Abstract:Deep drilling technology is one of the necessary means to solve the scientific and technological problems in deep exploration. This paper mainly introduces the research and development program of 5000m intelligent geological drilling technology and equipment. It starts from the conceptual design of great-deep wire-line coring drilling diameter series, drilling tool classification, and equipment configuration, and is followed by R & D of drilling intelligent control, key drilling technology and equipment, high-performance wire-line coring drill pipes, small diameter and high-efficiency series drilling tools, environmental protection drilling fluid system and waste slurry treatment technology, integration and demonstration of drilling technology and equipment, etc. The program is aimed to achieve key technological breakthrough in intelligent control, portability and modularization; and build the ultra-deep hole drilling equipment and technology system mainly with the wireline core drilling process. It will provide technical and equipment support for China’s deep exploration plan.

Abstract:Continuous research and development of the key technology and equipment for deep intelligent geological drilling is the main trend of drilling technology development, and also the necessary scientific and technological means to realize deep exploration. This article briefly looks back the evolution course of the geological core drilling technologies and equipment, and describes intelligent automatic drilling technology and intelligent automatic drilling tools. In regard to the progresses made in the research project of “intelligent and automatic 5000m drilling technologies and equipment” in China, this article introduces in detail the research objectives, research contents and expected results of the project with proposal on the development goals of intelligent automatic drilling technology and equipment so as to provide technology equipment support for us to explore both the mystery in the deep earth and the deep resources.

Abstract:Increase in drilling depth poses higher requirements on the performance of wireline coring tool. With analysis of the research and development status, structural design feature and ultra-deep hole application of the wireline coring tool at home and abroad, this paper summarizes technical problems with the wireline coring tool for ultra-deep hole drilling, such as fishing reliability of the latching mechanism, signal reliability of the landing mechanism, working stability of the core jamming indicating mechanism, service life of the swivel mechanism. The causes of the above problems are also examined. All these lay a good foundation for the optimum design of the wireline coring tool used for 5000m ultra-deep holes.

Abstract:As a volumetric power drill, the screw PDM has good output hard characteristic and is one of the most widely used downhole power tools. The heat resistance of the screw drill is the research hot spot, improvement of which can expand its application scope and extend its working life. It has a good development prospect in the field of deep high temperature drilling. This paper introduces the basic principle and characteristics of screw drilling tools, and investigates the current development of conventional screw drill tools with the focus on the development status quo of all metal screw drilling tools and the development of domestic metal screw drilling tools. The development trend and key technology of the all metal screw drilling tool are put forward to provide reference for domestic research and development of the leading edge tool.

Abstract:In view of the realistic demand of the national strategy for resource and energy drilling equipment, in regard to the different process characteristics of large-depth geological drilling and hydrocarbon & geothermal drilling, keeping in mind the two objectives of “multi-process compatibility and wellhead automatic adaptation”, and with inheriting and integration of the advantages of the existing systems, this paper proposes a dual-power AC variable frequency top drive drilling system design applicable to diamond core drilling and hydrocarbon & geothermal drilling. Through detailed comparison with other typical top drive systems in terms of the overall structure, control system and key components for the automation of wellhead operations, the design can give full play to the advantages of multi-processes, high efficiency and automation, and achieve a good balance between the advanced technology, process adaptation and industrial economy.

Abstract:The drawwork of 5000m geological core drilling rig is designed to meet the new requirements of deep exploration engineering for drilling equipment. Our project team was awarded the research and development program of 5000m geological core drilling rig. As the core part of the drilling rig, the drawwork needs to meet the requirements of automatic and intelligent drilling. After investigation of the development status of the drawwork, the project team determined the operation parameters and the scheme with reference to the structure of the oil drilling drawwork, and completed the design of the drawwork with design and selection of the key part. Through capacity checking calculation, it is proved that the operation parameters of the drawwork are reasonable, which can meet the requirements of ultra-deep hole core drilling technology, and can be applied in geothermal, shallow oil and gas exploration and production and other fields.

Abstract:In deep-hole geological core drilling, wireline core drilling technology has great advantages for improving drilling quality and production efficiency. In wireline core drilling, the winch is the main part of the geological drilling equipment. With the development, maturity and wide application of wireline coring technology over nearly half a century, the wireline winch system has become more safe and reliable. Through analysis of the advantages and disadvantages of the wireline coring winches at home and abroad, this paper proposes a design scheme for the 5000m rope coring winch, which adopts a split structure and consists of two parts: the AC inverter cabinet and the winch itself. The key technical parameters of the design of the 5000m wire coring winch are calculated with the results as: the total power of the winch 60kW, maximum lifting force of the matching 12mm steel wire rope 50kN, and the fastest lifting speed of the light hub 60m/min. Aiming at the work conditions such as overlapping, cross cutting, and biting of lines, which are common during the lifting process of the rope core winch, the double fold grooves are designed.

Abstract:The mud pump is among the important equipment for geological drilling. The article introduces the present situation of mud pumps equipped for deep core drilling and relationship between the parameters of flowrate, pressure and hole depth, with the focus on the mud pump design for 5000m intelligent geological drilling. The reasons to choose the final design are explained through comparison of various design alternatives with the main technical parameters and performance characteristics provided. In addition, the new technology and measures for dealing with the key technical difficulties on the design are present with some preview, which provides important theoretical basis for development of the mud pump.

Abstract:wireline coring drill pipe for geological ultra-deep hole is structurally different from the API oil drill pipe; thus their mechanical properties cannot be determined by the relevant formulas of API oil drill pipe directly. In view of the lack of theoretical basis and calculation method, this paper analyzes the stress of the double shoulder drill pipe joint for geological ultra-deep hole, carries out the theoretical research on the calculation of tensile load and torsional load for the tool joint, and develops the theoretical calculation model of the wireline coring drill pipe’s mechanical properties. Through the finite element analysis and property test, the mechanical properties of the H-5000 drill pipe are determined, and the accuracy of the calculation method is verified. The proposals for improving the drill pipe structure and the next research direction are put forward, which provide technical support for deployment of the high-performance thin-wall wireline coring drill pipe in the 5000m geological core drilling works.

Abstract:The performance of aluminum alloy drill rods is the bottleneck of the development of deep drilling technology. With the design of the drill string structure as the basis and in view of engineering requirements of ultra-deep hole drilling, the selection and evaluation of high strength and heat resistant aluminum alloy drill rod material were studied. The results showed that: the solution aging of 2219 aluminum alloy was 535℃/1h, 165℃/20 h, 2618 was 530℃/1h, 200℃/20h, respectively. The mechanical properties of 2219 aluminum alloy were better than 2618 aluminum alloy after long time heat exposure at ambient temperature and worse than 2618 aluminum alloy at transient high temperature. The element Zr in 2219 aluminum alloy can slow down the solute diffusion rate in the process of heat exposure, and it is beneficial to improve the residual strength after heat exposure.

Abstract:In order to improve wear resistance of the key wearable parts of deep drilling tools, high velocity oxygen fuel spray (HVOF) technology was used to prepare WC-10Co4Cr coating on 35CrMo steel substrate. The scanning electron microscope (SEM), X-ray energy dispersive spectrometer (EDS), X-ray diffractometer (XRD), micro-hardness tester, Vickers hardness tester and friction and wear tester were used to analyze the microstructure, mechanical properties and friction and wear behavior of the coating. The results showed that the WC-10Co4Cr coating prepared by HVOF technology had a dense microstructure and excellent mechanical properties. The porosity of the coating was 1.3±0.1%, with the microhardness of 1392 ± 45 HV0.3, and the fracture toughness of 7.11 ± 0.10 MPa·m1/2. Compared with 35CrMo steel substrate, the coating has more excellent wear resistance, and with the increase of sliding speed, the friction coefficient of WC-10Co4Cr coating decreases and the wear rate increases; The wear failure mechanism of coating mainly includes abrasive wear, adhesive wear and fatigue wear.

Abstract:The small diameter turbodrill reducer is an important part of the tool for deep hole drilling. Replacing traditional gears with asymmetric gears is an effective way to increase the load capacity of the reducer. The root radius and pressure angle on the working sides of the asymmetric gear are the key parameters of the symmetric gear. In order to further study the influence of the root radius and the pressure angle on the working side on the bending stress, the solar gear in the 127mm diameter turbodrill reducer is used as the research object to establish a force model of the asymmetric gear with the theoretical calculation formula for the bending stress of the asymmetric gear. established by the plane cross section method. Through the finite element method, the symmetrical gear and the asymmetric gear are compared and analyzed. The simulation results show that as the root radius increases, the radius of curvature of the gear root transition curve increases; thus, improving the bending stress concentration. Increasing the pressure angles on the working side can effectively reduce the bending stress; however, when the pressure angle exceeds a certain value, the bending stress gradually tends to be stable. The theoretical analysis is in good agreement with the simulation results, and the research conclusions can provide the basis and reference for optimizing the main parameters of the asymmetric gear.

Abstract:In the process of scientific drilling, to ensure the basic verticality of the upper section of the ultra deep hole is the prerequisite for drilling the ultra deep hole to the target layer smoothly. Many drilling projects have to be completed prematurely, where the boreholes can not drill to the expected target depth due to the uncontrollable hole deviation. The availability of automatic vertical drilling tools breaks the limitation of traditional deviation prevention and correction methods, and drives the well deviation control technology to develop rapidly. At present, the actuator diameter of vertical drilling tools is large, the required displacement is high, the response speed is slow, and the whole performance test can only be carried out on the stable platform. This paper introduces a new small diameter actuator which uses mud pressure difference as the power source with the design of its performance test system. The internal pressure, pushing force, discharge and response speed of the new actuator were tested on the system separately, and the results showed that the new actuator had the advantages of small structure, high efficiency, small displacement and fast response. The test system can verify the feasibility of the new actuator before testing the whole prototype of the vertical drilling tool.

Abstract:The metal-to-metal volumetric power drilling tool is one of the current hotspots in high-temperature drilling research. It is subject to complex conditions such as metal friction, high-speed erosion, high-temperature corrosion, torsion, and vibration in the well, which places higher requirements on material selection and manufacturing processes. This article first investigates the common material composition, mechanical properties and processing performance of the stator and rotor of the motor in the existing downhole tools, and then analyzes the requirements and difficulties of ultra-deep well drilling for the metal-to-metal drilling motor parts. The material for the rotor and stator is selected with a new copper-iron-based composite for the rotor components. Investigation and analysis is also conducted on the existing machining process with the recommendation put forward, providing a reference basis for the design and service life research on metal-to-metal power drill motor components.

Abstract:In view of the technical problem that performance of the drill bit carcass decreases significantly due to the high temperature environment in drilling of deep wells, studies were conducted on the effect of the type of hollow spheres, the number of hollow spheres, and the adding amount of hollow spheres on the mechanical properties of the hot-pressed sintered diamond drill bit at ambient temperature and high temperature. The results showed that the 3540 mesh yttrium-stabilized zirconia hollow spheres were suitable to be added in the matrix of the carcass, and when the addition amount of yttrium-stabilized zirconia hollow spheres was 10%, the overall performance of the carcass reached the best. The impact toughness and flexural strength also reached their maximum values of 3J/cm2 and 903.75MPa, respectively. Addition of an appropriate amount of hollow spheres to the carcass composite will enhance the surface roughness of the carcass, and improve the cutting performance of the diamond carcass and the mechanical properties at high temperatures due to presence of the spherical pore structure.

Abstract:Drilling state monitoring while drilling is intended to describe drilling modes, judge the operating performance timely, and analyze the causes of non-optimal modes so as to guide the driller to adjust parameters in time to ensure efficient, safe and stable drilling. Therefore, it is of theoretical and practical value to study drilling mode identification based on state monitoring while drilling. In this paper, the support vector machine is used to identify the drilling mode based on monitoring data. According to the identification results, drilling efficiency is evaluated, and factors affecting the efficiency are discussed to improve drilling performance. Finally, simulation experiments are carried out with the practical drilling data to verify the feasibility and effectiveness of the proposed method.

Abstract:In recent years, geological drilling has made great progress in the field of drilling equipment and technology, but research on drilling accidents warning is still insufficient. To ensure safety and efficiency of the drilling process and reduce the losses caused by accidents, a lost circulation and kick accidents warning method for the drilling process is proposed in this paper. First, the drilling parameters that characterize accidents are selected through the analysis of accidents. Second, considering the uncertainty of the changes of drilling parameters when an accident occurs, a lost circulation and kick accidents warning model is established based on Bayesian network. Third, to effectively extract the trend of drilling parameters from actual drilling data with noises, the normalization, moving average and least square linear fitting methods are jointly used to judge the node status. Finally, the actual drilling data is used to verify the lost circulation and kick accidents warning model. The influence of different trend judgment boundaries and moving windows on the alarm performance is discussed. The experimental results show that the warning model effectively provides warning of the lost circulation and kick accidents. And a proper trend judgment boundary and moving window can reduce alarm delay, false alarm and missed alarm.

Abstract:The geological conditions in deep formations are very complex, especially in bedding strata. Nowadays, with increase in drilling depth, the instability of the borehole caused by the failure of weak planes will seriously affect the drilling progress. In this paper, the physical and mechanical properties of rocks with weak planes are summarized and analyzed, and the applicability of strength anisotropy models are discussed. Considering the permeability anisotropy and heat transfer anisotropy of the rocks with weak planes, the specific borehole stability theory is further developed for the surrounding rock with weak planes. It is found that some strength anisotropic models may lose their applicability under certain circumstances; furthermore, neglect of the anisotropic characteristics of the permeability and heat transfer of the weak-plane rocks in the deep strata in the high temperature environment may lead to big errors in the calculation of stresses, failure area and collapse pressure of the borehole.

Abstract:In view of green exploration requirements of national deep geological resources, difficulty in borehole wall protection due to small annulus in extra-deep geological drilling in complex formation, and pollution from waste drilling fluid, an environmentally-friendly high-temperature drilling fluid was developed using high temperature crosslinking and protection technology. Tests showed that after rolling at 150℃, the drilling fluid had good rheological properties, fluid loss reduction, shale expansion suppression, as well as easy degradation (BOD5/CODCr value of 21.5%) and cost-effectiveness. It has broad application prospects in green exploration and geological drilling where strict environmental protection requirements are exercised.

Abstract:Harmless treatment of waste drilling fluid is an important job for us to implement the concept of green exploration. Through laboratory test analysis and site survey, the pollution characteristics of waste drilling fluid in different fields of geological drilling were studied, and also its basic properties and its influence on the environment were investigated. With waste drilling fluid from Well Xiangtaodi-2 as the subject of study, research was done on the destabilizing technology with optimization of the gel breaker and flocculant materials to obtain the basic formula for destabilization treatment. The experimental results showed that de-stabilization and flocculation can be achieved of the waste drilling fluid rapidly, and pollution indicators, such as COD, suspended solids, chroma, declined significantly; which can create favorable conditions for the next deep treatment to achieve harmless emissions.

Abstract:Aimed at the technical problem with lost circulation treatment in geological drilling, study has been carried out on polymer crosslinked gel. Utilizing the single factor method, the different additives for crosslinked gel systems has been optimized. With environment-friendly vegetable gum as gelation agent, a kind of delayed crosslinked gel has been prepared by adding crosslinking control agent N1 and crosslinking agent No.1. This gel was successful applied in the field plugging test of Guangxi Uranium exploration hole ZK6-37-1, and the problem of lost return has been resolved. Research results indicate that this gel has controlled cross-linking time(10 to 75min), higher gel strength (≥6 MPa), and has a broad application prospect in solving lost return.