CN114635654A - Method, system, device and computer readable storage medium for determining well cleanliness - Google Patents
Method, system, device and computer readable storage medium for determining well cleanliness Download PDFInfo
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- CN114635654A CN114635654A CN202111583469.9A CN202111583469A CN114635654A CN 114635654 A CN114635654 A CN 114635654A CN 202111583469 A CN202111583469 A CN 202111583469A CN 114635654 A CN114635654 A CN 114635654A
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B21/00—Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B37/00—Methods or apparatus for cleaning boreholes or wells
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B47/00—Survey of boreholes or wells
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/20—Design optimisation, verification or simulation
- G06F30/27—Design optimisation, verification or simulation using machine learning, e.g. artificial intelligence, neural networks, support vector machines [SVM] or training a model
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06Q—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES; SYSTEMS OR METHODS SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES, NOT OTHERWISE PROVIDED FOR
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Abstract
The invention provides a method, a system, equipment and a computer readable storage medium for determining the cleanliness of a well hole, wherein the determining method comprises the following steps: during drilling, dividing drill cuttings transfer into a first cleaning area, a second cleaning area and a third cleaning area according to a well inclination angle; determining wellbore cleanliness by calculating a drill cuttings particle transfer ratio for the first clean zone; for the second clean area, determining the cleanliness of the well hole by calculating the diameter ratio of the thickness of the debris bed in the well hole and the annulus stopping return speed; for the third clean zone, the borehole cleanliness is determined by calculating the ratio of the cuttings bed thickness to the borehole diameter. The analysis system comprises a data storage module, a screening module, a data acquisition module, a well cleanliness calculation module and a well cleanliness determination module. The invention can utilize real-time data and dynamic data of a drilling site to quickly and accurately calculate and analyze related parameters of drilling engineering in real time, and can master the cleaning condition of a well in real time.
Description
Technical Field
The present invention relates to the technical field of oil and gas drilling and production engineering, and in particular, to a method for determining the cleanliness of a borehole, a system for analyzing the cleanliness of a borehole, an apparatus for analyzing the cleanliness of a borehole, and a computer-readable storage medium storing a computer program.
Background
With the increasing demand of modern society for petroleum, petroleum exploration and development present globalization characteristics. The drilling construction area is spread all over the world and is widely distributed under the complex surface and complex underground geological conditions of oceans, deserts, marshes, hills, mountainous areas and the like, the complexity of the drilling construction and the uncertainty of the drilling construction process are increased, and higher requirements are provided for the drilling engineering design and the risk analysis and control technology. Drilling engineering data analysis, drilling risk analysis and control, drilling scheme real-time optimization and the like of complex wells all need drilling engineering software to provide technical support. The drilling engineering software plays an increasingly important role in improving the drilling benefit, enhancing the drilling operation safety and the like.
For example, most of southwest areas of China are unconventional oil and gas fields such as shale gas and dense gas, and cluster well horizontal wells are adopted for realizing benefit development; and other areas are generally conventional oil and gas fields, and highly deviated wells and horizontal wells are generally adopted for realizing efficient development. In the drilling process, the problem of well cleaning is one of key influence factors of drilling of a highly deviated well and a horizontal well, and particularly for the highly deviated well and the horizontal well, the uncleanness of the well conditions can not only cause the occurrence of complex conditions such as slow diamond, resistance to tripping, resistance to electrical measurement and the like, but also can cause the occurrence of drill sticking when being more serious, thereby seriously influencing the economic benefit.
In field construction, the well cleaning condition of each well is generally calculated manually, so that a large amount of time cost and labor cost are consumed, the well cleaning condition cannot be obtained quickly, and the accuracy of well cleaning calculation cannot be ensured. In addition, the existing well hole calculation model is only suitable for calculating the well hole cleaning condition of a conventional oil and gas field, and for an unconventional oil and gas field with a special topography, the calculation error is large, the guidance error is easily caused to the drilling production, and the emergencies such as tripping, jamming and the like are caused.
For example, a patent document a entitled method for determining a borehole cleaning effect in a profiled borehole, which is disclosed in 2019, 5, 28, and publication No. CN 109812236, describes a method for determining a borehole cleaning effect in a profiled borehole, which includes first establishing a geometric model of the profiled borehole based on drilling basic parameters, then obtaining a rock debris concentration distribution at each position of the borehole in a stable state through numerical calculation, and finally determining a borehole cleaning effect through the rock debris concentration distribution. The method can accurately calculate the flow state of the drilling fluid and the concentration distribution of rock debris in the special-shaped well hole.
A patent document entitled method, apparatus and computer storage medium for analyzing cleanliness of a well bore disclosed at 22.10.2021, and publication No. CN 113530525 a describes a method for analyzing cleanliness of a well bore, including: after the borehole to be monitored is determined, historical drilling data of the borehole to be monitored is obtained, and a corresponding hook-carried well deep modeling diagram is constructed according to a preset comprehensive friction coefficient scale and the historical drilling data of the borehole to be monitored. And marking actual measurement parameter points corresponding to the target measurement sites on the hook-carried well deep modeling diagram according to torque friction data actually measured at the target measurement sites in the borehole to be monitored. And determining the actual friction coefficient corresponding to each actual measurement parameter point according to the standard friction coefficient curve. And determining the cleanliness of the well to be monitored according to the actual friction coefficient of the current measurement site and the previous measurement site. According to the method, a model of key parameters is established, and the cleanliness of the well is determined by comparing field actual drilling data with model data.
At present, no borehole cleaning calculation model aiming at unconventional oil and gas fields exists in China, and no system software related to borehole cleaning analysis calculation is developed.
Disclosure of Invention
The present invention aims to address at least one of the above-mentioned deficiencies of the prior art. For example, one of the objectives of the present invention is to provide a method and an analysis system for determining the cleanliness of a borehole, so as to grasp the cleanliness of the borehole in real time, and according to the actual situation, through analysis and calculation, the performance index and drilling parameters of the drilling fluid can be optimized, and the production of the borehole can be guided in real time.
In order to achieve the above object, an aspect of the present invention provides a method of determining cleanliness of a well bore, the method comprising: in the drilling process, the drill cuttings are transferred and divided into a first cleaning area, a second cleaning area and a third cleaning area according to the well inclination angle, wherein the first cleaning area comprises a small-inclination well section with the well inclination angle of 0-30 degrees, the second cleaning area comprises a medium-inclination well section with the well inclination angle of 30-60 degrees, and the third cleaning area comprises a large-inclination well section with the well inclination angle of 60-90 degrees;
determining wellbore cleanliness by calculating a drill cuttings particle transfer ratio for the first cleaning zone; for the second clean zone, determining the cleanliness of the well hole by calculating the ratio of the thickness of the debris bed to the diameter of the well hole and the annulus stopping and returning speed; for the third clean zone, determining the cleanliness of the borehole by calculating the ratio of the thickness of the cutting bed to the diameter of the borehole.
In one exemplary embodiment of the method for determining the cleanliness of a borehole of the present invention, the method for determining the cleanliness of a borehole may specifically include the steps of:
aiming at the first clean area, calculating a drilling cutting particle transmission ratio Rt by adopting a small-inclination well section well cleaning calculation model, if Rt is more than or equal to 0.5, determining that the cleanliness of the first clean area meets the cleaning effect, and if Rt is less than 0.5, determining that the cleanliness of the first clean area does not meet the cleaning effect;
the small-inclination well section well cleaning calculation model is shown in formulas (1) to (3):
in the formulae (1) to (3), VsxThe settling velocity of drill cutting particles, m/s; dsIs the equivalent diameter of drill cutting particles, cm; rhosIs the density of drill cutting particles in g/cm3；ρmIs the density of the drilling fluid in g/cm3；
The shape coefficient of the drill cutting particles is dimensionless; vaThe drilling fluid is the annular return speed of the drilling fluid in m/s; qaIs the drilling fluid flow rate, L/s; dhIs the borehole diameter, mm; dpThe diameter is the outer diameter of the drill rod; rt is the transmission ratio of drill cutting particles and is dimensionless;
for the second clean zone, a midslope interval wellbore clean calculation model may be used to calculate a midslope interval rockRelative thickness H of scrap bedzxAnnular stop return velocity VpIf H iszxLess than or equal to 10 percent and Vp≥VaDetermining that the cleanliness of the second cleaning area meets the cleaning effect, and if H is higher than Hzx>10% or Vp<VaDetermining that the cleanliness of the second cleaning area does not meet the cleaning effect;
the well cleaning calculation model of the well section with the moderate inclination is shown in formulas (4) to (7):
hzx＝0.015Dh(AV+6.15AV0.5)(1+0.587E)(Vlzx-Va) Formula (5)
Hzx＝(hzx/Dh) X 100% formula (6)
In formulae (4) to (7), VlzxThe critical annular return velocity of the well section with the medium inclination is m/s; AV is the apparent viscosity of the drilling fluid, mpa.s; theta is a well inclination angle and degree; h iszxThe thickness of the detritus bed of the well section with the medium inclination is mm; hzxThe relative thickness of the detritus bed of the well section with the medium inclination is dimensionless; vpStopping the annular space to return the speed, m/s; a. thebedCross-sectional area of the cutting bed, mm, perpendicular to the axial direction of the borehole2(ii) a C is the concentration of rock debris in the rock debris bed and is dimensionless; g is gravity acceleration, m/s2(ii) a E is the eccentricity of the drill column and is dimensionless; l is the cross-sectional width of the detritus bed perpendicular to the axial direction of the well hole, and is mm; eta is the friction coefficient of the detritus bed and the lower well wall, and is generally 0.2; PV is plastic viscosity, mPa.s; YP is dynamic shear force, Pa; k is the consistency coefficient, Pa · sn(ii) a n is a fluidity index and is dimensionless;
aiming at the third cleaning area, the relative thickness H of the detritus bed of the highly-deviated well section can be calculated by adopting a highly-deviated well section well hole cleaning calculation modeldxIf H isdxLess than or equal to 10%, determining the third clearThe cleanliness of the clean area satisfies the cleaning effect if Hdx>Determining that the cleanliness of the third cleaning area does not meet the cleaning effect when the cleaning degree is 10%;
the high-inclination well section well cleaning calculation model is shown in formulas (18) to (23):
Hdx＝(hdx/Dh) X 100% of formula (23)
In formulae (18) to (23), VLdxThe critical annular return velocity is m/s at the highly deviated well section; vsdThe settling velocity of the drill cuttings at the highly-deviated well section is m/s; vjxThe mechanical drilling speed is m/h; cangThe correction coefficient of the well inclination angle is dimensionless; csizeThe drilling cutting size correction coefficient is dimensionless; cdenFThe drilling fluid density correction coefficient is dimensionless; crpmThe correction coefficient of the rotating speed of the drill column is dimensionless; qLdxThe displacement is L/s of the critical annular space of the debris-free bed; a'bedIs the area of the detritus bed, mm2；hdxThe thickness of the detritus bed of the highly-deviated well section is mm; qaThe discharge capacity of the drilling fluid is L/s; hdxThe relative thickness of the detritus bed of the highly-deviated well section is dimensionless.
In an exemplary embodiment of the method of determining borehole cleanliness of the present invention, the drill cuttings particle equivalent diameter dsCan be 0.5-3.0 cm; the drill cuttings particle form factor
Can be 0.5 to 1.0.
In an exemplary embodiment of the method of determining borehole cleanliness of the present invention, the borehole diameter DhThe borehole diameter can be obtained through borehole diameter logging, and for a well section which is not subjected to borehole diameter logging, the borehole diameter can be calculated according to the diameter of the drill bit and an expansion coefficient of 5% -10%.
In an exemplary embodiment of the method for determining the cleanliness of a borehole of the present invention, a cross-sectional width L of the cutting bed perpendicular to the axial direction of the borehole may be calculated by equation (8), and a cross-sectional area a of the cutting bed perpendicular to the axial direction of the borehole may be calculated by equation (9)bedThe formulas (8) and (9) are as follows:
in the formula, L is the cross-sectional width of the detritus bed perpendicular to the axial direction of the well hole, and is mm; dhIs the borehole diameter, mm; h iszxThe thickness of the detritus bed of the well section with the medium inclination is mm; a. thebedCross-sectional area of the cutting bed, mm, perpendicular to the axial direction of the borehole2。
In an exemplary embodiment of the method for determining the cleanliness of a borehole of the present invention, the apparent drilling fluid viscosity AV may be calculated by equation (10), the plastic viscosity PV may be calculated by equation (11), and the dynamic shear force YP may be calculated by equation (12), equations (10) to (12) are as follows:
wherein AV is the apparent viscosity of the drilling fluid, mpa.s;
reading for a rotational viscometer of 600 revolutions;
reading for a rotational viscometer of 300 revolutions; PV is plastic viscosity, mPa.s; YP is dynamic shear force, Pa.
In one exemplary embodiment of the method for determining the degree of cleanliness of a well bore of the present invention, the consistency coefficient K may be calculated by equation (13), and the fluidity index n may be calculated by equation (14), and equations (13) to (14) are as follows:
in the formula, K is a consistency coefficient, Pa.sn; n is a fluidity index;
reading for a rotational viscometer of 600 revolutions;
read for a rotational viscometer of 300 revolutions.
In an exemplary embodiment of the method of determining borehole cleanliness of the present invention, the skew angle correction can be calculated by equation (24)Coefficient CangThe drill cutting size correction coefficient C can be calculated by equation (25)sizeThe drilling fluid density correction coefficient C can be calculated by the formula (26)denFThe drill string rotation speed correction coefficient C can be calculated by the formula (27)rpmThe expressions (24) to (27) are as follows:
Cang＝0.0342θ-0.000233θ2-0.213 formula (24)
Csize＝1.286-0.04094448dsFormula (25)
In the formula, CangThe correction coefficient of the well inclination angle is dimensionless; csizeThe drilling cutting size correction coefficient is dimensionless; cdenFThe drilling fluid density correction coefficient is dimensionless; crpmThe correction coefficient of the rotating speed of the drill column is dimensionless; theta is a well inclination angle and degree; dsIs the equivalent diameter of drill cutting particles, cm; ρ is a unit of a gradientmIs the density of the drilling fluid in g/cm3(ii) a N is the rotating speed of the drill string r/min.
The invention provides a well cleanliness analysis system, which comprises a data storage module, a screening module, a data acquisition module, a well cleanliness calculation module and a well cleanliness determination module, wherein the data storage module is configured to store real-time drilling data of a target well in a drilling process, and the real-time drilling data comprises drilling fluid performance data, drilling tool combination data, well body structure data, well track data, well diameter data and rock debris parameters; the screening module is configured to automatically screen and determine a clean area to which the well section to be calculated belongs according to the well inclination angle of the well section to be calculated, and output a partition result; the data acquisition module is respectively connected with the data storage module and the screening module and is configured to be capable of extracting input data required by cleaning condition calculation of a well section to be calculated from the data storage module based on the partition result; the well cleanliness calculation module comprises a selection unit, a first clean zone calculation unit, a second clean zone calculation unit and a third clean zone calculation unit, wherein the selection unit is connected with the screening module and is configured to control one of the first clean zone calculation unit, the second clean zone calculation unit and the third clean zone calculation unit to be connected with the data acquisition module according to a partition result of a well section to be calculated, the first clean zone calculation unit is configured to calculate and output a first calculation result, the first calculation result comprises a drill cuttings particle transmission ratio, the second clean zone calculation unit is configured to calculate and output a second calculation result, the second calculation result comprises a drill cuttings bed thickness occupied well bore diameter ratio and an annulus return stop velocity, the third clean zone calculation unit is configured to calculate and output a third calculation result, the third calculation comprises the ratio of the thickness of the cutting bed to the borehole diameter; the well cleanliness determination module is connected with the well cleanliness calculation module and is configured to analyze and determine the cleaning effect of the well section to be calculated according to the calculation result output by the well condition calculation module.
In an exemplary embodiment of the borehole cleanliness analysis system according to the present invention, the analysis system may further include an analysis module connected to the borehole cleanliness calculation module, configured to output a borehole cleaning analysis curve of the target well to judge the borehole cleanliness, and including a low-inclination drilling cuttings transport ratio curve drawing unit, a medium-inclination critical annulus return velocity and annulus return velocity curve drawing unit, a medium-inclination rock debris bed relative thickness curve drawing unit, a high-inclination critical annulus return velocity and annulus return velocity curve drawing unit, a critical annulus displacement curve drawing unit, and a high-inclination rock debris bed relative thickness curve drawing unit.
In yet another aspect, the present invention provides an apparatus for analysis of borehole cleanliness, the apparatus comprising: a processor; a memory storing a computer program which, when executed by the processor, implements the method of determining borehole cleanliness as described above to obtain an analysis of borehole cleanliness.
A further aspect of the invention provides a computer readable storage medium having stored thereon a computer program which, when executed by a processor, implements a method of determining borehole cleanliness as described above to obtain an analysis of borehole cleanliness.
Compared with the prior art, the beneficial effects of the invention comprise at least one of the following:
(1) the method for determining the cleanliness of the well hole can overcome the defects of insufficient accuracy of the existing empirical method and large calculation error when the existing well hole calculation model calculates unconventional oil and gas fields with special topography, and can quickly and accurately calculate parameters such as the transmission ratio of drill cutting particles, the relative thickness of a rock debris bed, the annular stop return speed and the like under the current well hole so as to judge the cleaning condition of the current well hole;
(2) the well cleanliness analysis system can utilize real-time data and dynamic data of a drilling site to calculate and analyze related parameters of drilling engineering in real time, can master the well cleaning condition in real time, can optimize the performance indexes and drilling parameters of drilling fluid through analysis and calculation according to actual conditions, and can guide the production of drilling in real time;
(3) the invention realizes timely calculation and analysis of the related parameters of the drilling engineering, and has important significance for meeting the increasing requirements of the drilling engineering.
Drawings
The above and other objects and/or features of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings, in which:
FIG. 1 shows a schematic diagram of an exemplary embodiment of a wellbore cleanliness analysis system of the present invention.
FIG. 2 illustrates a small slope drill cuttings conveyance ratio graph for an exemplary embodiment of a wellbore cleanliness analysis system of the present disclosure; wherein, fig. 2A is a graph of the small-slope drill cuttings transfer ratio corresponding to the curve a1 in fig. 2; FIG. 2B is a graph of the small slope drill cuttings transfer ratio corresponding to curve A2 of FIG. 2; FIG. 2C is a graph of the small slope drill cuttings transfer ratio corresponding to curve A3 of FIG. 2; FIG. 2D is a graph of the small slope drill cuttings transfer ratio corresponding to curve A4 in FIG. 2; FIG. 2E is a graph of the small slope cuttings transfer ratio corresponding to curve A5 in FIG. 2; fig. 2F is a graph of the small slope drill cuttings transfer ratio corresponding to curve a6 in fig. 2.
FIG. 3 illustrates graphs of intermediate slope critical annulus return velocity and annulus return velocity for an exemplary embodiment of a wellbore cleanliness analysis system of the present invention.
FIG. 4 illustrates a plot of the relative thickness of a medium slope formation cuttings bed for an exemplary embodiment of a wellbore cleanliness analysis system of the present invention.
Description of reference numerals:
the system comprises a data storage module, a 2-screening module, a 3-data acquisition module, a 4-borehole cleanliness calculation module, a 41-selection unit, a 42-first clean area calculation unit, a 43-second clean area calculation unit, a 44-third clean area calculation unit and a 5-borehole cleanliness determination module.
Detailed Description
The wellbore cleanliness determination methods, systems, devices, and computer-readable storage media of the present invention will be described in detail below in connection with exemplary embodiments.
It should be noted that "first," "second," "third," and the like are merely for convenience of description and for ease of distinction, and are not to be construed as indicating or implying relative importance.
Shale gas, dense gas and other unconventional oil and gas fields adopt cluster well horizontal wells for realizing benefit development; in order to realize efficient development of conventional oil and gas fields, highly deviated wells and horizontal wells are generally adopted. The well cleaning problem is one of the key influence factors of drilling of a highly deviated well and a horizontal well, and the drilling production can be guided in real time by mastering the well cleaning condition in real time and optimizing the performance index and the drilling parameter of the drilling fluid through analysis and calculation according to the actual condition.
The migration mechanism of the drill cuttings in different well deviation sections is different in the drilling process. Therefore, the drill cuttings transportation is divided into three cleaning areas according to the well deviation, wherein a small-inclination well section (0-30 degrees) is an easy-cleaning area, a middle-inclination well section (30-60 degrees) is an unstable cuttings bed area, and a large-inclination well section (60-90 degrees) is a stable cuttings bed area. The wellbore cleaning calculation models are different due to different drilling cuttings migration mechanisms in different cleaning zones.
To achieve the above object, an aspect of the present invention provides a method for determining cleanliness of a well bore.
In an exemplary embodiment of the invention, a method of determining well bore cleanliness may comprise:
(1) during drilling, the drill cuttings are transferred and divided into a first cleaning area, a second cleaning area and a third cleaning area according to a well inclination angle, wherein the first cleaning area (namely an easy cleaning area) comprises a small-inclination well section with the well inclination angle of 0-30 degrees, the second cleaning area (namely an unstable cuttings bed area) comprises a medium-inclination well section with the well inclination angle of 30-60 degrees, and the third cleaning area (namely a stable cuttings bed area) comprises a large-inclination well section with the well inclination angle of 60-90 degrees.
(2) Determining, for the first clean zone, a wellbore cleanliness by calculating a drill cuttings particle transport ratio for the first clean zone; for the second clean area, determining the cleanliness of the well hole by calculating the diameter ratio of the detritus bed thickness in the well hole and the annulus stopping return speed of the second clean area; for the third clean zone, the wellbore cleanliness is determined by calculating the ratio of the formation bed thickness of the third clean zone to the wellbore diameter.
By carrying out partition processing on the well sections, the well cleanliness of the well sections with different slopes can be calculated in a targeted manner, the calculation can be carried out on unconventional oil and gas fields with special topography, and the calculation error is small. The judgment indexes such as the drill cutting particle transmission ratio, the ratio of the thickness of the rock cutting bed to the borehole diameter, the annular stopping return speed and the like can be obtained through a calculation model, and can also be obtained through field drilling measurement.
Specifically, the method of determining the cleanliness of the wellbore may include the steps of:
and S1, obtaining drilling construction parameters of the target well, including drilling fluid performance data, drilling tool combination data, well body structure data, well deviation data and well diameter data.
S2, analyzing the inclination of each well section of the target well, and dividing the target well into three cleaning zones according to the size of the inclination angle, wherein the three cleaning zones are respectively a first cleaning zone with an inclination angle of 0-30 degrees, a second cleaning zone with an inclination angle of 30-60 degrees and a third cleaning zone with an inclination angle of 60-90 degrees.
And S3, calculating the cleanliness of different cleaning areas by using different wellbore cleaning calculation models.
(1) For the first clean zone, which is a low slope interval (0-30), the transport ratio of the drill cuttings particles is used as a prejudice criterion for wellbore cleaning since the cuttings bed will not generally form due to the low angle of the well.
Calculating the transmission ratio Rt of drill cutting particles by adopting a small-inclination well section well cleaning calculation model, and if the Rt is more than or equal to 0.5, determining that the cleanliness of the first cleaning area meets the cleaning effect; and if Rt is less than 0.5, determining that the cleanliness of the first clean area does not meet the cleaning effect, and adjusting the drilling fluid performance and/or the drilling fluid discharge capacity. The small-inclination well section well cleaning calculation model is shown in formulas (1) to (3).
Settling velocity V of drill cuttings particles at small-inclination well sectionsxAnd (4) calculating.
In the formula, VsxThe settling velocity of drill cutting particles, m/s; d is a radical ofsIs the equivalent diameter of drill cutting particles, cm; rhosIs the density of drill cutting particles in g/cm3；ρmIs the density of the drilling fluid in g/cm3；
The drill cutting particle shape factor is determined according to the shape of the drill cutting particles.
Wherein the drill cutting particle equivalent diameter dsIt may be 0.5-3.0 cm, for example, the equivalent diameter of the drill cutting particles may be calculated as 0.5cm, 1.0cm, 1.5cm, 2.0cm, 2.5cm and 3.0cm, respectively.
Drill cutting particle form factor
Can be 0.5 &1.0, e.g., drill cutting particle shape factor when the drill cutting particle shape is spherical
Can be 1.0; drill cutting particle form factor when the drill cutting particle form is ellipsoidal
May be 0.9; drill cutting particle shape factor when the drill cutting particle shape is polygonal
Can be 0.8; drill cutting particle form factor when the drill cutting particle form is elongated
Can be 0.6; drill cutting particle shape factor when the drill cutting particle shape is sheet-like
May be 0.5.
Drilling fluid annular space return velocity VaAnd (4) calculating.
In the formula, VaThe drilling fluid is the annular return speed of the drilling fluid in m/s; qaIs the drilling fluid flow rate, L/s; dhIs the borehole diameter, mm; dpIs the outer diameter of the drill rod in mm.
Wherein the diameter D of the boreholehThe method can be obtained by caliper logging, and for a well section which is not subjected to caliper logging, the diameter of the well bore can be calculated according to the diameter of the drill bit and an expansion coefficient of 5-10%.
Calculating the drilling cutting particle transmission ratio Rt.
In the formula, Rt is a drillChip particle transport ratio, dimensionless; vsxThe settling velocity of drill cutting particles, m/s; vaThe drilling fluid annular return velocity is m/s.
(2) Aiming at the second clean zone, the zone is a well section with a medium inclination (30-60 degrees), so that a detritus bed is easy to form, and the borehole diameter ratio occupied by the thickness of the detritus bed and the annulus stop return speed can be used as the pre-judgment standard for borehole cleaning.
The relative thickness (namely the ratio of the thickness of the rock debris bed to the borehole diameter) H of the rock debris bed of the middle slope well section can be calculated by adopting a well cleaning calculation model of the middle slope well sectionzxAnd annular stop return velocity VpIf H iszxLess than or equal to 10 percent and Vp≥VaDetermining that the cleanliness of the second cleaning area meets the cleaning effect; if Hzx>10% or Vp<VaAnd determining that the cleanliness of the second cleaning area does not meet the cleaning effect, and adjusting the drilling fluid performance and/or the drilling fluid discharge capacity. The well cleaning calculation model of the well section with the medium inclination is shown in formulas (4) to (14).
And (6) calculating the thickness of the rock debris bed.
The critical annular return velocity V of the well section with the intermediate inclination can be calculated firstlyLzxThen calculating the thickness h of the detritus bed of the well section with the intermediate inclinationzxRelative thickness H of detritus bed in well section with moderate inclinationzx。
And (3) critical annular return velocity of the well section with medium inclination:
in the formula, VlzxThe critical annular return velocity of the well section with the medium inclination is m/s; AV is the apparent viscosity of the drilling fluid, mpa.s; theta is a well inclination angle and degree; d is a radical ofsIs the equivalent diameter of drill cutting particles, cm; rhosIs the density of drill cuttings particles, g/cm3；ρmIs the density of the drilling fluid in g/cm3。
Predicting the thickness of the cuttings bed of the well section with medium inclination:
hzx＝0.015Dh(AV+6.15AV0.5)(1+0.587E)(Vlzx-Va) Formula (5)
In the formula，hzxThe thickness of the detritus bed of the well section with the medium inclination is mm; dhIs the borehole diameter, mm; vLzxThe critical annular return velocity of the well section with the medium inclination is m/s; AV is the apparent viscosity of the drilling fluid, mpa.s; vaThe drilling fluid is the annular return speed of the drilling fluid in m/s; e is the eccentricity of the drill string, dimensionless, and the default value is 2100000.
Relative thickness of cuttings bed (percentage of cuttings bed to wellbore diameter) in well section with medium inclination:
Hzx＝(hzx/Dh) X 100% formula (6)
In the formula, HzxThe relative thickness of the cuttings bed of the well section with the medium inclination is dimensionless; h iszxThe thickness of the detritus bed of the well section with the medium inclination is mm; dhIs the borehole diameter, mm.
And calculating the annular stopping return speed.
In the formula, theta is a well inclination angle and degree; a. thebedCross-sectional area of the cutting bed, mm, perpendicular to the axial direction of the borehole2(ii) a C is the concentration of rock debris in the rock debris bed and is dimensionless; g is the acceleration of gravity, m/s2(ii) a E is the eccentricity of the drill column and is dimensionless; l is the cross-sectional width of the detritus bed perpendicular to the axial direction of the well hole, and is mm; eta is the friction coefficient of the detritus bed and the lower well wall, and is generally 0.2; rhosIs the density of drill cuttings particles, g/cm3；ρmIs the density of the drilling fluid in g/cm3；DhIs the borehole diameter, mm; dpThe diameter is the outer diameter of the drill rod; PV is plastic viscosity, mPa.s; YP is dynamic shear force, Pa; k is the consistency coefficient, Pa · sn(ii) a n is a fluidity index and is dimensionless.
Calculating relevant parameters.
The drilling fluid annulus return velocity V can be calculated by the formula (2)aThe cross-sectional width L of the rock debris bed perpendicular to the axial direction of the borehole can be calculated by the formula (8), and the cross-sectional area A of the rock debris bed perpendicular to the axial direction of the borehole can be calculated by the formula (9)bedThe apparent viscosity AV of the drilling fluid can be calculated by the formula (10), and the plastic viscosity can be calculated by the formula (11)PV, dynamic shear force YP can be calculated by formula (12), consistency coefficient K can be calculated by formula (13), fluidity index n can be calculated by formula (14), and formulae (8) to (14) are as follows:
in the formula, L is the cross-sectional width of the detritus bed perpendicular to the axial direction of the borehole, and is mm; dhIs the borehole diameter, mm; h iszxThe thickness of the detritus bed of the well section with the medium inclination is mm.
In the formula, AbedCross-sectional area of the cutting bed, mm, perpendicular to the axial direction of the borehole2；DhIs the borehole diameter, mm; h iszxThe thickness of the detritus bed of the well section with the medium inclination is mm.
Wherein AV is the apparent viscosity of the drilling fluid, mpa.s;
read for 600 revolutions of the rotational viscometer.
Wherein PV is a plastic viscosity, mPa · s;
read for rotational viscometer 600 revolutions;
read for a rotational viscometer of 300 revolutions.
In the formula, YP is dynamic shear force Pa;
reading for a rotational viscometer of 300 revolutions; PV is the plastic viscosity, mPas.
In the formula, K is a consistency coefficient, Pa.sn; n is a fluidity index, and is dimensionless;
read for a rotational viscometer of 300 revolutions.
In the formula, n is a fluidity index and is dimensionless;
reading for a rotational viscometer of 600 revolutions;
read for a rotational viscometer of 300 revolutions.
(3) Aiming at the third cleaning area, the area is a highly-deviated well section (60-90 degrees), is a stable area of the detritus bed, and can use the diameter percentage of the detritus bed in the well as the pre-judgment standard of well cleaning.
The relative thickness H of the detritus bed of the highly-deviated well section can be calculated by adopting a well cleaning calculation model of the highly-deviated well sectiondxIf H isdxThe cleanliness of the third cleaning area is determined to meet the cleaning effect if the cleanliness is less than or equal to 10 percent; if HdxAnd if the cleaning degree of the third cleaning area is more than 10%, determining that the cleaning degree of the third cleaning area does not meet the cleaning effect, and adjusting the performance and/or the discharge capacity of the drilling fluid. High-inclination well section well cleaning calculation moduleThe type is shown in formulas (15) to (27).
First, the critical annular return velocity V of highly-deviated well sectionLdxAnd (4) calculating.
VLdx＝Vt+VsddFormula (15)
Vsdd＝VsdCangCsizeCdenFCrpmFormula (17)
From the above formulas (15) to (17), it can be seen that the critical annular return velocity V of the highly deviated well sectionLdxComprises the following steps:
in the formula, VLdxThe critical annular return velocity is m/s at the highly deviated well section; vtCritical rock debris transmission speed, m/s; vsddThe equivalent settling velocity of the drilling cuttings at the highly deviated well section is m/s; vjxThe mechanical drilling speed is m/h; dhIs the borehole diameter, mm; dpThe diameter is the outer diameter of the drill rod; vsdThe settling velocity of the drill cuttings at the highly-deviated well section is m/s; cangThe correction coefficient of the well inclination angle is dimensionless; csizeThe drilling cutting size correction coefficient is dimensionless; cdenFThe drilling fluid density correction coefficient is dimensionless; crpmThe correction coefficient of the rotating speed of the drill column is dimensionless; AV is the apparent drilling fluid viscosity, mpa.s.
And secondly, calculating the thickness of the detritus bed of the highly-deviated well section.
Through simultaneous solving equations (20) - (22), the thickness h of the detritus bed of the highly-deviated well section can be solved and obtaineddx。
In the formula, QLdxThe displacement is L/s of the critical annular space of the debris-free bed; vLdxThe critical annular return velocity is m/s at the highly deviated well section; dhIs the borehole diameter, mm; dpThe diameter is the outer diameter of the drill rod; a'bedIs the area of the detritus bed, mm2；hdxThe thickness of the detritus bed of the highly-deviated well section is mm; qaIs the drilling fluid displacement, L/s.
Calculating the relative thickness of the detritus bed (namely the percentage of the detritus bed in the diameter of the borehole) of the highly deviated well section.
Hdx＝(hdx/Dh) X 100% of formula (23)
In the formula, HdxThe relative thickness of the detritus bed of the highly-deviated well section is dimensionless; h isdxThe thickness of the detritus bed of the highly-deviated well section is mm; dhIs the borehole diameter, mm.
And fourthly, calculating related parameters.
The correction coefficient C of the inclination angle can be calculated by the formula (24)angThe drill cutting size correction coefficient C can be calculated by the equation (25)sizeThe drilling fluid density correction coefficient C can be calculated by the formula (26)denFThe drill string rotation speed correction coefficient C can be calculated by the formula (27)rpmThe expressions (24) to (27) are as follows.
Cang＝0.0342θ-0.000233θ2-0.213 formula (24)
Csize＝I.286-O.04094448dsFormula (25)
In the formula, CangThe correction coefficient is a well skew angle correction coefficient, and is dimensionless; csizeThe drilling cutting size correction coefficient is dimensionless; cdenFThe drilling fluid density correction coefficient is dimensionless; crpmThe correction coefficient of the rotating speed of the drill column is dimensionless; theta is a well inclination angle and degree; dsIs the equivalent diameter of drill cutting particles, cm; rhomIs the density of the drilling fluid in g/cm3(ii) a And N is the rotating speed of the drill string and r/min.
In another aspect, the invention provides a system for analyzing cleanliness of a well bore.
In another exemplary embodiment of the present invention, as shown in FIG. 1, a wellbore cleanliness analysis system may be comprised of a data storage module, a screening module, a data acquisition module, a wellbore cleanliness calculation module, and a wellbore cleanliness determination module.
The data storage module 1 is configured to store real-time drilling data of a target well in a drilling process, wherein the real-time drilling data comprises drilling fluid performance data, drilling tool assembly data, well structure data, well track data, well diameter data and rock debris parameters.
The screening module 2 is configured to automatically screen and determine a clean zone to which the well section to be calculated belongs according to the well angle of the well section to be calculated, and output a partition result. For example, when the inclination angle of the well is 0-30 degrees, the well section to be calculated is a small-inclination well section and belongs to a first cleaning area; when the inclination angle is 30-60 degrees, the well section to be calculated is a middle inclination well section and belongs to a second cleaning area; and when the well inclination angle is 60-90 degrees, the well section to be calculated is a high-inclination well section and belongs to a third cleaning area.
The data acquisition module 3 is respectively connected with the data storage module 1 and the screening module 2, and is configured to be capable of extracting input data required by cleaning condition calculation of a well section to be calculated from the data storage module based on the partition result.
The wellbore cleanliness calculation module 4 includes a selection unit 41, a first clean zone calculation unit 42, a second clean zone calculation unit 43, and a third clean zone calculation unit 44.
Wherein the selection unit 41 is connected to the screening module 2 and is configured to be able to control one of the first clean zone calculation unit 42, the second clean zone calculation unit 43 and the third clean zone calculation unit 44 to be connected to the data acquisition module 3 depending on the result of the partitioning of the interval to be calculated.
When the partition result output by the sieving module 2 is the first cleaning zone, the selection unit 41 controls the first cleaning zone calculation unit 42 to be connected with the data acquisition module 3, and the first cleaning zone calculation unit 42 is configured to be capable of calculating and outputting a first calculation result, which includes the drill cuttings particle transfer ratio.
When the partition result output by the screening module 2 is the second clean area, the selection unit 41 controls the second clean area calculation unit 43 to be connected with the data acquisition module 3, and the second clean area calculation unit 43 is configured to be capable of calculating and outputting a second calculation result, wherein the second calculation result comprises the ratio of the thickness of the rock debris bed to the borehole diameter and the annulus stopping and returning speed.
When the partition result output by the screening module 2 is a third cleaning area, the selection unit 41 controls the third cleaning area calculation unit 44 to be connected with the data acquisition module 3, and the third cleaning area calculation unit 44 is configured to be capable of calculating and outputting a third calculation result, wherein the third calculation result comprises the ratio of the thickness of the rock debris bed to the borehole diameter.
The well cleanliness determination module 5 is connected with the well cleanliness calculation module 4 and is configured to analyze and determine the cleaning effect of the well section to be calculated according to the calculation result output by the well condition calculation module.
For example, a target well is a Dolichthys 001-X8 well with a well depth of 7559.65m and a drill cutting diameter ds2mm, drilling fluid density of 1.43g/cm3600 revolution reading of rotational viscometer
At 84, the rotational viscometer reads 300 revolutions
At 47, drilling fluid flow rate QaThe concentration was 14.1L/s. The planned calculation well section is 7290-7365 m, the inclination angle is 30-60 degrees, the planned calculation well section belongs to a second clean area, and a well cleaning calculation model of the middle inclination well section is selected to calculate the cleanliness of the well. The results of the calculations obtained using the well cleanliness analysis system are shown in Table 1, including the critical annulus return velocity V for the middip intervallzxDrilling fluid annular space velocity return VaRelative thickness of the cutting bed (i.e. the ratio of the thickness of the cutting bed to the borehole diameter) H in the medium slope intervalzxAnd annular stop return velocity Vp。
TABLE 1 borehole cleanliness calculations for intervals 7290m to 7365m
From the calculation results in Table 1, it can be seen that H of the interval is to be calculatedzx≤10％，Vp<VaAnd judging that the cleanliness of the well section does not meet the cleaning effect.
In this embodiment, the well cleanliness analysis system may further include an analysis module, connected to the well cleanliness calculation module, configured to output a well cleanliness analysis curve of the target well to determine the well cleanliness.
The analysis module can comprise a small-inclination drilling cuttings transmission ratio curve drawing unit, a medium-inclination critical annulus return speed and annulus return speed curve drawing unit, a medium-inclination rock debris bed relative thickness curve drawing unit, a large-inclination critical annulus return speed and annulus return speed curve drawing unit, a critical annulus displacement curve drawing unit and a large-inclination rock debris bed relative thickness curve drawing unit.
The small-inclination drilling cuttings transmission ratio curve drawing unit can automatically draw a small-inclination drilling cuttings transmission ratio curve according to the calculation result of the first cleaning area calculation unit so as to judge the current well cleaning condition.
For example, fig. 2 is a small slope drill cuttings transfer ratio curve, and the abscissa in fig. 2 represents the small slope drill cuttings transfer ratio and the ordinate represents the well depth (unit: m). Fig. 2A-2F are graphs of the small slope drill cuttings conveyance ratio of corresponding curves a 1-a 6 of fig. 2. Curve a1 represents the low slope cuttings transfer ratio Rt (i.e., 0.5) for safety critical, curve a2 represents the low slope cuttings transfer ratio Rt1 for a cuttings particle equivalent diameter of 2mm, curve A3 represents the low slope cuttings transfer ratio Rt2 for a cuttings particle equivalent diameter of 5mm, curve a4 represents the low slope cuttings transfer ratio Rt3 for a cuttings particle equivalent diameter of 10mm, curve a5 represents the low slope cuttings transfer ratio Rt4 for a cuttings particle equivalent diameter of 15mm, and curve a6 represents the low slope cuttings transfer ratio Rt5 for a cuttings particle equivalent diameter of 20 mm.
It can be seen from figure 2 that when the cuttings particle equivalent diameter is 2mm, curve a2 is located to the right of curve a1, the small slope cuttings transport ratio Rt1> Rt for all intervals downhole, so all intervals meet the cleaning effect. When the drill cutting particle equivalent diameter is 5mm, a part of the curve A3 is positioned on the left side of the curve A1, a part of the curve A3 is positioned on the right side of the curve A1, namely the small-slope drill cutting transmission ratio Rt2< Rt of a well section with the downhole depth of 2700-3800 m does not meet the cleaning effect, and the small-slope drill cutting transmission ratio Rt2> Rt of the well section with the downhole depth of 3800m or less meets the cleaning effect. When the drill cutting particle equivalent diameter is 10mm, a part of the curve A4 is positioned on the left side of the curve A1, a part of the curve A4 is positioned on the right side of the curve A1, namely the small-slope drill cutting transmission ratio Rt3< Rt of a well section with the downhole depth of 2700-3800 m does not meet the cleaning effect, and the small-slope drill cutting transmission ratio Rt3> Rt of a well section with the downhole depth of 3800m or less meets the cleaning effect. When the equivalent diameter of the drill cuttings particles is 15mm, a part of the curve A5 is positioned on the left side of the curve A1, a part of the curve A5 is positioned on the right side of the curve A1, namely the small-slope drill cuttings transmission ratio Rt4< Rt of a well section with the downhole depth of 2700-2900 m does not meet the cleaning effect, and the small-slope drill cuttings transmission ratio Rt4> Rt of the well section with the downhole depth of 4000m or less meets the cleaning effect. When the equivalent diameter of the drill cutting particles is 20mm, the curve A6 is positioned at the left side of the curve A1, namely the small-slope drill cutting transmission ratio Rt5< Rt of all the well sections in the well, so that all the well sections cannot meet the cleaning effect.
The middle-inclination critical annulus return speed and annulus return speed curve drawing unit can automatically draw a middle-inclination critical annulus return speed and annulus return speed curve according to the calculation result of the second cleaning area calculation unit, and is used for carrying out contrastive analysis on the middle-inclination critical annulus return speed and the annulus return speed so as to judge the current well cleaning condition.
For example, FIG. 3 is a plot of intermediate slope critical annulus return velocity and annulus return velocity, with the abscissa of FIG. 3 representing annulus return velocity (in m/s), the ordinate representing well depth (in m), and the curve B1 representing drilling fluid annulus return velocity VaCurve B2 shows the critical annulus return velocity V for 2mm equivalent diameter cuttings lzx1, Curve B3 shows the corresponding critical annulus return velocity V for a 5mm equivalent diameter drill cuttings particle lzx2, Curve B4 shows the corresponding critical annulus return velocity V for a 10mm equivalent diameter drill cuttings particle lzx3, Curve B5 shows the corresponding mid-slope critical annulus return velocity V for a 15mm equivalent diameter drill cuttings particlelzxCurve B6 shows the critical annulus return velocity V for a 20mm equivalent diameter drill cuttings particle lzx5。
As can be seen in FIG. 3, when the equivalent diameter of the drill cuttings particles is 2mm, curve B2 is located to the left of curve B1, and the critical annular return velocity V of the medium slope lzx1 and drilling fluid annular space velocity return VaThe difference is less than 0, sozx1<0，H zx1<0. When the equivalent diameter of the drill cuttings particles is 5mm, the curve B3 is positioned at the left side of the curve B1, and the critical annular back velocity V of the medium slope lzx2 and drilling fluid annular space velocity return VaThe difference is less than 0, sozx2<0，H zx2<0. When the equivalent diameter of the drill cuttings particles is 10mm, the curve B4 is positioned at the right side of the curve B1, and the critical annular back velocity V of the medium slope Lzx3 and drilling fluid annular space velocity return VaThe difference is greater than 0, so h zx3>0，H zx3>0. When the equivalent diameter of the drill cuttings particles is 15mm, the curve B5 is positioned at the right side of the curve B1, and the critical annular back velocity V of the medium slope lzx4 and drilling fluid annular space return velocity VaThe difference between the values of the two parameters is greater than 0,therefore h iszx4>0，H zx4>0. When the equivalent diameter of the drill cuttings particles is 20mm, the curve B6 is positioned at the right side of the curve B1, and the intermediate-slope critical annulus return velocity V lzx5 and drilling fluid annular space return velocity VaThe difference is greater than 0, so h zx5>0，H zx5>0。
The relative thickness curve drawing unit of the medium-slope detritus bed can automatically draw the relative thickness curve of the medium-slope detritus bed according to the calculation result of the second cleaning area calculation unit so as to judge the current well cleaning condition.
For example, FIG. 4 is a plot of relative thickness of a formation bed, with the abscissa of FIG. 4 representing relative thickness of a formation bed (in:%), the ordinate representing depth of hole (in m), and the curve C1 representing relative thickness of a critical formation bed Hzx(i.e., 10%) curve C2 shows the relative bed thickness H for a 1mm equivalent drill cuttings particle diameter zx1, Curve C3 shows the relative bed thickness H for a 2mm equivalent diameter drill cuttings particle zx2, Curve C4 shows the relative bed thickness H for a drill cuttings particle equivalent diameter of 3mmzxCurve C5 shows the relative bed thickness H for a 4mm equivalent drill cutting particle diameterzxCurve C6 shows the relative bed thickness H for a cutting particle equivalent diameter of 5mm zx5。
As can be seen from fig. 4, the curve C2, the curve C3, the curve C4, the curve C5 and the curve C6 respectively correspond to the equivalent diameters of drill cuttings particles of 1mm, 2mm, 3mm, 4mm and 5mm, which are all located on the left side of the curve C1, i.e. the relative thicknesses of the cuttings bed at the equivalent diameters of the five drill cuttings particles are less than 10%.
The large-inclination critical annulus return speed and annulus return speed curve drawing unit can automatically draw a large-inclination critical annulus return speed and annulus return speed curve according to the calculation result of the third cleaning area calculation unit, and is used for carrying out contrastive analysis on the large-inclination critical annulus return speed and the annulus return speed so as to judge the current well cleaning condition. The actual annulus return speed needs to be larger than the critical annulus return speed to ensure that the current borehole is clean.
The critical annular discharge capacity curve drawing unit can automatically draw a critical annular discharge capacity curve according to the calculation result of the third cleaning area calculation unit, and is used for carrying out contrastive analysis on the critical annular discharge capacity and the actual annular discharge capacity so as to judge the current well cleaning condition. The actual discharge capacity needs to be larger than the critical annular discharge capacity to ensure that the current borehole is clean, and the actual annular return speed needs to be larger than the critical annular return speed to ensure that the current borehole is clean.
The large-inclination rock debris bed relative thickness curve drawing unit can automatically draw a large-inclination rock debris bed relative thickness curve according to the calculation result of the third cleaning area calculation unit so as to judge the current well cleaning condition.
Yet another aspect of the invention provides a computer program for borehole cleanliness analysis.
In an exemplary embodiment of the present invention, the method of determining borehole cleanliness of the present invention can be compiled as a corresponding degree code or instruction and programmed as a computer program. The program code or instructions, when executed by a processor, can implement a method of determining borehole cleanliness as described above to obtain an analysis of borehole cleanliness.
Yet another aspect of the present invention provides a computer-readable storage medium storing a computer program.
In one exemplary embodiment of the invention, a computer program is stored in a computer readable storage medium, which when executed, may implement the method of determining borehole cleanliness of the present invention. The computer readable storage medium may be any data storage device that stores data that can be read by a computer system. For example, examples of computer-readable storage media may include: read-only memory, random access memory, compact disc read-only memory, magnetic tape, floppy disk, optical data storage device, and carrier wave (such as data transmission through the internet via a wired or wireless transmission path).
Yet another aspect of the invention provides a computer apparatus for borehole cleanliness analysis.
In one exemplary embodiment of the invention, a computer apparatus for borehole cleanliness analysis may include a processor and a memory. The memory is used to store a computer program for implementing the method of determining the cleanliness of a well bore of the present invention to obtain an analysis result of the cleanliness of the well bore.
In summary, the beneficial effects of the invention include at least one of the following:
(1) the method for determining the cleanliness of the well hole can overcome the defects of insufficient accuracy of the existing empirical method and large calculation error when the existing well hole calculation model calculates unconventional oil and gas fields with special topography, and can quickly and accurately calculate parameters such as the transmission ratio of drill cutting particles, the relative thickness of a rock debris bed, the annular stop return speed and the like under the current well hole so as to judge the cleaning condition of the current well hole;
(2) the well cleanliness analysis system can utilize real-time data and dynamic data of a drilling site to calculate and analyze related parameters of drilling engineering in real time, can master the well cleaning condition in real time, can optimize drilling fluid performance indexes and drilling parameters through analysis and calculation according to actual conditions, and guides drilling production in real time;
(3) the invention realizes timely calculation and analysis of the related parameters of the drilling engineering, and has important significance for meeting the increasing requirements of the drilling engineering.
Although the present invention has been described above in connection with the exemplary embodiments and the accompanying drawings, it will be apparent to those of ordinary skill in the art that various modifications may be made to the above-described embodiments without departing from the spirit and scope of the claims.
Claims (12)
1. A method of determining well bore cleanliness, the method comprising: in the drilling process, the drill cuttings are transferred and divided into a first cleaning area, a second cleaning area and a third cleaning area according to the well inclination angle, wherein the first cleaning area comprises a small-inclination well section with the well inclination angle of 0-30 degrees, the second cleaning area comprises a medium-inclination well section with the well inclination angle of 30-60 degrees, and the third cleaning area comprises a large-inclination well section with the well inclination angle of 60-90 degrees;
determining wellbore cleanliness by calculating a drill cuttings particle transfer ratio for the first cleaning zone; for the second clean zone, determining the cleanliness of the well hole by calculating the ratio of the thickness of the debris bed to the diameter of the well hole and the annulus stopping and returning speed; and for the third cleaning area, determining the cleanliness of the borehole by calculating the ratio of the thickness of the rock debris bed to the diameter of the borehole.
2. The method of determining well bore cleanliness of claim 1, comprising in particular the steps of:
aiming at the first clean area, calculating a drilling cutting particle transmission ratio Rt by adopting a small-inclination well section well cleaning calculation model, if Rt is more than or equal to 0.5, determining that the cleanliness of the first clean area meets the cleaning effect, and if Rt is less than 0.5, determining that the cleanliness of the first clean area does not meet the cleaning effect;
the small-inclination well section borehole cleaning calculation model is shown in formulas (1) to (3):
in the formulae (1) to (3), VsxThe settling velocity of drill cutting particles, m/s; dsIs the equivalent diameter of drill cutting particles, cm; rhosIs the density of drill cutting particles in g/cm3；ρmIs the density of the drilling fluid in g/cm3；
The shape coefficient of the drill cutting particles is dimensionless; vaThe drilling fluid is the annular return speed of the drilling fluid in m/s; qaIs the drilling fluid flow rate, L/s; dhIs the borehole diameter, mm; dpThe diameter is the outer diameter of the drill rod; rt is the transmission ratio of drill cutting particles and is dimensionless;
calculating the relative thickness H of the detritus bed of the intermediate slope well section by adopting a well cleaning calculation model of the intermediate slope well section aiming at the second cleaning areazxAnd annular stop return velocity VpIf H iszxLess than or equal to 10 percent and Vp≥VaDetermining that the cleanliness of the second cleaning area meets the cleaning effect, and if H is reachedzx>10% or Vp<VaDetermining that the cleanliness of the second cleaning area does not meet the cleaning effect;
the well cleaning calculation model of the well section with the moderate inclination is shown in formulas (4) to (7):
hzx＝0.015Dh(AV+6.15AV0.5)(1+0.587E)(Vlzx-Va) Formula (5)
Hzx＝(hzx/Dh) X 100% formula (6)
In formulae (4) to (7), VlzxThe critical annular return velocity of the well section with the medium inclination is m/s; AV is the apparent viscosity of the drilling fluid, mpa.s; theta is a well inclination angle and degree; h iszxThe thickness of the detritus bed of the well section with the medium inclination is mm; hzxThe relative thickness of the detritus bed of the well section with the medium inclination is dimensionless; vpStopping the annular space to return the speed, m/s; a. thebedCross-sectional area of the cutting bed, mm, perpendicular to the axial direction of the borehole2(ii) a C is the concentration of rock debris in the rock debris bed and is dimensionless; g is the acceleration of gravity, m/s2(ii) a E is the eccentricity of the drill column and is dimensionless; l is the cross-sectional width of the detritus bed perpendicular to the axial direction of the well hole, and is mm; eta is the friction coefficient of the detritus bed and the lower well wall, and is generally 0.2; PV is plastic viscosity, mPa.s; YP is dynamic shear force, Pa; k is the consistency coefficient, Pa · sn(ii) a n is a fluidity index,dimensionless;
aiming at the third clean area, calculating the relative thickness H of the detritus bed of the highly-deviated well section by adopting a highly-deviated well section well hole clean calculation modeldxIf H isdxLess than or equal to 10%, determining that the cleanliness of the third cleaning area meets the cleaning effect, and if H is less than or equal to 10%, determining that the cleanliness of the third cleaning area meets the cleaning effectdxIf the cleaning degree of the third cleaning area is more than 10 percent, determining that the cleaning degree of the third cleaning area does not meet the cleaning effect;
the high-inclination well section well cleaning calculation model is shown in formulas (18) to (23):
Hdx＝(hdx/Dh) X 100% formula (23)
In formulae (18) to (23), VLdxThe critical annular return velocity is m/s at the highly deviated well section; vsdThe settling velocity of the drill cuttings at the highly-deviated well section is m/s; vjxThe mechanical drilling speed is m/h; cangThe correction coefficient of the well inclination angle is dimensionless; csizeThe drilling cutting size correction coefficient is dimensionless; cdenFThe drilling fluid density correction coefficient is dimensionless; crpmThe correction coefficient of the rotating speed of the drill column is dimensionless;QLdxthe displacement is L/s of the critical annular space of the debris-free bed; a'bedIs the area of the detritus bed, mm2；hdxThe thickness of the detritus bed of the highly-deviated well section is mm; qaThe discharge capacity of the drilling fluid is L/s; hdxThe thickness of the rock debris bed at the highly-deviated well section is dimensionless.
3. The method of determining wellbore cleanliness of claim 2, wherein the drill cuttings particle equivalent diameter ds0.5-3.0 cm; the drill cuttings particle form factor
0.5 to 1.0.
4. A method of determining well bore cleanliness according to claim 3, wherein the well bore diameter DhAnd obtaining through borehole diameter logging, and calculating the borehole diameter according to the expansion coefficient of 5-10% and the drill diameter of a well section which is not subjected to borehole diameter logging.
5. The method for determining cleanliness of a well bore according to claim 4, wherein a cross-sectional width L of the cutting bed perpendicular to an axial direction of the well bore is calculated by equation (8), and a cross-sectional area A of the cutting bed perpendicular to the axial direction of the well bore is calculated by equation (9)bedThe formulas (8) and (9) are as follows:
in the formulas (8) and (9), L is the cross-sectional width of the detritus bed perpendicular to the axial direction of the borehole, and is mm; dhIs the borehole diameter, mm; h iszxThe thickness of the detritus bed of the well section with the medium inclination is mm; a. thebedIs perpendicular to the borehole axisCross-sectional area of the bed of upward cuttings, mm2。
6. The method of determining the cleanliness of a well bore according to claim 5, wherein the apparent drilling fluid viscosity AV is calculated by equation (10), the plastic viscosity PV is calculated by equation (11), and the dynamic shear force YP is calculated by equation (12), and equations (10) to (12) are as follows:
in the formulas (10) to (12), AV is the apparent viscosity of the drilling fluid, mpa.s;
reading for a rotational viscometer of 600 revolutions;
read for rotational viscometer 300 revolutions; PV is plastic viscosity, mPa.s; YP is dynamic shear force, Pa.
7. The method for determining borehole cleanliness according to claim 5, wherein the consistency coefficient K is calculated by equation (13), and the fluidity index n is calculated by equation (14), and equations (13) to (14) are as follows:
in the formulae (13) to (14), K is a consistency factor Pa · sn(ii) a n is a fluidity index;
reading for a rotational viscometer of 600 revolutions;
read for a rotational viscometer of 300 revolutions.
8. The method of determining well cleanliness according to claim 5, wherein the skew angle correction coefficient C is calculated by equation (24)angCalculating the drill cutting size correction coefficient C by equation (25)sizeCalculating the drilling fluid density correction coefficient C by the formula (26)denFCalculating the drill string rotation speed correction coefficient C by the formula (27)rpmThe expressions (24) to (27) are as follows:
Cang＝0.0342θ-0.000233θ2-0.213 formula (24)
Csize＝1.286-0.04094448dsFormula (25)
In formulae (24) to (27), CangThe correction coefficient of the well inclination angle is dimensionless; csizeThe drilling cutting size correction coefficient is dimensionless; cdenFThe drilling fluid density correction coefficient is dimensionless; crpmThe correction coefficient of the rotating speed of the drill column is dimensionless; theta is a well inclination angle and degree; dsIs the equivalent diameter of drill cutting particles, cm; rhomFor drilling wellsLiquid Density, g/cm3(ii) a And N is the rotating speed of the drill string and r/min.
9. A well cleanliness analysis system comprising a data storage module, a screening module, a data acquisition module, a well cleanliness calculation module, and a well cleanliness determination module, wherein,
the data storage module is configured to store real-time drilling data of a target well during drilling, the real-time drilling data including drilling fluid performance data, drilling tool assembly data, well bore structure data, wellbore trajectory data, caliper data, and cuttings parameters;
the screening module is configured to automatically screen and determine a clean area to which the well section to be calculated belongs according to the well inclination angle of the well section to be calculated, and output a partition result;
the data acquisition module is respectively connected with the data storage module and the screening module and is configured to be capable of extracting input data required by cleaning condition calculation of a well section to be calculated from the data storage module based on the partition result;
the wellbore cleanliness calculation module includes a selection unit, a first clean zone calculation unit, a second clean zone calculation unit, and a third clean zone calculation unit, wherein,
the selection unit is connected with the screening module and is configured to control one of the first clean zone calculation unit, the second clean zone calculation unit and the third clean zone calculation unit to be connected with the data acquisition module according to the partition result of the well section to be calculated,
the first cleaning zone calculation unit is configured to be capable of calculating an output first calculation result, the first calculation result comprising a drill cuttings particle transfer ratio,
the second clean zone calculation unit is configured to calculate and output a second calculation result, wherein the second calculation result comprises the ratio of the thickness of the debris bed to the borehole diameter and the annulus stopping and returning speed,
the third cleaning area calculation unit is configured to be capable of calculating and outputting a third calculation result, wherein the third calculation result comprises a ratio of the thickness of the rock debris bed to the borehole diameter;
the well cleanliness determination module is connected with the well cleanliness calculation module and is configured to analyze and determine the cleaning effect of the well section to be calculated according to the calculation result output by the well condition calculation module.
10. The system of claim 9, further comprising an analysis module connected to the well cleanliness calculation module, configured to output a well cleaning analysis curve of a target well to determine well cleanliness, and comprising a low slope cuttings transport ratio curve plotting unit, a medium slope critical annulus return velocity and annulus return velocity curve plotting unit, a medium slope cuttings bed relative thickness curve plotting unit, a high slope critical annulus return velocity and annulus return velocity curve plotting unit, a critical annulus displacement curve plotting unit, and a high slope cuttings bed relative thickness curve plotting unit.
11. An apparatus for analysis of well cleanliness, the apparatus comprising:
a processor;
a memory storing a computer program which, when executed by the processor, implements the method of determining borehole cleanliness according to any one of claims 1-8 to obtain an analysis of borehole cleanliness.
12. A computer-readable storage medium storing a computer program, characterized in that the computer program, when being executed by a processor, carries out the method of determining the cleanliness of a borehole according to any one of claims 1-8, for obtaining an analysis result of the cleanliness of the borehole.
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