CN115032368B - Fracturing fracture self-supporting diversion capacity overall process evaluation method - Google Patents
Fracturing fracture self-supporting diversion capacity overall process evaluation method Download PDFInfo
- Publication number
- CN115032368B CN115032368B CN202210639027.XA CN202210639027A CN115032368B CN 115032368 B CN115032368 B CN 115032368B CN 202210639027 A CN202210639027 A CN 202210639027A CN 115032368 B CN115032368 B CN 115032368B
- Authority
- CN
- China
- Prior art keywords
- self
- supporting
- fracturing
- crack
- rock
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/24—Earth materials
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
- G01N3/10—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces generated by pneumatic or hydraulic pressure
- G01N3/12—Pressure testing
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/10—Geothermal energy
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Immunology (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Physics & Mathematics (AREA)
- Pathology (AREA)
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Remote Sensing (AREA)
- Food Science & Technology (AREA)
- Medicinal Chemistry (AREA)
- Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
Abstract
The invention discloses a whole process evaluation method for self-supporting flow conductivity of a fracturing fracture, which mainly comprises the following steps: collecting reservoir section outcrop with natural cracks, cutting into cubic rock samples and drilling; after the well bore is cleaned, selecting sealant to solidify the well bore and the rock sample; constructing a true triaxial confining pressure device system, and fracturing to obtain a rough fracture rock plate; adopting a 3D laser scanner to scan the crack wall surface to obtain wall surface point cloud data; calculating a roughness JRC value by utilizing the point cloud data; and constructing a novel fracture self-supporting diversion capacity testing diversion chamber device, and evaluating the self-supporting diversion capacity change rules under the conditions of different closing stresses, different slippage and different roughness. According to the invention, the rock plate is obtained through true triaxial fracturing, the wall cloud image and the roughness are obtained through scanning, the self-supporting diversion capacity is tested and evaluated, the optimal slip quantity and the roughness JRC value of the self-supporting diversion capacity of the fracturing fracture can be optimized, and the guiding significance is provided for the self-supporting fracturing process well selection and layer selection in fracturing construction.
Description
Technical Field
The invention relates to a flow conductivity evaluation method, in particular to a fracture self-supporting flow conductivity overall process evaluation method, and belongs to the field of oil gas development and yield improvement.
Background
The fracturing technology is a key technical means for benefit development of unconventional oil and gas reservoirs, and in the fracturing process, the initiation and expansion rule and the diversion characteristic of the fracture determine the reservoirTwo key factors of the reconstruction volume of the layer and the effective fracturing period. Fracturing can form a variety of complex fractures including filled fractures, shear slip fractures, and in-situ closed fractures, subject to factors such as ground stress, rock strength, and the extent of natural fracture development. With the increase of the complexity of the stitch net, the average support concentration of the propping agent in the artificial crack is less than 0.5kg/m 2 Or the supporting area is smaller than 10%, most of the secondary cracks are not filled with propping agent, but the shearing sliding of the wall surface of the self-supporting fracture is caused due to the factors of non-uniformity of stratum, deviation stress, mismatching of perforation phase angles and the like, the protrusions of the shearing fracture surface can effectively support the cracks, and the residual seam width can still be kept under the action of closing stress, so that the self-supporting fracture with certain diversion capacity is formed. The self-supporting effect plays an important role in increasing the yield of oil gas. The self-supporting cracks are important channels for oil gas flow, so that the research on the flow rule of gas and liquid in the cracks and the evaluation of the self-supporting diversion capability of the fracturing cracks have important guiding significance for unconventional reservoir development and reasonable evaluation of the productivity of oil and gas wells.
At present, the self-supporting diversion capability of the fracturing fracture is mainly obtained by adopting an indoor test method at home and abroad, firstly, the self-supporting diversion capability of the fracturing fracture is obtained from an outcrop rock sample or a downhole rock core, and the fracture surface is obtained by adopting a manual fracturing method. Secondly, the rock samples obtained through fracturing are subjected to shearing dislocation and then combined and packaged for flow conductivity testing, in the method, due to the fact that the sizes of the cut rock plates are different, the sealing performance of an API flow guide chamber is poor, blowby gas exists in an annular space, and the final flow conductivity testing result is inaccurate and has large errors. In addition, the study of the influence of the slip quantity of the crack generally considers that the self-supporting crack flow conductivity has no linear relation with the slip quantity, but a proper slip quantity actually exists to obtain the optimal flow conductivity. Therefore, based on the above needs, a self-supporting diversion capacity overall process evaluation method is established for the fracturing fracture, and an important pushing effect is played on fracturing construction design.
Disclosure of Invention
The invention aims to provide a full-process evaluation method for the self-supporting flow conductivity of a fracturing fracture.
The invention provides a whole process evaluation method for self-supporting diversion capability of a fracturing fracture, which comprises the following steps:
and S10, collecting an outcrop rock sample of a reservoir section with a natural fracture, cutting the outcrop rock sample into a cubic rock sample, drilling holes on opposite rock samples along the directions forming different included angles (0-90 degrees) with the bedding direction after cutting, simulating different wells, considering the minimization of the stress concentration effect of the well wall, and determining the radius of the well according to a well Zhou Yingli calculation formula.
In step S11 and step S10, the well Zhou Yingli has the following calculation formula:
wherein a is the radius of the rock sample shaft and m; r is the radial distance of any point of the rock sample, m; sigma (sigma) ν Is vertical stress and MPa; sigma (sigma) h Is the minimum horizontal principal stress, MPa; θ is the angle (°) of the radial direction from the direction of minimum horizontal principal stress;
and S20, after the drilling is completed, cleaning the inside and inner wall adhesion fragments of the well hole by using a high-pressure water gun, and standing for more than 24 hours. Polishing and etching the lower end of the fracturing shaft, increasing the roughness of the pipeline, winding a paper adhesive tape with the same radius as the shaft hole above the open hole of the shaft, selecting sealant with better fluidity to seal the shaft hole and the shaft hole annular space, and fixing the rock sample and the shaft hole.
And S30, constructing a true triaxial confining pressure device experimental system, determining the stress difference according to reservoir geological conditions, setting triaxial confining pressure stress by using a pressure system, preparing fracturing fluid, starting a pumping system to perform true triaxial fracturing of the rock sample, and fracturing the rock sample into a plurality of rock samples with rough crack wall surfaces.
And S40, referring to the reserved rock plate size of the diversion chamber, considering a larger rock plate dislocation slip amount, marking the upper, lower, left and right surfaces of the position of the crack surface required by the rock sample after fracturing in S30, and cutting the upper and lower crack wall surfaces along the marked size by adopting a large-scale cutting machine to obtain a pair of rock plates for self-supporting diversion capability test.
And S50, scanning and imaging the fractured rough crack surface in the step S40 by adopting a four-mesh 3D laser scanner, and obtaining point cloud coordinate parameters of the rough wall surface after scanning. Writing a cloud picture drawing program, and drawing a crack wall cloud picture; and writing a roughness JRC value calculation program to calculate the roughness JRC value. And comparing the crack surface cloud image with the physical image, and carrying out wall surface characteristic analysis by combining the roughness parameters.
And S51, programming by using Matlab software based on a parameter calculation formula, writing a cloud drawing program, drawing a crack wall cloud drawing, and analyzing the influence of the distribution of concave-convex points on the crack wall on the roughness.
And S52, writing a roughness JRC calculation program, bringing the point cloud data into roughness JRC solving software to obtain a rock fracture surface protruding point increasing variable function fitting curve, and obtaining a roughness JRC value.
In step S52, the method for calculating the roughness JRC value includes the following steps:
step S521, calculating an increment function V (r) between the protruding points of the fracture surface, and the calculation formula is as follows:
wherein r is the distance between measuring points, mm; z (x) i ) Is x i The height of the point bulge is mm; n (r) is the calculated times when the measuring point distance is r, and the dimensionless is zero;
step S522, calculating fractal dimension D according to the relation of the increment function V (r) obtained in step S521, wherein the calculation formula is as follows:
where β is plotted on the ordinate of log [ V (r) ] and on the abscissa of log (r) with a smaller value of r, approximating the slope of the linear segment.
Step S523, calculating a roughness coefficient JRC value according to the fractal dimension D value calculated in step S522, wherein the calculation formula is as follows:
JRC＝85.267(D-1) 0.5679
and step S60, grouping rock plates with small difference of the JRC values according to the JRC values of the crack wall surface roughness finally obtained in the step S50 so as to ensure that the initial conditions of the self-supporting diversion experiment of the fracturing cracks are the same.
And step S70, improving the original API diversion chamber by the cut rock plate obtained in the step S40, constructing a novel self-supporting diversion capability test diversion chamber device, defining the self-supporting diversion capability of the fracturing fracture, testing the diversion capability of the fracturing fracture, and evaluating the diversion capability change rules under different closing pressures and different roughness conditions. And defining the self-supporting diversion capacity increasing rate omega of the fracturing fracture, and evaluating the change rule of the self-supporting diversion capacity increasing rate along with the closing pressure under different slippage.
And S71, determining the crack sliding quantity according to a calculation formula of the maximum sliding quantity of the fracturing crack self-supporting diversion capacity rock plate. The calculation formula of the maximum slip is as follows:
wherein u is max Is the shear slippage of the crack, mm; l is half-length of the slit, m; v is the rock poisson ratio, dimensionless; e is the Young's modulus of the rock, GPa; sigma (sigma) 1 Is the maximum principal stress, MPa; sigma (sigma) 3 Is the minimum principal stress, MPa;
and S72, constructing the novel diversion chamber slippage according to the slippage calculated in the S71. And fixing one rock plate, and after the other rock plate is staggered to the target sliding amount, temporarily fixing by using transparent glue, bonding the prepared sliding gaskets and cushion blocks with the rock plate by using glue to ensure that the upper length and the lower length of the rock plate are consistent, and completing the manufacturing of the self-supporting diversion capacity testing rock plate.
Step 73, testing the rock plate according to the self-supporting diversion capability constructed in the step 72, wherein the point cloud coordinate parameters of the rough crack wall surface of the rock plate are obtained in the step 50, the length direction of the rock plate is assumed to be an X coordinate parameter, the width direction is assumed to be a Y coordinate parameter, the height direction is assumed to be a Z coordinate parameter, dislocation slip is carried out in the length direction, data values except for dislocation of the slip are removed according to the slip quantity of the crack determined in the step 71, and the self-supporting crack width W of the fracturing crack under slip is calculated according to the following formula:
wherein L is the length of the rock plate, and mm; d is the width of the rock plate, mm; h is the crack slip, mm; r is the distance between the measuring points, mm; z is Z i,j Is that the coordinates of the upper rock plate point are (X i ，Y j ) Is a protrusion height value of mm; z is Z i ' +h,j Is that the coordinates of the lower rock plate point are (X i+h ，Y j ) Is a protrusion height value of mm;
step S74, determining a diversion capacity test closing pressure according to the level main stress of the reservoir according to the initial fracture width W of the novel diversion chamber obtained in the step S73, monitoring the actual self-supporting fracture width according to a diversion capacity test system displacement meter, and finally calculating the self-supporting diversion capacity of the fracturing fracture according to the following calculation formula:
in the formula, the K-self-supporting crack permeability, um 2 ；W F Self-supporting slit width, mm; c is a correction coefficient, dimensionless; μ is the viscosity of the injected liquid at the experimental temperature, mpa·s; q is the liquid injection flow, cm 3 S; ΔP is the differential pressure between two monitoring points of the novel diversion chamber, and kPa;
and S75, evaluating the change rule of the flow conductivity under the conditions of different closing pressures and no roughness according to the self-supporting flow conductivity of the fracturing fracture obtained in the step S74. And defining an evaluation parameter self-supporting flow conductivity increasing rate omega, and evaluating the change rule of the flow conductivity increasing rate omega along with the closing pressure under different slippage. Self-supporting guide thereofThe flow capacity increase rates were ω, respectively 3,1 、ω 5,3 The calculation formula is as follows:
wherein K is 3,i -the crack slip h is 3mm of self-supporting flow conductivity at the ith closed pressure point; k (K) 1,i -the crack slip h is 1mm of self-supporting flow conductivity at the ith closed pressure point; k (K) 5,i -the crack slip h is the self-supporting flow conductivity at the ith closed pressure point at 5 mm; omega 3,1 -a self-supporting flow conductivity increase rate when the crack slip h is changed from 1mm to 3 mm; omega 5,3 -a self-supporting flow conductivity increase rate when the crack slip h is changed from 3mm to 5 mm;
compared with the prior art, the invention has the following advantages:
(1) The constructed true triaxial confining pressure fracturing device system can realize a large-scale reservoir rock core fracturing experiment, and the fracturing crack effect under different conditions can be effectively evaluated by changing the type of fracturing fluid, the performance of the fracturing fluid, the confining pressure and the stress difference.
(2) The built novel self-supporting diversion chamber device for testing diversion capability can simulate the self-supporting crack diversion capability test under different slippage, and the adopted sealing structure can effectively solve the problems of failure sealing of the diversion capability test rock plate and large error of test results.
(3) The method comprises the steps of constructing a whole process evaluation method of the self-supporting diversion capability of the fracturing fracture, obtaining a fracture rock plate through fracturing, scanning the rock plate to obtain a wall cloud picture and roughness, carrying out a self-supporting diversion capability experiment, and evaluating the change rule of the self-supporting diversion capability of the fracturing fracture under the conditions of different closure stresses, different slippage and different roughness. The method provides guidance for well selection and layer selection of the self-supporting fracturing process in fracturing construction.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention.
Drawings
FIG. 1 is a schematic view of a wellbore circumferential stress distribution in an embodiment of the invention
FIG. 2 is a schematic diagram of a fracturing unit system according to an embodiment of the invention
FIG. 3 is a schematic cross-sectional view of consolidation of a core and a wellbore according to an embodiment of the invention
FIG. 4 is a top view of a true triaxial confining pressure device in an embodiment of the invention
FIG. 5 is a flowchart of a process for drawing a cloud image of a crack wall surface according to an embodiment of the present invention
FIG. 6 is a flowchart of a crack wall roughness calculation process according to an embodiment of the invention
FIG. 7 is a cloud view of the crack walls of the rock plates C21 and C5 in an embodiment of the invention
FIG. 8 is a top view of a novel self-supporting crack conductivity test chamber device in accordance with an embodiment of the present invention
FIG. 9 is a cross-sectional view of a novel self-supporting crack conductivity test flow chamber device A-A according to an embodiment of the present invention
Icon: 001-true triaxial confining pressure device; 002-X direction pressure system; 003-Y direction pressure system; 004-Z direction pressure system; 005-a supercharging system; 006-a warming system; 007-pumping system; 008-cooling system
1-cubic rock sample; 2-sealing glue; 3-wellbore tubing; 4-paper tape; a 5-Z direction backing plate; 6-Z stress system; 7-Y direction backing plate; 8-X direction backing plate; 9-Y direction bearing plates; a 10-Y directional stress system; 11-X direction bearing plate; 12-X directional stress system
101-an upper cover plate; 102-an upper press plate; 103-bolts; 104-water pressure pumping joint; 105-a fluid outlet valve; 106 outlet pressure monitoring head; 107—an inlet pressure monitoring head; 108-fluid inlet valve
201-self-supporting upper rock plate; 202-right slip pad; 203-upper cushion blocks; 204-annular space on the rubber sleeve; 205-rubber sleeve; 206-self-supporting lower rock plate; 207-lower platen; 208-self-supporting fracture; 209-left slip pad; 210-lower cushion block; 211-a rubber sleeve lower annular space; 212-a lower cover plate; 213-diversion chamber body
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the invention, as presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be made by a person skilled in the art without making any inventive effort, are intended to be within the scope of the present invention.
It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures. Meanwhile, in the description of the present invention, the terms "first", "second", and the like are used only to distinguish the description, and are not to be construed as indicating or implying relative importance.
Specific examples are as follows:
the invention provides a whole process evaluation method for self-supporting diversion capability of a fracturing fracture, which comprises the following steps:
and S10, collecting shale outcrop rock samples with natural cracks, cutting the outcrop rock samples into cubic rock samples 1 with the dimensions of 300mm multiplied by 300mm, drilling the opposite rock samples 1 along the parallel bedding direction (angle of 0 DEG), simulating a horizontal well, considering the minimization of the stress concentration effect of the well wall, and determining the radius of the well shaft to be 5mm according to a well Zhou Yingli calculation formula.
The outcrop rock sample can be shale, sandstone, conglomerate and the like.
In step S11 and step S10, the well Zhou Yingli has the following calculation formula:
wherein a is the radius of the rock sample shaft and m; r is the radial distance of any point in the rock sample, m; sigma (sigma) ν Is vertical stress and MPa; sigma (sigma) h Is the minimum horizontal principal stress, MPa; θ is the angle (°) of the radial direction from the direction of minimum horizontal principal stress;
and S20, after the drilling is completed, cleaning the inside and inner wall adhesion chip powder of the opposite side rock sample 1 in the well hole by using a high-pressure water gun, and standing for more than 24 hours to ensure that the sealant 2 has a better bonding effect with the wall of the well hole. Polishing and etching the lower end of the fracturing shaft pipeline 3 to increase the roughness of the pipeline, winding a paper adhesive tape 4 with the same size as the radius of the well bore above the open hole of the shaft, and preventing the sealant 2 from flowing into the bottom of the shaft to seal the pump injection port. And selecting resin type AB glue with better fluidity to seal the annular space between the well bore and the well bore, and solidifying the cubic rock sample and the well bore.
And S30, constructing a true triaxial fracturing device experimental system, and fracturing the cubic rock sample 1.
The experimental system of the true triaxial fracturing device comprises a true triaxial confining pressure device 001, a pressurizing system 005, a heating system 006, a pumping system 007 and a cooling system 008. And determining the stress difference as 2MPa according to the geological conditions of the reservoir, respectively pressing by using an X-direction 002, a Y-direction 003 and a Z-direction stress system 004, setting the minimum horizontal main stress as 8MPa, setting the maximum horizontal main stress as 10MPa and setting the vertical stress as 12MPa.
The example cubic rock sample 1 fracturing employs supercritical CO 2 And (3) fracturing, namely, modulating and heating system 006 to enable the phase state temperature to be higher than 31.8 ℃, modulating and pressurizing system 005 to enable the phase state pressure to be higher than 7.1MPa, starting a pumping system to perform true triaxial fracturing of the rock sample, and fracturing the rock sample into a plurality of rock samples with rough crack wall surfaces.
The fracturing may be supercritical CO 2 The fracturing may be nitrogen fracturing, hydraulic fracturing, other fracturing fluid fracturing, etc.
And S40, reserving the size of the rock plate by referring to the size of the API diversion chamber, marking the upper, lower, left and right sides of the position of the required fracture surface of the rock sample after fracturing in S30 by considering that the dislocation slippage of a larger rock plate is 10mm, and cutting the upper and lower fracture wall surfaces along the marked size by adopting a large-scale cutting machine to obtain the final fracture self-supporting diversion capability test rock plate with the size of 146mm multiplied by 37mm multiplied by 44mm.
And S50, scanning and imaging the rough crack surface of the rock plate by adopting a four-mesh 3D laser scanner after the fracturing in the step S40, and obtaining the point cloud coordinate parameters of the rough wall surface after scanning. Writing a cloud picture drawing program, and drawing a crack wall cloud picture; and writing a roughness JRC value calculation program to calculate the roughness JRC value. And comparing the crack surface cloud image with the physical image, and carrying out wall surface characteristic analysis by combining the roughness parameters.
And S51, programming by using Matlab software based on a parameter calculation formula, writing a cloud drawing program, drawing a crack wall cloud drawing, and analyzing the influence of the distribution of concave-convex points on the crack wall on the roughness.
And S52, writing a roughness JRC calculation program, bringing the point cloud data into roughness JRC solving software to obtain a rock fracture surface protruding point increasing variable function fitting curve, and obtaining a roughness JRC value.
In step S52, the method for calculating the roughness JRC value includes the following steps:
step S521, calculating an increment function V (r) between the protruding points of the fracture surface, and the calculation formula is as follows:
wherein r is the distance between measuring points, mm; z (x) i ) Is x i The height of the point bulge is mm; n (r) is the calculated times when the measuring point distance is r, and the dimensionless is zero;
step S522, calculating fractal dimension D according to the relation of the increment function V (r) obtained in step S521, wherein the calculation formula is as follows:
where β is plotted on the ordinate of log [ V (r) ] and on the abscissa of log (r) with a smaller value of r, approximating the slope of the linear segment.
Step S523, calculating a roughness coefficient JRC value according to the fractal dimension D value calculated in step S522, wherein the calculation formula is as follows:
JRC＝85.267(D-1) 0.5679
step S60, grouping rock plates with small difference of JRC values according to the crack wall roughness JRC values finally obtained in the step S50, wherein 9 pairs of rock plates are divided into 3 groups; the first group is numbered C10/C21/C3; the second group is C4/C5/C22; the third group is numbered C26/C8/C14. And the initial conditions of the self-supporting diversion experiment of the fracturing fracture are guaranteed to be the same, so that a single-factor control experiment is formed.
TABLE 1 shale supercritical CO 2 Fracturing different rock plate group table
And step S70, improving the original API diversion chamber by cutting the rock plate obtained in the step S40. The whole structure adopts square outline, compares former API water conservancy diversion room improvement, arranges annular gum cover 205 at novel water conservancy diversion room body 213 inner wall. The outer wall of the rubber sleeve 205 is respectively provided with an upper annular space 204 of the rubber sleeve and a lower annular space 211 of the rubber sleeve, the pressure is pumped into the joint 104 through the hydraulic pump, the inner wall of the rubber sleeve 205 deforms and protrudes to be in contact with the self-supporting rock plate for sealing, and the large permeability error caused by gas channeling is prevented.
Setting up a novel fracture self-supporting diversion capacity test diversion chamber device, defining fracture self-supporting diversion capacity, testing the diversion capacity, and evaluating the diversion capacity change rules under different closing pressures and different roughness conditions. And defining the self-supporting diversion capacity increasing rate of the fracturing fracture, and evaluating the change rule of the self-supporting diversion capacity increasing rate along with the closing pressure under different slippage.
And S71, determining the crack sliding quantity according to a calculation formula of the maximum sliding quantity of the fracturing crack self-supporting diversion capacity rock plate. The left sliding pad 209 and the right sliding pad 202 of the vacant part are corrected by horizontally shifting the upper rock plate and the lower rock plate. The calculation formula of the maximum slip is as follows, and the slip amount of the crack is determined to be 1mm,3mm and 5mm.
Wherein u is max Is the shear slippage of the crack, mm; l is half-length of the slit, m; v is the rock poisson ratio, dimensionless; e is the Young's modulus of the rock, GPa; sigma (sigma) 1 Is the maximum principal stress, MPa; sigma (sigma) 3 Is the minimum principal stress, MPa;
and S72, constructing the novel diversion chamber slippage according to the slippage gradient result calculated in the S71. The self-supporting lower rock plate 206 is fixed, the self-supporting upper rock plate 201 moves left and is staggered to the target sliding amount of 1mm,3mm and 5mm respectively, after the self-supporting upper rock plate 201 is temporarily fixed by transparent glue, the prepared left sliding gasket 209, the right sliding gasket 202, the upper cushion 203 and the lower cushion 210 are adhered to the staggered end surfaces of the rock plate by glue so that the upper length and the lower length of the rock plate are consistent, and the self-supporting diversion capability test rock plate manufacturing is completed.
Step S73, testing the rock plate according to the self-supporting diversion capability constructed in the step S72, wherein the point cloud coordinate parameters of the rough crack wall surface of the rock plate are obtained in the step S50, the length direction of the rock plate is assumed to be an X coordinate parameter, the width direction is assumed to be a Y coordinate parameter, the height direction is assumed to be a Z coordinate parameter, dislocation sliding is carried out in the length direction, the crack sliding amounts determined in the step S71 are respectively 1mm,3mm and 5mm, data values except dislocation of the sliding amounts are removed, and the calculation formula of the self-supporting crack width W of the fracturing crack under sliding is as follows:
wherein L is the length of the rock plate, and mm; d is the width of the rock plate, mm; h is the crack slip, mm; r is the distance between the measuring points, mm; z is Z i,j Is that the coordinates of the upper rock plate point are (X i ，Y j ) Is a protrusion height value of mm;Z i ' +h,j is that the coordinates of the lower rock plate point are (X i+h ，Y j ) Is a protrusion height value of mm;
step S74, taking the seam width W obtained in the step S73 as the initial seam width of the novel diversion chamber, knowing that the maximum horizontal main stress matched under the depth of the obtained outcrop rock sample and the geological reservoir is 61MPa, the minimum horizontal main stress is 42.2MPa, determining the upper line of the diversion capacity test closing pressure to be 40MPa, setting the closing stress data points to be 1.8MPa, 3.6MPa, 7.2MPa, 13.8MPa, 20.6MPa, 27MPa, 34MPa and 40MPa, monitoring the dynamic self-supporting seam width in the process of applying the closing stress according to a diversion capacity test system displacement meter, and finally calculating the self-supporting diversion capacity of the fracturing seam, wherein the calculation formula is as follows:
in the formula, the K-self-supporting crack permeability, um 2 ；W F Self-supporting slit width, mm; c is a correction coefficient, dimensionless; μ is the viscosity of the injected liquid at the experimental temperature, mpa·s; q is the liquid injection flow, cm 3 S; ΔP is the differential pressure between two monitoring points of the novel diversion chamber, and kPa;
TABLE 2 shale supercritical CO 2 Fracturing fracture self-supporting flow conductivity test result
And S75, evaluating the change rule of the flow conductivity under the conditions of different closing pressures and no roughness according to the self-supporting flow conductivity of the fracturing fracture obtained in the step S74. And defining an evaluation parameter self-supporting flow conductivity increasing rate omega, and evaluating the change rule of the flow conductivity increasing rate omega along with the closing pressure under different slippage. The self-supporting diversion capacity increase rates are omega respectively 3,1 、ω 5,3 The calculation formula is as follows:
wherein K is 3,i -the crack slip h is 3mm of self-supporting flow conductivity at the ith closed pressure point; k (K) 1,i -the crack slip h is 1mm of self-supporting flow conductivity at the ith closed pressure point; k (K) 5,i -the crack slip h is the self-supporting flow conductivity at the ith closed pressure point at 5 mm; omega 3,1 -a self-supporting flow conductivity increase rate when the crack slip h is changed from 1mm to 3 mm; omega 5,3 -a self-supporting flow conductivity increase rate when the crack slip h is changed from 3mm to 5 mm;
TABLE 3 flow conductivity increase rates for different sets of different slippage
According to different groups, under different slippage, the diversion capacity increasing rate curve is changed along with the closing pressure, and most diversion capacity increasing rate curves are 1-3 mm slippage which is higher than 3-5 mm, which means that the diversion capacity is increased greatly and the diversion capacity is changed less from 3mm to 5mm when slippage is increased from 1mm to 3 mm. According to the whole process evaluation method of the self-supporting diversion capability of the fracturing fracture, which is established above, the final conclusion is that the diversion capability of the self-supporting fracture has higher stress sensitivity under the condition of low closing stress (13.8 MPa), the diversion capability is quickly reduced along with the increase of the closing pressure, after the protruding point of the fracture surface is crushed, the opening degree of the fracture is reduced, no space is reduced, and the influence of the closing pressure on the diversion capability is reduced; the crack sliding quantity and the roughness jointly determine the flow conductivity of the self-supporting crack, the self-supporting crack is easy to form only when the self-supporting crack has higher wall surface roughness and proper sliding quantity, and the optimal sliding quantity result of the indoor experiment is about 3mm and the roughness JRC value is about 56.
The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention. It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.
The foregoing is merely illustrative of the present invention, and the present invention is not limited thereto, and any person skilled in the art will readily recognize that variations or substitutions are within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (6)
1. The whole process evaluation method for the self-supporting diversion capability of the fracturing fracture is characterized by comprising the following steps of:
s10, collecting a reservoir section outcrop rock sample with natural cracks, cutting the outcrop rock sample into a cubic rock sample (1), and drilling holes in the opposite Fang Yanyang (1) along different included angle directions with the bedding direction, wherein the included angle directions are 0-90 degrees, and simulating a horizontal well, an inclined well and a vertical well;
s20, cleaning the inner wall of a well bore after drilling is completed, polishing and etching the lower end of a fracturing well bore, increasing the roughness of a pipeline, winding a paper adhesive tape (4) with the same radius as the well bore above the open hole of the well bore, selecting sealant (2) with better fluidity to seal the annular space of the well bore and the well bore, and fixing a rock sample and the well bore;
s30, constructing a true triaxial confining pressure device experiment system, determining the stress difference according to reservoir geological conditions, setting triaxial confining pressure stress by using a pressure system, preparing fracturing fluid, starting a pumping system to perform true triaxial fracturing of a rock sample, and fracturing the rock sample into a plurality of rock samples with rough crack wall surfaces;
s40, marking the positions of the required fracture surfaces of the rock sample after fracturing in S30, namely cutting the upper and lower fracture wall surfaces along the marked sizes by using a large-scale cutting machine to obtain a pair of rock plates required to be tested for self-supporting diversion capability;
s50, scanning and imaging the fractured rough crack surface in the S40 by adopting a four-eye 3D laser scanner, and acquiring point cloud coordinate parameters of the rough wall surface after scanning; writing a cloud picture drawing program, and drawing a crack wall cloud picture; writing a roughness JRC value calculation program to calculate a roughness JRC value; comparing the crack surface cloud image with the physical image, and carrying out wall characteristic analysis by combining the roughness parameters;
s60, grouping rock plates with small difference of JRC values according to the JRC values of the crack wall surface roughness finally obtained in the step S50 so as to ensure that the initial conditions of the self-supporting diversion experiment of the fracturing cracks are the same;
s70, improving the original API diversion chamber by using the cut rock plate obtained in the step S40, and building a novel fracture self-supporting diversion capability test diversion chamber device; defining the self-supporting flow conductivity of the fracturing fracture, testing the flow conductivity of the fracturing fracture, and evaluating the change rule of the flow conductivity under the conditions of different closing pressures and different roughness; defining the self-supporting diversion capacity increasing rate omega of the fracturing fracture, and evaluating the change rule of the self-supporting diversion capacity increasing rate omega along with the closing pressure under different sliding amounts;
and (5) testing the rock plate according to the constructed self-supporting diversion capability, wherein the point cloud coordinate parameters of the rough crack wall surface of the rock plate and the crack sliding quantity obtained in the step (S50) are used for removing data values except for dislocation of the sliding quantity, and the initial crack width of the fracturing crack self-supporting rock plate under the self-supporting sliding quantity is calculated according to the following calculation formula:
wherein L is the length of the rock plate, and mm; d is the width of the rock plate, mm; h is the crack slip, mm; r is the distance between the measuring points, mm; z is Z i,j Is that the coordinates of the upper rock plate point are (X i ，Y j ) Is a protrusion height value of mm; z's' i+h,j Is that the coordinates of the lower rock plate point are (X i+h ，Y j ) Is the protrusion height of (2)Value, mm;
according to the obtained seam width W as the initial seam width of the novel diversion chamber, according to the dynamic self-supporting seam width in the process of applying the closing stress by the diversion capability test system displacement meter, the self-supporting diversion capability of the fracturing seam is finally calculated, and the calculation formula is as follows:
in the formula, the K-self-supporting crack permeability, um 2 ；W F Self-supporting slit width, mm; c is a correction coefficient, dimensionless; μ is the viscosity of the injected liquid at the experimental temperature, mpa·s; q is the liquid injection flow, cm 3 S; ΔP is the differential pressure between two monitoring points of the novel diversion chamber, and kPa;
the novel fracturing fracture self-supporting diversion capacity testing diversion chamber device mainly comprises a self-supporting upper rock plate (201), a self-supporting lower rock plate (206), a rubber sleeve (205), a left sliding gasket (209), a right sliding gasket (202), an upper cushion block (203), a lower cushion block (210), a diversion chamber body (213), a fluid inlet valve (108), a fluid outlet valve (105), an outlet pressure monitoring head (106), an inlet pressure monitoring head (107) and a water pressure pumping joint (104).
2. The method for evaluating the self-supporting diversion capability of a fracturing fracture overall process according to claim 1, wherein the experimental system of the true triaxial confining pressure device in the step S30 mainly comprises an X-direction stress system (12), a Y-direction stress system (10) and a Z-direction stress system (6).
3. The method for evaluating the self-supporting diversion capability of a fracturing fracture according to claim 1, wherein the fracturing fluid in the step S30 is water-based guanidine gum fracturing fluid, clean fracturing fluid, low-water foam fracturing fluid or CO 2 One of the anhydrous fracturing fluids.
4. The method for evaluating the self-supporting conductivity of a fracturing fracture according to claim 1, wherein the method for calculating the roughness JRC in the step S50 is as follows:
firstly, calculating an increment function V (r) between protruding points of a fracture surface, wherein the calculation formula is as follows:
wherein r is the distance between measuring points, mm; z (x) i ) Is x i The height of the point bulge is mm; n (r) is the calculated times when the measuring point distance is r, and the dimensionless is zero;
then, the fractal dimension D is calculated according to the acquired relation of the increment function V (r), and the calculation formula is as follows:
where β is plotted on the ordinate of log [ V (r) ] and on the abscissa of log (r) with a smaller r value, approximating the slope of the linear segment;
and finally, calculating a roughness JRC value according to the fractal dimension D value obtained in the step, wherein the calculation formula is as follows:
JRC＝85.267(D-1) 0.5679 。
5. the method for evaluating the whole process of the self-supporting diversion capability of the fracturing fracture according to claim 1, wherein the left sliding gasket (209) and the right sliding gasket (202) are used as the construction of the sliding quantity, the size of the sliding quantity of the fracture is determined according to a calculation formula of the maximum sliding quantity of the self-supporting diversion capability rock plate of the fracturing fracture, and the size of the maximum sliding quantity is calculated as follows:
wherein u is max Is the shear slippage of the crack, mm; l is half-length of the slit, m; v is the rock poisson ratio, dimensionless; e is the Young's modulus of the rock，GPa；σ 1 Is the maximum principal stress, MPa; sigma (sigma) 3 Is the minimum principal stress, MPa.
6. The method of claim 1, wherein the evaluation parameter in step S70 is a self-supporting conductivity increase rate ω, respectively ω 3,1 、ω 5,3 The calculation formula is as follows:
wherein K is 3,i -the crack slip h is 3mm of self-supporting flow conductivity at the ith closed pressure point; k (K) 1,i -the crack slip h is 1mm of self-supporting flow conductivity at the ith closed pressure point; k (K) 5,i -the crack slip h is the self-supporting flow conductivity at the ith closed pressure point at 5 mm; omega 3,1 -a self-supporting flow conductivity increase rate when the crack slip h is changed from 1mm to 3 mm; omega 5,3 -self-supporting flow conductivity increase rate when crack slip h changes from 3mm to 5mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210639027.XA CN115032368B (en) | 2022-06-07 | 2022-06-07 | Fracturing fracture self-supporting diversion capacity overall process evaluation method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210639027.XA CN115032368B (en) | 2022-06-07 | 2022-06-07 | Fracturing fracture self-supporting diversion capacity overall process evaluation method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115032368A CN115032368A (en) | 2022-09-09 |
| CN115032368B true CN115032368B (en) | 2023-08-04 |
Family
ID=83123386
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210639027.XA Active CN115032368B (en) | 2022-06-07 | 2022-06-07 | Fracturing fracture self-supporting diversion capacity overall process evaluation method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115032368B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116241248A (en) * | 2023-04-25 | 2023-06-09 | 西南石油大学 | Dynamic monitoring method for natural fracture state under true triaxial hydraulic fracturing and related equipment |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN205277410U (en) * | 2016-01-06 | 2016-06-01 | 西南石油大学 | Proppant is spread and is put and flow conductivity integration collimated light source device |
| CN106501488A (en) * | 2016-11-29 | 2017-03-15 | 中国石油大学(北京) | True triaxial sand fracturing testing machine and its test method |
| CN108397184A (en) * | 2018-05-18 | 2018-08-14 | 西南石油大学 | A kind of numerical computation method of self-supporting fracture condudtiviy |
| CN109653740A (en) * | 2018-12-26 | 2019-04-19 | 西南石油大学 | A kind of Carbonate Acid Fracturing self-supporting fracture permeabgility prediction technique |
| CN109869128A (en) * | 2019-03-22 | 2019-06-11 | 长江大学 | The device of flow conductivity is surveyed for measuring shale gas gas |
| CN111520135A (en) * | 2020-06-15 | 2020-08-11 | 西南石油大学 | Shale self-supporting fracture initial flow conductivity prediction method |
Family Cites Families (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| PL212870B1 (en) * | 2007-08-31 | 2012-12-31 | Neostrain Spolka Z Ograniczona Odpowiedzialnoscia | Device for measurement of scratch spacing width, cracks and gaps in building objects |
| WO2016122792A1 (en) * | 2015-01-28 | 2016-08-04 | Schlumberger Canada Limited | Method of performing wellsite fracture operations with statistical uncertainties |
| WO2017027433A1 (en) * | 2015-08-07 | 2017-02-16 | Schlumberger Technology Corporation | Method of performing integrated fracture and reservoir operations for multiple wellbores at a wellsite |
| CN108152183A (en) * | 2016-12-06 | 2018-06-12 | 中国石油天然气股份有限公司 | Acid-etched fracture etch profile and flow conductivity test method |
| CN107228800A (en) * | 2017-05-27 | 2017-10-03 | 中国石油大学(北京) | A kind of experimental method of indoor real-time dynamic monitoring hydraulic fracture slit width |
| CN207808473U (en) * | 2018-01-26 | 2018-09-04 | 福建福顺半导体制造有限公司 | TF blanking track feeding pipe expanders |
| CN108386179B (en) * | 2018-03-13 | 2019-04-02 | 西南石油大学 | A kind of optimization method of sandstone reservoir hydraulic fracturing proppants parameter |
| CN111305806B (en) * | 2018-11-27 | 2022-06-03 | 中国石油天然气股份有限公司 | Method and device for analyzing flow conductivity of self-supporting fracture |
| CN110320149B (en) * | 2019-08-02 | 2021-08-03 | 西南石油大学 | Flow direction adjustable irregular rock sample high-pressure permeation device and testing method |
| CN209976538U (en) * | 2019-09-26 | 2020-01-21 | 西南石油大学 | API flow guide chamber suitable for testing flow guide capacity of fractured rock plate |
| CN110805429A (en) * | 2019-10-09 | 2020-02-18 | 大港油田集团有限责任公司 | Dynamic fracture self-supporting fracturing process research device and diversion determination method thereof |
| CN110593842B (en) * | 2019-10-22 | 2020-05-05 | 西南石油大学 | Method for determining hydraulic fracturing self-supporting fracture flow conductivity of shale reservoir through experiment |
| CN111590949A (en) * | 2020-05-28 | 2020-08-28 | 泉州朔康工业设计服务有限公司 | Rotating structure of powder product pressing device for cosmetic processing |
| CN111948099B (en) * | 2020-08-13 | 2022-02-08 | 西南石油大学 | Testing device and method for evaluating backflow opportunity of fracturing fluid based on hydration |
| CN113238007A (en) * | 2021-05-27 | 2021-08-10 | 中国石油天然气股份有限公司 | Experimental method and device for temporary plugging simulation in rough crack |
| CN114382467B (en) * | 2022-01-14 | 2023-07-07 | 西南石油大学 | Acid etching-temporary plugging integrated dynamic seam width experimental device and temporary plugging agent evaluation method |
-
2022
- 2022-06-07 CN CN202210639027.XA patent/CN115032368B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN205277410U (en) * | 2016-01-06 | 2016-06-01 | 西南石油大学 | Proppant is spread and is put and flow conductivity integration collimated light source device |
| CN106501488A (en) * | 2016-11-29 | 2017-03-15 | 中国石油大学(北京) | True triaxial sand fracturing testing machine and its test method |
| CN108397184A (en) * | 2018-05-18 | 2018-08-14 | 西南石油大学 | A kind of numerical computation method of self-supporting fracture condudtiviy |
| CN109653740A (en) * | 2018-12-26 | 2019-04-19 | 西南石油大学 | A kind of Carbonate Acid Fracturing self-supporting fracture permeabgility prediction technique |
| CN109869128A (en) * | 2019-03-22 | 2019-06-11 | 长江大学 | The device of flow conductivity is surveyed for measuring shale gas gas |
| CN111520135A (en) * | 2020-06-15 | 2020-08-11 | 西南石油大学 | Shale self-supporting fracture initial flow conductivity prediction method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN115032368A (en) | 2022-09-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Lacy et al. | Fracture width and embedment testing in soft reservoir sandstone | |
| CN108590601B (en) | Experimental method for optimizing water injection expansion construction parameters | |
| Smith | Stimulation design for short, precise hydraulic fractures | |
| CN107816342B (en) | Visualization experiment device and method for migration rule of proppant in crack | |
| CN104406910A (en) | Apparatus and method for testing cementation capability of well cementation first and second interfaces under high-temperature high-pressure conditions | |
| Karaoguz et al. | Improved sweep in Bati Raman heavy-oil CO2 flood: bullhead flowing gel treatments plug natural fractures | |
| CN115032368B (en) | Fracturing fracture self-supporting diversion capacity overall process evaluation method | |
| CN108828190B (en) | Fracture simulation method for fractured compact sandstone oil and gas reservoir | |
| CN112098223B (en) | Test system and method for evaluating damage degree of drilling fluid to natural fracture | |
| CN111353205A (en) | Method for calculating stratum pressure and dynamic capacity of water-producing gas well of tight gas reservoir | |
| Farid Ibrahim et al. | Evaluation of the breakdown pressure to initiate hydraulic fractures of tight sandstone and shale formations | |
| CN117052347B (en) | Plugging simulation experiment device and method | |
| CN105678082B (en) | Double-pressure drop method for identifying type of oil-gas well acid fracturing communication reservoir | |
| CN111859701A (en) | Method for evaluating plastic volume shrinkage and pore pressure drop of well cementation cement slurry | |
| US20120000662A1 (en) | Viscosity differential fracturing for enhanced application of amendments to ground and groundwater | |
| CN114810051B (en) | Method for measuring embedding depth of propping agent in shale fracture conductivity test in real time | |
| CN110644965A (en) | Reservoir transformation method | |
| CN114592840B (en) | Temporary plugging fracturing method and application thereof | |
| CN113295537B (en) | Test method for unconventional reservoir fracturing fracture seepage capability evaluation | |
| CN115392150A (en) | Weak cementation reservoir fracturing feasibility evaluation method | |
| CN105257288A (en) | Method for determining tight reservoir original reservoir pressure based on injection pressure decline well testing technology | |
| CN115110931A (en) | Characterization method for pressure flooding water injection permeability increasing degree of low-permeability reservoir | |
| Etten | Experimental investigation on the effect of permeability on the optimum acid flux in carbonate matrix acidizing | |
| CN114165205B (en) | Fracturing fluid inter-well string flux calculating method considering imbibition | |
| Zhuang | Interference Testing and Pulse Testing in the Kenli Carbonate Oil Pool--A Case History |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |