Track control method for ultra-deep high-temperature slim-hole horizontal well

Abstract

The invention provides an ultra-deep high-temperature slim-hole horizontal well track control method, and relates to the technical field of oil drilling, the method comprises the following steps: aiming at an ultra-deep high-temperature slim-hole horizontal well, according to engineering drilling requirements, carrying out borehole track design, and determining a borehole track form and borehole track parameters; based on the borehole trajectory form and the borehole trajectory parameters, drilling tool combination optimization is conducted on each section of borehole trajectory, and a drilling tool combination optimization result corresponding to each section of borehole trajectory is determined; according to the optimal selection result of the drilling tool combination, the influence of the drilling tool combination on the build-up rate is analyzed, and the well deviation change rate of the drilling tool combination is determined; and determining the maximum control step length of the well track by combining the well track parameters and the drilling tool combination well deviation change rate and considering the actual drilling well deviation change rate difference. The method can ensure the target in the ultra-deep high-temperature horizontal well and improve the drilling speed under the condition that no measurement-while-drilling instrument exists, and has good application and popularization prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of oil drilling, and is applied to wellbore trajectory control of horizontal wells in ultra-deep, high-temperature, slim-bore conditions. Specifically, it relates to a method for controlling the trajectory of ultra-deep, high-temperature, slim-bore horizontal wells. Background Art

[0002] The reservoir of horizontal wells in Shunbei Oilfield in China is deep (7500-8500m) and the bottomhole temperature is high (160-200℃). The failure rate of measurement while drilling (MWD) instruments is high during the drilling of the lower well section. In some wells, the MWD instruments simply fail to work. In this case, not only is there no MWD instrument in the lower drill string assembly, but multi-point inclinometers and "hanging measurement" methods are not used to monitor the wellbore trajectory during drilling. Only when each drilling trip is pulled out of the wellbore, multi-point inclinometers and "casting measurement" methods are used to measure the wellbore trajectory corresponding to that drilling trip. Without MWD instruments, it is impossible to measure and control the wellbore trajectory in real time during drilling. The only option is to rely on the wellbore trajectory parameters obtained by "casting measurement" before each drilling trip to perform inclination calculations and design the trajectory to be drilled. Then, according to the trajectory control requirements of the wellbore to be drilled (mainly the well inclination change rate), the drill string assembly and drilling parameters for the next drilling trip are selected. In this case, whether using a bent screw drill assembly composite drilling or a conventional drill assembly rotary table drilling, only the well inclination angle can be controlled but the azimuth angle cannot be controlled, which affects the drilling efficiency and target accuracy.

[0003] In response to the problems of the prior art, the present invention provides a method for controlling the trajectory of an ultra-deep, high-temperature, slim-hole horizontal well. Summary of the Invention

[0004] In response to the problems of the current existing technology, the present invention provides a method for controlling the trajectory of an ultra-deep, high-temperature, slim-hole horizontal well, which comprises the following steps:

[0005] For ultra-deep, high-temperature, slim-hole horizontal wells, wellbore trajectory design is performed according to engineering drilling requirements to determine the wellbore trajectory form and wellbore trajectory parameters;

[0006] Based on the wellbore trajectory form and the wellbore trajectory parameters, respectively, performing drilling tool assembly optimization for each wellbore trajectory, and determining a drilling tool assembly optimization result corresponding to each wellbore trajectory;

[0007] Analyze the influence of the drilling tool assembly on the build-up rate based on the drilling tool assembly optimization result, and determine the well inclination change rate of the drilling tool assembly;

[0008] The maximum control step length of the wellbore trajectory is determined by combining the wellbore trajectory parameters and the well inclination change rate of the drilling tool assembly and taking into account the difference in well inclination change rate during actual drilling.

[0009] According to one embodiment of the present invention, the engineering drilling requirement refers to: for the deflection section of an ultra-deep, high-temperature, small-bore horizontal well, the first drilling trip uses a downhole measurement instrument for directional deflection, and the subsequent drilling does not use a downhole measurement instrument to ensure that there are no downhole measurement instruments in the lower deflection section and all horizontal sections.

[0010] According to one embodiment of the present invention, the wellbore trajectory is: vertical well section - deflection section - horizontal section, wherein the deflection section includes: directional deflection section - first slowly increasing deflection section - second slowly increasing deflection section, K z >>K w1 >K w2 , K z Indicates the deflection rate of the directional deflection section; K w1 Indicates the build rate of the first slowly increasing slope section; K w2 Indicates the slope rate of the second slowly increasing slope section.

[0011] According to one embodiment of the present invention, the wellbore trajectory parameters include but are not limited to: target vertical depth D t , closing distance C t , horizontal section well inclination angle α t , vertical depth of inclination point D a , directional deflection section deflection rate K z , directional deflection section deflection radius R z , well inclination angle α at the end of directional deflection section b , the first slowly increasing slope rate K w1 , the first slowly increasing slope section radius R w1 , the inclination angle α at the end of the first slowly increasing inclination section c , the second slowly increasing slope rate K w2 , the radius of the second slowly increasing inclined section R w2 .

[0012] According to one embodiment of the present invention, the drilling tool assembly optimization result corresponding to each wellbore trajectory is determined by the following steps:

[0013] For the directional deflection section, according to the deflection rate K of the directional deflection section z , determine the screw bending angle value and drilling method of the directional deflection section, and select a single-bend single-stabilizer drill tool assembly or a single-bend stabilizer-free drill tool assembly according to the downhole conditions;

[0014] For the first slowly increasing slope section, according to the first slowly increasing slope section slope rate K w1 , determine the screw bend angle value and drilling method for the first slow-increase section, and select a single-bend single-stabilizer drill string assembly or a single-bend stabilizer-free drill string assembly based on the well inclination angle at the end of the first drilling run of the first slow-increase section;

[0015] For the second slowly increasing slope section, according to the slope rate K of the second slowly increasing slope sectionw2 , determine the screw bending angle value and drilling method of the second slow-increase section, and select a single-bend double-stabilizer drill tool assembly or a double-stabilizer drill tool assembly based on the slow-increase or slow-decline effect;

[0016] For the horizontal section, the screw bending angle value and drilling method of the horizontal section are determined according to the target half-height, target half-width and maximum wellbore curvature required by the target area parameters and the wellbore trajectory control. According to the effect of slow increase or slow decrease in inclination, a single-bend double-stabilizer drill tool combination or a double-stabilizer drill tool combination is selected.

[0017] According to one embodiment of the present invention, the well inclination change rate of the drilling tool assembly is determined by the following steps:

[0018] For each drilling tool combination, the full-strength inclination rate K is calculated by the inclination rate prediction method. z1 、Full force slope reduction rate K z2 The average value of the full-force increase inclination rate and the full-force decrease inclination rate is taken as the composite drilling well inclination change rate K r ;

[0019] The orthogonal analysis method is used to find the factors affecting the composite drilling well deviation change rate K. r Based on the key influencing factors and influencing rules, the regression analysis method is used to construct the composite drilling well inclination change rate fitting expression corresponding to each drilling tool assembly to determine the well inclination change rate of the drilling tool assembly.

[0020] According to one embodiment of the present invention, the maximum control step length of the wellbore trajectory is determined by the following steps:

[0021] Based on the build-up rate corresponding to each wellbore trajectory and the well inclination change rate of the drilling tool assembly, the bottom hole distance and well inclination angle deviation between the original designed trajectory and the trajectory to be drilled after a single drilling trip are estimated;

[0022] The bottom hole distance is limited by referring to the target area parameters, the single-pass drilling step length is iteratively solved, and the maximum value is selected as the first maximum control step length;

[0023] The well inclination deviation is limited by referring to the target area parameters, the single-trip drilling step length is iteratively solved, and the maximum value is selected as the second maximum control step length;

[0024] Considering the drill bit footage limited by the drill bit life, the third maximum control step length is obtained;

[0025] The minimum value among the first maximum control step length, the second maximum control step length, and the third maximum control step length is taken as the maximum control step length of the wellbore trajectory.

[0026] According to one embodiment of the present invention, the first maximum control step size is determined by the following expression:

[0027]

[0028] Where: d represents the distance between the original design trajectory and the bottom of the well to be drilled; K0 represents the inclination rate of the original design wellbore trajectory; R0 represents the inclination radius corresponding to the inclination rate K0; K x Indicates the actual inclination rate of the drilling tool assembly, that is, the rate of change of the well inclination of the drilling tool assembly; R x Indicates the actual deflection radius of the drilling tool assembly; L x Indicates the progress of drilling in a single trip;

[0029] The second maximum control step size is determined by the following expression:

[0030] Δα=|Δα0-Δα x |=|K0-K x |L x

[0031] Where: Δα represents the deviation of the wellbore angle between the original design trajectory and the trajectory to be drilled; Δα0 represents the wellbore angle increment of the original design wellbore trajectory; Δα x Indicates the increment of the wellbore inclination angle of the wellbore trajectory to be drilled.

[0032] According to another aspect of the present invention, a storage medium is provided, which contains a series of instructions for executing the method steps described in any one of the above.

[0033] According to another aspect of the present invention, there is provided an ultra-deep, high-temperature, slim-hole horizontal well trajectory control device for executing any of the above methods, the device comprising:

[0034] The wellbore trajectory design module is designed for ultra-deep, high-temperature, slim-hole horizontal wells. It determines the wellbore trajectory form and wellbore trajectory parameters based on engineering drilling requirements.

[0035] a drilling tool assembly optimization module, which optimizes the drilling tool assembly for each wellbore trajectory based on the wellbore trajectory form and the wellbore trajectory parameters, and determines the drilling tool assembly optimization result corresponding to each wellbore trajectory;

[0036] a well inclination change rate prediction module, which analyzes the influence of the drilling tool assembly on the build-up rate based on the drilling tool assembly optimization result and determines the well inclination change rate of the drilling tool assembly;

[0037] The control step size optimization module combines the wellbore trajectory parameters and the well inclination change rate of the drilling tool assembly, considers the difference in well inclination change rate during actual drilling, and determines the maximum control step size of the wellbore trajectory.

[0038] The present invention provides a method for controlling the trajectory of an ultra-deep, high-temperature, small-bore horizontal well. Compared with the existing technology, the present invention has the following advantages: In response to the technical demand for wellbore trajectory control when no MWD instrument is available in an ultra-deep, high-temperature, small-bore horizontal well, the present invention provides a method for controlling the trajectory of an ultra-deep, high-temperature, small-bore horizontal well. The method can ensure that the horizontal well trajectory is controlled to hit the target and improve drilling efficiency when no MWD instrument is available in the lower deflection section and all horizontal sections, provide theoretical and technical support for the drilling site, and obviously have good application and promotion prospects.

[0039] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purposes and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0041] Figure 1 A flowchart showing the steps of a method for controlling trajectory of an ultra-deep, high-temperature, slim-hole horizontal well according to one embodiment of the present invention is shown;

[0042] Figure 2 A schematic diagram of a wellbore trajectory according to an embodiment of the present invention is shown;

[0043] Figure 3 A diagram showing the fitting result of the composite drilling well deviation change rate corresponding to a single-bend stabilizer-free drill tool assembly according to one embodiment of the present invention is shown;

[0044] Figure 4 A diagram showing the fitting results of the composite drilling well deviation change rate corresponding to a single-bend single-stabilizer drill tool assembly according to one embodiment of the present invention is shown;

[0045] Figure 5 A diagram showing the fitting results of the composite drilling well deviation change rate corresponding to a single-bend dual-stabilizer drilling tool assembly according to one embodiment of the present invention is shown;

[0046] Figure 6 A diagram showing the fitting results of the composite drilling well deviation change rate corresponding to the dual-stabilizer drilling tool assembly according to one embodiment of the present invention is shown.

[0047] In the accompanying drawings, the same reference numerals are used for the same parts. In addition, the accompanying drawings are not drawn according to the actual scale. DETAILED DESCRIPTION

[0048] To make the objectives, technical solutions and advantages of the present invention more clear, embodiments of the present invention are described in further detail below with reference to the accompanying drawings.

[0049] The prior art (CN111550184A) relates to a method for designing a borehole trajectory for ultra-deep horizontal wells. This method, in view of the particularity of ultra-deep horizontal wells, divides the strata at the predetermined deflection section into layers according to drillability, and increases the deflection layer by layer with a deflection rate for the strata with low drillability values ​​greater than that for the strata with high drillability values, thereby forming a layered "multi-increase + multi-adjustment" borehole trajectory optimization design scheme at the predetermined deflection section of the ultra-deep horizontal well, which helps to reduce the sliding drilling ratio of difficult-to-drill formations, quickly drill through highly abrasive formations, and reduce sliding footage in broken formations. However, the core idea of ​​this design method is to use the differences in formation drillability to select different deflection rates, reduce the sliding drilling ratio of difficult-to-drill formations, and quickly drill through highly abrasive formations. This design method requires alternating between sliding drilling and composite drilling methods, and the use of MWD measurement while drilling technology throughout the process, which is not suitable for ultra-deep horizontal wells without MWD drilling technology.

[0050] The prior art (CN104747165A) relates to a method for designing a three-dimensional horizontal wellbore profile, which includes the following steps: based on the deflection capability of existing drilling tools and drill bit assemblies, through the calculation and analysis of actual drilling friction and torque, the key design parameters of the first deflection point, the first deflection increase section, the twist azimuth point, the twist azimuth section, the second deflection point, the second deflection increase section of the three-dimensional well section are selected, and the optimization analysis and adjustment are performed to minimize the friction and torque of the three-dimensional horizontal well drilling, thereby forming an optimized design of the three-dimensional horizontal wellbore profile. The three-dimensional horizontal wellbore profile designed by this method has a smooth wellbore trajectory, low difficulty in controlling the actual drilling trajectory and low drilling friction and torque. It is closely integrated with current drilling tools and field applications, and has strong application and adaptability. However, this existing design method aims to reduce friction and torque, is not suitable for ultra-deep horizontal well MWD-free drilling technology, and does not involve a method for designing an ultra-deep horizontal well drill bit assembly.

[0051] The prior art (CN104481400A) relates to a three-dimensional horizontal wellbore trajectory control method. This technology determines the drilling parameters according to the drilling equipment and the formation lithology; measures the wellbore parameters by using a measurement while drilling tool, corrects the vertical depth of the formation using geological logging, designs the points to be drilled based on known measuring points, and uses the vertical depth as the control target to continuously correct the three-dimensional well section trajectory. Drilling to the end point of the three-dimensional well section ends by twisting the azimuth; again corrects the vertical depth of the target point using geological logging, performs two-dimensional drilling to the target point, and then uses the reservoir lithology and the horizontal section well inclination to determine the drill tool combination for horizontal section drilling. The typical feature of this prior art is that it uses a measurement while drilling tool to measure the wellbore parameters, corrects the vertical depth of the formation using geological logging, and performs geological guidance. However, this prior art focuses on using logging data and measurement while drilling technology to achieve geological guidance and target hitting, and is not suitable for ultra-deep horizontal well MWD-free drilling technology, nor does it involve ultra-deep horizontal well trajectory and drill tool combination design methods.

[0052] Existing technology (Sun Mingguang, Directional Drilling Technology for Ultra-deep Small Hole Horizontal Wells in Shunbei Oilfield, Drilling and Production Technology, 2020.2) mentioned: Shunbei Oilfield's ultra-deep small hole horizontal wells of Φ120.7mm or Φ149.2mm face many technical difficulties - large friction and torque, high difficulty in trajectory control; low prediction accuracy of screw drill bit deflection ability, and difficult selection; high failure rate and error rate of high-temperature downhole measurement instruments, which seriously affect the drilling cycle of the entire well. This existing technology optimization formed a "high + low" dual-increase track design profile, and provided an optimal bottom drilling tool combination solution that meets the needs of each directional well section project, thereby improving directional efficiency; formulated a supporting technical solution to improve the reliability and accuracy of high-temperature downhole measurement instruments, and formed a technical solution for directional drilling of ultra-deep small hole horizontal wells in Shunbei Oilfield. However, the ultra-deep slim-hole horizontal well trajectory described in this prior art is essentially a "high build-up rate section + low build-up rate section + horizontal section." All build-up and horizontal sections utilize a single-bend screw drill assembly and measurement-while-drilling technology, alternating between sliding and composite drilling methods, and continuously controlling the wellbore trajectory. Neither the horizontal well trajectory design nor the trajectory control scheme described in this prior art is suitable for ultra-deep horizontal well drilling without MWD.

[0053] Existing technology (Zou Xiaomin, Wellbore Trajectory Control Technology for Yuanba Ultra-Deep Horizontal Wells, Petroleum Geology and Engineering, March 2017) analyzed the difficulties in horizontal well construction in the Yuanba block and proposed a trajectory control technology solution for ultra-deep horizontal wells in the Yuanba area, including sidetracking technology for ultra-deep horizontal wells, wellbore trajectory control technology for the buildup section, landing control technology for ultra-deep horizontal wells, and horizontal section trajectory control technology. Based on this, high-temperature and high-pressure measuring instruments suitable for the Yuanba ultra-deep horizontal wells were selected, and ultra-deep wellbore trajectory control technology and operating procedures were established, improving drilling efficiency. However, the horizontal well trajectory control technology solution provided by this existing technology relies on measurement while drilling technology, provides a single drill tool assembly, and does not provide an optimized design solution for the ultra-deep horizontal well trajectory, thus failing to meet the requirements for ultra-deep horizontal well drilling technology without MWD.

[0054] In response to the above-mentioned defects of the prior art, the present invention provides a method for controlling the trajectory of ultra-deep, high-temperature, small-bore horizontal wells. After the first directional deflection section is drilled using an MWD instrument and a bent screw drill bit for directional deflection, the method can ensure that the horizontal well trajectory hits the target and improve drilling efficiency when no MWD is available in the lower deflection section, providing theoretical and technical support for the drilling site.

[0055] The present invention is mainly used in the research and application of trajectory control technology for ultra-deep, high-temperature, slim-hole horizontal wells when no MWD instrument is available. It can achieve the purpose of ensuring that ultra-deep horizontal wells hit the target and increase the drilling speed under the condition of no MWD instrument, and obviously has good application and promotion prospects.

[0056] Figure 1 A flowchart of the steps of a method for controlling an ultra-deep, high-temperature, slim-hole horizontal well trajectory according to an embodiment of the present invention is shown.

[0057] like Figure 1 As shown, in step S101, for an ultra-deep, high-temperature, slim-hole horizontal well, a wellbore trajectory is designed according to engineering drilling requirements, and the wellbore trajectory form and wellbore trajectory parameters are determined.

[0058] In one embodiment, in step S101, the engineering drilling requirement refers to: for the deflection section of an ultra-deep, high-temperature, slim-hole horizontal well, the first drilling trip uses a measurement while drilling instrument for directional deflection, and subsequent drilling does not use a measurement while drilling instrument to ensure that there is no measurement while drilling instrument in the lower deflection section and all horizontal sections.

[0059] Specifically, horizontal well reservoirs are buried deep (7500-8500m) and have high bottomhole temperatures (not less than 150°C, for example, 160-200°C). During drilling of the lower well section, the failure rate of measurement while drilling (MWD) instruments is high, and in some wells, the MWD instruments simply fail to function. In this case, not only is there no MWD instrument in the lower drill string assembly, but a multi-point inclinometer and "hanging measurement" method are not used to monitor the wellbore trajectory during drilling. Only when each drilling trip is pulled out of the hole are a multi-point inclinometer and "casting measurement" method used to measure the wellbore trajectory corresponding to that drilling trip. Therefore, the present invention is mainly used for horizontal well trajectory control in ultra-deep, high-temperature, small wellbores (for example, wellbore diameters not greater than 152.4mm) when no MWD instrument is available. It can achieve the purpose of ensuring that ultra-deep horizontal wells hit the target and increase drilling speed without MWD instruments.

[0060] In one embodiment, in step S101, the wellbore trajectory is: vertical well section - deflection section - horizontal section, wherein the deflection section includes: directional deflection section - first slowly increasing deflection section - second slowly increasing deflection section, K z >>K w1 >K w2 , K z Indicates the deflection rate of the directional deflection section; K w1 Indicates the build rate of the first slowly increasing slope section; K w2 Indicates the slope rate of the second slowly increasing slope section.

[0061] Specifically, the first drilling of the inclination section of ultra-deep, high-temperature, small-bore horizontal wells must be directional inclination using the MWD tool. In order to shorten the downhole working time of the MWD tool as much as possible and increase the well inclination as soon as possible before the MWD tool fails, the first drilling should use a high-inclination screw drill bit combination and a sliding drilling method to quickly increase the inclination, so that from the second drilling, a slow-inclination drill bit combination can be used to accurately hit the target. In this case, a multi-arc trajectory with a "high-front, low-back" inclination rate is most suitable. Taking into account that the pre-target displacement and inclination section of ultra-deep, high-temperature, small-bore horizontal wells are relatively short, it is sufficient to set up one high-inclination rate inclination section and two slow-inclination sections. The basic form of the wellbore trajectory is "straight well section-directional inclination section-first slow-inclination section-second slow-inclination section-horizontal section" (such as Figure 2 ).

[0062] In one embodiment, in step S101, the wellbore trajectory parameters include but are not limited to: target vertical depth D t , closing distance C t , horizontal section well inclination angle α t , vertical depth of inclination point D a , directional deflection section deflection rate K z , directional deflection section deflection radius R z , well inclination angle α at the end of directional deflection section b , the first slowly increasing slope rate K w1 , the first slowly increasing slope section radius Rw1 , the inclination angle α at the end of the first slowly increasing inclination section c , the second slowly increasing slope rate K w2 , the radius of the second slowly increasing inclined section R w2 .

[0063] like Figure 2 As shown, the vertical depth of the horizontal well target point D t , closing distance C t , horizontal section well inclination angle α t ; Vertical depth of inclination point D a , the directional deflection section deflection rate K z (corresponding to the deflection radius R z ), end point inclination angle α b , the first slowly increasing slope rate K w1 (corresponding to the deflection radius R w1 ), end point inclination angle α c , the second slowly increasing slope rate K w2 (corresponding to the deflection radius R w2 ). When no MWD instrument is available, in order to reduce the difficulty of trajectory control in the lower deflection section (slow increase section), the deflection rate K of the directional deflection section should be appropriately increased. z (20° / 30m or so), appropriately reduce the slope rate K of the slow-increasing section w1 and K w2 (not higher than 3° / 30m), control K z >>K w1 >K w2 .

[0064] In one embodiment, the wellbore trajectory parameters are designed using equation group (1):

[0065]

[0066] In one embodiment, if the vertical depth D of the inclination point is known a , directional deflection section deflection rate K z , the first slowly increasing slope rate K w1 , the second slowly increasing slope rate K w2 , then the well inclination angle α at the end of the directional deflection section is b , the inclination angle α at the end of the first slowly increasing inclination section c The solution method is shown in formula (2) and formula (3):

[0067]

[0068]

[0069] Where: D e 、C e All of them are intermediate variables and have no clear parameter meaning.

[0070] In one embodiment, in order to reduce the difficulty of hitting the target, the slope rate K can also be pre-set. z , K w1 and K w2 , the inclination angle α at the end of the first slowly increasing inclination section c , then the vertical depth of the inclination point is D a , well inclination angle α at the end of directional deflection section b The solution is shown in formula (4):

[0071]

[0072] like Figure 1 As shown, in step S102, based on the wellbore trajectory form and wellbore trajectory parameters, the drilling tool assembly is optimized for each wellbore trajectory to determine the drilling tool assembly optimization result corresponding to each wellbore trajectory.

[0073] Specifically, the most suitable trajectory design for ultra-deep, high-temperature, slim-hole horizontal wells is "vertical section - directional buildup section - first ramp-up section - second ramp-up section - horizontal section." Given the high failure rate of MWD instruments and the potential for unavailability, different drill tool combinations and drilling parameter optimization methods are required for the directional buildup section, first ramp-up section, second ramp-up section, and horizontal section.

[0074] In one embodiment, in step S102, the drilling tool assembly optimization result corresponding to each wellbore trajectory is determined by the following steps: for the directional deflection section, according to the directional deflection section deflection rate K z , determine the screw bending angle value and drilling method of the directional bend section, and select a single-bend single-stabilizer drill bit combination or a single-bend stabilizer-free drill bit combination according to the downhole conditions.

[0075] Specifically, the optimization method of the drilling tool assembly for the directional deflection section is as follows: considering that the first drilling run must use the MWD tool for directional deflection, and the remaining well sections may not have MWD tools available, the deflection rate K of the directional deflection section of the slim hole horizontal well is z A value of about 20° / 30m (18°~24° / 30m) and a screw bend angle of about 2.0° (1.75°~2.5°) are more appropriate. Furthermore, when downhole conditions are good (for example, the wellbore is stable and the wellbore is regular), it is appropriate to use a single-bend single-stabilizer drill bit combination, which helps to stabilize the tool face through sliding drilling and improve directional drilling efficiency; when downhole conditions are poor (for example, the wellbore is unstable and the wellbore is irregular), it is appropriate to use a single-bend, stabilizer-free drill bit combination, which helps to reduce the risk of stuck drill and improve the inclination rate. It should be noted that composite drilling is not allowed for screw drill bits with large bend angles (≥1.75°), and all directional inclination sections should use sliding drilling to increase inclination with full force.

[0076] In one embodiment, in step S102, the drilling tool assembly optimization result corresponding to each wellbore trajectory is determined by the following steps: for the first slowly increasing inclination section, according to the first slowly increasing inclination section build-up rate K w1 , determine the screw bending angle value and drilling method of the first slow-increase inclined section, and select a single-bend single-stabilizer drill bit combination or a single-bend stabilizer-free drill bit combination based on the well inclination angle at the end of the first drilling trip of the first slow-increase inclined section.

[0077] Specifically, the optimization method of the drilling tool assembly for the first slow-increase section is as follows: the well inclination angle at the end of the first directional inclination drilling is usually no more than 60°, and the first slow-increase section needs to continue to increase the inclination at a relatively fast speed to create conditions for the second slow-increase section to hit the target with a near-stable inclination. In this case, regardless of whether the MWD tool is available, the inclination rate K of the first slow-increase section is w1 A value of approximately 3° / 30m is suitable for drilling with a single-bend screw drill string assembly (bend angle of approximately 1.25°) and a high WOB. If the wellbore inclination is low at the end of the first run of the inclination increase section, a single-bend, stabilizer-free drill string assembly can help continue the inclination increase. If the wellbore inclination is high at the end of the first run of the inclination increase section, a single-bend, single-stabilizer drill string assembly can help slowly increase the inclination and stabilize the azimuth. Without MWD equipment, it is impossible to measure and control the wellbore inclination rate in real time. Before drilling, the drill string assembly and drilling parameters (primarily WOB) must be optimized according to the predetermined wellbore inclination rate. It is ideal if the wellbore inclination deviation between the actual drilling trajectory and the designed trajectory does not exceed 5° at the end of the first slow inclination increase section.

[0078] In one embodiment, in step S102, the drilling tool assembly optimization result corresponding to each wellbore trajectory is determined by the following steps: for the second slowly increasing inclination section, according to the second slowly increasing inclination section build-up rate K w2 , determine the screw bending angle value and drilling method of the second slowly increasing inclination section, and select a single-bend double-stabilizer drilling tool combination or a double-stabilizer drilling tool combination based on the slowly increasing or decreasing inclination effect.

[0079] Specifically, the optimization method of the drilling tool assembly for the second slow-increase section is as follows: the deviation of the actual drilling trajectory from the designed trajectory at the end of the first slow-increase section is usually no more than 5°. In this case, regardless of whether the MWD tool is available, the inclination rate K of the second slow-increase section is w2A value of approximately 1.0° / 30m is suitable for composite drilling using a single-bend dual-stabilizer drill string assembly (bend angle of approximately 1.25°) and medium weight-on-bit (WOB) drilling. Without an MWD instrument, it is impossible to measure and control the wellbore inclination rate in real time. Before drilling, the drill string assembly must be optimized and drilling parameters (WOB) must be optimized according to the predetermined wellbore inclination rate. It is ideal for the wellbore inclination angle deviation between the actual drill trajectory and the designed trajectory to not exceed 3° at the end of the second gradual inclination increase section. A conventional dual-stabilizer drill string assembly is also available. Adjusting the stabilizer diameter and position can achieve stable inclination, gradual inclination increase, and gradual inclination decrease effects. Existing composite drilling with a single-bend screw drill string assembly essentially achieves a gradual inclination increase. If a gradual inclination decrease is required to hit the target, a conventional dual-stabilizer gradual inclination decrease drill string assembly should be used instead when an MWD instrument is unavailable.

[0080] In one embodiment, in step S102, the optimal result of the drill tool assembly corresponding to each section of the wellbore trajectory is determined by the following steps: for the horizontal section, the screw bend angle value and the drilling method of the horizontal section are determined based on the target half-height and target half-width defined in the target area parameters and the maximum wellbore curvature required for wellbore trajectory control. Based on the effect of slow increase or slow decrease in inclination, a single-bend double-stabilizer drill tool assembly or a double-stabilizer drill tool assembly is selected.

[0081] Specifically, the optimization method for the horizontal section drill bit combination is as follows: at the end of the second slow-increase section, the deviation of the actual drilling trajectory from the designed trajectory in well inclination angle usually does not exceed 3°. In this case, regardless of whether the MWD instrument is available, the horizontal section is suitable for the use of a single-bend dual-stabilizer drill bit combination (bend angle of about 1.25°) and medium bit pressure composite drilling, controlling the well inclination change rate within 1.0° / 30m. A conventional dual-stabilizer drill bit combination is also required as a backup. Adjusting the stabilizer diameter and position can achieve stable inclination, slow-increase inclination, and slow-decline inclination effects. Existing single-bend screw drill bit combination composite drilling basically all achieves slow-increase inclination effects. When no MWD instrument is available, it is necessary to alternately use a conventional dual-stabilizer slow-decline inclination drill bit combination, and plan each drilling footage in advance based on the slow-increase and slow-decline effects.

[0082] like Figure 1 As shown, in step S103, based on the drilling tool assembly optimization result, the influence of the drilling tool assembly on the build-up rate is analyzed to determine the well inclination change rate of the drilling tool assembly.

[0083] Specifically, the core task of horizontal well trajectory control is to predict and control the build-up rate to ensure that the actual drilling trajectory hits the target and extends into the reservoir. The key to controlling the horizontal well trajectory to accurately hit the target and extend into the reservoir when MWD tools are unavailable lies in the ability to accurately predict and control the wellbore inclination rate of the drill string assembly before drilling. In this case, it is necessary to predict the wellbore inclination rate of composite drilling using a single-bent screw drill string assembly (without stabilizer, single stabilizer, or dual stabilizer) and the wellbore inclination rate of a conventional drill string assembly with dual stabilizers.

[0084] In one embodiment, in step S103, the drilling tool assembly inclination change rate is determined by the following steps: for each drilling tool assembly, the full-strength inclination rate K is calculated by using the inclination rate prediction method. z1 、Full force slope reduction rate K z2 The average value of the full-strength increase and full-strength decrease inclination rates is taken as the composite drilling inclination change rate K. r (Predict the well deviation change rate K corresponding to the given drilling tool combination under composite drilling conditions r ).

[0085] Specifically, the existing bent screw drilling assembly sliding slope rate prediction method (for example, the balance trend slope rate prediction method) is used to predict the full force slope rate K z1 (positive value), full-strength slope reduction rate K z2 (negative value), and take the average of the two as the composite drilling well inclination change rate K r , K r =(K z1 +K z2 ) / 2.

[0086] In one embodiment, in step S103, the well inclination change rate of the drilling tool assembly is determined by the following steps: the key influencing factors and influencing rules affecting the composite drilling well inclination change rate are found by using the orthogonal analysis method, and the composite drilling well inclination change rate fitting expression corresponding to each drilling tool assembly is constructed by using the regression analysis method to determine the well inclination change rate of the drilling tool assembly.

[0087] Specifically, the orthogonal analysis method is used to find the key influencing factors and laws that affect the well inclination change rate of the bent screw drill assembly composite drilling, and the regression analysis method is used to construct the well inclination change rate fitting formula of the bent screw drill assembly composite drilling. This can optimize the drill assembly and select the drilling parameters before drilling, so that the well inclination change rate prediction value K r The slope rate should be as close as possible to the corresponding section of the track to be drilled.

[0088] In practical applications, the composite drilling well inclination change rate K can be determined before drilling based on the composite drilling well inclination change rate fitting expression. r The drill string combination that is closest to the inclination rate of the corresponding section of the track to be drilled is selected as the drill string combination for this drilling trip. At this time, the composite drilling inclination change rate K r As the drilling tool assembly inclination change rate K x .

[0089] like Figure 1 As shown, in step S104, the maximum control step length of the wellbore trajectory is determined by combining the wellbore trajectory parameters and the well inclination change rate of the drilling tool assembly and considering the difference in the well inclination change rate during actual drilling.

[0090] Specifically, when MWD instruments are unavailable, the drill string assembly and drilling parameters for the next run can only be selected based on the wellbore trajectory parameters obtained during pre-testing. Horizontal wells require vector hits and small target parameters. To ensure accurate target hits during actual drilling without MWD, in addition to optimizing the drill string assembly and drilling parameters based on the predetermined wellbore inclination rate before drilling, it is also necessary to consider the actual wellbore inclination rate and rationally plan the footage for each run—that is, to plan the trajectory control step size appropriately.

[0091] In one embodiment, in step S104, the maximum control step length of the wellbore trajectory is determined by the following steps: based on the build-up rate corresponding to each section of the wellbore trajectory and the inclination change rate of the drill tool assembly, the bottomhole distance and the inclination angle deviation between the original design trajectory and the to-be-drilled trajectory after a single drilling trip are estimated; the bottomhole distance is limited by referring to the target area parameters, the single-trip drilling progress is iteratively solved, and the maximum value is selected as the first maximum control step length; the inclination angle deviation is limited by referring to the target area parameters, the single-trip drilling progress is iteratively solved, and the maximum value is selected as the second maximum control step length; the drill bit footage limited by the drill bit life is considered to obtain the third maximum control step length; and the minimum value among the first maximum control step length, the second maximum control step length, and the third maximum control step length is taken as the maximum control step length of the wellbore trajectory.

[0092] like Figure 2 As shown in the figure, the original design trajectory corresponding to the deflection rate is K0 (corresponding to the deflection radius is R0), and the (actual) deflection rate of the drilling tool assembly is K x (The corresponding deflection radius is R x ), the estimated drilling footage for this trip is L x , then drill into a control step length L x After that, the inclination angle increment of the original design trajectory is Δα0=K0L x , the inclination angle increment Δα of the track to be drilled x =K x L x The bottom hole distance d between the original design track and the track to be drilled and the calculation method of the well inclination angle deviation Δα are derived as shown in Equations (5) and (6).

[0093] In one embodiment, the first maximum control step size is determined by the following expression:

[0094]

[0095] Where: d represents the distance between the original design trajectory and the bottom of the well to be drilled; K0 represents the inclination rate of the original design (wellbore) trajectory; R0 represents the inclination radius of the original design wellbore trajectory (the inclination radius corresponding to the inclination rate K0); K x Indicates the (actual) build-up rate of the drilling tool assembly, that is, the rate of change of the well inclination of the drilling tool assembly; R x Indicates the drilling tool assembly deflection radius; L xIndicates the drilling progress in a single trip.

[0096] In one embodiment, the second maximum control step size is determined by the following expression:

[0097] Δα=|Δα0-Δα x |=|K0-K x |L x (6)

[0098] Where: Δα represents the deviation of the well inclination angle between the original design trajectory and the trajectory to be drilled; Δα0 represents the well inclination angle increment of the original design (wellbore) trajectory; Δα x Indicates the increment of the well inclination angle of the trajectory to be drilled.

[0099] Specifically, horizontal wells require vector hits and small target parameters. To ensure that the actual drilling trajectory does not deviate significantly and accurately hits the target under no MWD conditions, each drilling run must limit the bottom hole distance d and the well inclination angle deviation Δα. The bottom hole distance d and the well inclination angle deviation Δα can be limited by referring to the horizontal well target parameters (target half height), and then the first maximum control step length L can be iteratively calculated using formula (5): x1 , use formula (6) to find the second maximum control step length L x2 In addition, the drill bit footage L limited by the drill bit life must also be considered. x3 Finally, the maximum control step length L of the horizontal well trajectory is given. c =min{L x1 ,L x2 ,L x3}.

[0100] It should be noted that the above-mentioned maximum control step length optimization method for horizontal well trajectory is applicable to both the build-up section and the horizontal section.

[0101] Aiming at the technical demand for wellbore trajectory control in ultra-deep, high-temperature, slim-hole horizontal wells when no MWD instrument is available, the present invention provides a method for controlling the trajectory of ultra-deep, high-temperature, slim-hole horizontal wells. The method can ensure that the horizontal well trajectory hits the target and improves drilling efficiency when no MWD instrument is available in the lower build-up section and all horizontal sections, providing theoretical and technical support for drilling sites.

[0102] The ultra-deep, high-temperature, slim-bore horizontal well trajectory control method provided by the present invention can also be used in conjunction with a computer-readable storage medium, which stores a computer program. The computer program is executed to implement the ultra-deep, high-temperature, slim-bore horizontal well trajectory control method. The computer program is capable of executing computer instructions, which include computer program code. The computer program code can be in source code form, object code form, executable file, or some intermediate form.

[0103] Computer-readable storage media may include: any entity or device that can carry computer program code, recording media, USB flash drives, mobile hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc.

[0104] It should be noted that the content contained in computer-readable storage media can be appropriately increased or decreased according to the requirements of legislation and patent practices in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practices, computer-readable storage media do not include electrical carrier signals and telecommunications signals.

[0105] According to another aspect of the present invention, there is also provided an ultra-deep, high-temperature, small-bore horizontal well trajectory control device, which executes an ultra-deep, high-temperature, small-bore horizontal well trajectory control method. The device includes: a wellbore trajectory design module, a drill tool assembly optimization module, a well inclination change rate prediction module, and a control step size optimization module.

[0106] The wellbore trajectory design module designs wellbore trajectories for ultra-deep, high-temperature, slim-bore horizontal wells according to engineering drilling requirements and determines the wellbore trajectory form and wellbore trajectory parameters. The drill tool assembly optimization module optimizes the drill tool assembly for each wellbore trajectory section based on the wellbore trajectory form and wellbore trajectory parameters, and determines the drill tool assembly optimization result corresponding to each wellbore trajectory section. The well inclination change rate prediction module analyzes the impact of the drill tool assembly on the build rate based on the drill tool assembly optimization results and determines the well inclination change rate of the drill tool assembly. The control step size optimization module combines the wellbore trajectory parameters and the well inclination change rate of the drill tool assembly, taking into account the differences in the well inclination change rate during actual drilling, to determine the maximum control step size of the wellbore trajectory.

[0107] This invention addresses the trajectory control needs of ultra-deep horizontal wells when MWD instruments are unavailable. It provides an integrated technical solution for ultra-deep horizontal well trajectory design and trajectory control. The solution comprises four relatively independent modules: 1) an ultra-deep, high-temperature, slim-hole horizontal well trajectory design module (wellbore trajectory design module); 2) an ultra-deep, high-temperature, slim-hole horizontal well drill tool assembly optimization module (drill tool assembly optimization module); 3) a wellbore inclination rate rapid prediction module (wellbore inclination rate prediction module); and 4) a wellbore trajectory control step size optimization module (control step size optimization module). This invention ensures that horizontal well trajectories are on target and improves drilling efficiency when MWD instruments are unavailable in the lower build-up section and all horizontal sections, providing theoretical and technical support for drilling sites.

[0108] This invention addresses the need for wellbore trajectory control in ultra-deep, high-temperature, slim-bore horizontal wells when MWD equipment is unavailable. It provides a trajectory control method for ultra-deep, high-temperature, slim-bore horizontal wells. This method ensures on-target control of the horizontal well trajectory and improves drilling efficiency when MWD equipment is unavailable in the lower build-up section and all horizontal sections, providing theoretical and technical support for drilling sites. Using an ultra-deep, high-temperature, 149.2mm slim-bore horizontal well as an example, trajectory control was performed using the method provided by this invention.

[0109] 1. Ultra-deep, high-temperature, slim-hole horizontal well trajectory design

[0110] The basic form of the wellbore trajectory is "vertical well section-directional deflection section-first slowly increasing inclination section-second slowly increasing inclination section-horizontal section" (such as Figure 2 ).

[0111] Known target vertical depth D t =7600m, closing distance C t =300m, horizontal section well inclination angle α t =88°; directional deflection section deflection rate K z =20° / 30m, the slope rate K of the first slowly increasing slope section w1 =3° / 30m, the slope rate K of the second slowly increasing slope section w2 =1° / 30m, end point well inclination angle α c =85°, the key parameters to be determined include the well depth D at the inclination point a , well inclination angle α at the end of directional deflection section b The well depth D of the inclination point is obtained from formula (4): a =7461.43mm, well inclination angle α at the end of directional deflection section b =69.04°.

[0112] 2. Optimal Drilling Tool Assembly for Ultra-deep, High-Temperature Slim Hole Horizontal Wells

[0113] 1) Directional deflection section drilling tool assembly

[0114] Single-bend drill bit without stabilizer: Φ149.2mm drill bit + Φ130mm bent screw drill bit + Φ120.7mm drill collar + Φ88.9mm heavy-weight drill pipe; the bending angle of the bent screw drill bit is 1.75-2.5°, and the bending point is 1500mm away from the lower end face.

[0115] Single-bend single-stabilizer drill tool assembly (spare): Φ149.2mm drill bit + Φ130mm bent screw drill tool + Φ120.7mm drill collar + Φ88.9mm heavy drill pipe; the bent screw drill tool has a bending angle of 1.75-2.5°, a stabilizer diameter of 142mm, a center distance from the stabilizer to the lower end face of 600mm, a bending point distance from the lower end face of 1250mm, and a total drill tool length of 6460mm.

[0116] 2) First Slow-Increase Drilling Assembly

[0117] Single-bend single-stabilizer drilling tool combination: Φ149.2mm drill bit + Φ130mm bent screw drilling tool + Φ120.7mm drill collar + Φ88.9mm heavy-weight drill pipe; the bent screw drilling tool has a bending angle of 1.25-1.5°, a stabilizer diameter of 142mm, a center distance from the stabilizer to the lower end face of 600mm, a bending point distance from the lower end face of 1250mm, and a total length of the drilling tool of 6460mm.

[0118] Single-bend drill bit without stabilizer (spare): Φ149.2mm drill bit + Φ130mm bent screw drill bit + Φ120.7mm drill collar + Φ88.9mm heavy drill pipe; the bending angle of the bent screw drill bit is 1.25-2.5°, and the bending point is 1500mm away from the lower end face.

[0119] 3) Second slowly increasing inclined section + horizontal section drilling tool combination

[0120] Single-bend double-stable drill tool combination: Φ149.2mm drill bit + Φ130mm bent screw drill tool (with stabilizer) + Φ120.7mm short drill collar + Φ142mm stabilizer + Φ120.7mm drill collar + Φ88.9mm heavy-weight drill pipe; the bent screw drill tool has a bending angle of 1.0-1.25°, a stabilizer diameter of 142mm, a lower stabilizer position of 600mm, a bending point position of 1200mm, and a total drill tool length of 6600mm.

[0121] Conventional drilling tool assembly with double stabilizers: Φ149.2mm drill bit + Φ146mm near-bit stabilizer + 1 Φ120.7mm drill collar + Φ146mm stabilizer + Φ120.7mm drill collar × several.

[0122] 3. Rapid prediction method for the well inclination change rate of slim-hole horizontal wells

[0123] 1) Single-bend drill assembly without stabilizer

[0124] Reference drilling tool combination: Φ149.2mm drill bit + Φ130mm bent screw drill tool + Φ120.7mm drill collar + Φ88.9mm heavy drill rod; the bending angle of the bent screw drill tool is 0.75-1.5°, and the bending point is 1500mm away from the lower end face.

[0125] Based on the simulation analysis of the well inclination change rate of composite drilling of a single-bend stabilizer-free drilling tool assembly, the fitting results are shown in formulas (7) and Figure 3 As can be seen, the fitting index is 0.667, indicating a good fitting effect. The bend angle has the greatest impact on the well inclination rate, while the drill bit anisotropy index has a smaller impact on the well inclination rate. To adjust the well inclination rate, adjusting the bend angle is the first consideration.

[0126] K r=3.1827γ-1.4383I b -0.0076α+0.0135WOB-0.9859 (7)

[0127] Where K r Indicates the composite drilling well inclination change rate, ° / 30m; γ indicates the bending angle, °; I b represents the anisotropy index of the drill bit (the empirical value is 0.10-0.15); α represents the well inclination angle, in degrees; WOB represents the weight on bit, in kN.

[0128] 2) Single-bend single-stabilizer drill assembly

[0129] Reference drilling tool combination: Φ149.2mm drill bit + Φ130mm bent screw drill tool + Φ120.7mm drill collar + Φ88.9mm heavy drill pipe; the bent screw drill tool has a bending angle of 0.75-1.5°, a stabilizer diameter of 142mm, a center distance from the stabilizer to the lower end face of 600mm, a bending point distance from the lower end face of 1250mm, and a total length of the drilling tool of 6460mm.

[0130] Based on the simulation analysis of the well inclination change rate of the composite drilling of the single-bend single-stabilizer drilling tool assembly, the fitting results are shown in formulas (8) and Figure 4 As can be seen, the fitting index reaches 0.808, indicating a good fitting effect. The well inclination angle has the greatest impact on the well inclination change rate, while the stabilizer diameter has a smaller impact on the well inclination change rate. To adjust the well inclination change rate, adjusting the well inclination angle should be prioritized.

[0131] K r =-0.1755D s -1.8842γ+12.391I b +0.0531α+0.0502WOB+24.1361 (8)

[0132] Where K r Indicates the composite drilling well inclination change rate, ° / 30m; D s represents the diameter of the stabilizer, mm; γ represents the bending angle, degrees; I b represents the anisotropy index of the drill bit (the empirical value is 0.10-0.15); α represents the well inclination angle, in degrees; WOB represents the weight on bit, in kN.

[0133] 3) Single-bend dual-stabilizer drill bit assembly

[0134] Single-bend double-stable drill tool combination: Φ149.2mm drill bit + Φ130mm bent screw drill tool (with stabilizer) + Φ120.7mm short drill collar + Φ142mm stabilizer + Φ120.7mm drill collar + Φ88.9mm heavy-weight drill pipe; the bent screw drill tool has a bending angle of 0.75-1.5°, a stabilizer diameter of 142mm, a lower stabilizer position of 600mm, a bending point position of 1200mm, and a total drill tool length of 6600mm.

[0135] Based on the simulation analysis of the well inclination change rate of the composite drilling of the single-bend dual-stabilizer drilling tool assembly, the fitting results are shown in formulas (9) and Figure 5 As can be seen, the fitting index reaches 0.838, indicating a good fit. The stabilizer spacing has the greatest impact on the well inclination rate, followed by the lower stabilizer diameter and bend angle. The well inclination angle has a minimal impact on the well inclination rate. To adjust the well inclination rate, the priority considerations are adjusting the stabilizer spacing, the lower stabilizer position, and the bend angle.

[0136] K r =0.2187D s1 -0.1106D s2 +1.9483γ+0.765L 22 -3.0817I b +0.0109α+0.0145WOB-21.1791 (9)

[0137] Where K r Indicates the composite drilling well inclination change rate, ° / 30m; D s1 Indicates the diameter of the lower stabilizer, mm; D s2 represents the diameter of the upper stabilizer, mm; γ represents the bending angle, degrees; L 22 Indicates the distance between stabilizers, m; I b represents the anisotropy index of the drill bit (the empirical value is 0.10-0.15); α represents the well inclination angle, in degrees; WOB represents the weight on bit, in kN.

[0138] 4) Dual stabilizer conventional drilling tool assembly

[0139] Reference drilling tool combination: Φ149.2mm drill bit + Φ146mm near-bit stabilizer + Φ120.7mm (or Φ127mm) drill collar 1 + Φ146mm stabilizer + Φ120.7mm (or Φ127mm) drill collar × several.

[0140] Based on the simulation analysis of the well inclination change rate of the conventional drilling tool assembly with dual stabilizers, the fitting results are shown in formulas (10) and Figure 6As can be seen, the fitting index reaches 0.864, indicating a good fit. The lower stabilizer position has the greatest impact on the well inclination rate, followed by the upper stabilizer diameter, upper stabilizer position, and the drill bit anisotropy index. The well inclination angle has a smaller impact on the well inclination rate. To adjust the well inclination rate, adjusting the lower stabilizer position should be prioritized.

[0141]

[0142] Where K r Indicates the composite drilling well inclination change rate, ° / 30m; D s1 Indicates the diameter of the lower stabilizer, mm; L s1 Indicates the position of the lower stabilizer, m; D s2 Indicates the diameter of the upper stabilizer, mm; L s2 Indicates the position of the upper stabilizer, m; I b represents the anisotropy index of the drill bit (the empirical value is 0.10-0.15); α represents the well inclination angle, in degrees; WOB represents the weight on bit, in kN.

[0143] 4. Optimization of trajectory control step length for ultra-deep, high-temperature, slim-hole horizontal wells

[0144] Taking the original design trajectory (slow increase section) with an inclination rate of K0 = 3° / 30m as an example, after drilling a control step, the bottom hole distance between the original design trajectory and the trajectory to be drilled is limited to no more than 3m, the well inclination angle deviation is limited to no more than 3°, and the drill bit footage per drilling is limited to no more than 100m.

[0145] When the slope rate K of the track to be drilled (slowly increasing section) x =1° / 30m, the first maximum control step length L corresponding to the bottom hole distance is calculated by equations (5) and (6): x1 =60.4m, the second maximum control step length L corresponding to the well inclination deviation x2 =45m, maximum drill bit footage per drilling trip L x3 =100m, and finally find the maximum control step length L c =45m; when the slope of the track to be drilled (slowly increasing section) is K x =2.5° / 30m, we can calculate L x1 =120.9m, L x2 =180m, L x3 =100m, and finally find the maximum control step length L c =100m.

[0146] The above simulation analysis shows that the slope rate K of the track to be drilled (slow increase section) xThe greater the deviation from the original design trajectory (slow increase section) inclination rate K0, the shorter the wellbore trajectory control step. In order to reduce the number of trips, improve drilling efficiency and target accuracy, the drill tool combination and drilling parameters should be optimized before drilling so that the inclination rate K0 of the trajectory to be drilled (slow increase section) is x The slope rate K0 should be as close as possible to the original design track (slow increase section).

[0147] In summary, the present invention provides a method for controlling the trajectory of an ultra-deep, high-temperature, small-bore horizontal well. Compared with the existing technology, the present invention has the following advantages: In response to the technical demand for wellbore trajectory control when no MWD instrument is available in ultra-deep, high-temperature, small-bore horizontal wells, the present invention provides a method for controlling the trajectory of an ultra-deep, high-temperature, small-bore horizontal well. The method can ensure that the horizontal well trajectory is controlled to hit the target and improve drilling efficiency when no MWD is available in the lower inclination section and all horizontal sections, provide theoretical and technical support for the drilling site, and obviously have good application and promotion prospects.

[0148] It should be understood that the embodiments disclosed herein are not limited to the specific structures, processing steps, or materials disclosed herein, but should extend to equivalent substitutions of these features understood by those skilled in the relevant art. It should also be understood that the terminology used herein is for the purpose of describing specific embodiments only and is not intended to be limiting.

[0149] In the description of the present invention, unless otherwise specified, "plurality" means two or more; terms such as "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," and "tail" indicate positions or relationships based on those shown in the accompanying drawings. These terms are intended solely to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limiting the present invention. Furthermore, terms such as "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0150] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integral connection; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0151] Certain terms are used throughout this application document to indicate specific system components. As will be appreciated by those skilled in the art, different names may be used to indicate the same component, and thus this application document is not intended to distinguish between components that are only different in name but not in function. In this application document, the terms "comprise," "include," and "have" are used in an open format and should therefore be interpreted as meaning "including, but not limited to...". In addition, the terms "substantially," "substantially," or "approximately" that may be used herein refer to industry-accepted tolerances for the corresponding terms. The term "coupling," as used herein, includes direct coupling and indirect coupling via another component, element, circuit, or module, wherein for indirect coupling, the intervening component, element, circuit, or module does not change the information of the signal but can adjust its current level, voltage level, and / or power level. Inferred coupling (e.g., one element is coupled to another element by inference) includes direct and indirect coupling between two elements in the same manner as "coupling."

[0152] References in this specification to "one embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Therefore, appearances of the phrases "one embodiment" or "an embodiment" in various places throughout this specification do not necessarily refer to the same embodiment.

[0153] The embodiments of the present invention are presented for purposes of illustration and description and are not intended to be exhaustive or to limit the invention to the disclosed forms. Many modifications and variations will be apparent to those skilled in the art. The embodiments are chosen and described in order to better illustrate the principles of the invention and its practical application and to enable those skilled in the art to understand the invention and design various embodiments with various modifications as suited for specific applications.

[0154] Although the embodiments disclosed herein are as described above, the contents described herein are merely embodiments for facilitating understanding of the present invention and are not intended to limit the present invention. Any person skilled in the art of the present invention may make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed herein. However, the scope of patent protection of the present invention shall still be subject to the scope defined by the appended claims.

Claims

1. A method for controlling the trajectory of an ultra-deep, high-temperature, slim-hole horizontal well, characterized in that: The method comprises the following steps: For ultra-deep, high-temperature, slim-hole horizontal wells, wellbore trajectory design is performed according to engineering drilling requirements to determine the wellbore trajectory form and wellbore trajectory parameters; Based on the wellbore trajectory form and the wellbore trajectory parameters, respectively, performing drilling tool assembly optimization for each wellbore trajectory, and determining a drilling tool assembly optimization result corresponding to each wellbore trajectory; Analyze the influence of the drilling tool assembly on the build-up rate based on the drilling tool assembly optimization result, and determine the well inclination change rate of the drilling tool assembly; The maximum control step length of the wellbore trajectory is determined by combining the wellbore trajectory parameters and the well inclination change rate of the drilling tool assembly and taking into account the difference in well inclination change rate during actual drilling.

2. The ultra-deep, high-temperature, slim-hole horizontal well trajectory control method according to claim 1, characterized in that: The engineering drilling requirements refer to: for the deflection section of ultra-deep, high-temperature, small-bore horizontal wells, the first drilling trip uses a while-drilling measurement instrument for directional deflection, and subsequent drilling does not use a while-drilling measurement instrument to ensure that there are no while-drilling measurement instruments in the lower deflection section and all horizontal sections.

3. The method for controlling the trajectory of an ultra-deep, high-temperature, slim-hole horizontal well according to claim 1 or 2, wherein: The wellbore trajectory is: vertical well section - deflection section - horizontal section, wherein the deflection section includes: directional deflection section - first slowly increasing deflection section - second slowly increasing deflection section, K z >>K w1 >K w2 , K z Indicates the deflection rate of the directional deflection section; K w1 Indicates the build rate of the first slowly increasing slope section; K w2 Indicates the slope rate of the second slowly increasing slope section.

4. A method for controlling the trajectory of an ultra-deep, high-temperature, slim-hole horizontal well according to any one of claims 1 to 3, characterized in that: The wellbore trajectory parameters include but are not limited to: target vertical depth D t , closing distance C t , horizontal section well inclination angle α t , vertical depth of inclination point D a , directional deflection section deflection rate K z , directional deflection section deflection radius R z , well inclination angle α at the end of directional deflection section b , the first slowly increasing slope rate K w1 , the first slowly increasing slope section radius R w1 , the inclination angle α at the end of the first slowly increasing inclination section c , the second slowly increasing slope rate K w2 , the radius of the second slowly increasing inclined section R w2 .

5. A method for controlling the trajectory of an ultra-deep, high-temperature, slim-hole horizontal well according to any one of claims 3 to 4, characterized in that: Determine the optimal drilling tool assembly corresponding to each wellbore trajectory by the following steps: For the directional deflection section, according to the deflection rate K of the directional deflection section z , determine the screw bending angle value and drilling method of the directional deflection section, and select a single-bend single-stabilizer drill tool assembly or a single-bend stabilizer-free drill tool assembly according to the downhole conditions; For the first slowly increasing slope section, according to the first slowly increasing slope section slope rate K w1 , determine the screw bend angle value and drilling method for the first slow-increase section, and select a single-bend single-stabilizer drill string assembly or a single-bend stabilizer-free drill string assembly based on the well inclination angle at the end of the first drilling run of the first slow-increase section; For the second slowly increasing slope section, according to the slope rate K of the second slowly increasing slope section w2 , determine the screw bending angle value and drilling method of the second slow-increase section, and select a single-bend double-stabilizer drill tool assembly or a double-stabilizer drill tool assembly based on the slow-increase or slow-decline effect; For the horizontal section, the screw bending angle value and drilling method of the horizontal section are determined according to the target half-height, target half-width and maximum wellbore curvature required by the target area parameters and the wellbore trajectory control. According to the effect of slow increase or slow decrease in inclination, a single-bend double-stabilizer drill tool combination or a double-stabilizer drill tool combination is selected.

6. A method for controlling the trajectory of an ultra-deep, high-temperature, slim-hole horizontal well according to any one of claims 1 to 5, characterized in that: The drilling tool assembly inclination change rate is determined by the following steps: For each drilling tool combination, the full-strength inclination rate K is calculated by the inclination rate prediction method. z1 、Full force slope reduction rate K z2 The average value of the full-force increase inclination rate and the full-force decrease inclination rate is taken as the composite drilling well inclination change rate K r ; The orthogonal analysis method is used to find the factors affecting the composite drilling well deviation change rate K. r Based on the key influencing factors and influencing rules, the regression analysis method is used to construct the composite drilling well inclination change rate fitting expression corresponding to each drilling tool assembly to determine the well inclination change rate of the drilling tool assembly.

7. A method for controlling the trajectory of an ultra-deep, high-temperature, slim-hole horizontal well according to any one of claims 1 to 6, characterized in that: The maximum control step length of the wellbore trajectory is determined by the following steps: Based on the build-up rate corresponding to each wellbore trajectory and the well inclination change rate of the drilling tool assembly, the bottom hole distance and well inclination angle deviation between the original designed trajectory and the trajectory to be drilled after a single drilling trip are estimated; The bottom hole distance is limited by referring to the target area parameters, the single-pass drilling step length is iteratively solved, and the maximum value is selected as the first maximum control step length; The well inclination deviation is limited by referring to the target area parameters, the single-trip drilling step length is iteratively solved, and the maximum value is selected as the second maximum control step length; Considering the drill bit footage limited by the drill bit life, the third maximum control step length is obtained; The minimum value among the first maximum control step length, the second maximum control step length, and the third maximum control step length is taken as the maximum control step length of the wellbore trajectory.

8. The ultra-deep, high-temperature, slim-hole horizontal well trajectory control method according to claim 7, characterized in that: The first maximum control step size is determined by the following expression: Where: d represents the distance between the original design trajectory and the bottom of the well to be drilled; K0 represents the inclination rate of the original design wellbore trajectory; R0 represents the inclination radius corresponding to the inclination rate K0; K x Indicates the actual inclination rate of the drilling tool assembly, that is, the rate of change of the well inclination of the drilling tool assembly; R x Indicates the actual deflection radius of the drilling tool assembly; L x Indicates the progress of drilling in a single trip; The second maximum control step size is determined by the following expression: Δα=|Δα0-Δα x |=|K0-K x |L x Where: Δα represents the deviation of the wellbore angle between the original design trajectory and the trajectory to be drilled; Δα0 represents the wellbore angle increment of the original design wellbore trajectory; Δα x Indicates the increment of the wellbore inclination angle of the wellbore trajectory to be drilled.

9. A storage medium, characterized in that: It contains a series of instructions for executing the method steps according to any one of claims 1 to 8.

10. An ultra-deep, high-temperature, slim-hole horizontal well trajectory control device, characterized in that: The method according to any one of claims 1 to 8 is performed, wherein the device comprises: The wellbore trajectory design module is designed for ultra-deep, high-temperature, slim-hole horizontal wells. It determines the wellbore trajectory form and wellbore trajectory parameters based on engineering drilling requirements. a drilling tool assembly optimization module, which optimizes the drilling tool assembly for each wellbore trajectory based on the wellbore trajectory form and the wellbore trajectory parameters, and determines the drilling tool assembly optimization result corresponding to each wellbore trajectory; a well inclination change rate prediction module, which analyzes the influence of the drilling tool assembly on the build-up rate based on the drilling tool assembly optimization result and determines the well inclination change rate of the drilling tool assembly; The control step size optimization module combines the wellbore trajectory parameters and the well inclination change rate of the drilling tool assembly, considers the difference in well inclination change rate during actual drilling, and determines the maximum control step size of the wellbore trajectory.

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