Prospect of the hottest oil and gas drilling techn

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Prospects for oil and gas drilling technology

facing the 21st century, the sustainable utilization of global oil and gas resources will become more prominent, making drilling scientists and technicians face many new challenges and technical problems in technology, cost and environmental protection, which need to be carefully planned, studied and solved. Rotary drilling has been available since the beginning of the 20th century. So far, it is still widely used as one of the most important drilling methods in the oil and gas industry. Throughout the development process of rotary drilling, the obvious progress in technology and equipment has been made in the past 20 years. PDC bits appeared in the late 1970s, which is an obvious sign of progress in the field of drilling; In the 1980s, measurement while drilling (MWD) instruments, controllable downhole motors and horizontal well drilling technology have appeared one after another; In the 1990s, advanced measurement technologies such as logging while drilling (LWD) and seismic while drilling (SWD) were continuously put into use, and the drilling technology of extended reach wells and wells with complex structures, as well as the continuous flexible pipe technology, were rapidly developed and applied. In the future, driven by the cost difference in the upstream of the oil industry (i.e. driven by the benefit goal) and the human pursuit of higher goals of "health, safety and environment", the positive development momentum of rotary drilling technology will continue to increase after entering the 21st century

1. The key technology and theoretical basis of oil and gas drilling

in the process of drilling, how to make the bit drill along the preset track and maintain the stability of the wellbore, how to optimize the bit and drilling parameters to improve the ROP, how to realize drilling automation and intelligence to reduce drilling interruption, improve drilling quality and efficiency, how to effectively protect the reservoir to improve exploration and development benefits, and so on, These are the key technologies or academic problems of drilling

1.1 key technology

⑴ well trajectory control technology. It is a technology of directional drilling by using reasonable measures (including downhole tools, measurement and control system, etc.) to force the drill bit to break the formation along the preset track. From the actual needs, the research and development of advanced downhole controllable tools and measurement and control systems is the key to the development of wellbore trajectory control technology

⑵ borehole stabilization technology. This technology is based on the physical and chemical characteristics of the formation and the evaluation of mechanical instability. Through comprehensive technical measures such as the matching of drilling fluid system, the determination of reasonable drilling fluid density, and the optimization design of well structure and drilling technology, the wellbore can be kept stable to avoid or reduce downhole complex accidents such as leakage, kick, collapse, jamming, etc.

⑶ efficient rock breaking and well washing technology. It is a key technology to improve the ROP, mainly including the evaluation of formation anti drilling characteristics, the development or reasonable selection of drill bits, high-pressure jet rock breaking technology, hydraulic and mechanical rock breaking technology, drilling parameter optimization technology, and efficient cleaning and carrying cuttings technology

⑷ oil and gas reservoir protection technology. It is one of the key technologies to improve the efficiency of oil and gas resources exploration and development. The focus of future development is the rapid diagnosis technology of reservoir damage, the temporary plugging technology of drilling fluid in fractured reservoirs, the reservoir protection technology of exploration wells and the underbalanced drilling technology

1.2 theoretical basis

⑴ drilling engineering mechanics. It is used to study and solve the problems of fluid mechanics and solid mechanics (drill string mechanics, rock mechanics) related to drilling

⑵ drilling chemistry. It is used to study and solve the chemical problems related to drilling fluid and completion fluid

⑶ drilling engineering geology. It is used to study and solve the evaluation problems of formation drilling characteristics (such as lithology, drillability, anisotropy, physical and chemical elongation deformation, in-situ stress, pressure characteristics, instability, etc.) determined by the complex geological environment

1.3 cross research

the final realization of the above key technologies must also rely on the support of multi disciplines such as materials, power, machinery, measurement, control and communication (information transmission), and scientific and technological personnel in different fields must be organized to jointly tackle key problems and carry out extensive interdisciplinary cross research

2. Development trend of oil and gas drilling technology

on the one hand, with the development of oil and gas exploration and development, it is inevitable to put forward new requirements and higher expectations for the type and technical content of drilling, so as to promote the continuous innovation of drilling technology content; On the other hand, because drilling costs account for 50% - 80% of the exploration and development costs of the petroleum industry, constantly improving the level of drilling technology and engineering efficiency has become the main focus of oil companies to reduce exploration and development costs. To sum up, the main objectives of the development of oil and gas drilling technology are to meet the target needs of oil and gas exploration and development and improve the overall benefits of exploration and development; Second, improve the efficiency of drilling engineering and reduce the direct cost of drilling engineering

high pressure and high temperature wells, deep and ultra deep wells, special technology wells (including directional wells, horizontal wells, extended reach wells, complex structure wells, cluster wells, underbalanced drilling and casing drilling, etc.), slim holes and measurement while drilling (including geometric, geological and mechanical measurements) are all proposed to meet different oil and gas exploration and development needs, which is both a challenge to the traditional drilling technology, It is also an opportunity and driving force for the continuous development of drilling technology

from the current situation and development trend, rotary drilling will still be the most important drilling method in the oil and gas industry after entering the 21st century. Rotary drilling is also divided into rotary table drilling, downhole power drilling and composite rotary drilling with both. Rotary drilling with rotary table means that the whole drill string is in rotary motion and drives the drill bit to rotate at the same time; Downhole power drilling is that the rotor of downhole power drilling tool drives the drill bit to rotate for drilling, and the rotary table and the whole drill string can not rotate; Compound rotary drilling is to use downhole power drilling tools and at the same time start rotary drilling with rotary table. Research and practice have proved that each rotary drilling method has its own different drilling characteristics, advantages and disadvantages. Among them, the combined rotary drilling method has the advantages of rotary table drilling and downhole power drilling to a certain extent. It can not only continuously control the wellbore trajectory and reduce the number of trips, but also improve the ROP. It is a relatively efficient controllable drilling method. In the future, the system dynamics characteristics of this drilling method should be further studied and tested

in the 1980s, with the development of directional well and horizontal well drilling technology, the guided drilling system came into being. The downhole power motor with curved shell or eccentric stabilizer (called "guided motor") replaced the straight rod power motor and bent joint. Combining the steering motor with the wireless inclinometer while drilling system, the geometric steering of directional well and horizontal well drilling is successfully realized. On this basis, the first generation of wireless logging while drilling system was successfully developed in 1989, which made the directional drilling technology develop from geometric guidance to geological guidance. In order to effectively control the "tangent section" and "horizontal section" of horizontal wells or realize the continuous directional control of wellbore trajectory, a compound rotary drilling method is proposed based on the application of downhole dynamic sliding drilling with guided drilling system. Screw drill assembly with reverse double bend (DTU) or single bend double stabilizer and turbine drill assembly with eccentric stabilizer have been successfully applied in compound rotary drilling

no matter what type of oil and gas wells are drilled or what rotary drilling method is adopted, there are problems of drilling efficiency, which is also the essence of drilling technology research and development. The main problem affecting drilling efficiency can be attributed to the "discontinuity" during drilling. At present, the main causes of "discontinuity" include: single connection, replacement of bit and bottom hole assembly, drilling tool failure, wellbore instability (leakage, collapse, blowout, jamming, resistance), deviation correction operation, non measurement while drilling, failure to reach the optimal decision, and multi-level wellbore structure. In order to reduce the "interruption" of drilling, we must constantly study and improve the overall technology and equipment level of drilling, especially the research and development of information-based, intelligent and automated drilling technology need to be continuously strengthened

in order to maintain its technological advantages and the impact of substitutes such as waste paper pulp and finished black paper, the United States, which has always been in the leading position in the field of rotary drilling, launched a major long-term research and development plan in 1995, called "the national advanced drilling & excavation technologies" (nadet). The basic research in the early stage is mainly funded by the government, and the large-scale technology and product research and development (r&d) in the later stage mainly depends on the huge investment of industrial and mining enterprises. Through this research and development, it is expected that there will be revolution in rock crushing (efficient rock breaking), borehole purification (well flushing) and borehole stability, as well as revolution in bit, rock and borehole measurement and evaluation and directional control. The core task of this plan is to devote long-term efforts to the research and development of an intelligent @ application scope: the smart drilling systems

intelligent drilling system includes two parts: surface and downhole. Downhole intelligent drilling system is generally composed of downhole actuator, measurement system and control system. In the drilling process, the action of the downhole actuator should be completed according to the instructions of the control system, and the instructions issued by the control system should be determined according to the requirements of the designed well and the feedback signal of the actual drilling measurement. The future development of downhole intelligent drilling system will be characterized by the continuous updating of downhole actuator (bottom hole assembly), the continuous improvement of measurement system and the continuous improvement of automatic control. The ultimate development goal of underground intelligent drilling system is "underground drilling robot". The underground actuator is like the robot's hand, the control system is like the robot's brain, and the measurement system is like the robot's eyes and other sensory organs. This underground drilling robot is different from general industrial robots. It must be able to work effectively in the extremely complex underground geological environment and very harsh working conditions. It must be able to accurately detect the geological environment in front of and around it and its own state, and then make correct analysis and decisions. It can automatically adapt to the working environment and reach the ultimate underground goal along the predetermined route or requirements, It has successfully completed the sacred task entrusted by mankind to explore and exploit underground resources on the spot. This kind of underground drilling robot is the core of automatic drilling. It will be the result of further research and development of a variety of high-tech and products and their miniaturization integration. It represents the development trend of drilling and tunneling technology in the future and is expected to be realized in the first half of the 21st century

3. Important drilling technology for the 21st century

facing the 21st century, the enhanced oil recovery of old oil fields and the efficient development of low pressure and low permeability and heavy oil reservoirs, especially the research and development of advanced and applicable special process drilling technology; The drilling and development of high-pressure and high-temperature oil and gas reservoirs, especially high-pressure and high-temperature natural gas reservoirs, urgently need to break through the technical barriers of high-pressure and high-temperature drilling; The drilling and development of deep oil and gas resources requires further research and development of deep well and ultra deep well drilling technology, especially in the drilling efficiency of deep exploration wells, scientific research and development should be strengthened

3.1 high pressure and high temperature drilling technology

according to the international general concept, when the ground temperature exceeds 150 ℃, it is called high temperature, when the formation pressure equivalent density exceeds 1.8g/m3, or when it is necessary to use wellhead devices exceeding 70MPa, it is called high pressure, and the well name of both

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