CA3120909A1 - Method of evaluating capability of drilling fluid to consolidate well wall and break surrounding rock - Google Patents
Method of evaluating capability of drilling fluid to consolidate well wall and break surrounding rock Download PDFInfo
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- 238000005553 drilling Methods 0.000 title claims abstract description 127
- 239000012530 fluid Substances 0.000 title claims abstract description 112
- 239000011435 rock Substances 0.000 title claims abstract description 32
- 238000000034 method Methods 0.000 title claims abstract description 20
- 230000015572 biosynthetic process Effects 0.000 claims description 18
- 238000012360 testing method Methods 0.000 claims description 11
- 238000005520 cutting process Methods 0.000 claims description 5
- 238000012669 compression test Methods 0.000 claims description 4
- 238000005304 joining Methods 0.000 claims description 2
- 238000003825 pressing Methods 0.000 claims description 2
- 238000011158 quantitative evaluation Methods 0.000 abstract description 2
- 238000007596 consolidation process Methods 0.000 description 8
- 238000011156 evaluation Methods 0.000 description 5
- 239000007789 gas Substances 0.000 description 4
- 238000013461 design Methods 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000005764 inhibitory process Effects 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000003345 natural gas Substances 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 238000010008 shearing Methods 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
- 230000009897 systematic effect Effects 0.000 description 1
Classifications
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B49/00—Testing the nature of borehole walls; Formation testing; Methods or apparatus for obtaining samples of soil or well fluids, specially adapted to earth drilling or wells
- E21B49/005—Testing the nature of borehole walls or the formation by using drilling mud or cutting data
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- Mining & Mineral Resources (AREA)
- Physics & Mathematics (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
- Earth Drilling (AREA)
Abstract
A method of evaluating the capability of a drilling fluid to consolidate a well wall and break surrounding rock. The method comprises: according to the shear strength of sample contact surfaces, the shear strength between the sample contact surfaces after a drilling fluid acts thereon, and a friction angle between the sample contact surfaces after the drilling fluid acts thereon, calculating an amplitude increase in shear strength caused by the drilling fluid and an amplitude increase in friction angle caused by the drilling fluid, and evaluating the capability of the drilling fluid to consolidate a well wall and break surrounding rock according to an increase in a cohesive force between the sample contact surfaces after the drilling fluid acts thereon and the amplitude increase in shear strength caused by the drilling fluid and the amplitude increase in friction angle caused by the drilling fluid. The method of evaluating the capability of a drilling fluid to consolidate a well wall and break surrounding rock achieves quantitative evaluation of the capability of a drilling fluid to improve the shear strength between broken blocks, and provides reliable mechanical parameters for the stability of well walls in fractured strata.
Description
METHOD OF EVALUATING CAPABILITY OF
DRILLING FLUID TO CONSOLIDATE WELL WALL
AND BREAK SURROUNDING ROCK
TECHNICAL FIELD
[0001] The invention relates to the technical field of oil and natural gas drilling, and more specifically, to a method for evaluating the ability of drilling fluid to consolidate fractured surrounding rock of wellbore.
BACKGROUND
DRILLING FLUID TO CONSOLIDATE WELL WALL
AND BREAK SURROUNDING ROCK
TECHNICAL FIELD
[0001] The invention relates to the technical field of oil and natural gas drilling, and more specifically, to a method for evaluating the ability of drilling fluid to consolidate fractured surrounding rock of wellbore.
BACKGROUND
[0002] With the increase of oil and gas exploration and development depth, oil and gas drilling often encounters broken strata. Broken strata falling, collapse, leakage and so on, have become major problems for deep oil and gas drilling. On the basis of improving the inhibition and plugging performance of drilling fluid, strengthening the consolidation ability of drilling fluid to the wall rock of broken wellbore is the most effective method to reduce the instability and collapse of fractured wellbore to the maximum extent. Hence, scientifically and reasonably evaluating the cementation and consolidation ability of drilling fluid to broken confining pressure is not only an important basis for optimizing drilling fluid properties, but also an important basis for safe drilling engineering design, especially for drilling fluid design. It is of great significance for the establishment of fast and safe drilling technology in complex fractured strata.
[0003] The cementing and consolidation ability of drilling fluid to borehole wall broken rock is closely related to formation lithology, namely, the same drilling fluid system has different cementation or consolidation capacity for formation lithology of different lithologies. The consolidation capacity is also affected by environmental Date Recue/Date Received 2021-05-25 temperature and pressure, that is, they have different consolidation capacity under the conditions of the same lithologic formation and the same drilling fluid system, but under the conditions of different formation temperature and pressure. In that long term, due to the influence factors of the drilling fluid on the cementing or consolidation ability of the fractured rock and the restriction of the difficulty of drilling and coring in the fractured formation, the evaluation of drilling fluid performance is mainly aimed at the intact formation and part of fractured formation, and the evaluation of drilling fluid stabilizing wellbore performance is also mainly focused on the inhibition performance, plugging performance, rheological performance and wall-making performance of drilling fluid. However, the evaluation of cementing or consolidating ability of drilling fluid is less, and no systematic indoor evaluation method has been found.
SUMMARY
SUMMARY
[0004] Aiming at the defects existing in the prior art, the method of evaluating the ability of drilling fluid to consolidate fractured surrounding rock of wellbore solves the problem that the performance evaluation result of drilling fluid stabilized wellbore is inaccurate.
[0005] In order to achieve that purpose of the invention, the technical scheme adopt by the invention is that a method for evaluating the ability of drilling fluid to consolidate fractured surrounding rock of wellbore is provided. The method includes:
[0006] Si, obtaining a fresh and complete down-hole drilling core with the same lithology as a fractured formation, drilling a cylindrical sample, and evenly dividing the cylindrical sample into two disk samples along a middle line;
[0007] S2, obtaining a standard plunger sample by drilling the drilling core, perform a uniaxial compression test on the standard plunger sample by using a rock mechanics test machine, and calculating the uniaxial compressive strength (UCS) of the rock;
[0008] S3, connecting the two disk samples along a cut plane, and performing a shear Date Recue/Date Received 2021-05-25 strength of the disk samples under the normal load along the contact surface, and calculating the shear strength of the contact surface of the disk samples; the maximum normal load shall not be higher than one in twenty of the uniaxial compressive strength (UCS);
[0009] S4, joining and fixing the two disk samples along the cutting plane, placing in a pressure-resistant airtight container filled with drilling fluid, and applying pressure and temperature to the airtight container for a period of time;
[0010] S5, taking out the two disk samples from the airtight container and placing in a straight shear box, testing the shear strength under normal load along the contact surface; measuring the shear strength between the contact surface of the disk sample after the action of drilling fluid;
[0011] S6: calculating the friction angle between the disk sample contact surfaces after the action of drilling fluid and the cohesive force increment between the disk samples contact surfaces after the action of drilling fluid according to the shear resistance strength between the disk sample contact surfaces after the action of drilling fluid;
[0012] S7, calculating an increased amplitude of shear strength and the increased amplitude of friction angle of drilling fluid through the shear strength of the contact surface of the disk sample, the shear strength between the contact surfaces of the disk samples after the action of drilling fluid and the friction angle between the contact surfaces of the disk samples after the action of drilling fluid; and evaluating the ability of drilling fluid to consolidate fractured surrounding rock of well according to the increment of cohesive force between the contact surfaces of the disk samples, the increased shear strength and the increased amplitude of drilling fluid to friction angle.
[0013] Further, in the step Si, the cylindrical sample in step Si has a diameter of 50 mm and a length of 50 mm.
[0014] Further, the standard plunger sample in step S2 has a diameter of 25 mm and Date Recue/Date Received 2021-05-25 a length of 50 mm.
[0015] Further, the normal loads in the steps S3 and S5 each include 0 MPa, and a nMax; and the a nMax is the maximum normal load.
[0016] Further, the formula for calculating the shear strength of the contact surface of the disk samples in Step S3 is as follows: T fs = n tan cl) fs;rfsis the shear strength of the disk specimen contact surface, an is the applied normal stress, and (pfs is the friction angle of the disk specimen contact surface.
[0017] Further, the applied pressure in step S4 is equal to the formation pressure or the drilling fluid pressure; and the magnitude of the applied temperature is the actual temperature of the formation.
[0018] Further, in step S6, the formula for calculating the friction angle between the contact surfaces of disk samples after the action of drilling fluid is: T df =
a n tan cl) df Cdf; T df is the shear resistance strength between the contact surface of the disk sample after the action of the drill fluid, a n is the applied normal stress, cl) df is the friction angle between the contact surfaces of the disk samples after the action of the drilling fluid, Cdf is the cohesion increment between the contact surfaces of the disk sample after the action of drilling fluid.
a n tan cl) df Cdf; T df is the shear resistance strength between the contact surface of the disk sample after the action of the drill fluid, a n is the applied normal stress, cl) df is the friction angle between the contact surfaces of the disk samples after the action of the drilling fluid, Cdf is the cohesion increment between the contact surfaces of the disk sample after the action of drilling fluid.
[0019] Further, in the step S7, the formula for calculating the increase amplitude of the drilling fluid to the shear strength and the increase amplitude of the drilling fluid to the friction angle is:
T ¨T
= df fs X 100%
T fs df _________________________________ fs C = X 100%
(I) CI) fs Date Recue/Date Received 2021-05-25 C is an increased amplitude of drilling fluid to shear strength, T dfis anti-shear strength between contact surfaces of disk samples after drilling fluid action, T fsis anti-shear strength of contact surface of disk samples, C 4, is increased amplitude of drilling fluid to friction angle, cl) df is the friction angle between the contact surfaces of the disk samples after the action of drilling fluid and cl) fs is the friction angle of the contact surface of the disk samples.
T ¨T
= df fs X 100%
T fs df _________________________________ fs C = X 100%
(I) CI) fs Date Recue/Date Received 2021-05-25 C is an increased amplitude of drilling fluid to shear strength, T dfis anti-shear strength between contact surfaces of disk samples after drilling fluid action, T fsis anti-shear strength of contact surface of disk samples, C 4, is increased amplitude of drilling fluid to friction angle, cl) df is the friction angle between the contact surfaces of the disk samples after the action of drilling fluid and cl) fs is the friction angle of the contact surface of the disk samples.
[0020] The beneficial effects of the present invention are as follows: the method for evaluating the ability of drilling fluid to consolidate the wall rock to be crushed provided by the present invention realizes quantitative evaluation of the shear strength between broken blocks improved by drilling fluid, It provides reliable mechanical parameters for wellbore stability of fractured formation. In addition, that invention also provide scientific and effective experimental methods for optimize drilling fluid performance and drilling fluid optimization, and provides strong support for the establishment of wellbore stabilization system technology of fractured formation. It is of great significance to the safe and efficient drilling of deep oil and gas.
BRIEF DESCRIPTION OF DRAWINGS
BRIEF DESCRIPTION OF DRAWINGS
[0021] FIG. 1 is a flow chart of the present disclosure;
[0022] FIG. 2 is a graph of a uniaxial compression test result of a rock sample according to an embodiment of the present disclosure;
[0023] FIG. 3 is a schematic diagram of shear strength test results under different normal loads according to an embodiment of the present disclosure;
[0024] FIG. 4 is a schematic diagram of the shear strength test results under different normal loads after the drilling fluid is applied in an embodiment of the present disclosure.
Date Recue/Date Received 2021-05-25 DETAILED DESCRIPTION OF THE EMBODIMENTS
Date Recue/Date Received 2021-05-25 DETAILED DESCRIPTION OF THE EMBODIMENTS
[0025] Hereinafter, specific embodiments of the present disclosure will be described in order to facilitate understanding of the present disclosure by those skilled in the art, but it should be clear that the present disclosure is not limited to the scope of the specific embodiments. It will be apparent to those skilled in the art that various modifications without departing from the spirit and defined by the appended claims are within the protection scope. All inventions and creations adopting the concepts of the present invention are covered by the present disclosure.
[0026] As shown in FIG. 1, a method for evaluating the ability of drilling fluid to consolidate fractured surrounding rock of wellbore includes the following steps.
[0027] Si. obtaining a fresh and complete down-hole drilling core with the same lithology as a fractured formation, drilling a cylindrical sample, the diameter of which is 50mm and the length of which is 50mm. The cylindrical sample is evenly divided into two disk samples with a diameter of 50mm and a length of 20-25mm along the central line, and the two disk cutting planes are marked as A and B
respectively, and the length and diameter of the disk samples are tested. The apparent structure is observed, and the development characteristics of structural planes such as bedding and cracks are described.
respectively, and the length and diameter of the disk samples are tested. The apparent structure is observed, and the development characteristics of structural planes such as bedding and cracks are described.
[0028] S2, taking a standard plunger sample by drilling the core, the diameter of the standard plunger sample is 25mm, the length of the standard plunger sample is 50mm, and the rock mechanics test machine is used to perform the uniaxial compression test on the standard plunger sample. The uniaxial compressive strength (UCS) of the rock is calculated, and as shown in FIG. 2, the uniaxial compressive strength (UCS) of the rock is 62.7MPa.
[0029] In step S3, the two disc specimens are connected along the cutting plane, and the shearing strength is tested under the action of the normal load along the contact Date Recue/Date Received 2021-05-25 a plane. The normal load include 0 MPa, -nMax and a , wherein a is the 2 nMax nMax maximum normal load. The shear strength of the contact surface of the disk sample is calculated.
[0030] The formula for calculating the shear strength of the contact surface of the disc specimen is:
[0031] rfs = an tan (pfs
[0032] Where T is the shear strength of the disk specimen contact surface, a is fs the applied normal stress, p is the friction angle of the disk specimen contact surface.
fs
fs
[0033] According to the principle that the maximum normal load is not higher than one twenty of the uniaxial compressive strength (UCS), and the normal stress applied in the initial shear strength test is set as 0.1MPa, 0.20MPa and 0.40MPa respectively.
As shown in FIG. 3, the test results show that the shear strength is 0.0840 MPa, 0.1253 MPa and 0.2810 MPa in the order. According to the test results, the internal friction angle (shear strength) can be calculated as 34.5 .
As shown in FIG. 3, the test results show that the shear strength is 0.0840 MPa, 0.1253 MPa and 0.2810 MPa in the order. According to the test results, the internal friction angle (shear strength) can be calculated as 34.5 .
[0034] S4. the two disk samples are bonded and fixed along the cutting plane, and placed in a pressure-resistant airtight container filled with drilling fluid.
In addition, pressure and temperature are applied to the airtight container for a period of time. The applied pressure is equal to the formation pressure or the drilling fluid pressure, and the temperature is the actual formation temperature. The temperature and pressure is kept constant, and allow the drilling fluid to react with the disk sample for 1 hour.
In addition, pressure and temperature are applied to the airtight container for a period of time. The applied pressure is equal to the formation pressure or the drilling fluid pressure, and the temperature is the actual formation temperature. The temperature and pressure is kept constant, and allow the drilling fluid to react with the disk sample for 1 hour.
[0035] S5, The two disc specimens are taken out from the airtight container, and are placed in a straight shear box. A shear strength test is performed under the normal load of 0.10 MPa, 0.20 MPa and 0.40 MPa along the contact surface. The shear strength between the contact surfaces of the disk samples after the drilling fluid is measured to be 0.1280MPa, 0.1693MPa and 0.3676MPa. The shear strength under the action of each Date Recue/Date Received 2021-05-25 normal stress is shown in FIG. 4.
[0036] S6: the friction angle between the disk sample contact surfaces after the action of drilling fluid and the cohesive force increment between the disk sample contact surfaces after the action of drilling fluid are calculated according to the shear resistance strength between the disk sample contact surfaces after the action of drilling fluid.
[0037] The formula for calculating the friction angle between the contact surfaces of the disk sample after the action of drilling fluid is:
[0038] Tdf = an tan (pdf Cdf
[0039] In the above formula, T df is the shear resistance strength between the contact surface of the disk samples after the action of the drilling fluid, Gis the applied normal stress, is the friction angle between the contact surfaces of the disk sample after df the action of the drilling fluid, Cdfis the cohesion increment between the contact surface of the disk samples after the action of drilling fluid.
[0040] The friction angle between the contact surface of the disk samples is 39.57 , and the cohesion increment between the contact surface of the disk samples is 0.0283MPa after the action of drilling fluid.
[0041] S7, an increased amplitude of shear strength and the increased amplitude of friction angle of drilling fluid are calculated through the shear strength of the contact surface of the disk sample, the shear strength between the contact surfaces of the disk samples after the action of drilling fluid and the friction angle between the contact surfaces of the disk samples after the action of drilling fluid. The ability of drilling fluid to consolidate fractured surrounding rock of well is evaluated according to the increment of cohesive force between the contact surfaces of the disk samples, the increased shear strength and the increased amplitude of drilling fluid to friction angle.
[0042] The formula for calculating the increase of shear strength of drilling fluid and Date Recue/Date Received 2021-05-25 the increase of friction angle of drilling fluid is as follows:
T [0043] C = Tfs 100%
Tfs [0044] C =(Pflf (Pfs X 100%
(Pfs [0045] In that above formula, Cis the increased amplitude of shear strength of drilling fluid to drilling fluid, Tdf is anti-shear strength between contact surfaces of disk sample after drilling fluid action, Tfsis anti-shear strength of contact surface of disk sample,c is the increased amplitude of drilling fluid to friction angle, cod f is the friction angle between the contact surface of the disk samples after the action of drilling fluid and (pfs is the friction angle of the contact surface of the disk samples.
[0046] The increased amplitude of shear strength is 52.3%, 36.2% and 31.2%
under normal stress of 0.10 MPa, 0.20 MPa and 0.40 MPa respectively, and the increased amplitude of drilling fluid to friction angle is 14.2% under cementing or consolidation of drilling fluid.
Date Recue/Date Received 2021-05-25
T [0043] C = Tfs 100%
Tfs [0044] C =(Pflf (Pfs X 100%
(Pfs [0045] In that above formula, Cis the increased amplitude of shear strength of drilling fluid to drilling fluid, Tdf is anti-shear strength between contact surfaces of disk sample after drilling fluid action, Tfsis anti-shear strength of contact surface of disk sample,c is the increased amplitude of drilling fluid to friction angle, cod f is the friction angle between the contact surface of the disk samples after the action of drilling fluid and (pfs is the friction angle of the contact surface of the disk samples.
[0046] The increased amplitude of shear strength is 52.3%, 36.2% and 31.2%
under normal stress of 0.10 MPa, 0.20 MPa and 0.40 MPa respectively, and the increased amplitude of drilling fluid to friction angle is 14.2% under cementing or consolidation of drilling fluid.
Date Recue/Date Received 2021-05-25
Claims (8)
1. A method for evaluating the ability of drilling fluid to consolidate fractured surrounding rock of wellbore, comprising:
S 1, obtaining a fresh and complete down-hole drilling core with the same lithology as a fractured formation, drilling a cylindrical sample, and evenly dividing the cylindrical sample into two disk samples along a middle line;
S2, obtaining a standard plunger sample by drilling the drilling core, perform a uniaxial compression test on the standard plunger sample by using a rock mechanics test machine, and calculating the uniaxial compressive strength (UCS) of the rock;
S3, connecting the two disk samples along a cut plane, and performing a shear strength of the disk samples under the normal load along the contact surface, and calculating the shear strength of the contact surface of the disk samples; the maximum normal load shall not be higher than one in twenty of the uniaxial compressive strength (UCS);
S4, joining and fixing the two disk samples along the cutting plane, placing in a pressure-resistant airtight container filled with drilling fluid, and applying pressure and temperature to the airtight container for a period of time;
S5, taking out the two disk samples from the airtight container and placing in a straight shear box, testing the shear strength under normal load along the contact surface;
measuring the shear strength between the contact surface of the disk sample after the action of drilling fluid;
S6: calculating the friction angle between the disk sample contact surfaces after the action of drilling fluid and the cohesive force increment between the disk samples contact surfaces after the action of drilling fluid according to the shear resistance strength between the disk sample contact surfaces after the action of drilling fluid;
S7, calculating an increased amplitude of shear strength and the increased Date Recue/Date Received 2021-05-25 amplitude of friction angle of drilling fluid through the shear strength of the contact surface of the disk sample, the shear strength between the contact surfaces of the disk samples after the action of drilling fluid and the friction angle between the contact surfaces of the disk samples after the action of drilling fluid; and evaluating the ability of drilling fluid to consolidate fractured surrounding rock of well according to the increment of cohesive force between the contact surfaces of the disk samples, the increased shear strength and the increased amplitude of drilling fluid to friction angle.
S 1, obtaining a fresh and complete down-hole drilling core with the same lithology as a fractured formation, drilling a cylindrical sample, and evenly dividing the cylindrical sample into two disk samples along a middle line;
S2, obtaining a standard plunger sample by drilling the drilling core, perform a uniaxial compression test on the standard plunger sample by using a rock mechanics test machine, and calculating the uniaxial compressive strength (UCS) of the rock;
S3, connecting the two disk samples along a cut plane, and performing a shear strength of the disk samples under the normal load along the contact surface, and calculating the shear strength of the contact surface of the disk samples; the maximum normal load shall not be higher than one in twenty of the uniaxial compressive strength (UCS);
S4, joining and fixing the two disk samples along the cutting plane, placing in a pressure-resistant airtight container filled with drilling fluid, and applying pressure and temperature to the airtight container for a period of time;
S5, taking out the two disk samples from the airtight container and placing in a straight shear box, testing the shear strength under normal load along the contact surface;
measuring the shear strength between the contact surface of the disk sample after the action of drilling fluid;
S6: calculating the friction angle between the disk sample contact surfaces after the action of drilling fluid and the cohesive force increment between the disk samples contact surfaces after the action of drilling fluid according to the shear resistance strength between the disk sample contact surfaces after the action of drilling fluid;
S7, calculating an increased amplitude of shear strength and the increased Date Recue/Date Received 2021-05-25 amplitude of friction angle of drilling fluid through the shear strength of the contact surface of the disk sample, the shear strength between the contact surfaces of the disk samples after the action of drilling fluid and the friction angle between the contact surfaces of the disk samples after the action of drilling fluid; and evaluating the ability of drilling fluid to consolidate fractured surrounding rock of well according to the increment of cohesive force between the contact surfaces of the disk samples, the increased shear strength and the increased amplitude of drilling fluid to friction angle.
2. The method for evaluating the ability of drilling fluid to consolidate fractured surrounding rock of wellbore of claim 1, wherein the cylindrical sample in step S1 has a diameter of 50 mm and a length of 50 mm.
3. The method for evaluating the ability of drilling fluid to consolidate fractured surrounding rock of wellbore of claim 1, wherein the standard plunger sample in step S2 has a diameter of 25 mm and a length of 50 mm.
4. The method for evaluating the ability of drilling fluid to consolidate fractured surrounding rock of wellbore of claim 1, wherein the normal loads in the steps S3 and S5 each include 0 MPa, 21v1" and a nmax; and the a nmax is the maximum normal load.
5. The method for evaluating the ability of drilling fluid to consolidate fractured surrounding rock of wellbore of claim 1, wherein the formula for calculating the shear strength of the contact surface of the disk samples in Step S3 is as follows:
T fs = 0' n tan cp =
fs, Date Recue/Date Received 2021-05-25 Tfsis the shear strength of the disk specimen contact surface, an is the applied normal stress, and (pfs is the friction angle of the disk specimen contact surface.
6. The method for evaluating the ability of drilling fluid to consolidate fractured surrounding rock of wellbore of claim 1, wherein the applied pressure in step S4 is equal to the formation pressure or the drilling fluid pressure; and the magnitude of the applied temperature is the actual temperature of the formation.
T fs = 0' n tan cp =
fs, Date Recue/Date Received 2021-05-25 Tfsis the shear strength of the disk specimen contact surface, an is the applied normal stress, and (pfs is the friction angle of the disk specimen contact surface.
6. The method for evaluating the ability of drilling fluid to consolidate fractured surrounding rock of wellbore of claim 1, wherein the applied pressure in step S4 is equal to the formation pressure or the drilling fluid pressure; and the magnitude of the applied temperature is the actual temperature of the formation.
6. The method for evaluating the ability of drilling fluid to consolidate fractured surrounding rock of wellbore of claim 1, wherein in step S6, the formula for calculating the friction angle between the contact surfaces of disk samples after the action of drilling fluid iS:
T df = 0' n tan cp df Cdf;
df is the shear resistance strength between the contact surface of the disk sample after the action of the drill fluid' a n is the applied normal stress' cl) df is the friction angle between the contact surfaces of the disk samples after the action of the drilling fluid, Cdf is the cohesion increment between the contact surfaces of the disk sample after the action of drilling fluid.
df is the shear resistance strength between the contact surface of the disk sample after the action of the drill fluid' a n is the applied normal stress' cl) df is the friction angle between the contact surfaces of the disk samples after the action of the drilling fluid, Cdf is the cohesion increment between the contact surfaces of the disk sample after the action of drilling fluid.
8. The method for evaluating the ability of drilling fluid to consolidate fractured surrounding rock of wellbore of claim 1, wherein in the step S7, the formula for calculating the increase amplitude of the drilling fluid to the shear strength and the increase amplitude of the drilling fluid to the friction angle iS:
Date Recue/Date Received 2021-05-25 T T
C T = df fs X 100%
T fs df fs C = X 100%
fs C T is an increased amplitude of drilling fluid to shear strength, T dfis anti-shear strength between contact surfaces of disk samples after drilling fluid action, T fsis anti-shear strength of contact surface of disk samples, C 4, is increased amplitude of drilling fluid to friction angle, cl) df is the friction angle between the contact surfaces of the disk samples after the action of drilling fluid and cl) fs is the friction angle of the contact surface of the disk samples.
Date Recue/Date Received 2021-05-25
Date Recue/Date Received 2021-05-25 T T
C T = df fs X 100%
T fs df fs C = X 100%
fs C T is an increased amplitude of drilling fluid to shear strength, T dfis anti-shear strength between contact surfaces of disk samples after drilling fluid action, T fsis anti-shear strength of contact surface of disk samples, C 4, is increased amplitude of drilling fluid to friction angle, cl) df is the friction angle between the contact surfaces of the disk samples after the action of drilling fluid and cl) fs is the friction angle of the contact surface of the disk samples.
Date Recue/Date Received 2021-05-25
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911026896.X | 2019-10-26 | ||
| CN201911026896.XA CN110761779B (en) | 2019-10-26 | 2019-10-26 | Method for evaluating surrounding rock crushing capability of drilling fluid consolidation well wall |
| PCT/CN2020/114848 WO2021077938A1 (en) | 2019-10-26 | 2020-09-11 | Method of evaluating capability of drilling fluid to consolidate well wall and break surrounding rock |
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| Publication Number | Publication Date |
|---|---|
| CA3120909A1 true CA3120909A1 (en) | 2021-04-29 |
| CA3120909C CA3120909C (en) | 2023-09-19 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA3120909A Active CA3120909C (en) | 2019-10-26 | 2020-09-11 | Method of evaluating capability of drilling fluid to consolidate well wall and break surrounding rock |
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| Country | Link |
|---|---|
| CN (1) | CN110761779B (en) |
| CA (1) | CA3120909C (en) |
| WO (1) | WO2021077938A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115653567A (en) * | 2022-08-16 | 2023-01-31 | 吉林大学 | Experimental device and method for evaluating well wall stability effect |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110761779B (en) * | 2019-10-26 | 2021-03-23 | 西南石油大学 | Method for evaluating surrounding rock crushing capability of drilling fluid consolidation well wall |
| CN113255174B (en) * | 2021-07-15 | 2021-09-17 | 西南石油大学 | Drilling tooth mechanics calculation method considering rock dynamic strength and mixed crushing mode |
| US11733136B2 (en) | 2021-12-10 | 2023-08-22 | Saudi Arabian Oil Company | Fluid sensitivity evaluation method for superior water-based mud design |
| CN114839024B (en) * | 2022-07-04 | 2022-09-20 | 中国矿业大学(北京) | Method for testing and evaluating characteristics of fractured rock mass while drilling |
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| US9835746B2 (en) * | 2013-08-24 | 2017-12-05 | Schlumberger Technology Corporation | Formation stability modeling |
| CN108254262B (en) * | 2016-12-28 | 2021-03-30 | 中国石油天然气股份有限公司 | Rock bedding crack shearing parameter prediction method and device |
| CN107014746A (en) * | 2017-03-30 | 2017-08-04 | 西南石油大学 | A kind of evaluation method of broken formation drilling fluid Reinforcing Shaft ability |
| WO2018185095A1 (en) * | 2017-04-03 | 2018-10-11 | Repsol, S.A. | Method of estimating the region of damage due to collapse in the wall of a borehole during the drilling operation |
| CN109653736A (en) * | 2017-10-11 | 2019-04-19 | 中国石油化工股份有限公司 | A kind of experimental provision and method for appraisal drilling liquid caving-preventing characteristic |
| CN108387685B (en) * | 2018-01-09 | 2019-03-29 | 中国石油大学(华东) | The method and apparatus of the weak consolidated formation drilling fluid stabilizing borehole evaluation of effect of deep water superficial part |
| CN109187228A (en) * | 2018-09-30 | 2019-01-11 | 西南石油大学 | A kind of indoor evaluation method of shale formation drilling fluid stabilizing borehole ability |
| CN110761779B (en) * | 2019-10-26 | 2021-03-23 | 西南石油大学 | Method for evaluating surrounding rock crushing capability of drilling fluid consolidation well wall |
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| CN115653567A (en) * | 2022-08-16 | 2023-01-31 | 吉林大学 | Experimental device and method for evaluating well wall stability effect |
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