CN108798660A - Hydraulic fracturing stress measurement device - Google Patents

Abstract

The invention provides a hydraulic fracturing stress measurement device, which belongs to the field of rock mass stress measurement equipment, and includes an upper packer, a lower packer, a fracturing pipe and a water flow valve; the water flow valve includes a valve body and a center Rod; the valve body is provided with a stepped inner cavity and passage; the inner cavity includes a first chamber and a second chamber; a blind hole and a first water outlet hole are provided on the central rod, and the upper part of the central rod protrudes from the first chamber. And the top end is connected with the drill pipe, and the lower part of the central rod is located in the second chamber; the upper packer is provided with an upper connecting pipe; the lower packer is provided with a lower connecting pipe; the top and bottom ends of the fracturing pipe are respectively connected with the upper connecting pipe , and the lower connecting pipe; the fracturing pipe is provided with a second water outlet hole; a hose is connected between the upper packer and the lower packer. The hydraulic fracturing method stress measurement device provided by the present invention uses the drill pipe and the water flow valve to respectively pressurize the packer and the fracturing pipe, and does not need to install a high-pressure rubber hose in the borehole, which reduces the operation steps of going into the well and realizes Single circuit supply pressure.

Description

Hydraulic fracturing stress measuring device

technical field

The invention belongs to the technical field of rock mass stress measuring equipment, and more specifically relates to a hydraulic fracturing method stress measuring device.

Background technique

In-situ stress is the initial stress existing in the crustal rock mass, and it is also one of the important physical property parameters of the solid earth. In-situ stress is the root force that causes deformation, instability and destruction of rock mass, and is also an important parameter that affects the exploitation of deep energy such as oil, shale gas, and hot dry rock. Therefore, the measurement of ground stress has important scientific and practical significance in the study of earthquake mechanism, energy exploitation, design of mine tunnels, and construction of large dam foundations.

Hydraulic fracturing is the main measurement method for determining rock mass stress promulgated by the International Society of Rock Mechanics. Its principle is to use a pair of expandable rubber packers to seal a section of drilled rock mass at a predetermined test depth, and then pump The injected liquid exerts pressure on the section of the borehole until the rock mass ruptures. According to the pressure characteristic value of the fracturing process curve and the direction of the fracture, the ground stress value, direction and its variation along the depth are determined.

Existing hydraulic fracturing method stress measurement devices generally adopt dual-circuit pressure supply, one route pressurizes the packer through the high-pressure rubber hose through the ground high-pressure pump, and the other route the ground high-pressure pump through the fracturing pipe to fracturing the pressure. The section is pressurized, so as to realize the whole process of hydraulic fracturing stress measurement. This method can simultaneously monitor the pressure changes of the packer and the fracturing section during the experiment, but it is cumbersome to operate the downhole equipment in the downhole process. For small-diameter drilling, the sum of the dimensions of the high-pressure hose and the drill pipe has exceeded Drilling diameter, this method is not applicable.

Contents of the invention

The object of the present invention is to provide a hydraulic fracturing stress measurement device to solve the technical problems of the double-circuit stress measurement device in the prior art, which are cumbersome to operate in the downhole process and unsuitable for small-diameter drilling stress measurement.

In order to achieve the above object, the technical solution adopted by the present invention is to provide a hydraulic fracturing stress measuring device, comprising an upper packer and a lower packer arranged at intervals, and connecting the upper packer and the The fracturing pipe of the lower packer is characterized in that it also includes a water flow valve connected to the top of the upper packer for supplying water to the upper packer or the fracturing pipe;

The water flow valve includes a valve body and a central rod located in the valve body that can move relative to the valve body; the valve body is provided with a stepped inner cavity in the axial direction; the valve body is also provided with a The channel communicating with the inner cavity of the upper packer; the stepped inner cavity includes a first chamber and a second chamber located below the first chamber; the inner diameter of the first chamber is smaller than the first chamber the inner diameter of the second chamber; the first chamber communicates with the channel;

The outer diameter of the central rod is equal to the inner diameter of the first chamber; the central rod is axially provided with a blind hole, the upper part of the central rod protrudes from the valve body, and the top end of the central rod is in contact with the drill Rod connection, the blind hole communicates with the inner cavity of the drill pipe; the lower part of the central rod is located in the second chamber, and the side wall of the central rod is provided with the channel or the second chamber. the first water outlet hole;

The upper packer is provided with an upper connecting pipe passing through in the axial direction; the top end of the upper connecting pipe is located in the second chamber; the lower packer is provided with a lower connecting pipe passing through in the axial direction; The top and bottom ends of the fracturing pipe are respectively connected to the upper connecting pipe and the lower connecting pipe; the fracturing pipe is provided with a second outlet hole; the upper packer and the lower packer A flexible pipe is connected between them; the flexible pipe communicates with the inner cavity of the upper packer and the inner cavity of the lower packer respectively.

Further, the fracturing tube includes a first fracturing tube and a second fracturing tube sleeved in the first fracturing tube, and the fixed positions of the first fracturing tube and the second fracturing tube are adjustable.

Further, a pressure sensor is fixed on the outer wall of the first fracturing pipe.

Further, the first fracturing pipe is sleeved with a water outlet joint; the second water outlet hole is located on the first fracturing pipe; the second water outlet hole communicates with the water outlet joint

Further, both ends of the fracturing pipe are respectively connected to the upper connecting pipe and the lower connecting pipe via a first connector and a second connector.

Further, both ends of the fracturing pipe are respectively threaded with the first connector and the second connector; the lower end of the upper connecting pipe is threaded with the first connector; the upper end of the lower connecting pipe is connected with the The second connector is threaded.

Further, the two ends of the upper packer are respectively provided with fixed sleeves; the two ends of the lower packer are also respectively provided with fixed sleeves.

Further, the first water outlet hole is arranged radially along the central rod; the passage includes a first passage arranged radially along the valve body and a second passage arranged axially along the valve body; The second passage is spaced apart from the second chamber, and the first passage communicates with the first chamber.

Further, the part of the central rod protruding from the valve body is provided with a first boss protruding radially outward; the outer diameter of the first boss is larger than the inner diameter of the first chamber ; The bottom end of the central rod is provided with a second boss protruding radially outward; the outer diameter of the second boss is larger than the inner diameter of the second chamber.

The beneficial effect of the hydraulic fracturing method stress measuring device provided by the present invention is that: compared with the prior art, the hydraulic fracturing method stress measuring device of the present invention uses the drill pipe and the water flow valve to send water to the packer and the fracturing device respectively. Tube pressurization, no need to install high-pressure hose in the borehole, reducing the steps of downhole operation, and realizing single-circuit pressure supply. The hydraulic fracturing method stress measuring device provided by the invention is suitable for drilling holes with various diameters.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the accompanying drawings that need to be used in the descriptions of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only of the present invention. For some embodiments, those of ordinary skill in the art can also obtain other drawings based on these drawings without paying creative efforts.

Fig. 1 is a structural schematic diagram 1 of a hydraulic fracturing stress measuring device provided by an embodiment of the present invention;

Fig. 2 is a structural schematic diagram II of a hydraulic fracturing stress measurement device provided by an embodiment of the present invention;

Figure 3 is a partially enlarged view of Figure 1;

FIG. 4 is a partially enlarged view of FIG. 2 .

In the figure: 10, upper packer; 11, upper connecting pipe; 12, first connector; 20, lower packer; 21, lower connecting pipe; 22, second connector; 30, fracturing pipe; 31 , the first fracturing pipe; 32, the second fracturing pipe; 33, the second water outlet hole; 34, the pressure sensor; 35, the shell; 36, the water outlet joint; 40, the water circulation valve; 41, the valve body; Two chambers; 412, channel; 42, center rod; 421, first water outlet hole; 422, blind hole; 423, first boss; 424, second boss; 50, hose; 60, fixed sleeve plate; 70, drill pipe; 80, drilling.

Detailed ways

In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

It should be noted that when an element is referred to as being “fixed” or “disposed on” another element, it may be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

It is to be understood that the terms "length", "width", "top", "bottom", "front", "rear", "left", "right", "vertical", "horizontal", "top" , "bottom", "inner", "outer" and other indicated orientations or positional relationships are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying the referred device Or elements must have a certain orientation, be constructed and operate in a certain orientation, and thus should not be construed as limiting the invention.

In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be interpreted as indicating or implying relative importance or implicitly specifying the quantity of indicated technical features. Thus, a feature defined as "first" and "second" may explicitly or implicitly include one or more of these features. In the description of the present invention, "plurality" and "several" mean two or more, unless otherwise specifically defined.

Please refer to FIG. 1 and FIG. 2 together, and now the hydraulic fracturing method stress measuring device provided by the present invention will be described. The hydraulic fracturing stress measurement device includes an upper packer 10 arranged at intervals, a lower packer 20, a fracturing tube 30 connecting the upper packer 10 and the lower packer 20, and a The top of the packer 10 is used for a water flow valve 40 that supplies water to the upper packer 10 or the frac tubing 30 .

The water circulation valve 40 includes a valve body 41 and a central rod 42 located in the valve body 41 and movable relative to the valve body 41 .

The valve body 41 is axially provided with a stepped inner chamber, the stepped inner chamber includes a first chamber and a second chamber 411 located below the first chamber, the inner diameter of the first chamber is smaller than that of the second chamber 411 The inner diameter, the centerline of the first chamber and the centerline of the second chamber 411 coincide with the centerline of the valve body 41 respectively. The valve body 41 is also provided with a channel 412 communicating with the inner cavity of the upper packer 10 . The first chamber communicates with channel 412 .

The outer diameter of the central rod 42 is equal to the inner diameter of the first chamber; the central rod 42 is axially provided with a blind hole 422, the top of the central rod 42 protrudes from the valve body 41, and the top of the central rod 42 is connected with the drill rod 70, and the blind hole 422 communicates with the inner cavity of the drill rod 70; the lower part of the central rod 42 passes through the first chamber and is located in the second chamber 411, and the side wall of the central rod 42 is provided with a first chamber communicating with the passage 412 or the second chamber 411. Water outlet hole 421.

The upper packer 10 is provided with an upper connecting pipe 11 passing through in the axial direction, and the top end of the upper connecting pipe 11 is located in the second chamber 411 ; the lower packer 20 is provided with a lower connecting pipe 21 passing through in the axial direction. A hose 50 is connected between the upper packer 10 and the lower packer 20 , and the hose 50 communicates with the inner chamber of the upper packer 10 and the inner chamber of the lower packer 20 respectively.

The top end and the bottom end of the fracturing pipe 30 are respectively connected with the upper connecting pipe 11 and the lower connecting pipe 21 . The fracturing tube 30 is provided with a second water outlet hole 33 .

The process of measuring the stress of the hydraulic fracturing method stress measuring device provided by the present invention is as follows:

The center rod 42 is connected to the drill pipe 70 which is used to place the stress measurement device to the target test depth of the borehole 80 . The drill rod 70 is pulled upwards so that the first water outlet hole 421 is located in the first chamber and communicates with the channel 412 . The surface high-pressure water pump feeds water into the inner cavity of the drill pipe 70, and the water flows through the blind hole 422, the first water outlet hole 421, and the channel 412 into the inner cavity of the upper packer 10, and then enters the inner cavity of the lower packer 20 through the hose 50. lumen. As water is continuously injected into the inner cavity of the upper packer 10 and the inner cavity of the lower packer 20, the upper packer 10 and the lower packer 20 expand under the action of water pressure until they are close to the hole wall of the borehole 80, and the upper packer 10 and the lower packer 20 expand The borehole section between the packer 10 and the lower packer 20 is isolated.

Then, the drill pipe 70 is pressed down so that the first water outlet hole 421 is located in the second chamber 411, and the ground high-pressure water pump feeds water into the inner chamber of the drill pipe 70, and the water flows through the blind hole 422, the first water outlet hole 421, and the second chamber in sequence. The chamber 411 , the first connecting pipe 11 and the fracturing pipe 30 are finally led out from the second water outlet hole 33 into the isolated drilling section to realize pressurized fracturing of the rock mass in the isolated drilling section. In this process, the change process of water injection pressure is measured by the pressure sensor on the surface to obtain the fracture pressure, retension pressure and closing pressure of the fracturing fracture, and then obtain the maximum and minimum principal stress values in the measured depth section.

After the measurement is completed, the drill pipe 70 is lifted up, the first water outlet hole 421 is connected to the channel 412, the surface manifold is opened, and the atmosphere is connected. When removed, the packer shrinks to its original state. So far, the stress measurement of a measuring point is over. The stress measuring device can move to the next target position to continue the measurement.

Compared with the prior art, the hydraulic fracturing stress measuring device provided by the present invention uses the drill pipe 70 and the water flow valve 40 to pressurize the packer and the fracturing pipe 30 respectively, and does not need to be installed in the borehole 80. High-pressure rubber hose reduces downhole operation steps and realizes single-circuit pressure supply.

Further, please refer to Fig. 3 and Fig. 4, as a specific embodiment of the hydraulic fracturing method stress measuring device provided by the present invention, the first water outlet hole 421 is arranged along the radial direction of the central rod 42; The first passage radially arranged on the body 41 and the second passage axially arranged along the valve body 41; the second passage is spaced apart from the second chamber 411, and the first passage communicates with the first chamber.

Further, please refer to Fig. 2 and Fig. 4, as a specific embodiment of the hydraulic fracturing method stress measuring device provided by the present invention, the bottom end of the central rod 42 is provided with a second protrusion protruding radially outward. platform 424 , the outer diameter of the second boss 424 is larger than the inner diameter of the second chamber 411 . The inner diameter of the first water outlet hole 421 is equal to the inner diameter of the first channel. The axial distance from the bottom end of the first water outlet hole 421 to the top surface of the second boss 424 is equal to the axial distance from the bottom end of the first channel to the top surface of the second chamber 411 . The central rod 42 can be driven upward by the drill rod 70. When the second boss 424 is in contact with the top surface of the second chamber 411, the central rod 42 does not move upward, and the first water outlet hole 421 is located in the first chamber at this time. , and communicate with the channel 412, because the second boss 424 is in contact with the top surface of the second chamber 411, the second chamber 411 is blocked, water can only flow into the channel 412 from the first water outlet hole 421, and finally flow into the upper compartment device 10. The second boss 424 is used to prevent the central rod 42 from being pulled out of the second chamber 411, and when the second boss 424 is in contact with the top surface of the second chamber 411, it is used to make the first water outlet hole 421 and the channel 412 connected.

Further, please refer to Fig. 1 and Fig. 3, as a specific embodiment of the hydraulic fracturing method stress measuring device provided by the present invention, the part of the central rod 42 protruding from the valve body 41 is provided with radially outward Protruding first boss 423 . The outer diameter of the first boss 423 is larger than the inner diameter of the first chamber. The axial distance from the bottom surface of the first boss 423 to the top surface of the blind hole 422 is greater than the axial height of the first cavity. The central rod 42 can be driven downward by the drill rod 70. When the first boss 423 is in contact with the top surface of the valve body 41, the central rod 42 does not move downward, and the first water outlet hole 421 is located in the second chamber at this time. 411. Since the inner diameter of the first chamber is equal to the outer diameter of the central rod 42, the outer wall of the central rod 42 blocks the channel 412, and water can only flow into the second chamber 411 from the first outlet hole 421, and finally flow into the fracturing tube 30 . The first boss 423 is used to prevent the central rod 42 from being pressed into the first chamber, and when the first boss 423 is in contact with the top surface of the valve body 41, it is used to ensure that the first water outlet hole 421 is located in the second chamber 411 .

Further, please refer to Fig. 1 or Fig. 2, as a specific embodiment of the hydraulic fracturing method stress measuring device provided by the present invention, the fracturing tube 30 includes a first fracturing tube 31 and a The second fracturing tube 32 inside 31, the fixed positions of the first fracturing tube 31 and the second fracturing tube 32 are adjustable. The first fracturing pipe 31 and the second fracturing pipe 32 are flexibly connected, and can be threaded or clamped. The overall length of the fracturing tube 30 is the length between the top end of the first fracturing tube 31 and the bottom end of the second fracturing tube 32, and this length can be adjusted according to the fixed positions of the first fracturing tube 31 and the second fracturing tube 32. Adjustment. Different rock masses require different lengths of isolated drilling sections to measure stress. The length of the fracturing tube 30 is adjustable, so that the stress measurement device can meet the stress measurement requirements of different rock masses.

Further, please refer to Fig. 1 or Fig. 2, as a specific embodiment of the hydraulic fracturing method stress measuring device provided by the present invention, the outer wall of the first fracturing tube 31 is covered with a casing 35, and inside the casing 35 is fixed a Pressure sensor 34. The pressure sensor 34 can directly collect the water pressure of the isolated borehole section, which improves the measurement accuracy. The water pressure value collected by the pressure sensor 34 is stored in the data processor. After the fracturing test is completed, the data processor is lifted to the ground and passed Read the data processor to get the pressure record curve.

Further, please refer to Fig. 1 or Fig. 2, as a specific embodiment of the hydraulic fracturing method stress measuring device provided by the present invention, the first fracturing pipe 31 is provided with a water outlet joint 36, and the second water outlet hole 33 Located on the first fracturing pipe 31 , the second water outlet hole 33 communicates with the water outlet joint 36 . The water outlet hole of the water outlet joint 36 is arranged along the radial direction of the first fracturing tube 31 . After the second fracturing tube 32 is completely inserted into the first fracturing tube 31, the top surface of the second fracturing tube 32 is located below the second water outlet hole 33 and the water outlet joint 36, so as to ensure that the fracturing tube 30 can move toward the isolation drill. The hole section is normally filled with water.

Further, please refer to Fig. 1 or Fig. 2, as a specific embodiment of the hydraulic fracturing method stress measuring device provided by the present invention, the two ends of the fracturing tube 30 are connected through the first connector 12 and the second connector respectively. 22 is connected with upper connecting pipe 11, lower connecting pipe 21. Specifically, the upper end of the first fracturing tube 31 and the lower end of the upper connecting tube 11 are respectively screwed to the first connector 12, and the lower end of the second fracturing tube 32 and the upper end of the lower connecting tube 21 are respectively connected to the second connector 22. threaded connection. The upper connecting pipe 11, the fracturing pipe 30 and the lower connecting pipe 21 are connected by means of a connector and threaded connection, which facilitates the assembly of the three.

Further, please refer to Fig. 1 or Fig. 2, as a specific embodiment of the hydraulic fracturing stress measurement device provided by the present invention, the two ends of the upper packer 10 are respectively provided with fixed sleeve plates 60, and the lower packer 10 is The two ends of the device 20 are also respectively provided with fixed sleeves 60 . The fixing sleeve plate 60 is used for fixing the upper connecting pipe 11 on the upper packer 10 and fixing the lower connecting pipe 21 on the lower packer 20 .

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. within range.

Claims (9)

1. The hydraulic fracturing method stress measuring device, comprising an upper packer arranged at intervals, a lower packer, and a fracturing tube connecting the upper packer and the lower packer, characterized in that: including a water flow valve connected to the top of the upper packer for supplying water to the upper packer or the fracturing tubing; The water flow valve includes a valve body and a central rod located in the valve body that can move relative to the valve body; the valve body is provided with a stepped inner cavity in the axial direction; the valve body is also provided with a The channel communicating with the inner cavity of the upper packer; the stepped inner cavity includes a first chamber and a second chamber located below the first chamber; the inner diameter of the first chamber is smaller than the first chamber the inner diameter of the second chamber; the first chamber communicates with the channel; The outer diameter of the central rod is equal to the inner diameter of the first chamber; the central rod is axially provided with a blind hole, the upper part of the central rod protrudes from the valve body, and the top end of the central rod is in contact with the drill Rod connection, the blind hole communicates with the inner cavity of the drill pipe; the lower part of the central rod is located in the second chamber, and the side wall of the central rod is provided with the channel or the second chamber. the first water outlet hole; The upper packer is provided with an upper connecting pipe passing through in the axial direction; the top end of the upper connecting pipe is located in the second chamber; the lower packer is provided with a lower connecting pipe passing through in the axial direction; The top and bottom ends of the fracturing pipe are respectively connected to the upper connecting pipe and the lower connecting pipe; the fracturing pipe is provided with a second outlet hole; A flexible pipe is connected between the upper packer and the lower packer; the flexible pipe communicates with the inner cavity of the upper packer and the inner cavity of the lower packer respectively. 2. The hydraulic fracturing stress measuring device according to claim 1, wherein the fracturing tube comprises a first fracturing tube and a second fracturing tube set inside the first fracturing tube, The fixed positions of the first fracturing tube and the second fracturing tube are adjustable. 3. The hydraulic fracturing stress measuring device according to claim 2, characterized in that: a pressure sensor is fixed on the outer wall of the first fracturing pipe. 4. The hydraulic fracturing stress measuring device according to claim 2, characterized in that: the first fracturing pipe is provided with a water outlet joint; the second water outlet hole is located in the first fracturing pipe above; the second water outlet hole communicates with the water outlet joint. 5. The hydraulic fracturing method stress measuring device according to claim 1, characterized in that: the two ends of the fracturing pipe respectively pass through the first connector, the second connector and the upper connecting pipe, the The lower connecting pipe is connected. 6. The hydraulic fracturing stress measurement device according to claim 5, characterized in that: the two ends of the fracturing pipe are respectively threaded with the first connector and the second connector; the upper connecting pipe The lower end is threaded with the first connector; the upper end of the lower connecting pipe is threaded with the second connector. 7. The hydraulic fracturing stress measuring device according to claim 1, characterized in that: the two ends of the upper packer are respectively provided with fixed sleeve plates; the two ends of the lower packer are also respectively provided with There are fixed sets of plates. 8. The hydraulic fracturing stress measuring device according to claim 1, characterized in that: the first water outlet hole is arranged radially along the central rod; A first passage and a second passage arranged axially along the valve body; the second passage is spaced apart from the second chamber, and the first passage communicates with the first chamber. 9. The hydraulic fracturing stress measuring device according to claim 1, characterized in that: the part of the central rod protruding from the valve body is provided with a radially outwardly protruding first boss The outer diameter of the first boss is greater than the inner diameter of the first chamber; the bottom end of the center rod is provided with a second boss protruding radially outward; the outer diameter of the second boss The diameter is greater than the inner diameter of the second chamber.