Calculation method and system for minimum rock-carrying displacement of booster pipelines in deepwater riser drilling

Abstract

The present invention discloses a method and system for calculating the minimum rock-carrying displacement of a deepwater riser drilling booster pipeline. The method comprises: calculating the circulation return velocity of the drilling fluid in each well section based on wellbore structural parameters and drilling fluid parameters, each well section including an open hole section, a casing section, and a riser section; calculating the upward migration velocity of the cuttings in the casing section and the open hole section using a particle migration velocity prediction model, further calculating the total migration time of the cuttings in the casing section and the open hole section and the total circulation time of the drilling fluid under a given number of circulation cycles, and then determining the maximum allowable time and minimum velocity for the cuttings to return upward in the riser section; calculating the minimum flow velocity of the drilling fluid in the riser section using a particle migration velocity prediction model; and determining the minimum rock-carrying displacement of the booster pipeline based on the circulation return velocity and minimum flow velocity of the drilling fluid in the riser section. Through the above scheme, the minimum displacement of the booster pipeline assisted rock carrying can be accurately calculated.

Description

Technical Field

[0001] The present invention relates to the technical field of deepwater drilling, and in particular to a method and system for calculating the minimum rock-carrying displacement of a deepwater riser drilling booster pipeline. Background Art

[0002] In deepwater drilling, riser drilling is often used. Traditional riser drilling relies on the riser system. When the drilling fluid returns from the casing annulus to the riser section, the flow rate drops sharply due to the sudden increase in the annular cross-sectional area, reducing the rock carrying efficiency and even causing downhole accidents such as pipe sticking. In addition, due to the larger size of the risers required for deepwater drilling, its minimum rock carrying capacity is significantly higher than that of land and shallow water drilling. If this problem is solved simply by increasing the circulating displacement of the drilling fluid, it is easy to lead to increased circulation friction, increased vertical pressure, decreased pump efficiency, and even potential safety hazards such as well leakage, thereby increasing non-productive time. Therefore, in deepwater drilling, especially when the pressure window of the target layer is narrow, it is difficult to improve the rock carrying capacity of the drilling fluid by increasing the drilling pump displacement.

[0003] To overcome this technical bottleneck, adding subsea booster lines has become an effective solution for improving drilling fluid circulation velocity and enhancing rock-carrying capacity. By adding booster lines, the flow rate in the riser annulus can be increased, thereby enhancing cuttings transport efficiency, without increasing the load on the main circulation system. However, a comprehensive theoretical framework for calculating the minimum flow rate for booster lines to assist rock transport remains elusive. While booster lines are used to increase flow rates in the riser section, the calculation of minimum flow rates lacks systematic theoretical support, leading to a conflict between safety and energy efficiency in engineering applications. Insufficient booster line flow rates prevent cuttings from being returned promptly, potentially leading to the risk of stuck pipe; while excessive flow rates increase pumping power, resulting in unnecessary energy consumption. Conventional methods for calculating the minimum rock-carrying flow rate within the wellbore annulus typically calculate the particle settling velocity based on the particle resistance coefficient. This assumption then assumes that the drilling fluid return velocity within the annulus is equal to this settling velocity, thereby inferring the minimum flow rate and flow rate required for rock transport. However, in real-world drilling operations, wellbore cleaning time cannot be extended indefinitely. Even if the drilling fluid flow rate is slightly higher than the particle settling velocity, it cannot ensure that all particles are successfully returned to the wellhead within a limited time.

[0004] In summary, the existing technology has low accuracy in calculating the minimum displacement of the booster pipeline to assist in rock carrying. Summary of the Invention

[0005] Based on this, it is necessary to provide a method and system for calculating the minimum rock-carrying displacement of a deepwater riser drilling booster pipeline to address the technical problem that the existing technology has low accuracy in calculating the minimum displacement of the booster pipeline to assist in rock carrying.

[0006] The present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a method for calculating the minimum rock-carrying displacement of a deepwater riser drilling booster pipeline, the method comprising:

[0008] Collect the wellbore structure parameters, cuttings characteristic parameters and drilling fluid parameters of deepwater drilling wells, and determine the number of drilling fluid circulation cycles;

[0009] Based on the wellbore structure parameters and drilling fluid parameters, the circulation return rate of the drilling fluid in each well section of the deepwater drilling wellbore is calculated, and the each well section includes an open hole section, a casing section, and a water-receiving pipe section; based on the circulation return rate of the drilling fluid in the open hole section and the casing section, the cuttings characteristic parameters, and the drilling fluid parameters, the upward return migration rate of the cuttings in the casing section and the open hole section is calculated using a pre-constructed particle migration velocity prediction model; based on the upward return migration rate of the cuttings in the casing section and the open hole section, the total migration time of the cuttings in the casing section and the open hole section is calculated;

[0010] Based on the wellbore structure parameters, drilling fluid parameters and the number of drilling fluid circulation cycles, the total circulation time of the drilling fluid in the deepwater drilling wellbore is calculated; based on the total migration time and the total circulation time, the minimum velocity required for the cuttings to return from the annulus of the watertight pipe section is determined; based on the minimum velocity, the cuttings characteristic parameters and the drilling fluid parameters, the minimum flow rate of the drilling fluid in the watertight pipe section is calculated using the particle migration velocity prediction model;

[0011] The minimum rock-carrying capacity of the booster pipeline is determined based on the circulation return velocity and the minimum flow velocity of the drilling fluid in the water-receiving pipe section.

[0012] Furthermore, based on the wellbore structural parameters and the drilling fluid parameters, the circulation return rate of the drilling fluid in each well section of the deepwater drilling wellbore is calculated. The specific calculation expression is:

[0013] ;

[0014] in, V f is the circulation rate of drilling fluid, Q t is the drilling fluid pump displacement, A is the cross-sectional area of the annulus in different well sections.

[0015] Furthermore, the particle migration velocity prediction model includes a particle migration velocity prediction model corresponding to a power-law fluid and a particle migration velocity prediction model corresponding to a Herbach fluid;

[0016] The particle migration velocity prediction model corresponding to the power-law fluid is expressed as follows:

[0017] ;

[0018] ;

[0019] ;

[0020] The particle migration velocity prediction model corresponding to the Heba fluid is expressed as follows:

[0021] ;

[0022] ;

[0023] ;

[0024] in, V f is the circulation rate of drilling fluid, V s is the upward migration velocity of cuttings, C D is the drag coefficient; Re s is the particle Reynolds number, ρ s is the particle density of rock cuttings, d is the particle size of rock debris particles, g is the acceleration due to gravity, ρ f is the drilling fluid density, K is the viscosity coefficient of drilling fluid, n is the fluidity index of drilling fluid, τ 0 is the yield value of drilling fluid.

[0025] Furthermore, the minimum rock-carrying capacity of the booster pipeline is determined based on the circulation return velocity and the minimum flow velocity of the drilling fluid in the riser section, specifically including:

[0026] Determining whether the circulation return velocity of the drilling fluid in the riser section is greater than the minimum flow velocity;

[0027] If the circulation return velocity of the drilling fluid in the watertight pipe section is less than the minimum flow velocity, determine the speed difference between the circulation return velocity of the drilling fluid in the watertight pipe section and the minimum flow velocity, and determine the minimum rock carrying capacity of the booster pipeline based on the speed difference.

[0028] Furthermore, based on the wellbore structural parameters, the drilling fluid parameters and the number of drilling fluid circulation cycles, the total circulation time of the drilling fluid in the deepwater drilling wellbore is calculated, specifically including:

[0029] Calculating the circulation volume of the drilling fluid in the deepwater drilling wellbore based on the wellbore structural parameters;

[0030] The total circulation time of the drilling fluid in the deepwater drilling wellbore is calculated according to the circulation volume, the drilling fluid parameters and the number of drilling fluid circulation cycles.

[0031] Furthermore, determining the minimum velocity required for cuttings to return from the annulus of the riser section based on the total migration time and the total circulation time specifically includes:

[0032] Calculating a maximum allowable time for cuttings to return from the annulus of the riser section based on the total migration time and the total circulation time;

[0033] Based on the maximum allowed time and the depth of the watertight pipe section, the minimum speed required for the rock cuttings to return from the annulus of the watertight pipe section is calculated.

[0034] Furthermore, the wellbore structure parameters include well depth, casing section depth, riser section depth, open hole section depth, drill string inner diameter, drill string outer diameter, casing annulus inner diameter and riser annulus inner diameter; the cuttings characteristic parameters include particle size and density; and the drilling fluid parameters include drilling fluid density, drilling fluid displacement and rheological parameters.

[0035] In a second aspect, the present invention provides a system for calculating the minimum rock-carrying displacement of a deepwater riser drilling booster pipeline, comprising:

[0036] An acquisition module is used to collect wellbore structural parameters, cuttings characteristic parameters and drilling fluid parameters of a deepwater drilling wellbore, and determine the number of circulation cycles of the drilling fluid;

[0037] A first calculation module is configured to calculate, based on the wellbore structure parameters and the drilling fluid parameters, the circulation return rate of the drilling fluid in each well section of the deepwater drilling wellbore, wherein the each well section includes an open hole section, a casing section, and a water-receiving pipe section; calculate, based on the circulation return rate of the drilling fluid in the open hole section and the casing section, the cuttings characteristic parameters, and the drilling fluid parameters, the upward return migration rate of the cuttings in the casing section and the open hole section using a pre-constructed particle migration velocity prediction model; and calculate, based on the upward return migration rate of the cuttings in the casing section and the open hole section, the total migration time of the cuttings in the casing section and the open hole section;

[0038] The second calculation module is used to calculate the total circulation time of the drilling fluid in the deep-water drilling wellbore based on the wellbore structure parameters, drilling fluid parameters and the number of drilling fluid circulation cycles; determine the minimum speed required for the cuttings to return from the annulus of the watertight pipe section according to the total migration time and the total circulation time; and calculate the minimum flow rate of the drilling fluid in the watertight pipe section using the particle migration speed prediction model according to the minimum speed, the cuttings characteristic parameters and the drilling fluid parameters;

[0039] The determination module is used to determine the minimum rock carrying capacity of the booster pipeline according to the circulation return velocity and the minimum flow velocity of the drilling fluid in the water-resistant pipe section.

[0040] At least one technical solution adopted by the present invention can achieve the following beneficial effects: by combining the calculation of the minimum rock-carrying displacement with the parameter of the number of drilling fluid circulation cycles, the present invention more accurately considers the time threshold required for the complete migration of rock cuttings, thereby avoiding the risk of rock cuttings retention and pipe sticking caused by the inaccurate calculation results of the minimum rock-carrying displacement in the prior art (the prior art generally assumes that a drilling fluid flow rate slightly higher than the particle settling velocity is sufficient to meet the rock-carrying requirements, resulting in the calculated pressurized pipeline rock-carrying displacement being unable to ensure that the rock cuttings are completely returned to the wellhead within a limited time). The present invention calculates the upward migration velocity of cuttings in the casing and openhole sections by constructing a particle migration velocity prediction model. This model integrates three key elements of cuttings migration: solid / liquid physical properties (cuttings particle size, drilling fluid / cuttings density), drilling fluid rheological properties (yield stress, consistency coefficient, and fluidity index), and annular geometry constraints (wellbore structure, wellbore dimensions, etc.). Taking into account the shear thinning or yield stress of the actual drilling fluid, this model can produce a more accurate cuttings upward migration velocity compared to existing techniques that directly use empirical formulas for the drag coefficient of Newtonian fluids (such as the Stokes equation or the Schiller-Naumann equation). Furthermore, the present invention reveals the dynamic coupling mechanism between drilling fluid flow rate, cuttings particle drag properties, and wellbore hydraulics. By integrating cuttings size, density, fluid rheological parameters (yield stress, consistency coefficient, and fluidity index), and riser geometry (annulus inner and outer diameters, depth), the model improves its adaptability to actual operating conditions. Therefore, compared with the existing technology, the present invention can more accurately calculate the minimum rock carrying capacity of the booster pipeline, which can not only improve the auxiliary rock discharge effect of the booster pipeline and ensure that the rock cuttings can be smoothly returned from the wellbore, but also avoid excessive rock carrying capacity of the booster pipeline, reduce energy consumption, and take into account both safety and economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0042] Figure 1 A flow chart of the method for calculating the minimum rock-carrying displacement of a deepwater riser drilling booster pipeline provided by the present invention;

[0043] Figure 2 A flow chart of another method for calculating the minimum rock-carrying displacement of a deepwater riser drilling booster pipeline provided by the present invention;

[0044] Figure 3 The minimum rock carrying capacity of the water-relief booster pipeline under different drilling fluid circulation cycles provided by the present inventionQ s Changes with drilling fluid displacement;

[0045] Figure 4 Schematic diagram of the minimum rock-carrying displacement calculation system for the deepwater riser drilling booster pipeline provided by the present invention. DETAILED DESCRIPTION

[0046] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention and corresponding drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0047] The server mentioned in the present invention can be a server installed on a business platform, or a device such as a desktop computer or laptop computer capable of executing the solution of the present invention. For ease of explanation, the following description will only use the server as the execution entity. The following, combined with the accompanying drawings, details the technical solutions provided by various embodiments of the present invention.

[0048] refer to Figure 1 The method for calculating the minimum rock-carrying displacement of a deepwater riser drilling booster pipeline in the present invention specifically comprises the following steps:

[0049] S10: collecting wellbore structural parameters, cuttings characteristic parameters and drilling fluid parameters of the deepwater drilling wellbore, and determining the number of circulation cycles of the drilling fluid.

[0050] In this embodiment, the wellbore structural parameters include well depth ( H t ), casing section depth ( H c ), open hole depth ( H b ), riser section depth ( H r ), drill string inner diameter ( D PI )、Drill string outer diameter( D PO ), open hole section wellbore diameter ( D b ), casing annulus inner diameter ( D C ) and the inner diameter of the riser annulus ( D r ), cuttings characteristic parameters include particle size ( d ) and density ( ρ s ), drilling fluid parameters include drilling fluid density ( ρ f ), drilling fluid displacement ( Q t ) and rheological parameters (yield value τ 0. Consistency coefficient K , liquidity index n ).

[0051] Specifically, refer to Figure 2 At step "Start", enter the basic parameters and the number of drilling fluid circulation cycles n c Among them, the basic parameters refer to the wellbore structure parameters, cuttings characteristic parameters and drilling fluid parameters, the number of drilling fluid circulation cycles n c As a restriction.

[0052] S20: Based on the wellbore structure parameters and drilling fluid parameters, the circulation return rate of the drilling fluid in each well section of the deepwater drilling wellbore is calculated, and each well section includes the open hole section, the casing section and the water-receiving pipe section; based on the circulation return rate of the drilling fluid in the open hole section and the casing section, the cuttings characteristic parameters and the drilling fluid parameters, the pre-built particle migration velocity prediction model is used to calculate the upward migration velocity of the cuttings in the casing section and the open hole section; based on the upward migration velocity of the cuttings in the casing section and the open hole section, the total migration time of the cuttings in the casing section and the open hole section is calculated.

[0053] S30: Based on the wellbore structure parameters, drilling fluid parameters and the number of drilling fluid circulation cycles, calculate the total circulation time of the drilling fluid in the deepwater drilling wellbore; determine the minimum speed required for the cuttings to return from the annulus of the watertight pipe section based on the total migration time and the total circulation time; calculate the minimum flow rate of the drilling fluid in the watertight pipe section using the particle migration velocity prediction model based on the minimum speed, cuttings characteristic parameters and drilling fluid parameters.

[0054] In this embodiment, the circulation return rate of the drilling fluid in each well section in the wellbore refers to the circulation return rate of the drilling fluid in the annulus of each well section, which is recorded as V f Annulus refers to the annular space formed between each well section (such as open hole section, casing section, and riser section) and the adjacent drill string, including the open hole section annulus, casing section annulus, and riser section annulus. The annular flow rate of the drilling fluid in the open hole section annulus, casing section annulus, and riser section annulus is recorded as V bh 、 V c and V r .

[0055] In this embodiment, based on the circulation return rate of the drilling fluid in the open hole section and the casing section, the cuttings characteristic parameters and the drilling fluid parameters, the pre-built particle migration velocity prediction model is used to calculate the upward migration velocity of the cuttings in the casing section and the open hole section. The Newton iteration method is used to calculate the upward migration velocity of the cuttings in the annulus of the casing section and the open hole section for different non-Newtonian drilling fluids (power law fluid or Herbach fluid). V s .

[0056] Specifically, the particle migration velocity prediction model corresponding to the power-law fluid is expressed as follows:

[0057] (1)

[0058] (2)

[0059] (3)

[0060] The particle migration velocity prediction model corresponding to the Heba fluid is expressed as follows:

[0061] (4)

[0062] (5)

[0063] (6)

[0064] in, V f is the circulation rate of drilling fluid, V s is the upward migration velocity of cuttings, C D is the drag coefficient; Re s is the particle Reynolds number, ρ s is the particle density of rock cuttings, d is the particle size of rock debris particles, g is the acceleration due to gravity, ρ f is the drilling fluid density, K is the viscosity coefficient of drilling fluid.

[0065] After obtaining the upward migration speed of the cuttings in the casing section and the open hole section, the total migration time of the cuttings in the casing section and the open hole section is calculated according to the length of the casing section and the open hole section.

[0066] Furthermore, based on the wellbore structural parameters, drilling fluid parameters, and the number of drilling fluid circulation cycles, calculating the total circulation time of the drilling fluid in the deepwater drilling wellbore specifically includes:

[0067] The circulation volume of drilling fluid in deepwater drilling wellbore is calculated based on wellbore structural parameters.

[0068] The total circulation time of drilling fluid in deepwater drilling wellbore is calculated based on the circulation volume, drilling fluid parameters and the number of drilling fluid circulation cycles.

[0069] Specifically, the circulation volume of drilling fluid in a deepwater drilling wellbore refers to the total volume of drilling fluid circulating in the drill string and annulus. The calculation expression is as follows:

[0070] (7)

[0071] in, V tot Refers to the circulation volume of drilling fluid in the wellbore. A dp 、 A bh 、 A c 、 A r are the cross-sectional areas of the drill string, open hole annulus, casing annulus, and riser annulus, respectively. H tot Refers to the depth of the well, H c Refers to the depth of the casing section, H r Refers to the depth of the riser section.

[0072] After obtaining the circulation volume of drilling fluid in deep-water drilling wellbore, further calculate the single circulation time of drilling fluid in deep-water drilling wellbore T cycle , the expression is as follows:

[0073] (8)

[0074] in, Q t Refers to the drilling fluid displacement.

[0075] Specifically, the single circulation time of the drilling fluid in the deepwater drilling wellbore is multiplied by the number of drilling fluid circulation cycles. n c , get the total circulation time of drilling fluid in deepwater drilling wellbore, T tot The calculation expression is as follows:

[0076] (9)

[0077] In this embodiment, the minimum velocity required for cuttings to return from the annulus of the riser section is determined based on the total migration time and the total circulation time, specifically including:

[0078] Based on the total migration time and the total circulation time, calculate the maximum allowable time required for the cuttings to return from the annulus of the watertight pipe section.

[0079] Based on the maximum allowable time and the riser depth, calculate the minimum velocity required for cuttings to return from the annulus of the riser.

[0080] Specifically, based on the total migration time and the total circulation time, the maximum allowable time required for cuttings to return from the annulus of the riser section is calculated as follows: the total migration time of cuttings in the casing section and the open hole section is subtracted from the total circulation time of the drilling fluid in the wellbore to obtain the maximum allowable time required for cuttings to return from the annulus of the riser section. Furthermore, the minimum speed required for cuttings to return from the annulus of the riser section is obtained by dividing the maximum allowable time required for cuttings to return from the annulus of the riser section by the depth of the riser section. V cm , the calculation expression is:

[0081] (10)

[0082] In this embodiment, the particle migration velocity prediction model is used to calculate the minimum flow velocity of the drilling fluid in the riser section based on the minimum velocity, cuttings characteristic parameters, and drilling fluid parameters as follows:

[0083] Based on the minimum velocity required for cuttings to return from the annulus of the riser section V cm , cuttings characteristic parameters and drilling fluid parameters, using formula (1)-formula (6), the minimum flow rate of drilling fluid in the watertight pipe section can be inferred.

[0084] S40: Determine the minimum rock-carrying capacity of the booster pipeline based on the circulation return velocity and minimum flow rate of the drilling fluid in the riser section.

[0085] based on Figure 1The method for calculating the minimum rock-carrying capacity of a booster line for deepwater riser drilling shown in the figure combines the calculation of the minimum rock-carrying capacity with the parameter of the number of drilling fluid circulation cycles. This more accurately considers the time threshold required for complete migration of cuttings, avoids the problem of cuttings deposition caused by the infinite time assumption in existing technologies, and thus solves the risks of cuttings retention and pipe sticking (existing technologies generally assume that a drilling fluid flow rate slightly higher than the particle settling velocity is sufficient to meet the rock-carrying requirements, resulting in the calculated booster line rock-carrying capacity being unable to ensure that the cuttings are completely returned to the wellhead within a limited time). The present invention calculates the upward migration velocity of cuttings in the casing and openhole sections by constructing a particle migration velocity prediction model. This model integrates three key elements of cuttings migration: solid / liquid physical properties (cuttings particle size, drilling fluid / cuttings density), drilling fluid rheological properties (yield stress, consistency coefficient, and fluidity index), and annular geometry constraints (wellbore structure, wellbore dimensions, etc.). Taking into account the shear thinning or yield stress of the actual drilling fluid, combined with velocity gap analysis, the annular velocity in the riser section is consistently above the critical rock-carrying velocity, ensuring continuous upward migration of cuttings and achieving a more accurate upward migration velocity. Furthermore, the present invention reveals the dynamic coupling mechanism between drilling fluid displacement, cuttings particle drag properties, and wellbore hydraulics. By integrating cuttings size, density, fluid rheological parameters (yield stress, consistency coefficient, and fluidity index), and riser geometry (annulus inner diameter and depth), the model improves its compatibility with actual operating conditions. Therefore, by quantifying the velocity gap and the boosting displacement, the present invention can more accurately calculate the minimum rock-carrying displacement of the boosting pipeline compared to the existing technology. This not only improves the auxiliary rock discharge effect of the boosting pipeline and ensures that the rock cuttings can be smoothly discharged from the deep-water drilling wellbore, but also avoids excessive rock-carrying displacement of the boosting pipeline, reduces energy consumption, and takes into account both safety and economy.

[0086] When applying the method for calculating the minimum rock carrying capacity of the deepwater riser drilling booster pipeline provided by the present invention, it is not necessary to use Figure 1 The steps are executed in the order shown. The specific execution order of the steps can be determined according to needs, and the present invention does not limit this.

[0087] Furthermore, in one or more embodiments of the present invention, the minimum rock-carrying capacity of the booster pipeline is determined based on the circulation return velocity and the minimum flow velocity of the drilling fluid in the riser section, specifically including:

[0088] Determine whether the circulation return velocity of the drilling fluid in the riser section is greater than the minimum flow rate.

[0089] If the circulation return velocity of the drilling fluid in the riser section is less than the minimum flow velocity, determine the velocity difference between the circulation return velocity of the drilling fluid in the riser section and the minimum flow velocity, and determine the minimum rock carrying capacity of the booster pipeline based on the velocity difference.

[0090] In this embodiment, reference Figure 2, after obtaining the minimum flow rate of drilling fluid in the riser section (in the annulus) V dm The circulation velocity of drilling fluid in the riser section (annular flow velocity V r ) After that, judge V dm and V r If the size V dm Less than V r , the riser booster pipeline does not need to be opened, otherwise the riser booster pipeline needs to be opened, and the velocity difference between the circulation return velocity of the drilling fluid in the riser section and the minimum flow velocity is determined. Based on the velocity difference, the minimum rock carrying capacity of the booster pipeline is determined. The calculation expression is:

[0091] (11)

[0092] in, Q s Add additional displacement to the boost line.

[0093] Optionally, if the calculation result does not meet the field operation requirements (such as displacement exceeding the limit or energy consumption being too high), the number of cycles or drilling fluid rheological parameters can be adjusted and the calculation can be repeated. Output the final minimum displacement value Q s and the corresponding optimization parameter combinations.

[0094] This embodiment scheme calculates the minimum rock-carrying capacity of the watertight riser booster pipeline based on the flow rate gap logic, quantifies the booster pipeline demand, and shortens the drilling fluid circulation time by optimizing the booster pipeline capacity, greatly improving the operation efficiency, reducing the drilling downtime due to rock cuttings retention, reducing the non-production time cost, and avoiding insufficient or excessive rock-carrying capacity of the booster pipeline, thereby achieving the dual-objective optimization of safety and economy.

[0095] The following is a further introduction to this solution with reference to specific embodiments:

[0096] Taking the wellbore parameters of a deepwater drilling as an example, the drilling fluid density is input as 1200 kg / m 3 , drill pipe outer diameter 0.127 m, drill pipe inner diameter 0.109 m, riser inner diameter 558.8 mm, riser depth 1000 m, casing section inner diameter 0.2445 m, casing section depth 1800 m, open hole section inner diameter 0.2 m, open hole section depth 1200 m, drilling fluid displacement 220 m 3 / h, rock cuttings particle size 5 mm, rock cuttings density 2600 kg / m 3 , drilling fluid viscosity coefficient 0.2 Pa.s n, drilling fluid fluidity index 0.6. Through the above process, the minimum rock carrying capacity of the riser booster pipeline is calculated under the conditions of target circulation weeks of 1 week, 1.5 weeks and 2 weeks. Q s Changes with drilling fluid displacement.

[0097] like Figure 3 As shown in the figure, the minimum displacement of the booster pipeline decreases linearly with the increase of drilling fluid displacement. Under the three cycle conditions, when the displacement increases from 160 m 3 / h increased to 260 m 3 / h, the minimum displacement of the booster pipeline is 114.7 m 3 / h, 56.3m 3 / h, 31.9 m 3 / h dropped to 99.4 m 3 / h, 7.3 m 3 / h,0 m 3 / h, indicating that high displacement can significantly reduce the dependence on the booster pipeline. Extending the cycle period can further reduce the demand for the booster pipeline. 3 / h as an example, the minimum displacement of the booster pipeline corresponding to one cycle is 106.3 m 3 / h, 1.5 cycles down to 29.3 m 3 / h, a 72.4% reduction, while two cycles do not require additional booster capacity. However, extending the cycle time increases operation time and pump energy costs, requiring a balance between economic efficiency and rock-carrying efficiency. Taking a 215 m³ / h displacement as an example, two cycles take approximately 6152.8 seconds longer than one cycle. The cost balance between the additional cycle time and the need for 106.3 m³ / h of booster capacity should be comprehensively evaluated.

[0098] The above is a method for calculating the minimum rock carrying capacity of a deepwater riser drilling booster pipeline provided by one or more embodiments of the present invention. Based on the same idea, the present invention also provides a corresponding system for calculating the minimum rock carrying capacity of a deepwater riser drilling booster pipeline, such as Figure 4 Shown, including:

[0099] The acquisition module is used to collect the wellbore structure parameters, cuttings characteristic parameters and drilling fluid parameters of the deepwater drilling wellbore, and determine the number of circulation cycles of the drilling fluid.

[0100] The first calculation module is used to calculate the circulation return rate of the drilling fluid in each section of the deep-water drilling wellbore based on the wellbore structure parameters and the drilling fluid parameters. Each section includes the open hole section, the casing section and the water-repellent pipe section; based on the circulation return rate of the drilling fluid in the open hole section and the casing section, the cuttings characteristic parameters and the drilling fluid parameters, the pre-built particle migration velocity prediction model is used to calculate the upward return migration velocity of the cuttings in the casing section and the open hole section; based on the upward return migration velocity of the cuttings in the casing section and the open hole section, the total migration time of the cuttings in the casing section and the open hole section is calculated.

[0101] The second calculation module is used to calculate the total circulation time of the drilling fluid in the deep-water drilling wellbore based on the wellbore structure parameters, drilling fluid parameters and the number of drilling fluid circulation cycles; determine the minimum speed required for the cuttings to return from the annulus of the watertight pipe section according to the total migration time and the total circulation time; and calculate the minimum flow rate of the drilling fluid in the watertight pipe section using the particle migration velocity prediction model based on the minimum speed, cuttings characteristic parameters and drilling fluid parameters.

[0102] The determination module is used to determine the minimum rock carrying capacity of the booster pipeline based on the circulation return velocity and minimum flow rate of the drilling fluid in the water-receiving pipe section.

[0103] Regarding the specific definition of the minimum rock-carrying displacement calculation system for deepwater riser drilling and boosting pipelines, please refer to the definition of the minimum rock-carrying displacement calculation method for deepwater riser drilling and boosting pipelines mentioned above, which will not be repeated here. The various modules in the minimum rock-carrying displacement calculation system for deepwater riser drilling and boosting pipelines can be fully or partially implemented by software, hardware and their combination. The modules can be embedded in or independent of the processor in the computer device in hardware form, or can be stored in the memory of the computer device in software form, so that the processor can call and execute the operations corresponding to the above modules.

[0104] The present invention also provides a computer-readable storage medium, which stores a computer program, which can be used to execute the Figure 1 A calculation method for the minimum rock-carrying capacity of a booster pipeline for deepwater riser drilling is provided.

[0105] Those skilled in the art will appreciate that all or part of the processes in the described method embodiments can be implemented by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the described method embodiments. Any reference to memory, storage, database, or other media used in the embodiments provided herein may include at least one of non-volatile and volatile memory. Non-volatile memory may include read-only memory (ROM), magnetic tape, floppy disk, flash memory, or optical storage. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can take various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0106] The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of the present invention.

Claims

1. A method for calculating the minimum rock-carrying capacity of a deepwater riser drilling booster pipeline, characterized in that: include: Collect the wellbore structure parameters, cuttings characteristic parameters and drilling fluid parameters of deepwater drilling wells, and determine the number of drilling fluid circulation cycles; Based on the wellbore structure parameters and drilling fluid parameters, the circulation return rate of the drilling fluid in each well section of the deepwater drilling wellbore is calculated, and the each well section includes an open hole section, a casing section, and a water-receiving pipe section; based on the circulation return rate of the drilling fluid in the open hole section and the casing section, the cuttings characteristic parameters, and the drilling fluid parameters, the upward return migration rate of the cuttings in the casing section and the open hole section is calculated using a pre-constructed particle migration velocity prediction model; based on the upward return migration rate of the cuttings in the casing section and the open hole section, the total migration time of the cuttings in the casing section and the open hole section is calculated; Based on the wellbore structure parameters, drilling fluid parameters and the number of drilling fluid circulation cycles, the total circulation time of the drilling fluid in the deepwater drilling wellbore is calculated; based on the total migration time and the total circulation time, the minimum velocity required for the cuttings to return from the annulus of the watertight pipe section is determined; based on the minimum velocity, the cuttings characteristic parameters and the drilling fluid parameters, the minimum flow rate of the drilling fluid in the watertight pipe section is calculated using the particle migration velocity prediction model; Determine the minimum rock-carrying capacity of the booster pipeline based on the circulation return velocity and minimum flow rate of the drilling fluid in the riser section; The particle migration velocity prediction model includes a particle migration velocity prediction model corresponding to a power-law fluid and a particle migration velocity prediction model corresponding to a Herbach fluid; The particle migration velocity prediction model corresponding to the power-law fluid is expressed as follows: The particle migration velocity prediction model corresponding to the Heba fluid is expressed as follows: Among them, V f is the circulation velocity of drilling fluid, V s is the upward migration velocity of cuttings, C D is the resistance coefficient; Re s is the particle Reynolds number, ρ s is the particle density of rock cuttings, d is the particle size of rock cuttings, g is the acceleration of gravity, ρ f is the density of drilling fluid, K is the viscosity coefficient of drilling fluid, n is the fluidity index of drilling fluid, and τ0 is the yield value of drilling fluid.

2. The method for calculating the minimum rock carrying capacity of a deepwater riser drilling booster pipeline according to claim 1, wherein: Based on the wellbore structural parameters and the drilling fluid parameters, the circulation return rate of the drilling fluid in each well section of the deepwater drilling wellbore is calculated. The specific calculation expression is: Among them, V f is the circulation rate of drilling fluid, Q t is the displacement of drilling fluid pump, and A is the cross-sectional area of the annulus in different well sections.

3. The method for calculating the minimum rock carrying capacity of a deepwater riser drilling booster pipeline according to claim 1, wherein: The minimum rock-carrying capacity of the booster pipeline is determined based on the circulation return velocity and minimum flow rate of the drilling fluid in the riser section, specifically including: Determining whether the circulation return velocity of the drilling fluid in the riser section is greater than the minimum flow velocity; If the circulation return velocity of the drilling fluid in the watertight pipe section is less than the minimum flow velocity, determine the speed difference between the circulation return velocity of the drilling fluid in the watertight pipe section and the minimum flow velocity, and determine the minimum rock carrying capacity of the booster pipeline based on the speed difference.

4. The method for calculating the minimum rock carrying capacity of a deepwater riser drilling booster pipeline according to claim 1, wherein: Calculating the total circulation time of the drilling fluid in the deepwater drilling wellbore based on the wellbore structure parameters, the drilling fluid parameters, and the number of drilling fluid circulation cycles, specifically comprising: Calculating a circulation volume of drilling fluid in the deepwater drilling wellbore based on the wellbore structural parameters; The total circulation time of the drilling fluid in the deepwater drilling wellbore is calculated according to the circulation volume, the drilling fluid parameters and the number of drilling fluid circulation cycles.

5. The method for calculating the minimum rock carrying capacity of a deepwater riser drilling booster pipeline according to claim 1, wherein: Determining the minimum velocity required for cuttings to return from the annulus of the riser section based on the total migration time and the total circulation time, specifically including: Calculating a maximum allowable time for cuttings to return from the annulus of the riser section based on the total migration time and the total circulation time; Based on the maximum allowed time and the depth of the watertight pipe section, the minimum speed required for the rock cuttings to return from the annulus of the watertight pipe section is calculated.

6. The method for calculating the minimum rock carrying capacity of a deepwater riser drilling booster pipeline according to claim 1, wherein: The wellbore structure parameters include well depth, casing section depth, riser section depth, open hole section depth, open hole section wellbore diameter, drill string inner diameter, drill string outer diameter, casing annulus inner diameter and riser annulus inner diameter; the rock cutting characteristic parameters include particle size and density; the drilling fluid parameters include drilling fluid density, drilling fluid displacement and rheological parameters.

7. The minimum rock-carrying capacity calculation system for deepwater riser drilling booster pipeline is characterized by: include: An acquisition module is used to collect wellbore structural parameters, cuttings characteristic parameters and drilling fluid parameters of a deepwater drilling wellbore, and determine the number of circulation cycles of the drilling fluid; A first calculation module is configured to calculate, based on the wellbore structure parameters and the drilling fluid parameters, the circulation return rate of the drilling fluid in each well section of the deepwater drilling wellbore, wherein the each well section includes an open hole section, a casing section, and a water-receiving pipe section; calculate, based on the circulation return rate of the drilling fluid in the open hole section and the casing section, the cuttings characteristic parameters, and the drilling fluid parameters, the upward return migration rate of the cuttings in the casing section and the open hole section using a pre-constructed particle migration velocity prediction model; and calculate, based on the upward return migration rate of the cuttings in the casing section and the open hole section, the total migration time of the cuttings in the casing section and the open hole section; a second calculation module, configured to calculate a total circulation time of the drilling fluid in the deepwater drilling wellbore based on the wellbore structural parameters, the drilling fluid parameters, and the number of drilling fluid circulation cycles; Determine the minimum velocity required for cuttings to return from the annulus of the riser section based on the total migration time and the total circulation time; calculate the minimum flow rate of the drilling fluid in the riser section using the particle migration velocity prediction model based on the minimum velocity, the cuttings characteristic parameters, and the drilling fluid parameters; a determination module, configured to determine a minimum rock-carrying displacement of the booster pipeline according to a circulation return velocity and a minimum flow velocity of the drilling fluid in the riser section; The particle migration velocity prediction model includes a particle migration velocity prediction model corresponding to a power-law fluid and a particle migration velocity prediction model corresponding to a Herbach fluid; The particle migration velocity prediction model corresponding to the power-law fluid is expressed as follows: The particle migration velocity prediction model corresponding to the Heba fluid is expressed as follows: Among them, V f is the circulation velocity of drilling fluid, V s is the upward migration velocity of cuttings, C D is the resistance coefficient; Re s is the particle Reynolds number, ρ s is the particle density of rock cuttings, d is the particle size of rock cuttings, g is the acceleration of gravity, ρ f is the density of drilling fluid, K is the viscosity coefficient of drilling fluid, n is the fluidity index of drilling fluid, and τ0 is the yield value of drilling fluid.

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