Construction method of ultra-large-diameter drilling well penetrating through ultra-thick sandstone aquifer

Abstract

The invention discloses a construction method of a super-large-diameter drilling well penetrating through a super-thick sandstone aquifer. The construction method comprises the following steps that first-time drilling is conducted to the designed depth, and an open hole is formed; a crawler crane is adopted to hoist and lower the surface casing; drilling for the second time to the designed depth and forming a second open hole; a crawler crane is adopted to hoist the straight seam pipe and lower the straight seam pipe; the surface casing pipe is connected with the straight seam pipe in a sealing manner; after the surface casing and the straight seam pipe are installed, well cementation construction is conducted; according to the method, the safety and the reliability of the originally adopted pipe lowering equipment and the pipe lowering method are analyzed and evaluated according to the overweight condition of a deep well with an ultra-large well diameter and a well entering sleeve, and in order to guarantee the safety of the equipment and the interior of a hole in the pipe lowering process to the maximum extent, shorten the sleeve installation time as much as possible and reduce the pipe lowering risk, the safety of the equipment and the interior of the hole is guaranteed. The crawler-type heavy-load crane is applied to the field of large-diameter engineering well construction for the first time, and a new technical path is provided for installation of large-diameter engineering well casings with the same scale.

Description

Technical Field

[0001] The invention relates to the technical field of coal mining, and in particular to a super-large diameter drilling construction method for penetrating a thick sandstone aquifer. Background Art

[0002] At present, coal resources still play an important role in my country's primary energy consumption. Due to the advantages of location and coal quality, traditional coal-producing provinces such as Shanxi, Henan, Anhui, Shaanxi, Hebei, and Northeast China have increased the unfavorable factors of safe and civilized production such as gas, water hazards, and ground temperature as the mining depth increases. However, large coal mining enterprises still maintain a large production capacity, and the production and marketing situation is still good. Its role in stabilizing my country's energy supply is still indispensable. In order to stabilize production capacity and ensure safe and civilized production, mining enterprises in major coal-producing provinces actively promote mine upgrading and transformation in accordance with green mine requirements, conscientiously implement the green mine construction standard "Guidelines for the Construction of Green Mines of Solid Minerals (Trial)" (T / CMAS), minimize the output and discharge of waste, strengthen gas and water hazard management, improve the underground production environment, improve the comprehensive utilization rate of resources, and enhance the level of safe and civilized production in mines, and strive to achieve green mining. In this context, as an important part of green mine construction, large-diameter multifunctional wells that are implemented for the purpose of safety, energy reduction and high efficiency, such as mine gas extraction, ice cooling, strong drainage, ventilation, material feeding, cable laying and mine rescue and escape, are increasingly favored by various mining companies. At present, the number of domestic mine surface large-diameter drilling engineering construction cases is increasing year by year, and there are hundreds of projects in major coal-producing areas each year. The construction, implementation and commissioning of these large-diameter engineering wells have provided safety guarantees for the green mine construction and mine safety production of many coal (mining) industry groups, effectively solved the bottlenecks of mine safety production such as mine gas control (utilization), heat damage control, flood control, emergency rescue, etc., and have been highly recognized by various coal (mining) industry groups. It can be foreseen that with the further improvement of the country's requirements for green mine construction, the market size of large-diameter multifunctional wells will continue to increase, and the economic, social and environmental benefits it brings will become increasingly apparent, providing broad space for the advancement of large-diameter engineering drilling technology and the economic development of the drilling industry.

[0003] In recent years, due to the thick sandstone aquifer of the Luohe Formation overlying the coal seam in the Binchang mining area, as the mining depth of the coal mine increases, the cracks between the underground tunnels and the overlying strata further increase, and the mine water hazards under the comprehensive mining conditions of the coal mine are increasing. In this context, as an important part of mine safety production construction, the large-diameter engineering wells mainly based on mine strong drainage and cable holes implemented in the Binchang mining area have gradually received attention from various mining companies in the Binchang mining area. And with the further improvement of the country's requirements for safe mine construction, the market scale of large-diameter engineering wells in Shaanxi will become larger and larger, and the economic, social and environmental benefits it brings are huge.

[0004] Currently, there is no safe and effective construction method for wells with large diameters, deep completion depths, heavy casing weights, difficult lowering, and crossing complex formations. Summary of the invention

[0005] The purpose of the present invention is to provide a method for drilling a large diameter well through a thick sandstone aquifer to solve the problems existing in the above-mentioned prior art and provide a new technical path for the installation of casing of large-diameter engineering wells of the same scale.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] A method for drilling a large-diameter well through a thick sandstone aquifer comprises the following steps:

[0008] Perform the first drilling to the designed depth and form an opening, wherein the opening has a hole diameter of not less than 1400 mm and a hole depth of not less than 40 m;

[0009] Use crawler crane to lift and lower the surface casing;

[0010] Drilling a second time to the designed depth and forming a second opening, the diameter of the second opening being not less than 1000 mm and the depth being not less than 910 m;

[0011] Use crawler crane to hoist and lower the straight seam pipe;

[0012] The surface casing is sealed and connected to the straight seam pipe;

[0013] After the surface casing and the straight seam pipe are installed, cementing construction is carried out.

[0014] Preferably, finite element digital analysis is used to perform numerical simulation calculations on various force-bearing units and structures in the pipe lowering operation, and based on digital simulation, the casing installation plan and the structural parameters of the special pipe lowering equipment are comprehensively evaluated and optimized.

[0015] Preferably, the surface casing is a spiral casing.

[0016] Preferably, the spiral sleeve has a diameter of 1220 mm and a wall thickness of 14 mm, and the straight seam pipe has a diameter of 720 mm and a wall thickness of 24 mm or 32 mm.

[0017] Preferably, the crawler crane is a 650-ton crawler heavy-duty crane.

[0018] Preferably, welding is adopted between the surface casing and the straight seam pipe and between adjacent straight seam pipes.

[0019] Preferably, the surface casing and the straight seam pipe, as well as adjacent straight seam pipes, are connected by sleeve joints, and threads are provided on the inner walls of the sleeve joints.

[0020] Preferably, the cementing construction is to inject cement mortar between the inner walls of the first opening and the second opening and the outer walls of the surface casing and the straight seam pipe.

[0021] Compared with the prior art, the present invention has achieved the following technical effects:

[0022] Aiming at the situation of ultra-large diameter deep wells and overweight casing entering the well, the present invention analyzes and evaluates the safety and reliability of the pipe lowering equipment and methods previously used. In order to maximize the safety of equipment and the hole during the pipe lowering process, shorten the casing installation time as much as possible, and reduce the risk of pipe lowering, this invention applies a crawler heavy-duty crane to the construction field of large-diameter engineering wells for the first time, providing a new technical path for the installation of casing in large-diameter engineering wells of the same scale. DETAILED DESCRIPTION

[0023] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] The purpose of the present invention is to provide a method for drilling a large diameter well through a thick sandstone aquifer to solve the problems existing in the above-mentioned prior art and provide a new technical path for the installation of casing of large-diameter engineering wells of the same scale.

[0025] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below in conjunction with specific implementation methods.

[0026] A method for drilling a large-diameter well through a thick sandstone aquifer comprises the following steps: drilling a hole to a designed depth for the first time and forming an opening, wherein the diameter of the opening is not less than 1400 mm and the depth is not less than 40 m; hoisting a surface casing with a crawler crane and lowering it; drilling a hole to a designed depth for the second time and forming a second opening, wherein the diameter of the second opening is not less than 1000 mm and the depth is not less than 910 m; hoisting a straight seam pipe with a crawler crane and lowering it; and Sealed connection; after the surface casing and the straight seam pipe are installed, cementing construction is carried out; the present invention aims at ultra-large diameter deep wells and overweight casing entering the well, and analyzes and evaluates the safety and reliability of the pipe lowering equipment and pipe lowering methods previously used. In order to maximize the safety of equipment and the hole during the pipe lowering process, shorten the casing installation time as much as possible, and reduce the risk of pipe lowering, a crawler heavy-duty crane is applied to the field of large-diameter engineering well construction for the first time, providing a new technical path for the installation of casing in large-diameter engineering wells of the same scale.

[0027] The present invention conducts a multi-factor comparative analysis of previous high-quality and efficient representative engineering examples, studies and adopts scientific, reasonable, safe and reliable drilling equipment and drilling tool combinations, optimizes drilling and hole-forming methods, develops efficient and applicable combined drill bits, optimizes drilling parameters, adopts a reasonable mud system, selects mud materials, optimizes formulations and maintenance processes, and studies and forms drilling processes and mud processes suitable for large-diameter and large-depth engineering wells. For the first time, a drilling technology method system suitable for ultra-large-diameter drainage engineering wells in Jurassic coal-bearing strata was innovated in the Binchang mining area in Shaanxi Province, and the construction of the first high-difficulty large-diameter engineering well with an opening diameter of Φ1400mm, a final hole diameter of Φ1000mm, and a depth of more than 900m for mine drainage in China was realized, providing a technical demonstration for domestic large-diameter engineering well drilling projects.

[0028] Furthermore, finite element digital analysis was used to perform numerical simulation calculations on various force-bearing units and structures in the pipe lowering operation. Relying on digital simulation, the casing installation plan and the structural parameters of special pipe lowering equipment were comprehensively evaluated and optimized.

[0029] In view of the new situation of ultra-large diameter deep wells and overweight casing entering the well, the present invention re-analyzes and evaluates the rationality and safety of the special equipment for heavy-duty casing lowering used in the past, demonstrates the feasibility of the developed special equipment for heavy-duty casing lowering, introduces finite element digital analysis for the first time, performs numerical simulation calculations on various force units and structures in the lowering operation, relies on digital simulation, comprehensively evaluates and optimizes the casing installation plan and the structural parameters of the special equipment for lowering casing, and develops a 650-ton heavy-duty casing special equipment for ultra-large diameter engineering wells for the first time in China, providing more options for the construction of lowering equipment for large-diameter engineering wells, laying a foundation for the formulation of relevant tool standards and specifications and the development of larger-tonnage casing lowering equipment and special equipment, and has important reference significance for the development of special equipment for heavy-duty casing lowering and the installation of heavy-duty casing for large-diameter engineering wells in China.

[0030] Furthermore, the surface casing is a spiral casing.

[0031] Furthermore, the spiral sleeve has a diameter of 1220 mm and a wall thickness of 14 mm, and the straight seam pipe has a diameter of 720 mm and a wall thickness of 24 mm or 32 mm.

[0032] Furthermore, welding is used between the surface casing and the straight seam pipe and between the adjacent straight seam pipes; the coupling needs to be welded to one end of the casing in advance, and then welded when the pipe is lowered. In order to facilitate the concentricity adjustment of the two casings when connected, and to prevent accidents such as jamming between the casing and the pipe clamp during the docking process, the gap between the casing and the pipe clamp generally needs to be reserved for 5 to 8 mm. This welding method has a large gap and a loose interface. If the number of casing connections is large, a large tensile force will be generated, which may easily lead to accidents such as fracture of the connection port. The method of strengthening the ribs of the bare pipe butt welding needs to be grooved according to regulations. The groove position is located at the casing port. The size of the groove is usually 60 degrees. After direct butt welding, in order to ensure the firmness of the connection, rib strips need to be used for reinforcement. This method uses a casing straightening hoop to ensure the concentricity of the butt welding casing. For casings of different wall thicknesses, they can be welded through during the welding process, so the welding quality can be guaranteed. Since reinforcing ribs are used at both ends of the casing, the strength of the weld can even be greater than the steel pipe itself, so it can withstand the casing tension in deep wells.

[0033] Furthermore, the surface casing and the straight seam pipe as well as the adjacent straight seam pipes are connected by sleeve joints, and the inner wall of the sleeve joint is provided with threads.

[0034] Furthermore, the cementing construction is to inject cement mortar between the inner walls of the first opening and the second opening and the outer walls of the surface casing and the straight seam pipe; cementing can isolate complex strata, consolidate loose well sections, and also seal a certain stratum to establish a stable channel for the engineering well. During the cementing process, construction personnel should pay attention to and prevent the occurrence of hazards such as blowouts and casing being squeezed and destroyed.

[0035] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for drilling a large-diameter well through a thick sandstone aquifer, characterized in that: The following steps are involved: Perform the first drilling to the designed depth and form an opening, wherein the opening has a hole diameter of not less than 1400 mm and a hole depth of not less than 40 m; Use crawler crane to lift and lower the surface casing; Drilling a second time to the designed depth and forming a second opening, the diameter of the second opening being not less than 1000 mm and the depth being not less than 910 m; Use crawler crane to hoist and lower the straight seam pipe; The surface casing is sealed and connected to the straight seam pipe; After the surface casing and the straight seam pipe are installed, cementing construction is carried out.

2. The method for drilling a large-diameter well through a thick sandstone aquifer according to claim 1, characterized in that: Finite element digital analysis is used to carry out numerical simulation calculations on various force-bearing units and structures in the pipe lowering operation. Relying on digital simulation, the casing installation plan and the structural parameters of special pipe lowering equipment are comprehensively evaluated and optimized.

3. The method for drilling a large-diameter well through a thick sandstone aquifer according to claim 1, characterized in that: The surface casing is a spiral casing.

4. The method for drilling a large-diameter well through a thick sandstone aquifer according to claim 2, characterized in that: The spiral sleeve has a diameter of 1220 mm and a wall thickness of 14 mm, and the straight seam pipe has a diameter of 720 mm and a wall thickness of 24 mm or 32 mm.

5. The method for drilling a large-diameter well through a thick sandstone aquifer according to claim 1, characterized in that: The crawler crane is a 650-ton crawler heavy-duty crane.

6. The method for drilling a large-diameter well through a thick sandstone aquifer according to claim 1, characterized in that: The surface casing and the straight seam pipe and the adjacent straight seam pipes are welded.

7. The method for drilling a large-diameter well through a thick sandstone aquifer according to claim 1, characterized in that: The surface sleeve and the straight seam pipe as well as the adjacent straight seam pipes are connected by sleeve joints, and the inner wall of the sleeve joint is provided with threads.

8. The method for drilling a large-diameter well through a thick sandstone aquifer according to claim 1, characterized in that: The cementing construction is to inject cement mortar between the inner walls of the first opening and the second opening and the outer walls of the surface casing and the straight seam pipe.