Directional drilling process for shale oil slim-hole well

Abstract

The invention discloses a directional drilling process for a shale oil slim-hole well, which comprises the following steps of: S1, sequentially constructing a drilling directional section and a drilling stable inclination section in a three-opening slim hole, adopting a combined drilling tool in the drilling directional section and the drilling stable inclination section, and adopting high-performance water-based drilling fluid in the drilling directional section and the drilling stable inclination section; s2, in the process of drilling a directional section and a stable inclined section, the MWD wireless inclinometer measures and obtains actual well track data, imports the actual well track data into track calculation software to obtain a well actual drilling track, and speculates a rear section well track trend through the calculation software; and S3, the actual well track data obtained in the step S2 are compared with the designed well track data, and the tool face angle of the combined drilling tool is adjusted according to the comparison result. By means of the technology, the average mechanical drilling speed of a test well group is 11.1 m / h, and the average mechanical drilling speed is increased by 5.4% on year-on-year basis. The average drilling period is 29.11 days, and 57.9% of drilling time is saved on year-on-year basis.

Description

Technical Field

[0001] The present invention relates to a drilling process, more specifically, to a directional drilling process for shale oil slim hole wells. Background Art

[0002] At present, the shale oil directional wells in the northern Jiangsu Basin mainly adopt the three-opening conventional size wellbore wellbore structure, specifically: the first opening adopts a 406.4mm conventional wellbore and runs a 339.7mm surface casing; the second opening adopts a 311.2mm conventional wellbore and runs a 244.5mm technical casing; the third opening adopts a 215.9mm conventional wellbore and runs a 139.7mm production casing.

[0003] In order to further reduce costs and increase efficiency and improve development benefits, the above-mentioned wellbore structure was optimized, and the wellbore size of each opening was slimmed down. The optimized wellbore structure is as follows: the first opening uses a 311.2mm conventional wellbore and runs a 244.5mm surface casing; the second opening uses a 215.9mm conventional wellbore and runs a 139.7mm technical casing; the third opening uses a 118.0mm slim wellbore and runs a 95.25mm production casing. Therefore, the wells using the above-mentioned wellbore structure are called slim-bore wells.

[0004] In the early stages of shale oil directional wells in the northern Jiangsu Basin, conventional wellbore and casing structures were typically used in a three-splinter system. To further reduce costs and increase efficiency, optimizing conventional wellbore dimensions to smaller wellbore and casing structures offers significant advantages in drilling cost control. However, due to the characteristics of small wellbores, directional drilling using existing rock-breaking tools and drilling fluids can lead to low penetration rates, severe pressure buildup, and poor wellbore stability. Summary of the Invention

[0005] Based on this, it is necessary to provide a directional drilling process for shale oil small hole wells to address the above technical problems.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A directional drilling process for shale oil slim-hole wells, comprising the following steps:

[0008] Step S1, drilling a directional section and a stable inclination section in sequence in three slim-hole wells, using a modular drilling tool in the directional section and the stable inclination section, the modular drilling tool comprising a drill bit, a screw, a non-magnetic drill rod, a weighted drill rod, and a main drill rod connected in sequence, an MWD wireless inclinometer being provided inside the non-magnetic drill rod, and using a high-performance water-based drilling fluid in the directional section and the stable inclination section, the high-performance water-based drilling fluid comprising, by mass percentage, 3.0% bentonite, 1% fluid loss additive, 0.1% viscosity reducer, 4-8% high-temperature anti-slump agent, 7.5-11% plugging and anti-slump agent, 7-8% inhibitor, 1-4% lubricant, 3-4% shielding and temporary plugging agent, 0.5% inorganic treatment agent, and active water;

[0009] Step S2: During the directional drilling section and the steady-angle drilling section, the MWD wireless inclinometer measures and obtains actual wellbore trajectory data, imports the actual wellbore trajectory data into trajectory calculation software to obtain the actual wellbore trajectory, and uses the calculation software to infer the trajectory trend of the subsequent section of the wellbore;

[0010] Step S3: Compare the actual wellbore trajectory data obtained in step S2 with the designed wellbore trajectory data, and adjust the tool face angle of the modular drilling tool according to the comparison result so that the actual wellbore trajectory of the rear section is consistent with the designed wellbore trajectory, accurately hit the target, and achieve the geological goal.

[0011] As a preferred embodiment of the present invention,

[0012] The fluid loss additive comprises polyanionic cellulose and carboxymethyl cellulose in a mass ratio of 1:1;

[0013] The viscosity reducing agent is polyacrylamide potassium salt;

[0014] The high temperature resistant and anti-collapse agent comprises sulfomethyl phenolic resin and lignite resin in a mass ratio of 1:1;

[0015] The plugging and anti-collapse agent comprises SMSHIELD-2, SMFP-2, SMNP-2 and SMNR-1 in a mass ratio of 1 to 2:1:0.75 to 1.5:1;

[0016] The inhibitor comprises polyamine and potassium chloride in a mass ratio of 1:15 to 23;

[0017] The lubricant comprises SMJH-1 and SMLUB-E in a mass ratio of 1:1;

[0018] The shielding temporary blocking agent is ultrafine calcium carbonate;

[0019] The inorganic treating agent is caustic soda.

[0020] As a preferred embodiment of the present invention, the wellbore trajectory data includes depth, well inclination and azimuth.

[0021] As a preferred embodiment of the present invention, during the process of drilling the directional section and the steady-angle section, the drilling parameters adopted are as follows: bit weight 20-40kN, displacement 6-12L / s, and drilling speed 40-50r / min.

[0022] As a preferred embodiment of the present invention, during the directional drilling section, when sliding drilling is performed, the trajectory measurement interval is no more than 10m, when composite drilling is performed, the trajectory measurement interval is no more than 20m, and during the steady-angle drilling section, measurement is performed every 30 to 60m during drilling.

[0023] As a preferred embodiment of the present invention, the tool face angle is divided into the following intervals:

[0024] When the tool face angle is 0-90°, it is the range of increasing well inclination and azimuth;

[0025] When the tool face angle is 90°-180°, it is the range of decreasing well inclination and increasing azimuth;

[0026] When the tool face angle is 180°-270°, it is the range of decreasing well inclination and azimuth;

[0027] When the tool face angle is 180°-360°, it is the range of increasing well inclination and decreasing azimuth.

[0028] As a preferred embodiment of the present invention, the outer diameter of the drill bit is 118 mm, and the connecting buckle type is 231;

[0029] The outer diameter of the screw is 95 mm, and the connecting buckle is 230×210;

[0030] The outer diameter of the non-magnetic drill rod is 105 mm, and the connecting buckle type is 211×210;

[0031] The outer diameter of the weighted drill rod is 89 mm, and the connecting buckle type is 211×210;

[0032] The outer diameter of the main drill rod is 73 mm, and the connecting buckle type is 211×210.

[0033] Compared with existing technologies, the present invention has the following beneficial effects: Using the directional drilling technology provided by the present invention, the average mechanical penetration rate of the test well group was 11.1 m / h, a 5.4% year-on-year increase compared to conventional wellbore sizes of the same type. The average drilling cycle was 29.11 days, a 57.9% year-on-year reduction, achieving the goal of reducing costs and increasing efficiency in slim-hole wells. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the solutions in the present invention, a brief introduction will be given below to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0035] Figure 1 The diagram is a structural diagram of a combined drilling tool for directional drilling of shale oil slim-hole wells according to the present invention. DETAILED DESCRIPTION

[0036] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0037] The directional drilling process for shale oil slim hole wells includes the following steps:

[0038] Step S1: Drilling the directional section and the steady-angle section in sequence in the three-well slim hole, using a combined drilling tool in the directional section and the steady-angle section. Figure 1 As shown, the combined drilling tool includes a drill bit 1, a screw 2, a non-magnetic drill rod 3, a weighted drill rod 4, and a main drill rod 6 connected in sequence. The non-magnetic drill rod 3 is provided with an MWD wireless inclinometer 5. A high-performance water-based drilling fluid is used in the directional drilling section and the stable inclination drilling section. The high-performance water-based drilling fluid contains, by weight, 3.0% bentonite, 1% fluid loss reducer, 0.1% viscosity reducer, 4-8% high-temperature anti-slump agent, 7.5-11% plugging and anti-slump agent, 7-8% inhibitor, 1-4% lubricant, 3-4% shielding temporary plugging agent, 0.5% inorganic treatment agent, and active water.

[0039] Step S2: During the directional and steady-angle drilling phases, the MWD wireless inclinometer 5 measures and obtains actual wellbore trajectory data. This data is then imported into trajectory calculation software to obtain the actual wellbore trajectory, and the trajectory trend of the subsequent phase is inferred using the calculation software. The wellbore trajectory data includes depth, inclination, and azimuth.

[0040] Step S3: Compare the actual wellbore trajectory data obtained in step S2 with the designed wellbore trajectory data, and adjust the tool face angle of the modular drilling tool according to the comparison result so that the actual wellbore trajectory of the rear section is consistent with the designed wellbore trajectory, accurately hit the target, and achieve the geological goal.

[0041] It should be noted that the specific dimensions of the combined drilling tool are as follows:

[0042] The outer diameter of the drill bit 1 is 118mm, and the connection buckle type is 231; the outer diameter of the screw 2 is 95mm, and the connection buckle type is 230×210; the outer diameter of the non-magnetic drill rod 3 is 105mm, and the connection buckle type is 211×210; the outer diameter of the weighted drill rod 4 is 89mm, and the connection buckle type is 211×210; the outer diameter of the main drill rod 6 is 73mm, and the connection buckle type is 211×210.

[0043] It should be noted that the fluid loss additive comprises polyanionic cellulose and carboxymethyl cellulose in a mass ratio of 1:1. The use of this fluid loss additive protects clay particles from agglomeration, thereby increasing dispersion, improving mud cake quality, and reducing drilling fluid loss.

[0044] The viscosity reducer is potassium polyacrylamide. By selecting this viscosity reducer, the viscosity of the drilling fluid can be improved to meet design requirements, ensuring proper rock carrying capacity, allowing drill cuttings to be returned from the bottom of the well, and preventing the formation of cuttings beds.

[0045] The high-temperature resistant anti-collapse agent comprises sulfomethylphenolic resin and lignite resin in a mass ratio of 1:1. By selecting the above-mentioned high-temperature resistant anti-collapse agent, it is possible to ensure the stability of the wellbore wall and prevent formation collapse in high-temperature formations.

[0046] The plugging and anti-collapse agent contains SMSHIELD-2, SMFP-2, SMNP-2, and SMNR-1, with a mass ratio of 1-2:1:0.75-1.5:1. Among them, SMSHIELD-2 (a temperature-sensitive plugging and anti-collapse agent) has a temperature-sensitive deformation temperature of 100-150°C; SMNP-2 (a micro-nano plugging agent) has a particle size distribution of 50-1000nm and a plugging rate of more than 90%; SMNR-1 (a nanoemulsion) is temperature-resistant to 150°C and has a particle size distribution of 10-200nm. The mechanism of action is to adopt a combination of nano- and micro-meter compounds, synergistic rigidity and deformability, and a combination of stacking plugging and mosaic film formation to achieve broad-spectrum plugging and tight sealing, ensuring instantaneous and long-term plugging capabilities. Compared with conventional drilling fluid systems, it can further enhance wellbore stability.

[0047] The inhibitor contains polyamine and potassium chloride in a mass ratio of 1:15 to 23. The inhibitor can effectively inhibit shale hydration, given the clay mineral characteristics of the formation, which is primarily illite with mixed layers of illite and montmorillonite.

[0048] This lubricant contains SMJH-1 and SMLUB-E in a 1:1 mass ratio. SMJH-1 undergoes a tribochemical reaction under high load, transforming into a high-temperature-resistant, high-strength chemical lubricating film that reduces roughness. SMLUB-E is amphiphilic, efficiently adsorbing polar groups to form a well-structured hydrophobic adsorption film, effectively reducing contact surface friction. Using this ratio of SMJH-1 and SMLUB-E as a lubricant, the lubrication coefficient is reduced by more than 90%.

[0049] The shielding temporary plugging agent is ultrafine calcium carbonate. By selecting the shielding temporary plugging agent, micro-cracks in the formation can be blocked, preventing filtrate from entering through the cracks and reducing drilling fluid loss.

[0050] The inorganic treatment agent is caustic soda, which can control the pH value within the designed range. At the same time, the OHˉ ions provided can promote the hydration and dispersion of clay, thereby increasing the viscosity and shear force of the drilling fluid.

[0051] It should be noted that during the drilling of the directional section and the steady-angle section, the drilling parameters adopted are as follows: bit pressure 20-40kN, displacement 6-12L / s, and drilling speed 40-50r / min.

[0052] During the directional drilling section, when performing sliding drilling, the trajectory measurement interval is no more than 10m; during compound drilling, the trajectory measurement interval is no more than 20m; during the steady-angle drilling section, measurement is taken every 30 to 60m during drilling.

[0053] The tool face angle is divided into the following intervals: when the tool face angle is 0-90°, it is the interval for increasing well inclination and increasing azimuth; when the tool face angle is 90°-180°, it is the interval for decreasing well inclination and increasing azimuth; when the tool face angle is 180°-270°, it is the interval for decreasing well inclination and decreasing azimuth; when the tool face angle is 180°-360°, it is the interval for increasing well inclination and decreasing azimuth.

[0054] The following is an example of the Fu-2 shale oil formation in the Subei Basin.

[0055] During the directional and stabilization drilling stages, trajectory measurements are taken at intervals no greater than 10 meters during sliding drilling and no greater than 20 meters during composite drilling. To increase drilling speed, the trajectories can be further relaxed, with measurements taken every 30-60 meters. During the directional and stabilization drilling stages, the actual wellbore trajectory is measured using the MWD wireless inclinometer 5 within the non-magnetic drill pipe 3. If the inclination and azimuth angles are consistent with the design, composite drilling continues. If not, the following methods can be used to ensure compliance.

[0056] During the process of drilling the directional section and the steady-angle section, the actual drilling wellbore trajectory data is obtained through the above-mentioned MWD instrument; the actual drilling wellbore trajectory data is imported into the trajectory calculation software to obtain the actual drilling trajectory of the wellbore, and the calculation software is used to infer the trajectory trend of the subsequent section of the wellbore.

[0057] Compare the actual wellbore trajectory with the planned trajectory. Based on the measurement results, by comparing the measured wellbore inclination and azimuth with the planned wellbore inclination and azimuth, the tool face angle of the next drill assembly tool is adjusted to align the later wellbore trajectory with the planned trajectory, accurately hitting the target and achieving the geological objective.

[0058] The tool face angles are categorized as follows: 0-90° for increasing well inclination and azimuth; 90-180° for decreasing well inclination and increasing azimuth; 180-270° for decreasing well inclination and decreasing azimuth; and 180-360° for increasing well inclination and decreasing azimuth. Select the angle based on actual conditions.

[0059] In the wellbore trajectory design, according to the geological target requirements, two targets can be designed in the wellbore trajectory, one of which is the geological target, called target A; the other is the control target, called target B. This ensures more accurate target hitting during the actual drilling process and improves the high-quality target hitting rate;

[0060] During the directional drilling process, since the natural inclination trend of the target layer is downward, the actual drilling inclination angle can be increased by 2-3° compared with the designed well inclination angle before entering the A target point, so as to reduce sliding drilling in the later stage, increase composite drilling, make the trajectory smoother, and provide a better wellbore environment for later operations.

[0061] Due to the small annular clearance and high pressure loss associated with slim-hole drilling, the following parameters were optimized based on previous drilling experience: WOB 20-40 kN, displacement 6-12 L / s, and ROP 40-50 r / min. The displacement refers to the drilling pump's capacity, and the ROP refers to the top drive's speed.

[0062] In summary, utilizing this drill assembly in conjunction with the drilling fluid system, trajectory control method, and drilling parameters achieved an average ROP of 11.1 m / h in the test well. The trajectory and drilling fluid density design met 100% compliance. The maximum full-angle change rate was controlled at 2-5° / 30m, a decrease of approximately 1-2° / 30m year-on-year. This significantly improved directional performance and rock-carrying capacity, boosting drilling efficiency.

[0063] The high performance water-based drilling fluid is further described below.

[0064] According to the mass proportions, high-performance water-based drilling fluid is prepared: 3.0% bentonite, 1% filtration reducer, 0.1% viscosity reducer, 5% high-temperature anti-collapse agent, 10% plugging and anti-collapse agent, 7% inhibitor, 2% lubricant, 3% shielding temporary plugging agent, 0.5% inorganic treatment agent and active water.

[0065] The fluid loss additive comprises polyanionic cellulose and carboxymethyl cellulose in a mass ratio of 1:1;

[0066] The viscosity reducer is potassium salt of polyacrylamide;

[0067] The high temperature anti-collapse agent contains sulfomethyl phenolic resin and lignite resin in a mass ratio of 1:1;

[0068] The plugging and anti-collapse agent contains SMSHIELD-2, SMFP-2, SMNP-2, and SMNR-1 in a mass ratio of 1:1:1:1;

[0069] The inhibitor contained polyamine and potassium chloride in a mass ratio of 1:20;

[0070] The lubricant contains SMJH-1 and SMLUB-E in a mass ratio of 1:1;

[0071] The temporary shielding agent is ultrafine calcium carbonate;

[0072] The inorganic treatment agent is caustic soda.

[0073] Through indoor tests, high-performance water-based drilling fluids were compared with conventional water-based drilling fluids and oil-based drilling fluids. The results are shown below:

[0074] Comparison of inhibition: Rolling recovery rate and linear expansion rate are two important indicators for evaluating inhibition.

[0075] Table 1 Comparison of inhibition

[0076]

[0077] As shown in Table 1, after rolling at high temperature of 150°C for 20 hours, the rolling recovery rate is 84.56% in conventional water-based drilling fluid; while the rolling recovery rate in the high-performance water-based drilling fluid system is increased to 98.46%, which is very close to the 99.01% of oil-based drilling fluid.

[0078] The final linear expansion rate is 11.66% for conventional water-based drilling fluids, while the linear expansion rate for the high-performance water-based drilling fluid system is only 2.9%, close to the 1.19% for oil-based drilling fluids. These experiments demonstrate that the high-performance water-based drilling fluid system exhibits far superior inhibition compared to conventional water-based drilling fluids and is comparable to that of oil-based drilling fluids.

[0079] Comparison of Plugging Performance: A high-temperature, high-pressure dynamic plugging tester was used to evaluate the plugging performance of conventional water-based drilling fluid, high-performance water-based drilling fluid, and oil-based drilling fluid. The experimental results are shown in Table 2. Under the same filter plate specifications, the dynamic filtration loss of conventional water-based drilling fluid was 26.4 mL, that of high-performance water-based drilling fluid was 4.6 mL, and that of oil-based drilling fluid was 3.8 mL. This demonstrates that the high-performance water-based drilling fluid has comparable plugging performance to that of oil-based drilling fluid.

[0080] Table 2 Comparison of plugging performance

[0081] Drilling fluid system Filtration loss (mL) Conventional water-based 26.4 High performance water-based 4.6 Oil-based drilling fluid 3.8

[0082] Lubrication Performance Evaluation: The lubrication performance of the three systems was evaluated using an extreme pressure lubrication tester and a mud cake viscosity tester. The results are shown in Table 3. Comparison shows that the high-performance water-based drilling fluid has an extreme pressure lubrication coefficient of 0.092 and a mud cake viscosity coefficient of 0.061. Its lubrication performance is roughly equivalent to that of oil-based drilling fluid and far superior to that of conventional water-based drilling fluid systems.

[0083] Table 3 Comparison of lubrication properties of different drilling fluids at room temperature

[0084] system Extreme pressure lubrication coefficient Mud cake viscosity coefficient Conventional water-based 0.262 0.168 High-performance water-based drill 0.092 0.061 Oil-based drilling fluid 0.081 0.054

[0085] As can be seen from the above, high-performance water-based drilling fluid can achieve the following goals: inhibiting formation hydration and dispersion, effectively sealing micro-fractures in the formation and preventing filtrate from entering through the fractures; reducing rock strength and high-temperature and high-pressure fluid loss to ensure stability; and lowering the friction coefficient of the mud cake and improving the lubricity of the drilling fluid, thereby reducing friction and torque.

[0086] The directional drilling process provided by the present invention is based on small-hole drilling. On the one hand, by selecting small-sized rock-breaking tools and optimizing small-sized drill tool combinations and drilling parameters, the drill bit's rock-breaking ability can be improved when the annular space gap is small, ensuring displacement and efficient rock carrying, thereby achieving the effect of increasing drilling speed; on the other hand, in order to achieve the expected directional effect and geological goals in small-hole conditions, the use of high-performance water-based drilling fluid with the above-mentioned mass percentage components can enhance the drilling fluid's inhibition, sealing and lubricity, improve the directional effect, avoid drilling pressure support, improve drilling efficiency, and further enhance the rock carrying capacity to avoid accumulation of cuttings beds.

[0087] Using the directional drilling technology provided by this invention, the average mechanical penetration rate of the test well group was 11.1 m / h, a year-on-year increase of 5.4%, compared with conventional wellbore sizes of the same type. The average drilling cycle was 29.11 days, a year-on-year reduction of 57.9%, achieving the goal of reducing costs and increasing efficiency in small-bore wells.

[0088] Obviously, the embodiments described above are only part of the embodiments of the present application, rather than all the embodiments. The drawings provide preferred embodiments of the present application, but do not limit the patent scope of the present application.

Claims

1. A directional drilling process for shale oil slim-hole wells, comprising the following steps: Step S1, drilling a directional section and a stable inclination section in sequence in three small boreholes, using a combined drilling tool in the directional section and the stable inclination section, the combined drilling tool comprising a drill bit (1), a screw (2), a non-magnetic drill rod (3), a weighted drill rod (4) and a main drill rod (6) connected in sequence, an MWD wireless inclinometer (5) being provided inside the non-magnetic drill rod (3), using a high-performance water-based drilling fluid in the directional section and the stable inclination section, the high-performance water-based drilling fluid comprising, by mass percentage, 3.0% of bentonite, 1% of a fluid loss reducer, 0.1% of a viscosity reducer, 4-8% of a high-temperature anti-slump agent, 7.5-11% of a plugging and anti-slump agent, 7-8% of an inhibitor, 1-4% of a lubricant, 3-4% of a shielding temporary plugging agent, 0.5% of an inorganic treatment agent and active water; Step S2: During the process of drilling the directional section and the steady-angle section, the MWD wireless inclinometer (5) measures and obtains actual wellbore trajectory data, and imports the actual wellbore trajectory data into the trajectory calculation software to obtain the actual wellbore trajectory, and infers the trend of the subsequent wellbore trajectory through the calculation software; Step S3: Compare the actual wellbore trajectory data obtained in step S2 with the designed wellbore trajectory data, and adjust the tool face angle of the modular drilling tool according to the comparison result so that the actual wellbore trajectory of the rear section is consistent with the designed wellbore trajectory, accurately hit the target, and achieve the geological goal.

2. The directional drilling process for shale oil slim hole wells according to claim 1, characterized in that: The fluid loss additive comprises polyanionic cellulose and carboxymethyl cellulose in a mass ratio of 1:1; The viscosity reducing agent is polyacrylamide potassium salt; The high temperature resistant and anti-collapse agent comprises sulfomethyl phenolic resin and lignite resin in a mass ratio of 1:1; The plugging and anti-collapse agent comprises SMSHIELD-2, SMFP-2, SMNP-2 and SMNR-1 in a mass ratio of 1 to 2:1:0.75 to 1.5:1; The inhibitor comprises polyamine and potassium chloride in a mass ratio of 1:15 to 23; The lubricant comprises SMJH-1 and SMLUB-E in a mass ratio of 1:1; The shielding temporary blocking agent is ultrafine calcium carbonate; The inorganic treating agent is caustic soda.

3. The directional drilling process for shale oil slim hole wells according to claim 1, characterized in that: The wellbore trajectory data includes depth, well inclination and azimuth.

4. The directional drilling process for shale oil slim hole wells according to claim 1, characterized in that: During the directional drilling and the steady-angle drilling, the drilling parameters used are as follows: WOB 20-40 kN, displacement 6-12 L / s, and ROP 40-50 r / min.

5. The directional drilling process for shale oil slim hole wells according to claim 1, characterized in that: During the directional drilling section, when performing sliding drilling, the trajectory measurement interval is no more than 10m; during compound drilling, the trajectory measurement interval is no more than 20m; during the steady-angle drilling section, measurement is taken every 30 to 60m during drilling.

6. The directional drilling process for shale oil slim hole wells according to claim 1, characterized in that: The tool face angle is divided into the following intervals: When the tool face angle is 0-90°, it is the range of increasing well inclination and azimuth; When the tool face angle is 90°-180°, it is the range of decreasing well inclination and increasing azimuth; When the tool face angle is 180°-270°, it is the range of decreasing well inclination and azimuth; When the tool face angle is 180°-360°, it is the range of increasing well inclination and decreasing azimuth.

7. The directional drilling process for shale oil slim hole wells according to claim 1, characterized in that: The outer diameter of the drill bit (1) is 118 mm, and the connecting buckle type is 231; The outer diameter of the screw (2) is 95 mm, and the connecting buckle shape is 230×210; The outer diameter of the non-magnetic drill rod (3) is 105 mm, and the connecting buckle type is 211×210; The outer diameter of the weighted drill rod (4) is 89 mm, and the connecting buckle type is 211×210; The outer diameter of the main drill rod (6) is 73 mm, and the connecting buckle type is 211×210.

Images