Refracturing special-shaped hole temporary plugging method and related device

Abstract

The invention discloses a temporary plugging method for a refracturing special-shaped hole and a related device. The method comprises the steps that in a candidate well, the shape and size of a special-shaped hole corresponding to primary fracturing perforation are obtained; a special-shaped hole and a circular hole are machined in a sleeve of the migration simulation device; a rupture disk with preset rupture pressure is mounted at the position of the circular hole; a special-shaped hole temporary plugging experiment is carried out, and the specification and size range of a temporary plugging component used for temporary plugging construction is determined; the number of temporary plugging components used for temporary plugging construction is determined; and the pre-determined temporary plugging component is conveyed into the range of the shaft through fracturing fluid, and temporary plugging construction of the special-shaped hole is conducted. According to the method, the plugging accuracy and success rate of the special-shaped hole can be increased, plugging of an old crack formed by primary fracturing perforation can be completed, the crack initiation efficiency of a new crack formed by repeated fracturing perforation can be improved, and benefit potential tapping of remaining oil in a candidate well is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of oil and gas exploitation, and particularly relates to a repeated fracturing irregular hole temporary plugging method and related device. BACKGROUND

[0002] In recent years, the application of horizontal well drilling and volume fracturing technology in unconventional reservoirs has shown great development potential. The evaluation of the liquid production profile of horizontal wells shows that nearly 40% of the perforation clusters do not effectively crack to produce artificial fractures, and the large inter-fracture spacing in the early horizontal well volume fracturing design leads to the difficulty in establishing an effective displacement system in unconventional reservoirs, and there is a large amount of reserves that cannot be utilized between hydraulic fractures, so it is urgent to tap the development potential of remaining oil in low-yield and low-efficiency wells through repeated fracturing of horizontal wells. In the field of conventional oil and gas reservoir development, straight wells or directional wells can improve the yield of low-yield and low-efficiency wells through repeated fracturing, and ultimately improve the recovery of oil and gas fields. However, unconventional oil and gas reservoirs use horizontal well staged fracturing as the main engineering technology, and the sand fracturing process is eroded by proppants, causing the perforation to become irregular, and the number of perforations is generally more than 20 times that of straight wells, so the influence of perforation hole deformation on repeated fracturing construction has to be considered. SUMMARY

[0003] In view of the above problems, the purpose of the present application is to provide a repeated fracturing irregular hole temporary plugging method and related device.

[0004] In the first aspect, the embodiments of the present application provide a repeated fracturing irregular hole temporary plugging method, comprising:

[0005] In the candidate well, the wellbore range corresponding to the irregular hole temporary plugging construction section is determined; in the wellbore range, the shape and size of the irregular hole corresponding to the initial fracturing perforation are obtained;

[0006] On the casing of the migration simulation device, the irregular hole is processed according to the shape and size of the irregular hole corresponding to the initial fracturing perforation, and the circular hole is processed according to the standard of the repeated fracturing perforation; the rupture disc with a preset rupture pressure is installed at the position of the circular hole; the preset rupture pressure is used to simulate the critical pressure of the fracturing fluid corresponding to the repeated fracturing perforation opening;

[0007] The irregular hole temporary plugging experiment is carried out to determine the size range of the temporary plugging component used in the temporary plugging construction;

[0008] According to the number of irregular holes in the temporary plugging construction section, the number of temporary plugging components used in the temporary plugging construction is determined;

[0009] The pre-determined temporary plugging component is transported into the wellbore range by using the fracturing fluid to carry out the irregular hole temporary plugging construction.

[0010] In one embodiment, the step of delivering the predetermined temporary plugging components into the wellbore range by using the fracturing fluid to carry out the irregular shaped hole temporary plugging operation further comprises:

[0011] Under the condition of the same fracturing fluid displacement, comparing the difference between the wellhead pressure value after the temporary plugging operation and the wellhead pressure value before the operation, if the difference rises to the critical pressure of the fracturing fluid corresponding to the repeated fracturing perforation opening, the temporary plugging operation achieves the preset effect;

[0012] If the temporary plugging operation does not achieve the preset effect, a preset number of temporary plugging components are put in again until the preset effect is achieved.

[0013] In one embodiment, the predetermined temporary plugging components use temporary plugging components of the same size or a combination of temporary plugging components of multiple sizes.

[0014] In one embodiment, the step of carrying out the irregular shaped hole temporary plugging experiment to determine the size range of the temporary plugging components used in the temporary plugging operation comprises:

[0015] According to the shape and size of the irregular shaped hole obtained, selecting a preliminary size range of the temporary plugging components;

[0016] According to the selected preliminary size range and the selection principle that when the rupture disc ruptures, the fracturing fluid pumped out from the circular hole model does not flow out from the irregular shaped hole model, carrying out multiple irregular shaped hole temporary plugging experiments to determine an adjusted size range that meets the selection principle;

[0017] The adjusted size range is determined as the size range of the temporary plugging components used in the temporary plugging operation.

[0018] In one embodiment, the temporary plugging component is a temporary plugging knot.

[0019] In one embodiment, the diameter of the knot body of the temporary plugging knot ranges from 20 to 30 mm.

[0020] In one embodiment, the step of obtaining the shape and size of the irregular shaped hole corresponding to the initial fracturing perforation comprises:

[0021] Lowering a downhole imaging tool into the temporary plugging operation section through a coiled tubing to obtain an irregular shaped hole image in the temporary plugging operation section range; analyzing the irregular shaped hole image to obtain the shape and size of the irregular shaped hole corresponding to the initial fracturing perforation.

[0022] In one embodiment, the downhole imaging tool is an integrated array camera and ultrasonic imager.

[0023] In one embodiment, the wellbore is pre-cleaned before the integrated array camera and ultrasonic imager are run into the wellbore.

[0024] In a second aspect, an embodiment of the present application provides a device for simulating temporary plugging of a shaped perforation in repeated fracturing, comprising:

[0025] A casing, an oil pump and a pressure gauge; the oil pump is used to pump fracturing fluid into the casing, and the pressure gauge is used to monitor the pressure of the fracturing fluid in the casing;

[0026] The casing is provided with a shaped perforation and a circular perforation at intervals, and a rupture disc is installed at the position of the circular perforation; the rupture disc is used to simulate the state of repeated fracturing perforation when rupture occurs;

[0027] The shaped perforation is used to simulate the perforation corresponding to the initial fracturing perforation; and the circular perforation is used to simulate the perforation corresponding to the repeated fracturing perforation;

[0028] The device for simulating temporary plugging of a shaped perforation in repeated fracturing is used to block the shaped perforation corresponding to the initial fracturing perforation by the temporary plugging component delivered into the casing when simulating temporary plugging of a shaped perforation in repeated fracturing, increase the pressure of the fracturing fluid in the casing, and reach the preset rupture pressure of the rupture disc.

[0029] The beneficial effects of the above technical solutions provided by the embodiments of the present application at least include:

[0030] The embodiments of the present application provide a temporary plugging method and related device for a shaped perforation in repeated fracturing, which obtains the shaped perforation in actual working conditions, determines the size and quantity of the temporary plugging component in temporary plugging construction according to the shaped perforation, and performs temporary plugging construction by using the pre-determined temporary plugging component.

[0031] Further, the size range of the temporary plugging component determined by the embodiments of the present application is obtained through simulation of the actual temporary plugging construction process, the shape and size of the shaped perforation, and shaped perforation temporary plugging experimental practice, and has good reliability and accuracy.

[0032] Further, the temporary plugging component adopts a temporary plugging knot, and compared with other existing temporary plugging components, the temporary plugging knot has better plugging effect in the temporary plugging process for the special-shaped hole.

[0033] The technical solutions of the present application will be further described in detail below with the aid of the accompanying drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0034] The accompanying drawings are used to provide a further understanding of the present application, and constitute a part of the specification, and are used to explain the present application together with the embodiments of the present application, and do not constitute a limitation on the present application. In the drawings:

[0035] Figure 1 A flowchart of the temporary plugging method for the repeated fracturing special-shaped hole in the embodiments of the present application;

[0036] Figure 2 A schematic diagram of the special-shaped hole model in the embodiments of the present application;

[0037] Figure 3 A schematic diagram of the temporary plugging knot in the embodiments of the present application;

[0038] Figure 4 A schematic diagram of the device for simulating the temporary plugging construction of the repeated fracturing special-shaped hole in the embodiments of the present application. DETAILED DESCRIPTION

[0039] The embodiments of the present application provide a temporary plugging method for repeated fracturing special-shaped holes and related devices, although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to enable the scope of the present disclosure to be fully conveyed to those skilled in the art.

[0040] The embodiments of the present application provide a temporary plugging method for repeated fracturing special-shaped holes, referring to Figure 1 the schematic diagram, the method comprises the following steps:

[0041] S11, in a candidate well, determine the wellbore range corresponding to the temporary plugging construction section of the special-shaped hole; in the wellbore range, obtain the shape and size of the special-shaped hole corresponding to the initial fracturing perforation.

[0042] S12, on the casing of the migration simulation device, process a special-shaped hole according to the shape and size of the special-shaped hole corresponding to the initial fracturing perforation, and process a circular hole according to the standard of the repeated fracturing perforation; install a rupture disc with a preset rupture pressure at the position of the circular hole; the preset rupture pressure is used to simulate the critical pressure of the fracturing fluid corresponding to the repeated fracturing perforation opening; carry out a special-shaped hole temporary plugging experiment to determine the size range of the temporary plugging component used in the temporary plugging construction.

[0043] S13, determining the number of temporary plugging components used in the temporary plugging construction according to the number of the special-shaped holes in the temporary plugging construction section.

[0044] S14, delivering the pre-determined temporary plugging components into the wellbore range by using the fracturing fluid, and performing the special-shaped hole temporary plugging construction.

[0045] The embodiment of the present application provides a repeated fracturing special-shaped hole temporary plugging method, acquires special-shaped holes in a repeated fracturing construction section (also a temporary plugging construction section) in an actual working condition; for the special-shaped holes, the specification size range of temporary plugging components meeting a preset plugging effect is determined by developing a special-shaped hole temporary plugging experiment. Since the specification size of the temporary plugging components is determined based on the experiment, the temporary plugging components have higher reliability and accuracy; the number of the temporary plugging components is further determined; the temporary plugging construction of the repeated fracturing construction section is performed based on the determined specification size and number of the temporary plugging components, the success rate of the special-shaped hole plugging is effectively improved, the old fracture plugging and the new fracture initiation are ensured, and the benefit potential of the remaining oil in the old well is realized.

[0046] In step S11, first, the special-shaped hole temporary plugging construction section is determined for the selected multiple candidate wells. In one embodiment, the special-shaped hole temporary plugging construction section is determined according to the remaining oil saturation distribution in the corresponding reservoir. The main idea is as follows: a three-dimensional geological model and a three-dimensional geomechanical model are established for the candidate well, the boundary conditions are set for the model in combination with the relationship between the maximum horizontal principal stress and the minimum horizontal principal stress of the reservoir, the stress state in the fracturing construction process is considered, the fluid-solid coupling calculation is performed on the pressure field and the stress field in the time period from the initial fracturing to the repeated fracturing, and the remaining oil saturation distribution before the repeated fracturing of the reservoir is obtained. The region in which the remaining oil saturation exceeds a preset saturation value is determined as the special-shaped hole temporary plugging construction section.

[0047] Specifically, when the distribution of the remaining oil saturation is determined, the following steps are mainly included:

[0048] (1) The natural gamma (GR), permeability, porosity, saturation, lithofacies, longitudinal wave, transverse wave and Stoneley wave and other data obtained by well logging interpretation before the initial fracturing of the horizontal well are used to calculate the rock mechanics parameters of the single well, for example, the Techlog software can be used for calculation, and the calculation results are corrected according to the data measured by the core experiment, and the error between the experimental results and the calculation results should not exceed a preset value 5%.

[0049] (2) Establish a three-dimensional geological model and a three-dimensional geomechanical model, and set boundary conditions for the model in combination with the relationship between the maximum horizontal principal stress and the minimum horizontal principal stress of the reservoir. Specifically, a three-dimensional geological model and a three-dimensional geomechanical model can be established by using the Petrel geological modeling software in combination with the geological layering results and by using a Gaussian random function interpolation method, and quality control can be performed by using single-well attributes, boundary conditions for the model can be set in combination with the relationship between the maximum horizontal principal stress and the minimum horizontal principal stress of the reservoir, and the stress state of the far field of the three-dimensional model is ensured.

[0050] (3) In the established three-dimensional geological model and three-dimensional geomechanical model, the perforation position of the old well and the actual fracturing construction pump injection program are set, a planar three-dimensional hydraulic fracturing model is used to simulate the hydraulic fracture propagation, and the model is corrected by using net pressure fitting. Specifically, in the established three-dimensional geological model and three-dimensional geomechanical model, the old well is set according to the actual perforation position, the bridge plug depth, and the actual fracturing construction pump injection program, if the reservoir develops natural fractures, the discrete fracture network is set according to the length, azimuth, dip angle, and distance of the natural fractures in the imaging logging interpretation results, a planar three-dimensional hydraulic fracturing model is used to simulate the hydraulic fracture propagation, and the model is corrected by adjusting the fracturing fluid viscosity, the filtration coefficient, the friction, the horizontal principal stress size, and the azimuth fitting net pressure.

[0051] (4) A three-dimensional reservoir model based on an unstructured grid is established according to the fracture morphology, reservoir numerical simulation is carried out, and actual production data are used for history matching to obtain the remaining oil, pore pressure, temperature, and saturation at different production times. The seepage field and stress field during the period from the initial fracturing to the repeated fracturing are calculated by fluid-structure coupling, and the three-directional principal stress state before the repeated fracturing is obtained.

[0052] Specifically: a three-dimensional reservoir model based on an unstructured grid is established according to the fracture morphology, reservoir numerical simulation is carried out, and actual production data are used for history matching of daily oil production, daily water production, and bottom hole flowing pressure to obtain the distribution of the remaining oil, pore pressure, and saturation at different production times.

[0053] The seepage field and stress field during the period from the initial fracturing to the repeated fracturing are calculated by fluid-structure coupling, and the three-directional principal stress state before the repeated fracturing is obtained.

[0054] Preferably, the fluid-structure coupling calculation uses a solid deformation equation and a porous medium multiphase fluid seepage equation for description.

[0055] The tensor form expression of the solid deformation control equation is:

[0056] σ ij,j +f i- alpha delta ij p = 0

[0057]

[0058] d sigma = D e d epsilon

[0059] wherein:

[0060] sigma ij,j - rock stress tensor;

[0061] p - pore pressure, MPa;

[0062] alpha - Biot's coefficient;

[0063] f i - volume force;

[0064] delta ij - Korneker symbol;

[0065] u i,j , u j,i - displacement along the coordinate axes x, y, respectively;

[0066] D e - rock elastic constitutive matrix;

[0067] sigma, epsilon - stress tensor, strain tensor, respectively.

[0068] wherein the porous medium multiphase fluid seepage equation is:

[0069]

[0070] wherein:

[0071] K - permeability of the porous medium, mD;

[0072] I - oil or water phase;

[0073] mu - fluid viscosity, Pa s;

[0074] g - gravity acceleration (constant), m / s 2 ;

[0075] K rI - relative permeability of phase I;

[0076] D - I phase seepage velocity, m / s;

[0077] S I - I phase saturation, %;

[0078] q I- fluid flow in or out, kg / s;

[0079] φ - porosity, %.

[0080] After determining the remaining oil saturation distribution according to the above method, a construction section with a higher remaining oil saturation, i.e., a construction section exceeding a preset saturation value, is selected as a temporary plugging construction section of the shaped hole.

[0081] The shape and size of the shaped hole corresponding to the primary fracturing perforation in the wellbore range of the construction section are obtained by the following method.

[0082] In one embodiment, the downhole imaging tool is lowered into the temporary plugging construction section through the coiled tubing to obtain the shaped hole image in the temporary plugging construction section range; the shaped hole image is analyzed to obtain the shape and size of the shaped hole corresponding to the primary fracturing perforation. For example, a shaped hole model is made based on the shaped hole image collected in a certain candidate well, as shown in FIG. 1, from which it can be clearly seen that the hole shapes of these metal shaped hole models are different and the sizes are also different. Figure 2

[0083] In one embodiment, the downhole imaging tool adopts an integrated array camera and an ultrasonic imager.

[0084] When the downhole imaging tool is used to collect the shaped hole image, the integrated array camera and the ultrasonic imager can be lowered to a preset position of the temporary plugging construction section and then pulled up at a preset speed, for example, at a speed of 5-10 m, so as to obtain all the shaped holes in the temporary plugging construction section range.

[0085] To ensure that the shaped hole image with high clarity is collected, in one embodiment, before the downhole imaging tool is lowered, the coiled tubing can be lowered first and the wellbore is cleaned with a well flushing fluid until the wellhead return fluid is free of impurities. The specific method is as follows: after the coiled tubing is lowered in the wellbore, the wellbore is continuously flushed with the well flushing fluid at a preset well flushing fluid discharge rate, for example, a rate of 2-3 m 3 / min is selected, the well flushing fluid usage should meet the preset requirement, for example, the usage is not less than 2 times the wellbore volume, the pump cannot be stopped during the well flushing fluid flushing period, until the wellhead return fluid is free of impurities and the water quality at the wellhead and the wellhead is consistent.

[0086] In step S12, the specification size range of the temporary plugging component is mainly determined by experimental method. The inventors carried out temporary plugging experiments on shaped holes based on the improved migration simulation device to obtain the specification size range of the temporary plugging component.

[0087] ​First, the experimental preparation work is carried out, in an embodiment, referring to the shape and size of the special-shaped hole corresponding to the initial fracturing perforation obtained, the same special-shaped hole is cut on the casing of the migration simulation device; at the same time, referring to the repeated fracturing perforation standard, the circular hole is also cut on the casing of the migration simulation device. In order to be able to simulate the temporary plugging effect of the temporary plugging component on the special-shaped hole under the preset fracturing fluid pressure in the casing, the inventors install a rupture disc at the position of the circular hole processed on the casing after research, and the preset rupture pressure of the rupture disc is the critical pressure of the fracturing fluid corresponding to the repeated fracturing perforation opening. In an embodiment, the preset rupture pressure is 8 MPa, that is, when the pressure of the fracturing fluid in the casing of the migration simulation device reaches 8 MPa, the rupture disc will rupture.

[0088] In an embodiment, the temporary plugging component is a temporary plugging knot, which is composed of a knot body and a tail wing. Referring to FIG. 1, after comparing different types of temporary plugging components, the inventors consider the characteristics of different sizes and shapes of special-shaped holes, and select the temporary plugging knot as the temporary plugging component for plugging the special-shaped hole. The knot body part of the temporary plugging knot can plug the main hole section of the special-shaped hole, and the tail wing part of the temporary plugging knot can further fill and plug the remaining hole section. Compared with other temporary plugging components such as temporary plugging balls and temporary plugging particles, the temporary plugging knot has obvious plugging advantages. Figure 3 Next, the special-shaped hole temporary plugging experiment is carried out. Referring to FIG. 2, the experimental device is started, the temporary plugging knot is put into the casing from the temporary plugging component launching port, the rear end of the casing is closed, and the fracturing fluid is injected into the casing. At this time, the circular hole is in a closed state due to the installation of the rupture disc. In order to select the size range of the temporary plugging knot, during the temporary plugging experiment, only when the fracturing fluid flows out from the circular hole and not from the special-shaped hole after the pressure in the casing of the experimental device reaches the preset rupture pressure of the rupture disc, it is indicated that the plugging has reached the expected effect, and the size of the selected temporary plugging knot is appropriate.

[0089] Figure 4 In an embodiment, according to the shape and size of the special-shaped hole obtained, the preliminary size range of the temporary plugging component (temporary plugging knot) is first selected; according to the selected preliminary size range and according to the preset selection principle, the special-shaped hole temporary plugging experiment is carried out for multiple times to determine the adjusted size range that meets the selection principle; and the adjusted size range is determined as the size range of the temporary plugging knot used in the temporary plugging construction.

[0090] In an embodiment, according to the shape and size of the special-shaped hole obtained, the preliminary size range of the temporary plugging component (temporary plugging knot) is first selected; according to the selected preliminary size range and according to the preset selection principle, the special-shaped hole temporary plugging experiment is carried out for multiple times to determine the adjusted size range that meets the selection principle; and the adjusted size range is determined as the size range of the temporary plugging knot used in the temporary plugging construction.

[0091] ​In one embodiment, the selection principle is that when the rupture disc ruptures, the pump fracturing fluid flows out from the circular hole model, but not from the shaped hole model. This principle is selected by referring to the actual repeated fracturing new perforation opening condition to achieve complete plugging of the corresponding shaped hole of the primary perforation.

[0092] In one embodiment, the selected size range of the temporary plugging knot is 20-30 mm.

[0093] In step S13, the number of temporary plugging knots selected for temporary plugging construction is mainly determined. In one embodiment, the temporary plugging construction section is divided into multiple construction sections, and the number of temporary plugging knots in a single construction section can be determined according to a preset multiple of the number of shaped holes in the single construction section. For example, the preset multiple is 2-2.5 times, but the embodiment of the present application is not limited thereto. For example, in a candidate well, in a single construction section of the temporary plugging construction section, there are 6 clusters of old perforations, i.e., primary fracturing perforations, and the number of shaped holes in each cluster is 6, so the total number of shaped holes in the single construction section is 36. According to 2-2.5 times of the number of shaped holes, the number of temporary plugging knots is determined, so the single construction section in the candidate well needs to put in 72 temporary plugging knots.

[0094] In step S14, according to the size range and number of temporary plugging knots determined in steps S12-S13, the temporary plugging construction of the shaped hole in the selected well is performed.

[0095] According to the preset displacement of the repeated fracturing new perforation, the construction displacement is determined, and the construction displacement is equal to the single hole displacement and the number of shaped holes. The preset single hole displacement needs to ensure the initiation and sand transport of each cluster of new perforations. For example, the preset single hole displacement is 0.25 m 3 / min, and the construction displacement is equal to 36×0.25=9 m 3 / min. In addition, the viscosity value of the fracturing fluid is determined, for example, slick water can be used for the fracturing fluid, and the viscosity of the slick water without additional friction reducer is controlled to be 5-15 mPa·s. The pre-determined temporary plugging knot is transported to the temporary plugging construction section by using the prepared slick water.

[0096] In one embodiment, whether the temporary plugging construction reaches the preset effect can be determined according to the curve superposition method. Specifically, under the condition of the same fracturing fluid discharge, the difference between the wellhead pressure after the temporary plugging construction and the wellhead pressure before the temporary plugging construction is compared. If the difference can be increased to the preset critical pressure value of the fracturing fluid corresponding to the repeated fracturing perforating opening, then the temporary plugging construction reaches the preset effect. The critical pressure value is the same as the preset breaking pressure value of the rupture disc in the temporary plugging experiment in step S12. If the temporary plugging construction does not reach the preset effect, then a preset number of temporary plugging knots are put into the wellbore again, for example, the same number of temporary plugging knots as the first time can be supplemented, until the preset effect is reached and the stop is performed.

[0097] In one embodiment, within the range of the size of the temporary plugging knot determined in step S12, the same size of the temporary plugging knot is used, or a combination of temporary plugging knots of multiple sizes is used.

[0098] The embodiment of the present application provides a device for simulating temporary plugging construction of repeated fracturing special-shaped perforation, referring to Figure 4 as shown, comprising:

[0099] a casing, an oil pump and a pressure gauge; the oil pump is used for pumping fracturing fluid into the casing, and the pressure gauge is used for monitoring the pressure of the fracturing fluid in the casing;

[0100] the casing is provided with a special-shaped perforation and a circular perforation at intervals, and a rupture disc is installed at the position of the circular perforation; the rupture disc is used for simulating the repeated fracturing perforation state when the rupture occurs;

[0101] the special-shaped perforation is used for simulating the perforation corresponding to the initial fracturing perforation; and the circular perforation is used for simulating the perforation corresponding to the repeated fracturing perforation;

[0102] the device for simulating temporary plugging construction of repeated fracturing special-shaped perforation is used for plugging the special-shaped perforation corresponding to the initial fracturing perforation by the temporary plugging component delivered into the casing when simulating the temporary plugging construction of repeated fracturing special-shaped perforation, increasing the pressure of the fracturing fluid in the casing, until the pressure of the fracturing fluid reaches the preset breaking pressure of the rupture disc.

[0103] The device for simulating temporary plugging construction of repeated fracturing special-shaped perforation provided by the embodiment of the present application is improved on the basis of the migration simulation device. Referring to Figure 4As shown, the device provided by the embodiment of the present application further comprises a water supply tank and a water collecting tank; the front end of the sleeve is connected with the water supply tank through a first pipeline, and the rear end of the sleeve is connected with the water collecting tank through a second pipeline; the oil pump and the pressure gauge are arranged on the first pipeline; a temporary plugging component dropping port is arranged at the front end position of the sleeve, and is used for dropping the temporary plugging component; a rupture disc is arranged at the position of the circular hole, and when the pressure value of the fracturing fluid in the sleeve continuously increases and reaches the preset rupture pressure of the rupture disc, the rupture disc is ruptured. The preset rupture pressure is just corresponding to the fracturing fluid pressure in the wellbore when the repeated fracturing perforating opening is performed. Therefore, the rupture disc is ruptured, and the state under the repeated fracturing perforating condition can be simulated. After the rupture disc is ruptured, if the fracturing fluid flows out from the circular hole and does not flow out from the special-shaped hole, it is indicated that the plugging achieves the preset effect.

[0104] During the temporary plugging experiment, the rear end of the sleeve should be closed, so that the pressure of the fracturing fluid in the sleeve is increased until the rupture pressure of the rupture disc is reached. After the temporary plugging experiment is completed, the rear end of the sleeve is opened, so that the sleeve is communicated with the water collecting tank, and the water collecting tank is used for collecting the waste liquid and the temporary plugging component after the experiment is completed.

[0105] The inventor improves the migration simulation device, develops the device for simulating the repeated fracturing special-shaped hole temporary plugging construction, not only the special-shaped hole is arranged on the sleeve of the migration simulation device, and is used for simulating the special-shaped hole temporary plugging construction process, but also the rupture disc is arranged at the position of the circular hole, and the plugging degree and the plugging effect of the special-shaped hole when the repeated fracturing perforating is simulated, which is crucial for evaluating the plugging effect of the temporary plugging component, and provides an advantageous guarantee for subsequently determining the specification size range of the temporary plugging component.

[0106] Obviously, those skilled in the art can make various changes to the present application without departing from the spirit and scope of the present application. Thus, if these modifications of the present application belong to the scope of the claims of the present application and the equivalent technology thereof, the present application also intends to include these modifications.

Claims

1. A method of temporary plugging of a shaped hole for repeated fracturing, characterized in that, The method comprises the following steps: In the candidate well, the wellbore range corresponding to the abnormal shaped hole temporary plugging construction section is determined; in the wellbore range, the shape and size of the abnormal shaped hole corresponding to the primary fracturing perforation are obtained; On the casing of the migration simulation device, the abnormal shaped hole is processed according to the shape and size of the abnormal shaped hole corresponding to the primary fracturing perforation, and the circular hole is processed according to the repeated fracturing perforation standard; A rupture disc with a preset rupture pressure is installed at the position of the circular hole; the preset rupture pressure is used to simulate the critical pressure of the fracturing fluid corresponding to the repeated fracturing perforation opening; An abnormal shaped hole temporary plugging experiment is carried out to determine the specification size range of the temporary plugging component used in the temporary plugging construction; According to the number of abnormal shaped holes in the temporary plugging construction section, the number of temporary plugging components used in the temporary plugging construction is determined; The pre-determined temporary plugging component is delivered into the wellbore range by using fracturing fluid to carry out abnormal shaped hole temporary plugging construction.

2. The method of claim 1, wherein, The step of delivering the pre-determined temporary plugging component into the wellbore range by using fracturing fluid to carry out abnormal shaped hole temporary plugging construction further comprises the following steps: Under the condition of the same fracturing fluid discharge, the difference between the wellhead pressure value after the temporary plugging construction and the wellhead pressure value before the construction is compared; if the difference rises to the critical pressure of the fracturing fluid corresponding to the repeated fracturing perforation opening, the temporary plugging construction achieves the preset effect; If the temporary plugging construction does not achieve the preset effect, a preset number of temporary plugging components are put in again until the preset effect is achieved.

3. The method of claim 2, wherein, The pre-determined temporary plugging component is a temporary plugging component with the same specification size or a combination of temporary plugging components with multiple specification sizes.

4. The method of claim 1, wherein, The step of carrying out the abnormal shaped hole temporary plugging experiment to determine the specification size range of the temporary plugging component used in the temporary plugging construction comprises the following steps: According to the obtained shape and size of the abnormal shaped hole, a preliminary specification size range of the temporary plugging component is selected; According to the selected preliminary specification size range and the selection principle that when the rupture disc ruptures, the pumped fracturing fluid flows out of the circular hole model but not out of the abnormal shaped hole model, multiple abnormal shaped hole temporary plugging experiments are carried out to determine the adjusted specification size range that meets the selection principle; The adjusted specification size range is determined as the specification size range of the temporary plugging component used in the temporary plugging construction.

5. The method according to claims 1 to 4, characterized in that The temporary plugging component is a temporary plugging knot.

6. The method of claim 5, wherein, The diameter range of the knot body of the temporary plugging knot is 20-30 mm.

7. The method of claim 1, wherein, The step of obtaining the shape and size of the abnormal shaped hole corresponding to the primary fracturing perforation comprises the following steps: The downhole imaging tool is lowered into the temporary plugging construction section through the coiled tubing to obtain the abnormal shaped hole image in the temporary plugging construction section range; the abnormal shaped hole image is analyzed to obtain the shape and size of the abnormal shaped hole corresponding to the primary fracturing perforation.

8. The method of claim 7, wherein, The downhole imaging tool is an integrated array camera and ultrasonic imager.

9. The method of claim 7, wherein, Before the integrated array camera and ultrasonic imager are lowered into the wellbore, the wellbore is pre-cleaned.

10. A device for simulating a shaped perforation temporary plugging operation of a re-fracturing, characterized in that, The method comprises the following steps: A casing, an oil pump and a pressure gauge; the oil pump is used to pump fracturing fluid into the casing, and the pressure gauge is used to monitor the pressure of the fracturing fluid in the casing; The sleeve is provided with a special-shaped hole and a circular hole at intervals, and a rupture disc is installed at the position of the circular hole; the rupture disc is used to simulate the repeated fracturing perforation state when rupture occurs; The special-shaped hole is used to simulate the hole corresponding to the initial fracturing perforation; and the circular hole is used to simulate the hole corresponding to the repeated fracturing perforation; The device for simulating the temporary plugging construction of the repeated fracturing special-shaped hole is used to block the special-shaped hole corresponding to the initial fracturing perforation by the temporary plugging component delivered into the sleeve when the temporary plugging construction of the repeated fracturing special-shaped hole is simulated, increase the pressure of the fracturing fluid in the sleeve, and reach the preset rupture pressure of the rupture disc until the pressure of the fracturing fluid reaches the preset rupture pressure of the rupture disc.

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