting portion may have an outer wall provided with an outer cutting surface and an inner wall provided with a plurality of inner cutting surfaces, and a flow channel groove may be formed between any two adjacent inner cutting surfaces of the plurality of inner cutting surfaces, and the flow channel groove may communicate with the inner volume chamber.

Compared with the prior art, the beneficial effects of the invention comprise at least one of the following:

1. the linear speed of the central point of the large drill bit can be prevented from being zero during drilling, and the drilling speed can be improved;

2. the stability and the service life are good;

3. the small cutting head can be driven to rotate by the shunted drilling fluid;

4. the large cutting head and the small cutting head are arranged in a non-centrosymmetric manner, so that the small cutting head not only can rotate at a high speed under the driving of a downhole power device, but also can simultaneously revolve around the central axis of the large cutting head; therefore, the problems that the theoretical cutting speed of the central point of the drill bit is zero and the linear speed near the central point is low are solved, and the drilling speed is favorably improved.

Drawings

FIG. 1 is a schematic diagram illustrating an exemplary embodiment of a two-speed dual-core acceleration system for increasing the drilling speed of an oil or gas well in accordance with the present invention;

FIG. 2 illustrates a schematic diagram of a flow divider in an exemplary embodiment of a two speed dual center drilling acceleration system for increasing the drilling speed of an oil and gas well according to the present invention;

FIG. 3 shows a right side view of FIG. 2;

FIG. 4 shows a pictorial representation of FIG. 2;

FIG. 5 illustrates a schematic structural view of a centralizer in an exemplary embodiment of a two speed dual core acceleration system for increasing the drilling rate of oil and gas wells in accordance with the present invention;

FIG. 6 shows a right side view of FIG. 5;

FIG. 7 shows a pictorial representation of FIG. 5;

FIG. 8 illustrates a schematic diagram of a large cutting head in an exemplary embodiment of a two speed dual center drilling acceleration system for increasing the drilling speed of oil and gas wells in accordance with the present invention;

FIG. 9 shows a right side view of FIG. 8;

FIG. 10 is a pictorial diagram illustrating an exemplary embodiment of a two speed dual center drilling acceleration system for increasing the drilling speed of an oil and gas well in accordance with the present invention;

FIG. 11 is a schematic diagram illustrating an exemplary embodiment of a two-speed dual-center drilling acceleration system for increasing the drilling speed of an oil and gas well in accordance with the present invention.

The reference numerals are explained below:

1-flow dividing device, 2-outer cylinder, 3-downhole power device, 4-righting device, 5-big cutting head, 6-small cutting head, 1 a-water dividing hole, 1 b-central hole, 4 a-inner boss, 4 b-concave surface, 5 a-outer cutting surface, 5 b-inner cutting surface, 5 c-runner groove, 1 '-outer cylinder, 2' -downhole power device, 3 '-big cutting head and 4' -small cutting head.

Detailed Description

Hereinafter, the two-speed dual-core drilling acceleration system for increasing the drilling speed of an oil and gas well according to the present invention will be described in detail with reference to exemplary embodiments. It should be noted that "first", "second", "third", "fourth", "fifth", etc. are merely for convenience of description and for convenience of distinction, and are not to be construed as indicating or implying relative importance. "left," "right," "inner," "outer," and the like are merely for convenience of description and relative positional or positional relationships, and do not indicate or imply that the referenced components must have that particular orientation or position.

In general, to solve the problem of zero linear velocity at the center point of the drill bit, the inventor proposes a two-speed dual-center drilling acceleration system. The two-speed dual-core drilling speed-up system is characterized in that a large cutting head (also called a large drill bit) which is provided with a first central line, a nano-connecting part and a hollow cutting part is fixedly connected with each other along the first central line; and a small cutting head (also referred to as a small drill) having a second centerline; and the receiving coupling comprises a coupling member and an internal volume, the small cutting head being disposed in the internal volume of the large cutting head, the second centerline being parallel to but not coincident with the first centerline to achieve "bi-centering". At the same time, the large cutting head receives a first power for rotary drilling through the upper drill string and is provided with lubrication by drilling fluid from the upper drill string; the small cutting head obtains a second power for rotary drilling through the downhole power device, which is equivalent to the small cutting head rotating around the second central line, and the upper drill string can also drive the downhole power device to further drive the small cutting head to rotate, which is equivalent to the small cutting head revolving around the first central line, thereby realizing double speed.

FIG. 1 is a schematic diagram illustrating an exemplary embodiment of a two-speed dual-core acceleration system for increasing the drilling speed of an oil and gas well in accordance with the present invention.

As shown in fig. 1, in a first exemplary embodiment of the invention, a two-speed dual-core drilling acceleration system comprises a flow diversion device 1, an outer barrel 2, a downhole power unit 3, a centralizer 4, a large cutting head 5 and a small cutting head 6.

The large cutting head 5 has a first centre line (i.e. parallel to the left-right direction in fig. 1), a receiving coupling portion fixedly coupled to each other along the first centre line, and a hollow cutting portion having a first diameter. The cutting bit 6 has a second centre line and a second diameter. Here, the first diameter is the outer diameter of the cutting portion of the large cutting head 5. The receiving coupling has a coupling member and an internal volume disposed along a first centerline, the internal volume capable of receiving a cutting bit. That is, the cutting portion can cut the workpiece to be ground both inside and outside. For example, the cutting portion may have an outer wall provided with an outer cutting surface and an inner wall provided with a plurality of inner cutting surfaces, and a flow channel groove may be formed between any two adjacent inner cutting surfaces of the plurality of inner cutting surfaces, and the flow channel groove may communicate with the inner volume chamber. The second centerline is parallel to but not coincident with the first centerline, and the second diameter is smaller than the first diameter. That is, both the first center line and the second center line are parallel to the left-right direction in fig. 1, but a predetermined distance exists therebetween. For example, the distance between the first centerline and the second centerline may be 1/50-1/10 of the first diameter. As another example, the distance between the first centerline and the second centerline may be 1/20 for the first diameter.

The outer cylinder body 2 is sleeved outside the downhole power device 3, and an annular space is formed between the outer cylinder body and the downhole power device. And the left end of the outer cylinder 2 is connected with an upper drill string (not shown in fig. 1) through the diversion device 1, while the right end of the outer cylinder 2 is connected with a coupling piece of the large cutting head 5 (i.e. the left end of the large cutting head 5) through the righting device 4, so that the large cutting head 5 can drill under the drive of the upper drill string, and the downhole power device 3 rotates under the drive of the upper drill string. That is, the diverter device 1, the outer cylinder 2, the centralizer 4 and the large cutting head 5 are fixed integrally with the upper drill string and are rotatable together.

The downhole power unit 3 may have a power generation portion and a rotation output portion. Wherein the power generation section (e.g., the left section of the downhole power unit 3 in fig. 1) is capable of generating power and rotating the rotation output section. Further, the downhole power device can also form an annular space with the outer cylinder, and a power generation part of the downhole power device is fixedly connected with one or more of the upper drill string, the flow dividing device, the outer cylinder, the centering device and the large cutting head, so that the downhole power device can be driven by the upper drill string to rotate. The right end of the rotation output portion (e.g., the right portion of the downhole power unit 3 in fig. 1) enters the inner volume chamber of the receiving coupling portion of the large cutting head 5 to couple with the small cutting head, and can drive the small cutting head to rotate. That is, the downhole power device can generate power through the power generation part and drive the small cutting head to rotate around the second center line through the rotation output part; simultaneously, due to the drive of the upper drill string, the underground power device and the small cutting head can also revolve around the first central line. Thus, the angular velocity of the small cutting head will be greater than the angular velocity of the large cutting head. For example, the ratio of the angular velocity of the small cutting head to the angular velocity of the large cutting head may be 2 to 9: 1. for another example, the ratio of the angular velocity of the small cutting head to the angular velocity of the large cutting head may be 4 to 7: 1.

as shown in fig. 1, the centralizer is configured to centralize the power generating portion of the downhole power unit, thereby centralizing the small cutting head. That is, the centralizer is capable of centralizing the deflection caused by the rotation of the cutting head. However, the present invention is not limited thereto. For example, the centralizer may also be arranged to centralize the rotary output of the downhole power unit; or directly, centralize the cutting head, e.g., centralize the portion of the cutting head coupled to the rotational output. For example, the righting device may have a quincunx-like cavity that can more stably right the power generation portion or the rotational output portion, or can more stably right the portion of the cutting bit coupled with the rotational output portion.

The flow divider is configured to separate the drilling fluid in the upper drill string into a first flow and a second flow. The first fluid flow enters an annulus between the outer barrel and the downhole power plant and is able to flow to the large cutting head to lubricate the large cutting head. The second fluid stream enters a power generation section of the downhole power unit and serves as a power source for the power generation section. That is, the power generation section can convert the power of the second fluid flow into the rotational motion of the rotation output section. For example, the flow diversion device can have a water diversion member that can have a central aperture and a plurality of water diversion apertures disposed thereon. Wherein the plurality of cutwater holes are capable of communicating drilling fluid in an upper drill string with the annulus and forming the first fluid stream; the central bore is configured to communicate drilling fluid of an upper drill string with the power generation section and form the second fluid stream.

In addition, the small cutting head may also have a jet channel with a gradually decreasing radial cross-sectional area. One end of the jetting passage receives the second fluid flow passing through the power generation portion and is jetted out from the other end of the jetting passage to be jetted toward an object to be drilled (e.g., a surface to be drilled).

FIG. 1 is a schematic diagram illustrating an exemplary embodiment of a two-speed dual-core acceleration system for increasing the drilling speed of an oil and gas well in accordance with the present invention. FIG. 2 illustrates a schematic diagram of a flow diversion apparatus in an exemplary embodiment of a two speed dual center drilling acceleration system for increasing the drilling speed of an oil and gas well according to the present invention. Fig. 3 shows a right side view of fig. 2. And FIG. 4 shows a pictorial representation of FIG. 2.

In a second exemplary embodiment of the invention, as shown in fig. 1, a two-speed dual-core drilling acceleration system for increasing the drilling speed of an oil or gas well comprises a flow diversion device 1, an outer cylinder 2, a downhole power unit 3, a centralizer 4, a large cutting head 5 and a small cutting head 6.

In the exemplary embodiment, the left end of the outer cylinder 2 is connected with the upper drill string through the diversion device 1, and the right end of the outer cylinder 2 is connected with the large cutting head 5 through the centralizing device 4, so that the rotation torque of the upper drill string is transmitted to the large cutting head 5, and the large cutting head 5 can drill rotationally under the driving of the upper drill string. The outer cylinder 2 is indirectly connected with the upper drill string, and the outer cylinder 2 is indirectly connected with the large cutting head 5. For example, the left end of the outer cylinder 2 is connected with the right end of the shunt device 1 through threads, and the left end of the shunt device 1 is connected with the upper drill string through threads, so that the outer cylinder 2 is connected with the upper drill string, and the outer cylinder 2 can be driven by the upper drill string to rotate; the right end of the outer cylinder 2 is in threaded connection with the left end of the righting device 4, and the right end of the righting device 4 is in threaded connection with the left end of the large cutting head 5, so that the righting device 4 and the large cutting head 5 can rotate together with the outer cylinder 2. However, the present invention is not limited thereto, and the upper drill string and the flow dividing device, the flow dividing device and the outer cylinder, the outer cylinder and the centralizer, and the centralizer and the large cutting head may be connected by other means (for example, snap-fitting), as long as the connection of the upper drill string, the flow dividing device, the outer cylinder, the centralizer and the large cutting head and the transmission of the torque of the upper drill string can be realized.

In the present exemplary embodiment, the downhole power unit 3 is disposed inside the outer cylinder 2, and the downhole power unit 3 and the outer cylinder 2 are in a fixed state therebetween. The underground power device 3 can rotate under the driving of an upper drill column together with the outer cylinder body 2, and an annular space through which drilling fluid can flow is formed between the inside of the outer cylinder body 2 and the outside of the underground power device 3. For example, the downhole power unit 3 is disposed inside the outer cylinder 2 and is not in contact with the outer cylinder 2, and the space between the inside of the outer cylinder 2 and the outside of the downhole power unit 3 is an annulus through which drilling fluid flows.

The left end of the underground power device 3 is fixedly connected with the water diversion component of the flow diversion device 1 through threads, so that the outer cylinder body 2 and the underground power device 3 are in a fixed state. The upper drill column rotates to drive the flow dividing device 1 to rotate, and the flow dividing device 1 rotates to drive the outer cylinder 2 and the underground power device 3 to rotate. Of course, there are many ways of securing the outer barrel 2 to the downhole power unit 3. For example, a fastener may be provided between the inner wall of the outer cylinder 2 and the downhole power unit 3, which fastener is capable of allowing the passage of drilling fluid (e.g., the first fluid stream) while securing the outer cylinder 2 and the downhole power unit 3. However, the invention is not limited to this, and the outer cylinder and the downhole power device may be fixed in other ways as long as the outer cylinder and the downhole power device can be fixedly arranged.

In the exemplary embodiment, a flow divider is provided that is capable of dividing the drilling fluid in the upper drill string into a first flow and a second flow. The first fluid flow enters an annulus between the outer barrel and the downhole power plant and is able to flow to the large cutting head to lubricate the large cutting head. The second fluid stream enters a power generation section of the downhole power unit and serves as a power source for the power generation section. That is, the power generation section can convert the power of the second fluid flow into the rotational motion of the rotation output section. For example, the flow diversion device can have a water diversion member that can have a central aperture and a plurality of water diversion apertures disposed thereon. Wherein the plurality of cutwater holes are capable of communicating drilling fluid in an upper drill string with the annulus and forming the first fluid stream; the central bore is configured to communicate drilling fluid of an upper drill string with the power generation section and form the second fluid stream. For example, as shown in fig. 2-4, the flow diversion device 1 can be a cylinder-like structure. The water distribution component is arranged in the cylinder body along the radial section and comprises a central hole 1b and a plurality of water distribution holes 1a which are arranged around the central hole 1b and are not communicated with the central hole 1 b. A portion of the drilling fluid from the upper drill string enters the central bore 1b to form a second fluid stream; another portion of the drilling fluid enters the plurality of cutwater holes 1a to form a first stream. The central hole 1b or the peripheral wall thereof extends towards the right end and is in threaded connection with the left end of the downhole power device 3, so that the second liquid flow enters the power generation part of the downhole power device 3 to provide a power source. A plurality of water distribution holes 1a are associated with the annulus between the outer cylinder 2 and the downhole power unit 3 so that a first flow of fluid can enter the annulus and ultimately the large cutting head 5 to cool and lubricate the large cutting head 5. Here, the number of the plurality of water distribution holes 1a may be 2 to 6, and the water distribution holes 1a may be circular or elliptical water distribution holes. The ratio of the sum of the radial cross-sectional areas of the plurality of water distribution holes 1a to the radial cross-sectional area of the central hole 1b, that is, the ratio of the flow rates of the first liquid flow and the second liquid flow, may be 1: 0.5 to 2, for example 1: 1, etc. The drilling fluid from the upper drill string has a preset pressure, and the flow rates of the first fluid flow and the second fluid flow can be controlled by controlling the ratio of the radial sectional area of the water distribution holes 1a to the radial sectional area of the central hole 1b, so that the purpose of shunting is achieved. However, the present invention is not limited thereto, and the diversion device may have other structures as long as the diversion of the drilling fluid in the upper drill string can be achieved.

In the present exemplary embodiment, the downhole power unit has a power generation portion and a rotation output portion. The power generation unit is configured to generate power by the second fluid flow and rotate the rotation output unit. The rotation output part is a structure which can enter the inner volume cavity of the accommodating connecting part of the large cutting head to be connected with the small cutting head and can drive the small cutting head to rotate. For example, the power generation part of the downhole power device 3 may be a hydraulic drive motor or a hydraulic drive turbine, the second hydraulic flow drives the power generation part to rotate, the power generation part drives the rotation output part to rotate, and the right end of the rotation output part enters the inner volume cavity of the large cutting head 5 to drive the small cutting head 6 connected with the large cutting head to rotate. Or the left end extension part of the small cutting head 6 passes through the connecting piece of the large cutting head 5 to be connected with the rotation output part, so that the rotation is carried out by the rotation output part. However, the present invention is not limited thereto, and the downhole power device may have other structures as long as the downhole power device can generate power and drive the small cutting head to rotate under the action of the second fluid flow.

In the exemplary embodiment, the righting device can be provided with a plum blossom-like cavity, the plum blossom-like cavity can right a power generation part or a rotary output part of a downhole power device, or can right a part to be righted such as a part where a small cutting head is connected with the rotary output part, the part to be righted shakes in an outer cylinder, friction is reduced, and the stability and the service life of the double-speed double-core drilling speed-up system are improved.

FIG. 5 illustrates a schematic diagram of a centralizer in an exemplary embodiment of a two-speed dual-core acceleration system for increasing the drilling rate of oil and gas wells, according to the present invention. Fig. 6 shows a right side view of fig. 5. FIG. 7 shows a pictorial representation of FIG. 5.

As shown in fig. 5 to 7, the right end of the centering device 4 may be a cavity shaped like a plum blossom. The radial section of the plum blossom-shaped cavity is plum blossom-shaped. The plum blossom-like cavity can be arranged on the inner wall of the right end part of the righting device 4 and is surrounded by a plurality of inner bosses 4a along the circumferential direction. Of course, the cavity similar to the quincunx shape may be arranged in central symmetry along the central axis of the centering device 4, or in non-central symmetry along the central axis of the centering device 4, and is determined according to the specific situation of the part to be centered. For example, when the righted component is arranged in a non-centrosymmetric manner, the plum blossom-like cavity is also arranged in a non-centrosymmetric manner; when the righted part is arranged in a central symmetry manner, the plum blossom-like cavities are also arranged in a central symmetry manner. Here, the top surfaces of the inner bosses 4a are curved to fit the outer surface of the member to be centered, and the curved shape of the top surfaces of the plurality of inner bosses 4a is located on an imaginary circumference having a diameter slightly larger than the diameter of the member to be centered. Concave surfaces 4b are formed between two adjacent inner bosses 4a, and the number of concave surfaces 4b is equal to the number of inner bosses 4 a. Here, the concave surface may be a circular arc shape, a U shape, or a V shape. While the centering device 4 centers the centered member, the second fluid flow entering the annulus may enter the large cutting head 5 through the passage between the outer surface of the centered member and the quincunx-like cavity to cool and lubricate the large cutting head 5. The concave surface is provided here in order to increase the cross-sectional area of the passage through which the drilling fluid flows. However, the present invention is not limited in this regard and the centralizer may have other configurations as long as it is capable of centralizing the component being centralized and allowing the flow of drilling fluid (e.g., the first fluid stream) therethrough.

FIG. 8 illustrates a schematic diagram of a large cutting head in an exemplary embodiment of a two speed dual center drilling acceleration system for increasing the drilling speed of oil and gas wells in accordance with the present invention. Fig. 9 shows a right side view of fig. 8.

In the present exemplary embodiment, as shown in fig. 8 to 9, the large cutting head 5 includes a receiving coupling portion and a hollow cutting portion fixedly coupled to each other along a first centerline. In particular, the large cutting head may comprise a coupling member, an inner volume and a cutting portion fixedly coupled in sequence from left to right. Wherein the coupling is used for coupling a large cutting head 5 with upstream equipment (e.g. an upper drill string, an outer cylinder connected to the upper drill string, a centralizer, etc.), an inner volume for rotation of a small cutting head 6 therein in a direction parallel to the first centre line, and a cutting portion for cutting the face to be drilled. The connecting member and the inner volume together form a receiving connection.

The cutting portion has an outer wall provided with an outer cutting face 5a and an inner wall provided with a plurality of inner cutting faces 5b, and a flow channel groove 5c is formed between any two adjacent inner cutting faces 5b of the plurality of inner cutting faces 5 b. Specifically, the outer wall and the inner wall of the cutting portion of the large cutting head 5 are respectively provided with an external cutting surface 5a and an internal cutting surface 5b for cutting the rock face to be drilled, and a borehole (i.e., an annular borehole) with a columnar core at the middle part is formed on the rock face to be drilled through the combined action of the external cutting surface 5a and the internal cutting surface 5b, and the columnar core enters the inner volume cavity of the large cutting head 5 through the hollow cutting portion to be contacted with the small cutting head 6, so that the small cutting head 6 cuts the core into rock debris. The flow channel groove 5c formed between the adjacent two inner cutting surfaces 5b is used for discharging drilling fluid (e.g., from an upper drill rod, a small cutting head, etc.) inside the large cutting head 5 and debris formed by the small cutting head 6 cutting a columnar core out of the large cutting head 5. Here, the outer wall of the cutting part may be drill-shaped. For example, the outer cutting surfaces may be cones, cutting teeth, etc., which are progressively spaced from the first centerline from left to right and are helically disposed. Here, the number of the inner cutting surfaces 5b and the flow channel grooves 5c may be 3 to 8. For example, the number of the inner cutting faces and the runner grooves is 5. The number of the external cutting faces 5a is 3-8. For example, the number of the external cutting faces is 5.

The receiving coupling has a coupling and an inner volume arranged along a first centre line, the inner volume being capable of receiving a small cutting head 6 arranged along a second centre line, the second centre line being parallel to but not coinciding with the first centre line, the small cutting head 6 having an outer diameter smaller than the outer diameter of the cutting portion. Specifically, the receiving coupling portion of the large cutting head 5 includes a coupling member for coupling with an upstream equipment and an inner volume chamber for receiving the small cutting head 6, the inner volume chamber being disposed along a first centerline (i.e., a left-right direction in fig. 8), the inner volume chamber being capable of accommodating therein the small cutting head 6 disposed along a second centerline (i.e., a centerline of the small cutting head 6) for rotation therein with the large cutting head 5 and the small cutting head 6 being disposed in parallel but not in coincidence, the small cutting head 6 having an outer diameter smaller than that of the cutting portion of the large cutting head 5 so that the small cutting head 6 and the large cutting head 5 are disposed eccentrically. The inner wall of the connector may have an inner diameter that gradually decreases from left to right. For example, the coupling may be a cylindrical structure having threads on the inner wall, the large cutting head being fixedly coupled to the upstream equipment by the threads of the coupling. However, the present invention is not limited thereto, and the connecting member may be fixedly connected to the upstream device by means of snap-fitting or the like. Here, the inner diameter of the inner volume remains constant from left to right and is larger than the outer diameter of the small cutting head 6; the inner volume chamber may communicate with the runner groove 5 c. Debris generated by cutting the columnar core with the small cutting head 6 can be discharged out of the large cutting head 5 through the runner channel together with drilling fluid.

The top surface of the inner cutting surface 5b near the first centerline may be concavely curved (e.g., circular arc-shaped). The inner cutting faces 5b may be symmetrically arranged around the first center line. Here, the inner cutting surfaces 5b are symmetrically arranged around the first center line in order to facilitate better drainage of drilling fluid and debris generated by the small cutting head 6 cutting the columnar core out of the inner volume of the large cutting head 5. However, the present invention is not limited thereto, and for example, the inner cutting faces may be spirally arranged from left to right about the first centerline.

When drilling, the large cutting head 5 is directly or indirectly connected with an upper drill string, so that the drilling pressure and the torque are large, the cutting part of the large cutting head 5 is firstly contacted with a rock surface to be drilled to destroy the rock surface, the formation pressure is released, peripheral rocks are cut off to form an annular borehole, and a columnar core with a relatively easily-cut center is left. The columnar core enters the inner volume cavity from the hollow structure of the cutting part to be in contact with the small cutting head 6, the small cutting head 6 revolves around the central line of the large cutting head while rotating at a high speed under the driving of the underground power device, so that the high linear cutting speed is achieved, the columnar core cutting head can be cut into rock debris, the rock debris is discharged out of the large cutting head 5 from the runner groove 5c of the large cutting head 5 along with drilling fluid in an upper drill rod, the problem that the linear speed of the central point of a drill bit is zero can be avoided due to the mutual matching of the large cutting head 6 and the small cutting head 6, and the drilling speed is improved.

In the exemplary embodiment, the small cutting head 6 and the large cutting head 5 are arranged in a non-centrosymmetric manner, and the small cutting head 6 is arranged in the inner volume cavity of the large cutting head, so that the small cutting head can revolve around the central axis of the large cutting head under the drive of an upper drill string while rotating at a high speed under the drive of a downhole power device, thereby forming composite rotary drilling and solving the problem of low drilling speed caused by the linear velocity of the central point of the drill bit during drilling. For example, the central axis of the large cutting head 5 is a first centre line. The large cutting head 5 is provided with a receiving coupling portion and a hollow cutting portion along a first centre line, which are fixedly coupled to each other, said receiving coupling portion comprising a coupling member and an inner volume. The right end of the rotary output part of the downhole power unit 3 passes through the coupling into the inner volume chamber to be coupled with the small cutting head 6, or the left end of the small cutting head 6 passes through the coupling to be coupled with the rotary output part. Here, the diameter of the large cutting head 5 refers to the outer diameter of the cutting portion of the large cutting head 5. The centre axis of the small cutting head 6 is the second centre line and the diameter of the small cutting head 6 is the second diameter. When the first and second centre lines are parallel but not coincident, the small cutting head 6 and the large cutting head 5 are arranged non-centrosymmetrically.

Here, the distance between the first centerline and the second centerline may be 1/50 ~ 1/10 of the first diameter, such as 1/30 first diameter, 1/20 first diameter, and the like. When the distance between the first central line and the second central line is smaller than 1/50 the first diameter, the linear cutting speed of the central point of the drill bit is improved to some extent; when the distance between the first center line and the second center line is controlled to be 1/50-1/10 first diameter, the cutting speed of a center point line of the drill bit can be well improved, and the drilling speed can be well improved; when the distance between the first centre line and the second centre line is larger than 1/10 the first diameter, the chance of wear of the small cutting head 6 is increased, which may reduce the tool life to some extent.

When drilling operation is carried out, the large cutting head 5 rotates under the driving of an upper drill string, and meanwhile, the small cutting head 6 positioned in the inner volume cavity for accommodating the connecting part rotates at a high speed under the driving of the underground power device 3 and revolves around the first central line under the driving of the upper drill string to do compound motion. Here, the rotation speed of the large cutting head 5 can be controlled within a range of 60 to 80 revolutions per minute. The rotation speed range of the small cutting head 6 can be controlled to be 200-600 revolutions/min, and the revolution speed range of the small cutting head 6 can be controlled to be 60-80 revolutions/min. The angular velocity of rotation of the large cutting head 5 is R, the sum of the angular velocities of rotation and revolution of the small cutting head 6 is R, and the ratio R: R of the angular velocity R of the small cutting head 6 to the angular velocity R of the large cutting head 5 may be 2 to 9:1, more preferably 4 to 7: 1. when the ratio of R to R is controlled to be 2-9: 1, the drilling speed-up effect is better; when R is less than 2, the drilling speed is improved to a certain extent; when the R is more than 9, the power requirement of the downhole power device is higher, the abrasion probability of the small cutting head is increased, and the service life is reduced to a certain extent. Firstly, utilizing the characteristics of large drilling pressure and large torque of the large cutting head 5 to carry out early cutting on the stratum rock, releasing stratum stress, cutting off peripheral rock and leaving easy-to-cut core columnar rock; and then the characteristics of high rotating speed and high linear speed of the small cutting head 6 are utilized to cut the easy-to-cut core columnar rock, the advantages of mutual matching of the large cutting head and the small cutting head are complementary, the small cutting head overcomes the defects of low central linear speed and low cutting speed of the large cutting head, and the large cutting head overcomes the defects of low drilling pressure and low torque of the small cutting head, so that the problem of zero central linear speed of a drill bit is avoided, and the rock breaking efficiency is improved.

In the present exemplary embodiment, the small cutting head 6 is further provided with a jet channel with a gradually decreasing cross-sectional area of a flow passage, and the second fluid flow enters the small cutting head after driving the rotary output part to rotate, and is jetted onto the columnar core through the jet channel to perform high-pressure jet drilling. For example, the small cutting head 6 is provided with a plurality of jet channels along the second center line, and the cross-sectional area of the jet channels in the radial direction is gradually reduced. The second fluid drives the power generating part to rotate and then enters the cutting head 6 via the rotation output part, e.g. its central through hole. The second flow may enter from the larger cross-section end of the spray channel of the cutting bit 6, where the pressure gradually increases, eventually forming a high-pressure spray from the smaller cross-section end of the spray channel. The high-pressure jet drilling fluid can scour the columnar rock core at a high flow rate, help the small cutting head to cut the columnar rock core and improve the cutting efficiency of the small cutting head, and can better clean the internal cutting surface of the large cutting head to prevent cutting tooth mud bags and accelerate drilling. Here, the large cutting head and the small cutting head may be ordinary bits, and high-performance PDC bits may also be used. For example, a physical schematic diagram of the present exemplary embodiment may be as shown in fig. 10.

FIG. 11 is a schematic diagram illustrating an exemplary embodiment of a two-speed dual-center drilling acceleration system for increasing the drilling speed of an oil and gas well in accordance with the present invention.

In a third exemplary embodiment of the invention, as shown in fig. 11, a two-speed, bi-center drilling acceleration system may include an outer barrel 1 ', a downhole power unit 2', a large cutting head 3 ', and a small cutting head 4'.

The large cutting head 3' has a first centre line, a receiving coupling portion fixedly coupled to each other along said first centre line, and a hollow cutting portion having a first diameter. The small cutting head 4' has a second centre line and a second diameter. Here, the first diameter is the outer diameter of the cutting portion of the large cutting head 3'. And the receiving coupling has a coupling member and an inner volume arranged along the first centre line, which inner volume is capable of receiving a small cutting head 4'. That is, the cutting portion can cut the workpiece to be ground both inside and outside. For example, the cutting portion may have an outer wall provided with an outer cutting face and an inner wall provided with a plurality of inner cutting faces. A runner channel may be formed between any two adjacent inner cutting surfaces of the plurality of inner cutting surfaces, and the runner channel may be in communication with the internal volume. The second centerline is parallel to but not coincident with the first centerline, and the second diameter is smaller than the first diameter. That is, both the first centerline and the second centerline may be parallel to the drilling direction, but there is a predetermined distance between the first centerline and the second centerline. For example, the distance between the first centerline and the second centerline may be 1/50-1/10 of the first diameter. As another example, the distance between the first centerline and the second centerline may be 1/20 for the first diameter.

The outer cylinder 1 'is sleeved outside the downhole power device 2' and forms an annular space between the two. And the left end of the outer cylinder 1 'is directly connected with the upper drill string, and the right end of the outer cylinder 1' is directly connected with the connecting piece of the accommodating connecting part of the large cutting head 3 'so that the large cutting head 3' can drill under the driving of the upper drill string. That is, the outer cylinder 1 ', the large cutting head 3' and the upper drill string may be fixed as one and may rotate together.

The downhole power unit 2' may have a power generation portion and a rotation output portion. Wherein the power generation unit is capable of generating power and rotating the rotation output unit. Further, the downhole power device 2 'can also form an annular space with the outer cylinder 1', and a power generating part of the downhole power device 2 'can be fixedly connected with one or more of the upper drill string, the outer cylinder 1' and the large cutting head 3 ', so that the downhole power device 2' can rotate under the driving of the upper drill string. The right end of the rotary output part enters the volume cavity of the accommodating connection part of the large cutting head 3 ' to be connected with the small cutting head 4 ' and can drive the small cutting head 4 ' to rotate. The power source of the power generation part can be from drilling fluid or batteries or other electric power and the like.

That is, the downhole power device 2 'can generate power through the power generation part and drive the small cutting head 4' to rotate around the second central line through the rotation output part; at the same time, the downhole power means 2 'as well as the small cutting head 4' are able to revolve around the first centre line due to the drive of the upper drill string. Thus, the angular velocity of the small cutting head 4 'will be greater than the angular velocity of the large cutting head 3'. For example, the ratio of the angular velocity of the small cutting head 4 'to the angular velocity of the large cutting head 3' may be 2 to 9: 1. for another example, the ratio of the angular velocity of the small cutting head 4 'to the angular velocity of the large cutting head 3' may be 4 to 7: 1.

in a fourth exemplary embodiment of the present invention, the two-speed dual-center drilling acceleration system may be based on the third exemplary embodiment described above, and the outer cylinder 1 'further includes a quincunx-like cavity fixedly disposed in the right end portion of the outer cylinder 1'. The quincunx-like cavity can right the power generation part or the rotation output part of the downhole power device 2 ', or can right the part of the small cutting head 4' connected with the rotation output part. That is, the centralizer is capable of centralizing the deflection caused by the rotation of the small cutting head 4'. The power generating part, the rotation output part or the small cutting head 4 'can be rotated more stably by the quincunx-like cavity in the right end of the outer cylinder 1'.

In a fifth exemplary embodiment of the invention, a two-speed, dual-center drilling acceleration system may be based on the third exemplary embodiment described above, with the outer barrel 1 ' further comprising a water diversion member disposed within the left end of the outer barrel 1 ' and between the upper drill string and the power generation portion of the downhole power unit 2 '. The water diversion part is provided with a central hole and a plurality of water diversion holes. The plurality of cutwater holes are capable of providing a portion of the drilling fluid (i.e., the first fluid stream) in the upper drill string into the annulus between the outer cylinder 1 'and the downhole power unit 2' and, in turn, to the large cutting head 3 'for lubrication of the large cutting head 3'. The central bore is capable of providing another portion of the drilling fluid (i.e., the second fluid stream) of the upper drill string as a power source to the power generation portion of the downhole power plant 2'. The power generation part can convert the power of the second liquid flow into the rotary motion of the rotary output part, and then drive the small cutting head 4' to rotate.

In summary, the two-speed dual-core drilling acceleration system of the present invention has one or more of the following advantages:

1. the large cutting head and the small cutting head are arranged in a non-centrosymmetric manner, and the small cutting head revolves around the central axis of the large cutting head while rotating at a high speed under the driving of an underground power device, so that the problem that the theoretical cutting linear velocity of the central point of the drill bit is zero is solved, and the drilling speed is improved;

2. compared with the well with the same size, the torque and the cost of the bottom hole power drilling tool are reduced under the condition of realizing the same rotating speed;

3. under the conditions of not increasing the discharge capacity of the drilling fluid and the pressure of the pump, the speed-up effect of high-pressure jet drilling can be formed in the middle of the bottom of the well;

4. the large cutting head is driven by the drill disk, the small cutting head is driven by the rotary disk and the underground power device together, and the small cutting head has higher angular speed than the large cutting head, so that the small cutting head has higher linear speed, and the drilling speed is improved.

Although the present invention has been described above in connection with the exemplary embodiments and the accompanying drawings, it will be apparent to those of ordinary skill in the art that various modifications may be made to the above-described embodiments without departing from the spirit and scope of the claims.

Claims (10)

1. A double-speed double-core drilling speed-up system for increasing the drilling speed of oil-gas wells is characterized by comprising an outer cylinder, a downhole power device, a large cutting head and a small cutting head, wherein,

the large cutting head having a first centerline, a receiving coupling fixedly coupled to each other along the first centerline, and a hollow cutting portion having a first diameter, the small cutting head having a second centerline and a second diameter, the receiving coupling having a coupling member and an internal volume disposed along the first centerline, the internal volume being capable of receiving the small cutting head, the second centerline being parallel to but not coincident with the first centerline, the second diameter being smaller than the first diameter;

the outer cylinder is sleeved outside the underground power device and forms an annular space, the left end of the outer cylinder is directly connected with the upper drill string, and the right end of the outer cylinder is directly connected with the connecting piece of the large cutting head for accommodating the connecting part, so that the large cutting head can drill under the driving of the upper drill string, and the underground power device rotates under the driving of the upper drill string;

the downhole power device is provided with a power generation part and a rotation output part, wherein the power generation part can generate power and rotate the rotation output part, and the right end of the rotation output part enters the inner volume cavity of the accommodating connection part of the large cutting head to be connected with the small cutting head and can drive the small cutting head to rotate.

2. A double-speed double-center drilling speed-up system for increasing the drilling speed of an oil-gas well is characterized by comprising a flow dividing device, an outer cylinder, a downhole power device, a centering device, a large cutting head and a small cutting head, wherein,

the large cutting head having a first centerline, a receiving coupling fixedly coupled to each other along the first centerline, and a hollow cutting portion having a first diameter, the small cutting head having a second centerline and a second diameter, the receiving coupling having a coupling member and an internal volume disposed along the first centerline, the internal volume being capable of receiving the small cutting head, the second centerline being parallel to but not coincident with the first centerline, the second diameter being smaller than the first diameter;

the outer cylinder is sleeved outside the underground power device and forms an annular space, the left end of the outer cylinder is connected with an upper drill string through the flow dividing device, and the right end of the outer cylinder is connected with the connecting piece, containing the connecting portion, of the large cutting head through the righting device, so that the large cutting head can drill under the driving of the upper drill string, and meanwhile, the underground power device rotates under the driving of the upper drill string;

the downhole power device is provided with a power generation part and a rotation output part, wherein the power generation part can generate power and rotate the rotation output part, and the right end of the rotation output part enters the inner volume cavity of the accommodating connection part of the large cutting head to be connected with the small cutting head and can drive the small cutting head to rotate;

the righting device is configured to right the power generation portion, the rotary output portion, or the small cutting head;

the flow divider is configured to separate drilling fluid in the upper drill string into a first flow that enters the annulus and lubricates the large cutting head and a second flow that enters the power generation portion of the downhole power plant.

3. The system for increasing the drilling speed of an oil and gas well as recited in claim 1 or 2, wherein the distance between the first centerline and the second centerline is 1/50-1/10 of the first diameter.

4. A two speed dual center drilling acceleration system for increasing drilling speed of oil and gas wells according to claim 1 or 2, characterized in that the ratio of the angular speed of the small cutting head to the angular speed of the large cutting head is 4-7: 1.

5. a two speed dual center drilling acceleration system for increasing the drilling speed of oil and gas wells according to claim 2, characterized in that the small cutting head has a jet channel with a gradually decreasing radial cross-sectional area, one end of the jet channel receiving the second flow through the power generation section and emitting from the other end of the jet channel.

6. A two speed dual center drilling acceleration system for increasing the drilling speed of oil and gas wells as claimed in claim 2, characterized in that the centralizing device has a quincunx-like cavity that can centralize the power generation section or the rotary output section, or that can centralize the portion where the small cutting head is connected to the rotary output section.

7. The system of claim 2, wherein the flow diversion device comprises a water diversion member having a central bore and a plurality of water diversion bores, the plurality of water diversion bores communicating drilling fluid in the upper drill string with the annulus and forming the first fluid flow, the central bore communicating drilling fluid in the upper drill string with the power generation section and forming the second fluid flow.

8. A two speed, dual center drilling acceleration system for increasing the drilling speed of oil and gas wells as claimed in claim 1, wherein said outer cylinder further comprises a quincunx-like cavity fixedly disposed in said right end, said quincunx-like cavity being capable of centering said power generation section or said rotational output section, or being capable of centering the portion of the small cutting head coupled to the rotational output section.

9. The system of claim 1 or 8, wherein the outer cylinder further comprises a water diversion member disposed in the left end between the upper drill string and the power generation section, wherein the water diversion member has a central bore and a plurality of water diversion holes disposed therein, the plurality of water diversion holes being capable of communicating drilling fluid in the upper drill string with the annulus and forming a first flow, the central bore being capable of communicating drilling fluid in the upper drill string with the power generation section and forming a second flow, the first flow being capable of lubricating a large cutting head, the second flow being capable of powering the power generation section.

10. The system of claim 1 or 2, wherein the cutting portion has an outer wall provided with an outer cutting surface and an inner wall provided with a plurality of inner cutting surfaces, a runner groove is formed between any two adjacent inner cutting surfaces of the plurality of inner cutting surfaces, and the runner groove is communicated with the inner volume chamber.

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