Development Trend of Future Drilling Technology

The purpose of oilfield drilling is not only to build oil and gas channels, but also to discover more oil and gas resources and maximize oil and gas production and recovery. The problem faced by oil drilling engineering is always how to ensure "excellence, speed, economy, and HSE". The innovation of drilling technology has been launched to address these issues. Since the 1990s, drilling technology has developed rapidly, greatly promoting the real-time, informatization, digitization, visualization, integration, automation, and intelligence of drilling, making drilling "smarter". Based on the analysis of the development trend of cutting-edge drilling technology and technology under research at home and abroad, the current innovative research and development of drilling technology is mainly reflected in the following four aspects.

Future trend 1: Excellent

"Excellent" refers to high-quality, which means how to improve the engineering quality, better protect the oil and gas reservoir, and accurately monitor the borehole trajectory.

Increasing the transmission rate of downhole data and improving the complexity of two-way communication drilling targets have put forward increasingly high requirements for the control accuracy of borehole trajectory. Measurement while drilling (MWD), logging while drilling (LWD), geosteering, and rotary closed-loop steering drilling systems are important means to improve the accuracy of borehole trajectory control, and have been widely applied. Currently, the data transmission methods used for MWD and LWD are mud pulses or electromagnetic waves, but their data transmission rates are too slow to meet the new requirements of modern oil and gas exploration and development for downhole data transmission. In recent years, foreign countries have been exploring new data transmission methods, including acoustic waves, optical fibers, and wireline drill pipes. Currently, acoustic channels and fiber optic channels for conventional drill pipes are still being studied. In the field of wireline drill pipes, only the "soft connection" wireline drill pipes from American International Service Company, known as smart drill pipes, are currently being put into commercial application. The intelligent drill pipe is essentially a wireline drill pipe, with "soft connection" between cables realized through electromagnetic induction: the cable is embedded in the drill pipe, and the cables at both ends of the drill pipe joint have an induction ring; After the drill pipe is tightened, the two sensing rings do not directly contact, but instead achieve high-speed transmission of signals between the drill pipes through the principle of electromagnetic induction. Its main characteristics are: first, data transmission is high-speed, large capacity, and real-time: data transmission rate is up to 57600 bits/second; Second, truly realize two-way communication; The third is suitable for data transmission under any well conditions, including underbalanced drilling and gas drilling. Intelligent drill pipe has been put into commercial application in 2007, which is a significant breakthrough and milestone in downhole signal transmission technology. It has been recognized and supported by world-class oilfield technology service companies such as Halliburton, Baker Hughes, Schlumberger, and Weatherford, with promising application prospects. The next step is to develop intelligent drill pipes with data transmission rates of up to 100000 bits per second.

Developing forward looking while drilling and improving geosteering are major breakthroughs in MWD and LWD technologies. However, the current geosteering instrument is located at a distance of more than 0.91 meters from the drill bit, which can only measure the engineering and geological parameters of the newly drilled hole, and cannot detect the geological conditions in front of the drill bit. Therefore, it is necessary to develop seismic while drilling and other technologies with forward looking while drilling functions in order to timely discover the "sweet spot" ahead and better conduct geological guidance and reservoir guidance. Rotary steering drilling systems, such as Halliburton's Rotary Steering System and Baker Hughes' AutoTrak Rotary Closed Loop Drilling System, have replaced sliding steering drilling systems with rotary steering systems.

Future trend 2: Fast

"Fast" refers to high efficiency, which means how to improve drilling efficiency. "Fast" is an important goal consistently pursued by oil companies, drilling contractors, and technical service companies. In the past two or three years, the daily cost of drilling has skyrocketed, and improving the rate of penetration is particularly important, especially for deep and deepwater drilling. Explore new rock breaking methods with a view to achieving breakthroughs in rock breaking technology. Since the promotion and application of high-pressure jet drilling in the 1960s, the combined rock breaking method of mechanical rock breaking+hydraulic assisted rock breaking has occupied an absolute dominant position. In order to further improve the mechanical penetration rate, people have been exploring other rock breaking methods, such as chemical dissolution drilling, blasting drilling, electric spark drilling, microwave drilling, thermal fracturing drilling, rock furnace drilling, and so on. In recent years, the main rock breaking technologies still being explored abroad are laser drilling and plasma channel drilling.

The rock breaking mechanism of laser drilling is to use high-energy lasers to break, melt, and evaporate rocks. Laser drilling is still in the laboratory testing stage, and it is expected to be put into commercial application in 2020, which is expected to bring a revolution to drilling.

The developer of plasma channel drilling technology is a Norwegian Badger Explorer exploration company. The core of this technology is high voltage pulse energy technology. The rock breaking mechanism of plasma is to atomize the rock by electrical method, which uses high-voltage pulses to form high-energy plasma in the rock in front of the "drill bit". The plasma rapidly expands in the rock in less than a microsecond, leading to local rock fracture and breakage. This rock breaking technology is currently at the stage of principle verification, and its feasibility remains to be further verified. If it can ultimately pass field testing, it is expected to become a new simple, efficient, low-cost, low risk, and environmentally friendly rock breaking method, which will be mainly used for workover and slim hole drilling.

To improve high temperature and high pressure deep well drilling technology, further increase drilling speed, and reduce drilling costs, in order to make deep well drilling deeper, faster, more economical, and more environmentally friendly, the US Department of Energy established a deep well drilling plan, the Deep Trek Plan, in March 2001, aiming to organize the development of some new technologies and tools to improve the efficiency of deep well drilling and completion, and reduce the cost of deep well drilling and completion.

The Deep Trek program focuses on technology development in four key areas, namely, intelligent drilling systems, high-tech materials, advanced deep well drilling and completion methods, and new bit technology. This plan is an integration of a series of technological innovations, a concentrated embodiment of the cutting-edge drilling technology today, representing a new generation of deep well drilling technology, and reflecting the development direction of deep well drilling technology. Most of the individual technologies are still in the stage of laboratory research or field trials, and individual individual technologies have been put into commercial application. The overall technology will be put into commercial application this year. The Deep Trek plan will achieve "deeper" and "smarter" drilling goals, further promoting the progress of drilling technology.

Drilling rigs are diversified, digital, automated, intelligent, and easy to move. The AC variable frequency drilling rig introduced in the mid-1990s is a very important milestone in the development history of drilling rigs. The diversity of drilling rigs is mainly manifested in the emergence of large, medium, and small drilling rigs that adapt to different ground conditions, well depths, and operational needs, including various land drilling rigs, offshore drilling rigs, vehicular drilling rigs, and coiled tubing drilling rigs. Micro hole drilling rigs are being developed. On the basis of drilling rig automation equipment, foreign countries introduced automatic drilling rigs in the mid and late 1990s.

Automatic drilling rigs are divided into two categories: AC variable frequency electric drive and hydraulic drive. The main characteristics are as follows: First, to achieve automation of all pipe operations, including transmission, makeup, drilling, drainage, and stacking; The second is to significantly reduce the number of drilling personnel, and there are no more drillers on the drill floor and monkey board; The third is to significantly reduce the labor intensity of the driller and reduce human errors; Fourth, good mobility, easy installation and disassembly; Fifth, the land automatic drilling rig occupies a small area; Sixth, significantly improve operational efficiency and safety. Automated drilling rigs represent the highest level of oil drilling rigs today, and are an important development direction for oil drilling rigs. They are being promoted and applied on land and offshore. The development of new materials and materials that are conducive to improving drilling and completion efficiency and reducing drilling and completion costs has been a hot topic of advanced research abroad. The continuous emergence of new materials suitable for drilling and completion has greatly promoted the progress of drilling and completion technology and increased speed and cost. Continuous pipe drilling can greatly improve the tripping efficiency and reduce the floor area of the well pad. Aluminum alloy drill pipes, titanium alloy drill pipes, and carbon fiber drill pipes can greatly reduce the weight of drill pipes and improve their toughness. Nano additives can improve the performance of drilling fluid. Using expandable and self expandable pipes can solve many downhole problems and build single diameter wells. Super cement developed by M&D Industries of Louisiana has been put on the market.

Self expanding tubing was developed for the US Department of Energy's micro borehole program. It achieves elastic expansion through rotation, which is easy to operate and has a large radial expansion rate, with a maximum expansion rate of over 200%. After expansion, it can achieve self sealing, with a rated pressure resistance of up to 10000 psi. At the same time, a self expanding sieve tube has been successfully developed, with an expansion rate of 125% to 150%. Self expandable tubing is a new development of expandable tubing technology, which can be used not only in conventional wells but also in micro wells; It can be used for both rotary drilling and coiled tubing drilling. The self expanding pipe is still in the field test stage and is expected to be put into commercial application in the near future. Super cement is essentially a resin sealant developed for the US Department of Energy's Deep Well Drilling Program. Its basic ingredients are liquid resins and hardeners, and other admixtures can be added as needed. It is a non cement type cementing material that can replace cement and is a major breakthrough in cementing and cementing technology. It can reliably seal the annulus and maintain the integrity of the well for a long time in deep wells with high temperature and pressure. However, its current high cost limits its commercial application to offshore cementing operations. Through continuous improvement, its cost is expected to decrease and its application prospects are optimistic.

Vertical well deviation prevention and fast drilling technology The traditional deviation prevention technology mostly uses "light pressure lifting and drilling", at the expense of drilling speed. In recent years, the development of eccentric drilling tools, offset shaft drilling tools, flexible drilling tools, and other drilling tool assemblies has made certain improvements, but for high and steep structures and formations with strong deflecting ability, the well deviation control effect is still not ideal. The core of modern deviation prevention technology is to solve the contradiction between improving the quality of well bore and drilling speed. We must break through the shackles of traditional concepts and actively explore new deviation prevention technology. The strapdown automatic vertical drilling system with full independent property rights developed by Shengli Drilling Institute has been successfully applied again in Ningshen 1 #, Mahuangshan Block, Ordos. It has withstood the test of the site and really become a convoy for drilling deviation prevention and straightening. The technology mainly consists of downhole closed-loop control technology for vertical drilling system, deviation prevention actuator, rotary seal, and pressure balance system technology.

Future trend 3: Provinces

"Economy" refers to economy, which means how to save drilling and completion costs, reduce the cost of per ton of oil, and maximize benefits. "Province" has also been an important goal for all parties to work together. Drilling costs account for about 50% of the total exploration and development expenditure. Saving drilling costs is of great significance for reducing the total exploration and development expenditure, especially for developing low and ultra-low permeability oil and gas reservoirs and marginal oil and gas fields. Deep well drilling and deep water drilling also pose higher requirements for cost savings.

The controllable contact area between the wellbore and the reservoir should be increased as much as possible in order to increase storage and production and enhance oil recovery. The well construction technology has developed from horizontal wells, extended reach wells, and branch wells to multi branch wells, fish bone wells, tree root wells, and maximum reservoir contact area wells (MRC wells). Obviously, a major development trend of well construction technology is to maximize the controllable contact area between the wellbore and the reservoir to increase the control area of a single well, reduce the number of wells, increase storage and production, improve oil recovery, and reduce the cost per ton of oil.

Drilling ultra large displacement wells to achieve onshore offshore oil production refers to wells with a ratio of bottom horizontal displacement to vertical depth equal to or greater than 2, and wells with a ratio greater than 3 are ultra large displacement wells. To date, many extended reach wells have been drilled worldwide, most of them for the development of offshore oil fields. Many extended reach wells are drilled onshore for onshore oil production. From July 2003 to March 2008, Parker Drilling Company of the United States drilled 17 extended reach wells on the shore of Sakhalin Island in the Far East of Russia to develop offshore oil fields. These wells have repeatedly set world records for extended reach wells at the time, with the largest sounding depth of 11680m, second only to the latest world record of 12289.5m for extended reach wells, with a horizontal displacement of 10902.7m. They were drilled by Transocean in the offshore oil field of Qatar in May 2008, and the drilling took only 36 days.

Simplify the wellbore structure, build a single diameter well, use less casing, or even use no casing. The wellbore structure of conventional wells is tapered, which means that in order to deal with complex underground formations, it is necessary to run multiple layers of casing or liner and cement the well, which will inevitably consume a lot of mud, casing, and cement, extend the well construction cycle, and increase the cost of well construction. For this reason, the concept of single diameter well (Monocore) was proposed in the late 1990s on the basis of expandable tubing technology abroad. The single diameter well technology began commercial application in 2007.

The core technology of single diameter wells is expandable tubing, so the companies that currently possess single diameter well technology are those that are capable of producing expandable tubing, including Enventure Global Technologies, Weatherford, Baker Hughes, Schlumberger, and Halliburton.

The main characteristics of single diameter wells include: first, reducing the diameter of the upper wellbore and casing, simplifying the wellbore structure; The second is to reduce the amount of mud, casing, and cement used and the workload of cementing operations; Third, shorten the well construction cycle; Fourth, reduce the cost of well construction; Fifth, reducing drilling waste is conducive to environmental protection; Sixth, increase the diameter of the completed wellbore and improve the production of a single well. Currently, the single diameter well technology is still in the early stage of commercial application and is still under development. Research micro borehole technology to economically and effectively develop shallow remaining oil resources. There are 218 billion barrels of discovered remaining oil reserves in the United States with a burial depth of less than 1500 meters. In order to develop this portion of reserves economically and effectively, the US Department of Energy has been vigorously funding research on micro borehole technology since 2004.

A micro hole is a well with a diameter of no more than 31/2 inches. The current research and testing of micro hole technology is suitable for a maximum well depth of about 1500 meters. Microborehole technology is a system engineering that covers the fields of drilling, logging, production, and so on. In the field of drilling, we focus on researching new miniaturized surface equipment - miniaturized hybrid coiled tubing drilling machines and corresponding miniaturized mud circulation processing systems, as well as ultra-small downhole drilling tools and instruments - downhole power drilling tools (including guided mud motors), geological steering instruments, MWD, and LWD. The main characteristics of micro hole drilling are that it can significantly improve the efficiency of drilling rig relocation, reduce the floor area of the well pad, reduce the consumption of mud, casing, and cement, as well as power consumption, reduce drilling personnel, improve drilling efficiency, reduce drilling and completion costs, comprehensive development costs, and exploration and development risks, and reduce the impact of drilling on the environment.

The development history of lightweight drill pipes shows that there is a trend towards lightweight drill pipes. Currently, aluminum alloy drill pipes and titanium alloy drill pipes have been put into commercial application, but their costs are too high. In recent years, the United States Department of Energy has been funding the development of non-metallic lightweight drill pipes - carbon fiber drill pipes. Carbon fiber drill pipe is a drill pipe made of carbon fiber epoxy resin with steel joints at both ends. Due to the fact that carbon fiber is not as wear-resistant as steel, it is necessary to polish the surface of carbon fiber pipes and apply an extremely wear-resistant coating. The biggest technical difficulty of carbon fiber drill pipe is how to achieve reliable adhesion between the carbon fiber drill pipe body and the steel joint. The carbon fiber material is non magnetic and non conductive, making it easy to make cabled carbon fiber drill pipes. Carbon fiber drill pipe and