Well cementation construction process for horizontal well

Abstract

The invention relates to the technical field of petroleum drilling construction, and discloses a well cementation construction process for a horizontal well. Comprising the steps that after drilling of the horizontal well is completed, a casing pipe is put in, the well is circularly washed, leading liquid and cement paste are prepared, the fluctuation-rotation alternating pulse technology is adopted in the cement paste injection process, alternating pulse parameters are dynamically adjusted according to well section characteristics, and well cementation operation is completed. According to the method, hydraulic fluctuation and casing rotation are accurately separated on the time domain, mutual interference of the two technical means is avoided, meanwhile, the special flowing mode generated in the flowing state conversion period is utilized, the well cementation quality of the horizontal well is remarkably improved, and the well cementation efficiency is improved. The technical problems that in long horizontal section well cementation, a casing pipe is centered, the cement paste flow resistance is large, and the replacement efficiency is low are solved.

Description

Technical Field

[0001] The invention relates to the technical field of oil drilling construction, and more specifically, to a cementing construction process for a horizontal well. Background Art

[0002] Horizontal well cementing is a key link in oil and gas well engineering, and its quality directly affects the production efficiency and service life of oil and gas wells. With the development of horizontal well technology, the horizontal section is getting longer and longer, and the traditional cementing process faces many technical challenges: the horizontal section casing is difficult to center, resulting in uneven annulus and poor cement ring quality; the horizontal section is long, the cement slurry flow resistance is large, the displacement efficiency is low, and it is easy to form a flow "short circuit"; the geological conditions and pressure gradients at different locations of the horizontal well are very different, and a single cementing process is difficult to meet the needs of different sections. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a horizontal well cementing construction process.

[0004] The present invention provides a horizontal well cementing construction process, comprising the following steps:

[0005] Step 1: Complete the horizontal well drilling and run the casing;

[0006] Step 2, circulating well washing to clean the wellbore;

[0007] Step 3, preparing the leading liquid and cement slurry;

[0008] Step 4, pumping in the pilot fluid and cement slurry;

[0009] Step 5: During the cement slurry injection process, a wave-rotation alternating pulse method is used to make the hydraulic wave and the casing rotation alternate in the time domain, specifically including: a hydraulic wave stage lasting 10 seconds; a first transition period lasting 5 seconds; a casing rotation stage lasting 15 seconds; a second transition period lasting 5 seconds; and repeating the above cycle until the cement slurry injection is completed;

[0010] Step 6: Dynamically adjust the fluctuation-rotation alternating pulse parameters according to the properties of different sections of the horizontal well;

[0011] Step 7: Complete the cementing operation.

[0012] Preferred: wave-rotation alternating pulse, specifically:

[0013] Start the hydraulic wave device to generate hydraulic wave energy of a given frequency for 10 seconds;

[0014] Stop hydraulic fluctuations and enter the first transition period, which lasts for 5 seconds;

[0015] Start the casing rotating device to rotate the casing at a predetermined speed and direction for 15 seconds;

[0016] Stop the sleeve rotation and enter the second transition period, which lasts for 5 seconds;

[0017] Repeat the above cycle until the cement slurry injection is completed.

[0018] Preferably, during the hydraulic fluctuation stage, the frequency range of the hydraulic fluctuation is 2-8 Hz, and the fluctuation amplitude is controlled within 0.5-2.5 MPa.

[0019] Preferably, during the sleeve rotation stage, the sleeve rotation speed is controlled within the range of 10-30 rpm.

[0020] Preferably: in the first transition period, after the hydraulic fluctuation stops, the cement slurry continues to maintain a certain degree of fluctuation state under the action of inertia, forming a gradually attenuated fluctuation flow field.

[0021] Preferably: in the second transition period, after the casing stops rotating, the cement slurry in the annulus continues to rotate under the action of inertia, but the rotation speed gradually decreases, forming a rotation attenuation flow.

[0022] Preferably, in step 6, the fluctuation-rotation alternating pulse parameters are dynamically adjusted according to the properties of different sections of the horizontal well, specifically comprising: dividing the horizontal well into sections of different properties, including: complex sections where the casing is difficult to center, sections where the cement slurry is prone to flow short circuits, turning sections and difficult sections, and adopting different parameter adjustment methods for different sections.

[0023] Preferably: For complex sections where the casing is difficult to center, adjusting the wave-rotation alternating pulse parameters includes:

[0024] Extend the cannula rotation time to 20-25 seconds;

[0025] Increase the casing rotation speed to 20-40 rpm;

[0026] Keep the hydraulic fluctuation time and transition period unchanged.

[0027] Preferably, for the section where cement slurry is prone to flow short circuit, adjusting the wave-rotation alternating pulse parameters includes:

[0028] Increase the intensity of hydraulic wave energy to 1.5-3.0MPa;

[0029] Increase the hydraulic fluctuation frequency to 5-10Hz;

[0030] Extend the first transition period to 8-10 seconds;

[0031] Keep the casing rotation time and the second transition period time unchanged.

[0032] Preferably, for the turning section and the difficult section, adjusting the fluctuation-rotation alternating pulse parameters includes:

[0033] Adjust the time ratio of fluctuation and rotation;

[0034] Adjust the alternation frequency;

[0035] Comprehensively adjust hydraulic fluctuations and casing rotation parameters according to actual conditions.

[0036] The beneficial effects of the present invention are as follows: the present invention adopts the method of wave-rotation alternating pulse, through precise separation in the time domain, so that the hydraulic wave and the casing rotation are alternately performed in time instead of acting simultaneously, thus avoiding mutual interference between the two technical means;

[0037] The cyclic time sequence of hydraulic fluctuation-pause-casing rotation-pause is creatively designed, and the conversion process of flow state is used to generate a special cement slurry flow pattern during the transition period (pause period);

[0038] A method for dynamically adjusting the wave-rotation alternating pulse parameters according to the characteristics of different sections of horizontal wells was established to achieve refined cementing "tailored to the well";

[0039] The technical means of enhancing the fluidity of cement slurry during the flow state conversion period are utilized, so that the alternation of the two effects forms a special flow state conversion process, thereby enhancing the fluidity and replacement efficiency of the cement slurry.

[0040] Through the precise design of the time series, the two technical means can work separately in different time periods, avoiding the energy cancellation problem when used simultaneously, and at the same time cleverly utilizing the special flow effect produced during the flow state conversion period. DETAILED DESCRIPTION

[0041] The subject matter described herein will now be discussed with reference to example embodiments. It should be understood that the discussion of these embodiments is only to enable those skilled in the art to better understand and implement the subject matter described herein, and the functions and arrangements of the elements discussed may be changed without departing from the scope of protection of the contents of this specification. Various examples may omit, replace or add various processes or components as needed. In addition, the features described in some examples may also be combined in other examples.

[0042] At least one embodiment of the present invention discloses a horizontal well cementing construction process, comprising the following steps:

[0043] Step 1: Complete horizontal well drilling and run casing;

[0044] After the horizontal well is drilled, the wellbore is cleaned and the drill bit is pulled out according to the conventional drilling process requirements to ensure that there is no obvious collapse and shrinkage in the wellbore, and the wellbore is confirmed to be in good condition through logging. After that, the casing is lowered to the target depth, and the outer wall of the casing is equipped with a guide device.

[0045] The configuration of the guide device follows the following principles: increase the number of guide devices at the bends of the horizontal section and in areas prone to casing eccentricity; configure the guide devices at even intervals in the straight section; and match the specifications and stiffness of the guide device with the wellbore size and formation properties.

[0046] Step 2: Circulate well washing to clean the wellbore;

[0047] After the casing is in place, the circulating well washing operation is carried out, and the wellbore is cleaned with well washing fluid to establish a circulation path. The circulating well washing uses low-solid well washing fluid, and the flow rate is controlled within a range sufficient to carry the debris on the well wall, generally 1.0-2.5m / s. The purpose of circulating well washing is to remove the cuttings and mud skin in the wellbore to create good conditions for subsequent cementing operations.

[0048] During the circulation well washing process, the properties of the returned liquid are monitored until the cleanliness of the returned liquid meets the cementing requirements. This is a routine preparation before cementing and is a routine implementation content for those skilled in the art.

[0049] Step 3: Prepare the pilot fluid and cement slurry;

[0050] According to the geological characteristics, well depth and temperature conditions of the horizontal well, the pilot fluid and cement slurry are prepared according to the design parameters. The role of the pilot fluid is to clean the wellbore, improve the properties of the well wall and create good conditions for the injection of cement slurry. The formula of cement slurry meets the requirements of good fluidity, suitable thickening time and fast strength development.

[0051] The preparation of the pilot fluid and cement slurry belongs to the conventional technical content of the cementing process. Those skilled in the art can prepare them according to the specific well conditions and requirements, and will not be described in detail here.

[0052] Step 4: Pump in the pilot fluid and cement slurry;

[0053] First, the pilot fluid is pumped into the wellbore. The amount of the pilot fluid is generally 80-120% of the annular volume, and the flow rate is controlled at 1.0-2.0m / s to ensure that the wellbore is fully flushed. After the pilot fluid is injected, the cement slurry is continuously pumped in according to the preset plan, maintaining appropriate injection pressure and flow rate to avoid gas channeling and channeling.

[0054] During this stage, parameters such as injection pressure, flow rate and pumping volume are monitored to ensure that the cement slurry is injected into the wellbore as required. The process of pumping cement slurry is a conventional step in the cementing process, and the implementation method is well known to those skilled in the art.

[0055] Step 5: Using the wave-rotation alternating pulse method;

[0056] This step is the core innovation of this implementation method. During the cement slurry injection process, the wave-rotation alternating pulse technology is adopted to make the hydraulic wave and the casing rotation alternate in the time domain instead of acting simultaneously.

[0057] 5.1 Basic principles of wave-rotation alternating pulse technology;

[0058] In traditional technologies, when hydraulic fluctuations and casing rotation are applied simultaneously, the energy fields will interfere with or even cancel each other, resulting in poor cementing results. The innovation of this implementation method is to separate the effects of the two technologies in time to form a regular alternating action mode, which is specifically implemented as follows:

[0059] Start the hydraulic wave device to generate hydraulic wave energy of a given frequency for 10 seconds;

[0060] Stop hydraulic fluctuations and enter the first transition period, which lasts for 5 seconds;

[0061] Start the casing rotating device to rotate the casing at a predetermined speed and direction for 15 seconds;

[0062] Stop the sleeve rotation and enter the second transition period, which lasts for 5 seconds;

[0063] Repeat the above cycle until the cement slurry injection is completed.

[0064] This time sequence allows hydraulic fluctuations and casing rotation to each act within an independent time window, avoiding mutual energy interference. At the same time, by setting a transition period and utilizing the "memory effect" and "inertia effect" in fluid dynamics, the effects of the previous stage can be maintained and continued during the transition period, creating favorable conditions for the next stage.

[0065] 5.2 Specific implementation of the wave-rotation alternating pulse technology;

[0066] 5.2.1 Hydraulic fluctuation stage (10 seconds);

[0067] Start the hydraulic fluctuation equipment to generate hydraulic fluctuation energy of a given frequency. The frequency range of hydraulic fluctuation is 2-8Hz, and the fluctuation amplitude is controlled at 0.5-2.5MPa. The hydraulic fluctuation action time is 10 seconds, which is long enough to make the cement slurry form a clear fluctuating flow state while keeping the energy consumption within a reasonable range.

[0068] During this stage, hydraulic fluctuation energy acts on the cement slurry in the annulus through fluid transfer, breaking the static laminar state of the cement slurry, prompting it to form a fluctuating flow pattern, and improving the flushing effect of the cement slurry on the well wall and the replacement efficiency of the drilling fluid.

[0069] 5.2.2 The first transition period (5 seconds);

[0070] Stop the hydraulic fluctuation and enter the first transition period, which lasts for 5 seconds. During this period, no active external energy input is performed, and the cement slurry is allowed to flow on its own.

[0071] The innovation of this stage is that by using the principle of "flow inertia" in fluid dynamics, after the hydraulic fluctuation stops, the cement slurry will not immediately resume static flow, but will continue to maintain a certain degree of fluctuation under the action of inertia, forming a gradually decaying fluctuating flow field. This feature allows the cement slurry to maintain good fluidity during the transition period, and the flow pattern is different from that in the forced fluctuation stage, forming a "free decaying fluctuating flow".

[0072] The duration of this transition period is 5 seconds, which is the working duration determined after many tests. It can fully utilize the flow inertia effect and ensure that the fluctuation will not completely decay to static flow.

[0073] 5.2.3 Casing rotation phase (15 seconds);

[0074] Start the casing rotation device to rotate the casing at a set speed and direction for 15 seconds. The casing rotation speed is controlled within the range of 10-30rpm, and the rotation direction can be clockwise or counterclockwise, but it should be consistent in a complete cementing process.

[0075] The casing rotation action time is 15 seconds, which is longer than the hydraulic fluctuation stage. This is because the effect of casing rotation on the flow state of cement slurry needs some time to be fully established, especially in the long horizontal section.

[0076] During this stage, casing rotation drives the cement slurry in the annulus to form annular flow, which not only promotes the centering of the casing in the horizontal section, but also enhances the contact between the cement slurry and the well wall, improving the replacement efficiency. Casing rotation can also break the gel structure that may be formed by the cement slurry and maintain its good fluidity.

[0077] 5.2.4 Second transition period (5 seconds);

[0078] Stop the casing rotation and enter the second transition period, which lasts for 5 seconds. Also, no active external energy input is performed, and the cement slurry is allowed to flow on its own.

[0079] The innovation of this transition period is that after the casing rotation stops, the cement slurry in the annulus continues to rotate under the action of inertia, but the rotation speed gradually decreases, forming a "rotational attenuation flow". This flow state is different from both static flow and forced rotation, and has different fluid mechanics characteristics.

[0080] The second transition period lasts for 5 seconds, which is the same as the first transition period. It is a working duration verified by practice. It can fully utilize the rotational inertia effect and prepare for the hydraulic fluctuation effect of the next cycle.

[0081] 5.2.5 Repeat the cycle;

[0082] After completing the above four stages, the hydraulic fluctuation stage is entered again to form a complete cycle, which is repeated until the cement slurry injection is completed.

[0083] The difference between this step and the prior art is mainly reflected in the following aspects:

[0084] Through separation in the time domain, the mutual interference and energy cancellation problems when hydraulic fluctuations and casing rotation act simultaneously are avoided;

[0085] By designing a time sequence (10 seconds-5 seconds-15 seconds-5 seconds), the two technical means can play a role in the appropriate time window, while taking into account the needs of horizontal well cementing;

[0086] By introducing two transition periods and using the principle of "flow inertia" in fluid dynamics, two different flow states, "free attenuation wave flow" and "rotation attenuation flow", are formed. These two flow states are different from the flow states generated by forced fluctuations and forced rotations, and can act on cement slurry and wellbore wall in different ways.

[0087] Through the cyclic conversion of four different flow states (forced wave flow-free decay wave flow-forced rotation flow-rotation decay flow), a variety of flow field structures are created, breaking the radial symmetric flow limitations in traditional cementing, forming a multi-dimensional and multi-mode flow system, and improving the fluidity and replacement efficiency of cement slurry.

[0088] Step 6: Dynamically adjust the fluctuation-rotation alternating pulse parameters;

[0089] This step is to dynamically adjust the wave-rotation alternating pulse parameters according to the characteristics of different sections of the horizontal well, so as to achieve refined cementing "tailored to the well".

[0090] 6.1 Segment identification and parameter adjustment principles;

[0091] First, based on well logging data, drilling data and geological data, horizontal wells are divided into sections of different natures, mainly including:

[0092] Complex sections where casing is difficult to center: usually the wellbore expansion section, wellbore reduction section or the section with large formation fluctuations;

[0093] The sections where cement slurry is prone to flow short circuits are usually sections with large wellbore ellipticity and high wellbore wall roughness;

[0094] Turning sections and difficult sections: usually the transition areas between horizontal sections and vertical sections, or sections with complex geological conditions.

[0095] Different parameter adjustment methods are used for different levels:

[0096] 6.2 Specific adjustment methods;

[0097] 6.2.1 Complex sections where the casing is difficult to center;

[0098] In this section, the main problem is the uneven annulus caused by casing eccentricity. To address this problem, the wave-rotation alternating pulse parameters are adjusted as follows:

[0099] Extend the sleeve rotation time: extend the standard 15 seconds to 20-25 seconds to enhance the sleeve centering effect;

[0100] Increase the cannula rotation speed: Increase the standard 10-30rpm to 20-40rpm to increase the centrifugal force of the cannula rotation;

[0101] Keep the hydraulic fluctuation time and transition period unchanged to ensure the stability of the basic circulation mode.

[0102] This adjustment enhances the effect of cannula rotation on cannula centering while maintaining the basic characteristics of the wave-rotation alternating pulse technique.

[0103] 6.2.2 Sections where cement slurry is prone to flow short circuits;

[0104] In this section, the main problem is uneven cement slurry flow and insufficient replacement in some areas. To address this problem, the wave-rotation alternating pulse parameters are adjusted as follows:

[0105] Increase the intensity of hydraulic fluctuation energy: increase the standard 0.5-2.5MPa to 1.5-3.0MPa, and enhance the disturbance effect of hydraulic fluctuation on cement slurry flow;

[0106] Increase the frequency of hydraulic fluctuations: increase the standard 2-8Hz to 5-10Hz, enhancing the penetration of hydraulic fluctuations;

[0107] Extend the first transition period: extend the standard 5 seconds to 8-10 seconds, so that the "free decay wave flow" has more time to act on the annulus;

[0108] Keep the casing rotation time and the second transition period time unchanged.

[0109] This adjustment method enhances the effect of hydraulic fluctuations on the flow pattern of cement slurry and improves the flow uniformity of cement slurry in complex annuli.

[0110] 6.2.3 Turning sections and difficult sections;

[0111] In this segment, multiple technical problems coexist, and it is necessary to comprehensively adjust the wave-rotation alternating pulse parameters:

[0112] Adjust the time ratio of fluctuation and rotation: according to the specific situation, you can use different time ratios such as "10 seconds fluctuation - 5 seconds transition - 20 seconds rotation - 5 seconds transition" or "15 seconds fluctuation - 5 seconds transition - 15 seconds rotation - 5 seconds transition";

[0113] Adjust the alternating frequency: You can increase the number of fluctuation-rotation alternations per unit time by shortening the total time of the entire cycle (e.g., one cycle of 30 seconds);

[0114] Hydraulic fluctuations and casing rotation parameters are adjusted comprehensively according to actual conditions.

[0115] This comprehensive parameter adjustment method can provide more accurate technical solutions for complex situations in high-difficulty levels.

[0116] 6.3 Implementation and monitoring of parameter adjustments;

[0117] Parameter adjustment is carried out according to the pre-established cementing plan. During the cementing process, the adjustment effect is evaluated by real-time monitoring of parameters such as injection pressure, flow rate, casing torque, etc., and fine-tuning is performed when necessary.

[0118] The innovation of parameter adjustment is that it realizes the refinement of cementing technology and "constructs according to the actual situation of horizontal wells", thus improving the cementing success rate and cement ring quality.

[0119] Step 7: Complete cementing operation;

[0120] After the cement slurry is injected, maintain appropriate displacement pressure to ensure the stability of the cement slurry in the annulus. After the cement slurry initially sets, gradually release the pressure to complete the cementing operation.

[0121] This step is a conventional finishing step of the cementing process, and the implementation method thereof is well known to those skilled in the art and will not be described in detail here.

[0122] The horizontal well cementing construction process provided in this embodiment achieves the following technical effects through the wave-rotation alternating pulse technology and the dynamic parameter adjustment method:

[0123] Solved the technical interference problem: In traditional technology, when hydraulic fluctuations and casing rotation are applied simultaneously, the energy fields will interfere with or even cancel each other out. This implementation solves this technical problem by separating the two technical means in the time domain, allowing each of the two technical means to function independently within an appropriate time window.

[0124] Improved cement slurry fluidity and replacement efficiency: This implementation method utilizes the flow pattern generated during the flow state conversion period to form a cyclic conversion of four different flow states of "forced wave flow-free attenuation wave flow-forced rotation flow-rotation attenuation flow", creating a variety of flow field structures and improving cement slurry fluidity and replacement efficiency.

[0125] Refined cementing is achieved: This implementation method achieves refined cementing tailored to the characteristics of different well sections by dynamically adjusting the wave-rotation alternating pulse parameters, solving a number of problems such as casing centering, cement slurry flow short circuit and poor cementing quality in complex sections.

[0126] Improved cement ring integrity: This implementation method breaks the radial symmetric flow limitation in traditional cementing through the alternating effect of four different flow states, improves the adhesion of cement slurry to the well wall and the integrity of the annular cement ring.

[0127] Wide applicability and strong operability: This implementation method does not require additional equipment. It only needs to utilize the existing hydraulic fluctuation equipment and casing rotation device. Through the improvement of process flow and operation sequence, it can achieve technological breakthroughs and has good engineering applicability and operability.

[0128] In summary, this embodiment solves many technical problems in horizontal well cementing and improves the cementing quality of horizontal wells by improving the process flow, especially the application of wave-rotation alternating pulse technology, and has important engineering application value.

[0129] In order to verify the technical effect of the horizontal well cementing construction process proposed in this implementation method, the following series of experimental tests were carried out.

[0130] Experiment 1: Technology Interference Problem Solving Experiment

[0131] 1. Experimental purpose: To verify whether the wave-rotation alternating pulse technology can effectively solve the mutual interference problem of energy fields generated when hydraulic wave and casing rotation are applied simultaneously.

[0132] 2. Experimental setup

[0133] Laboratory simulation wellbore device, inner diameter 150mm, length 15m, of which the horizontal section length is 10m; hydraulic fluctuation generating device, adjustable frequency (0-10Hz), adjustable fluctuation amplitude (0-3MPa); casing rotation simulation device, adjustable speed (0-50rpm); cement slurry circulation system; pressure, flow, temperature sensor group; data acquisition system.

[0134] 3. Experimental steps

[0135] Prepare three sets of experiments:

[0136] Group A: only hydraulic wave technique was used;

[0137] Group B: only cannula rotation technique was used;

[0138] Group C: using both hydraulic fluctuation and casing rotation techniques;

[0139] Group D: using the wave-rotation alternating pulse technique;

[0140] For group A, the hydraulic fluctuation frequency was set to 5 Hz and the fluctuation amplitude was set to 1.5 MPa;

[0141] For group B, the cannula rotation speed was set to 20 rpm;

[0142] For group C, hydraulic fluctuation (5 Hz, 1.5 MPa) and cannula rotation (20 rpm) were applied simultaneously;

[0143] For group D, the fluctuation-rotation alternating pulse technique was implemented according to the time sequence of “10 s fluctuation (5 Hz, 1.5 MPa)-5 s transition-15 s rotation (20 rpm)-5 s transition”;

[0144] The same cement slurry and pilot fluid formulations, injection volumes, and operating conditions were used in each set of experiments;

[0145] The pressure fluctuation, casing torque, cement slurry flow rate and other parameters during the experiment are recorded by sensors;

[0146] After the experiment is completed, the quality indicators of the cement sheath are measured, including the density, uniformity, and bonding strength of the cement sheath with the well wall.

[0147] IV. Experimental Results

[0148] By comparing and analyzing the four groups of experimental data, the following results are obtained, as shown in Table 1:

[0149] Table 1: Comparison of energy transfer efficiency of different cementing technologies

[0150]

[0151] In the table: Energy transfer efficiency refers to the proportion of input energy effectively transferred in the wellbore; Comprehensive energy utilization refers to the proportion of input energy that actually contributes to cementing quality; Cement sheath quality score adopts a 100-point system, which is comprehensively evaluated based on cement sheath density, uniformity, bonding strength, etc.

[0152] V. Experimental Analysis

[0153] When hydraulic fluctuation and casing rotation were applied simultaneously (Group C), the two energy forms interfered with each other, causing their respective energy transfer efficiencies to drop to 52% and 55%, respectively, and the comprehensive energy utilization rate was only 53.5%, which was lower than the effect of using either technology alone. After the use of the fluctuation-rotation alternating pulse technology (Group D), the energy transfer efficiencies of hydraulic fluctuation and casing rotation reached 65% and 69%, respectively, close to the levels when used alone, but the comprehensive energy utilization rate was significantly improved to 85%, and the cement sheath quality score reached 91 points, 16-23 points higher than the other groups. This proves that the fluctuation-rotation alternating pulse technology effectively solves the problem of energy interference when the two technologies are used simultaneously.

[0154] Experiment 2: Experiment on improving cement slurry fluidity and replacement efficiency

[0155] 1. Purpose of the experiment

[0156] Verify whether the wave-rotation alternating pulse technology can effectively improve the fluidity and replacement efficiency of cement slurry, especially its performance in long horizontal sections.

[0157] 2. Experimental setup

[0158] The long horizontal section simulates the wellbore with an inner diameter of 120mm and a total length of 30m, of which the horizontal section is 25m long; a transparent observation window is set every 5m along the horizontal section to observe the flow state of cement slurry; a well wall mud skin simulation device can evenly coat the simulated mud skin on the inner surface of the well wall; a hydraulic fluctuation generating device and a casing rotation device; a tracer detection system; a high-precision flow meter and a pressure sensor array.

[0159] 3. Experimental steps

[0160] Prepare four sets of experiments:

[0161] Group A: conventional cementing process (no fluctuation, no rotation);

[0162] Group B: only hydraulic fluctuation technology (frequency 5 Hz, fluctuation amplitude 1.5 MPa) was used;

[0163] Group C: only the cannula rotation technique (20 rpm) was used;

[0164] Group D: wave-rotation alternating pulse technique;

[0165] Evenly coat the inner wall of the wellbore with simulated mud skin, with a thickness of about 2mm;

[0166] Add fluorescent tracers to drilling fluid and inject into the wellbore;

[0167] The pilot fluid and cement slurry are injected sequentially to simulate the cementing process;

[0168] The process of cement slurry replacing drilling fluid at each location is recorded through a transparent observation window;

[0169] Real-time monitoring of pressure and flow rate changes at each measuring point;

[0170] After completion, measure the mud skin removal rate and cement slurry filling rate at various locations in the wellbore.

[0171] IV. Experimental Results

[0172] By comparing the four groups of experimental data, the following results are obtained, as shown in Table 2 and Table 3:

[0173] Table 2: Comparison of cement slurry fluidity of different cementing technologies

[0174]

[0175] In the table: cement slurry dynamic-plastic ratio refers to the percentage reduction of dynamic plasticity relative to the conventional process (Group A); flow resistance reduction rate refers to the percentage reduction of flow resistance relative to the conventional process; cement slurry pulsation intensity refers to the pressure pulsation amplitude in cement slurry flow.

[0176] Table 3: Comparison of displacement efficiency of different cementing technologies

[0177]

[0178] V. Experimental Analysis

[0179] Compared with the conventional process, the wave-rotation alternating pulse technology (group D) reduced the dynamic plasticity of cement slurry by 38% and the flow resistance by 35%, showing a significant improvement in fluidity. At the same time, the pulsation intensity of cement slurry in group D reached 7800Pa, which was much higher than that in groups B and C, indicating that the alternating conversion of four different flow states produced a stronger flow disturbance effect.

[0180] The average displacement efficiency of the wave-rotation alternating pulse technology reached 89%, which is about 16 percentage points higher than the use of hydraulic wave or casing rotation technology alone, and 30 percentage points higher than the conventional process. Especially at the end of the horizontal section, the replacement rate of group D reached 86%, which is much higher than that of other groups, indicating that the alternating pulse technology has a significant effect on improving the displacement efficiency of long horizontal sections. At the same time, the mud skin removal rate of group D is also significantly higher than that of other groups, reaching 89%, proving that this technology can effectively improve the cleanliness of the well wall.

[0181] These results fully demonstrate that the wave-rotation alternating pulse technology creates a diverse flow field structure and effectively improves the fluidity and replacement efficiency of cement slurry by forming a cyclic conversion of four different flow states: "forced wave flow-free decay wave flow-forced rotation flow-rotation decay flow".

[0182] Experiment 3: Fine cementing implementation experiment

[0183] 1. Purpose of the experiment

[0184] Verify whether the method of dynamically adjusting the wave-rotation alternating pulse parameters according to the characteristics of different sections of the horizontal well can effectively solve the cementing quality problems in different well sections and achieve refined cementing.

[0185] 2. Experimental setup

[0186] Complex well type simulation device, including the following characteristic sections:

[0187] Simulate an elliptical wellbore section (5 m long) where the casing is difficult to center;

[0188] A high-roughness wellbore section (5 m long) simulating the cement slurry that is prone to flow short circuits;

[0189] Simulated turning section (3m long, curvature radius of 15m);

[0190] Hydraulic fluctuation and casing rotation control system, capable of adjusting parameters in real time;

[0191] Multi-point logging simulation system can monitor the casing eccentricity and cement slurry circulation status at each section;

[0192] Neutral logging simulation system for evaluating cement sheath quality;

[0193] Data acquisition and analysis system.

[0194] 3. Experimental steps

[0195] Prepare two sets of experiments:

[0196] Group A: using the wave-rotation alternating pulse technology with fixed parameters (without adjusting the parameters according to the characteristics of the well section);

[0197] Group B: The wave-rotation alternating pulse technique with dynamically adjusted parameters was used;

[0198] For group B experiments, set parameters according to the characteristics of different stages:

[0199] Elliptical wellbore sections where the casing is difficult to center: extend the casing rotation time to 25 seconds and increase the casing rotation speed to 35 rpm;

[0200] For high-roughness wellbore sections that are prone to flow short circuits: increase the hydraulic fluctuation energy intensity to 2.5MPa, the frequency to 8Hz, and extend the first transition period to 10 seconds;

[0201] Turning section: adopt the time sequence of "15 seconds fluctuation-5 seconds transition-15 seconds rotation-5 seconds transition", fluctuation frequency 6Hz, rotation speed 25rpm;

[0202] Carry out cementing operations and monitor cementing parameters at each section during the entire process;

[0203] After completion, the cementing quality indicators of each section are evaluated.

[0204] IV. Experimental Results

[0205] By comparing the data of the two groups of experiments, the following results are obtained, as shown in Table 4:

[0206] Table 4: Comparison of cementing quality between fixed parameters and dynamically adjusted parameters

[0207]

[0208] In the table: casing eccentricity refers to the degree of deviation between the center of the casing and the center of the wellbore. The lower the value, the better the centering effect. Micro-annulus index refers to the proportion of the tiny gap in the cement sheath. The lower the value, the more complete the cement sheath.

[0209] V. Experimental Analysis

[0210] Compared with the wave-rotation alternating pulse technology with fixed parameters, the method of dynamically adjusting parameters has achieved significant quality improvement in all characteristic segments:

[0211] In the elliptical wellbore section, by extending the casing rotation time and increasing the rotation speed, the casing eccentricity was reduced from 42% to 18%, and the cement sheath uniformity score was improved by 34.9%, effectively solving the casing centering problem.

[0212] In the high-roughness wellbore section, by increasing the intensity and frequency of hydraulic fluctuation energy and extending the first transition period, the replacement efficiency was increased from 76% to 92%, the wellbore bonding strength was increased by 50%, and the cement slurry flow short-circuit problem was effectively solved.

[0213] In the turning section, by adjusting the time ratio and parameters of fluctuation and rotation, the cement sheath integrity score was improved by 23.6% and the micro-annulus index was reduced by 75%, effectively solving the cementing problem in this section.

[0214] Overall, the method of dynamically adjusting parameters increased the average cementing quality score from 71 to 88, an increase of 23.9%, proving the effectiveness of this method in achieving refined cementing.

[0215] The experimental results show that the method of dynamically adjusting the wave-rotation alternating pulse parameters according to the characteristics of different sections of the horizontal well can provide accurate technical solutions to the cementing problems in different well sections, realize the refined cementing "tailored to the well", and significantly improve the overall cementing quality.

[0216] Experiment 4: Cement ring integrity improvement experiment

[0217] 1. Purpose of the experiment

[0218] To verify whether the wave-rotation alternating pulse technology can effectively improve the integrity of the cement sheath and reduce the occurrence of cement sheath channels and micro-annuli.

[0219] 2. Experimental setup

[0220] Large horizontal well simulator, inner diameter 180mm, length 20m;

[0221] The cross-section sampling device can take samples along the wellbore direction after cementing is completed;

[0222] Acoustic logging simulation system, used to measure the acoustic wave propagation parameters of cement sheath;

[0223] Pressure cycle test system, which can simulate the pressure changes during the production process;

[0224] CT scanning system, used for three-dimensional imaging and analysis of cement sheath structure;

[0225] Hydraulic surge and casing rotation device.

[0226] 3. Experimental steps

[0227] Prepare three sets of experiments:

[0228] Group A: conventional cementing process;

[0229] Group B: hydraulic fluctuation and casing rotation techniques were applied simultaneously;

[0230] Group C: undulation-rotation alternating pulse technique;

[0231] Cementing operations were carried out under the same conditions;

[0232] After the cement slurry solidifies, the acoustic parameters of the cement sheath are evaluated using an acoustic logging system;

[0233] Conduct pressure cycle tests on the wellbore to simulate pressure changes during production;

[0234] After the pressure cycle, the sonic logging evaluation is performed again;

[0235] Take samples at different locations in the wellbore and perform CT scanning analysis;

[0236] Measure and record cement sheath density, porosity, microcrack distribution and other parameters;

[0237] IV. Experimental Results

[0238] By comparing the three sets of experimental data, the following results are obtained, as shown in Table 5 and Table 6:

[0239] Table 5: Comparison of cement sheath integrity of different cementing technologies

[0240]

[0241] In the table: Cement sheath uniformity coefficient refers to the consistency of the circumferential thickness of the cement sheath. The closer the value is to 1, the better the uniformity. Microcrack index refers to the comprehensive evaluation of the number and length of microcracks per unit volume. The lower the value, the fewer microcracks.

[0242] Table 6: Change rate of cement sheath performance after pressure cycle test

[0243]

[0244] In the table: the acoustic attenuation change rate refers to the percentage change in the acoustic attenuation degree before and after the pressure cycle, and a negative value indicates an increase in attenuation; the cement sheath thickness change rate refers to the percentage decrease in cement sheath thickness caused by the pressure cycle; the microannulus growth rate refers to the percentage increase in microannulus area caused by the pressure cycle; the sealing integrity retention rate refers to the percentage of the cement sheath that maintains its original sealing performance after the pressure cycle.

[0245] V. Experimental Analysis

[0246] The cement sheath formed by the wave-rotation alternating pulse technology (group C) has significantly better physical properties than other groups: the cement sheath uniformity coefficient is as high as 0.92, close to the ideal value of 1; the cement sheath density reaches 1.94g / cm³, higher than that of groups A and B; the porosity is only 3.5%, about 40% of the conventional process; the microcrack index is 0.08, only 23% of the conventional process. This shows that the cement sheath structure formed by the alternating pulse technology is more dense and uniform, and the microscopic defects are significantly reduced.

[0247] After the pressure cycle test simulating the production process, the performance of the cement sheath in group C remained the most stable: the change rate of acoustic wave attenuation was only -7%, while that of group A was -26%; the change rate of cement sheath thickness was only -1.2%, much lower than that of other groups; the microannulus growth rate was only 6%, while that of group A was as high as 42%; the sealing integrity retention rate was as high as 93%, 32 percentage points higher than that of conventional processes. This shows that the cement sheath formed by the alternating pulse technology not only has high initial quality, but also has significantly improved stability during the production process.

[0248] CT scanning analysis further showed that the microstructure of the C group cement sheath was more uniform, the crystal arrangement was more compact, and the interface bonding was stronger. This was because the alternating action of four different flow states broke the radial symmetrical flow limitations in traditional cementing, allowing the cement slurry to penetrate and bond more fully at the microscopic level.

[0249] In summary, the wave-rotation alternating pulse technology significantly improves the integrity and durability of the cement sheath by optimizing the flow and displacement process of cement slurry, providing a more reliable guarantee for the long-term safe production of horizontal wells.

[0250] Experiment 5: Applicability and operability verification experiment

[0251] 1. Purpose of the experiment

[0252] Verify the engineering applicability and operational convenience of the wave-rotation alternating pulse technology, and evaluate its implementation difficulty and economy under different working conditions.

[0253] 2. Experimental setup

[0254] On-site cementing operation simulation system;

[0255] Conventional cementing equipment combination, including cement truck, mixing tank, pump truck, etc.;

[0256] hydraulic surge equipment and casing rotation devices;

[0257] Automated control systems;

[0258] Energy consumption monitoring system;

[0259] Operational complexity assessment system.

[0260] 3. Experimental steps

[0261] Design three different working conditions:

[0262] Working condition A: shallow well (1500m), standard wellbore size;

[0263] Working condition B: medium-deep well (3000m), long horizontal section (1500m);

[0264] Working condition C: deep well (4500m), high temperature and high pressure environment;

[0265] Under various working conditions, the construction simulations of conventional cementing technology and wave-rotation alternating pulse technology were carried out respectively;

[0266] Record the equipment requirements, staffing, operation process complexity, construction risk points and other parameters of the two processes under each working condition;

[0267] Record the energy consumption, time consumption, material consumption and other resource usage of the two processes under each working condition;

[0268] Invite 10 experienced cementing engineers to rate the ease of operation;

[0269] Comprehensively analyze the applicability and economic differences of the two processes under different working conditions.

[0270] IV. Experimental Results

[0271] By comparing and analyzing the data, the following results are obtained, as shown in Table 7 and Table 8:

[0272] Table 7: Comparison of operability between wave-rotation alternating pulse technology and conventional process under different working conditions

[0273]

[0274] In the table: the difference ratio represents the percentage increase of the alternating pulse technology relative to the conventional process; the operation complexity score is based on a 100-point system, and the lower the score, the simpler the operation.

[0275] Table 8: Economic comparison between wave-rotation alternating pulse technology and conventional process under different working conditions

[0276]

[0277] V. Experimental Analysis

[0278] Compared with conventional processes, the wave-rotation alternating pulse technology requires slightly more equipment and operating steps, and the operation complexity is slightly higher. However, with the increase of well depth and the complexity of well conditions, the difference in operation complexity between the two processes gradually decreases, and the difference is only 7% in working condition C. This shows that although the alternating pulse technology is slightly more complicated than the conventional process, it does not significantly increase the difficulty of operation, especially in difficult well conditions.

[0279] In terms of economy, the energy consumption and construction time of the alternating pulse technology are slightly higher than those of the conventional process, but as the well conditions become more complex, this difference gradually decreases, with the energy consumption difference being only 3.8% and the time difference being only 2.6% in condition C. More significantly, the alternating pulse technology reduces cement slurry usage in all conditions, with a saving of 8%-13.7%, while significantly improving the cementing success rate, with an increase of 25%-29.4% in complex well conditions.

[0280] Comprehensively analyzing the operability and economy, the applicability of the wave-rotation alternating pulse technology is reflected in the following aspects:

[0281] The technical implementation threshold is not high. It only requires adding a hydraulic fluctuation control system and a casing rotation parameter optimization system to conventional cementing equipment.

[0282] The operation complexity is moderate, and the difference with conventional processes is smaller in difficult well conditions;

[0283] Although the initial investment is slightly higher, the overall construction cost can actually be reduced by reducing the amount of cement slurry used and increasing the cementing success rate;

[0284] The technical effect becomes more significant as the complexity of the well conditions increases, and it is particularly suitable for cementing long horizontal sections and high-difficulty wells.

[0285] Evaluations by cementing engineers showed that after a short period of training, operators were able to quickly master the key points of implementing the alternating pulse technology, and the ease of operation received an average rating of 82 points (out of a full 100 points), indicating that the technology has good engineering practicality.

[0286] Experimental test summary

[0287] Through the above five sets of system experimental tests, the various technical effects of the horizontal well cementing construction process proposed in this implementation method have been fully verified:

[0288] The wave-rotation alternating pulse technology effectively solves the mutual interference problem of energy field when hydraulic wave and casing rotation are applied simultaneously through separation in the time domain, thus increasing the energy utilization rate by 31.5 percentage points.

[0289] The cyclic conversion of the four flow states formed a diverse flow field structure, which reduced the dynamic plasticity of the cement slurry by 38%, the flow resistance by 35%, and the average replacement efficiency reached 89%, which is 30 percentage points higher than the conventional process.

[0290] The method of dynamically adjusting parameters according to the characteristics of different sections of horizontal wells achieved refined cementing, which increased the average cementing quality score by 23.9% and effectively solved the cementing problems in different well sections.

[0291] The cement sheath structure formed by the wave-rotation alternating pulse technology is more dense and uniform, with a cement sheath uniformity coefficient of 0.92 and a porosity of only 3.5%, showing excellent stability in the pressure cycle test;

[0292] This technology has good engineering applicability and operability, especially in difficult well conditions. It can reduce cement slurry consumption by 8%-13.7% and increase cementing success rate by 11.8%-29.4%.

[0293] The above describes an embodiment of the present invention, but this embodiment is not limited to the above-mentioned specific implementation mode. The above-mentioned specific implementation mode is merely illustrative and not restrictive. Under the guidance of this embodiment, ordinary technicians in this field can also make more forms of equivalent embodiments, all of which are protected by this embodiment.

Claims

1. A horizontal well cementing construction process, characterized in that: The following steps are involved: Step 1: Complete the horizontal well drilling and run the casing; Step 2, circulating well washing to clean the wellbore; Step 3, preparing the leading liquid and cement slurry; Step 4, pumping in the pilot fluid and cement slurry; Step 5: During the cement slurry injection process, a wave-rotation alternating pulse method is used to make the hydraulic wave and the casing rotation alternate in the time domain, specifically including: a hydraulic wave stage lasting 10 seconds; a first transition period lasting 5 seconds; a casing rotation stage lasting 15 seconds; a second transition period lasting 5 seconds; and repeating the above cycle until the cement slurry injection is completed; Step 6: Dynamically adjust the fluctuation-rotation alternating pulse parameters according to the properties of different sections of the horizontal well; Step 7: Complete the cementing operation.

2. A horizontal well cementing construction process according to claim 1, characterized in that: In step 5, the wave-rotation alternating pulse is specifically: Start the hydraulic wave device to generate hydraulic wave energy of a given frequency for 10 seconds; Stop hydraulic fluctuations and enter the first transition period, which lasts for 5 seconds; Start the casing rotating device to rotate the casing at a predetermined speed and direction for 15 seconds; Stop the sleeve rotation and enter the second transition period, which lasts for 5 seconds; Repeat the above cycle until the cement slurry injection is completed.

3. A horizontal well cementing construction process according to claim 2, characterized in that: During the hydraulic fluctuation stage, the frequency range of the hydraulic fluctuation is 2-8Hz, and the fluctuation amplitude is controlled at 0.5-2.5MPa.

4. A horizontal well cementing construction process according to claim 2, characterized in that: During the casing rotation stage, the casing rotation speed is controlled within the range of 10-30 rpm.

5. A horizontal well cementing construction process according to claim 2, characterized in that: In the first transition period, after the hydraulic fluctuation stops, the cement slurry continues to maintain a certain degree of fluctuation state under the action of inertia, forming a gradually attenuated fluctuation flow field.

6. A horizontal well cementing construction process according to claim 2, characterized in that: In the second transition period, after the casing rotation stops, the cement slurry in the annulus continues to rotate under the action of inertia, but the rotation speed gradually decreases, forming a rotation attenuation flow.

7. A horizontal well cementing construction process according to claim 1, characterized in that: In step 6, the fluctuation-rotation alternating pulse parameters are dynamically adjusted according to the properties of different sections of the horizontal well, specifically including: dividing the horizontal well into sections of different properties, including: complex sections where casing is difficult to center, sections where cement slurry is prone to flow short circuits, turning sections and high-difficulty sections, and using different parameter adjustment methods for different sections.

8. A horizontal well cementing construction process according to claim 7, characterized in that: For complex sections where the casing is difficult to center, the parameters of the wave-rotation alternating pulse are adjusted as follows: Extend the cannula rotation time to 20-25 seconds; Increase the casing rotation speed to 20-40 rpm; Keep the hydraulic fluctuation time and transition period unchanged.

9. A horizontal well cementing construction process according to claim 7, characterized in that: For the section where cement slurry is prone to flow short circuit, the adjustment of the wave-rotation alternating pulse parameters includes: Increase the intensity of hydraulic wave energy to 1.5-3.0MPa; Increase the hydraulic fluctuation frequency to 5-10Hz; Extend the first transition period to 8-10 seconds; Keep the casing rotation time and the second transition period time unchanged.

10. A horizontal well cementing construction process according to claim 7, characterized in that: For turning sections and difficult sections, adjust the wave-rotation alternating pulse parameters including: Adjust the time ratio of fluctuation and rotation; Adjust the alternation frequency; Comprehensively adjust hydraulic fluctuations and casing rotation parameters according to actual conditions.

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