Overview of the application of new drilling technology

In the western development and geologic survey of land resources, the CPC Central Committee and the Ministry of Land and Resources have placed the exploration and development of water resources as the top priority. National groundwater resources survey and evaluation is an important part of the geological survey, in order to complete the task on time and in quality and to achieve the predetermined goals, in addition to the use of advanced geological theories and geological technology, it is also necessary to use advanced core sampling drilling new technology. If the conventional drilling technology for construction, there are many areas with a lot of technical difficulties, such as slow exploration, low efficiency, high cost; hole jamming, buried drilling accidents are frequent; easy to block the production layer fissure, mud skin paste hole wall; water-scarce areas there are also a large number of production water is difficult to solve, inevitably affecting the water resources survey and evaluation. This series of factors, we are required to change the original concept of technological innovation, select suitable for a certain area, advanced drilling technology, improve drilling efficiency, reduce costs, quality and quantity to complete the task, thus driving the promotion and application of new drilling technology.

During the period from the Sixth Five-Year Plan to the Eighth Five-Year Plan, the drilling technology progressed remarkably, and the diamond drilling technology with rope coring as the main body developed greatly, which drove the comprehensive change of the drilling technology, technology, method and equipment, etc. The controlled directional drilling technology has reached the international advanced level, and the percussion drilling technology has reached the international advanced level, and the percussion drilling technology has reached the international advanced level, which has reached the international advanced level. Controlled directional drilling technology has reached the international advanced level, impact rotary drilling technology has become a characteristic technology with independent intellectual property rights in China, and has reached the international advanced level; multi-process air drilling technology and reverse circulation drilling technology tends to be mature; drilling machinery and instruments have developed a series of products adapted to multi-process methods, and the technical equipment has basically become a complete set, which has played a positive role in the geological exploration.

2.2.2.1 Multi-process air drilling technology

Air drilling refers to the use of compressed air or gas-liquid mixtures containing compressed air as a circulating flushing medium when drilling, or both as the power of the rock-breaking equipment, but also as a flushing medium of a drilling process. In recent years, the development has been rapid, mature technology, and gradually formed a multi-process air drilling technology system including circulation medium, circulation mode, rock breaking method and application areas.

The main features are as follows: low-density media is conducive to improving the speed of rock crushing; can effectively cool the drill bit, remove the rock chips and rapid stratification; can protect the hole wall in unstable strata and less pollution of the environment; conducive to the protection of aquifers and low-pressure oil and gas reservoirs and improve the output rate; especially conducive to the construction of arid and water-scarce areas and the severe cold, frozen layer; but also conducive to the taboo on the use of liquid circulation of the anti-slip anchor holes and blasting holes construction in the open pit; air-drilling holes; air-drilling holes are also used for the construction of blasting holes. Blast hole construction; air down hole hammer drilling can greatly increase the speed of hard rock drilling; air lift reverse circulation drilling can realize more than 2 ~ 3m large diameter wells and more than 2,000m deep well construction.

Multi-process air drilling is regarded as one of the most widely used and promising drilling technologies today, and through the research and improvement during the "7th Five-Year Plan" and "8th Five-Year Plan" periods, it has formed a relatively mature modern fast and comprehensive drilling technology. "The promotion and application of multi-process air drilling technology has been selected and compiled by the State Science and Technology Commission into the "100 cases of national scientific and technological achievements key promotion plan projects with output value exceeding one hundred million yuan". The Institute has carried out research and development of multi-process air drilling technology by combining different applications in various fields and different geological conditions in various regions, and has developed a variety of double-wall drilling tools and supporting equipment such as SHB114/70, 127/70, 140/100, CSR73/33, CSR73/39 and so on through continuous improvement in practice. We have also developed many types of drilling rigs, such as SPC series water well drilling rigs, fully hydraulic power head type FD-300 drilling rigs, etc., and ADF type series of foaming agents that can be used in complex formations.

The application of multi-process air drilling technology has successfully solved a number of long-standing technical problems, such as drilling in arid and water-scarce areas, permafrost and leakage layers; drilling in areas where safe drilling cannot be guaranteed by other circulating media; drilling in areas where drilling quality cannot be guaranteed by other drilling methods; and drilling in a number of formations in which the efficiency of drilling is very low by other drilling methods, and so on.

The popularization and application of this technology has greatly improved the drilling speed and quality of hydrological wells, and the drilling speed can be increased by many times or even more than ten times by using air submerged hammer and air-lift reverse circulation drilling than the conventional same rotary drilling; it has produced great economic and social benefits, and, according to incomplete statistics, more than 1.3 million meters of drilling workload have been accomplished by the multi-process air drilling since its popularization, and the cumulative output value of the workload has been increased by only 20 units up to the year 1998. According to the statistics of 1998, the cumulative output value of more than 6.4 billion yuan, new profits and taxes of 0.9 billion yuan; has been for China's north of Jin, west of Henan, Shaanxi, Gansu, Ningxia and Inner Mongolia, Guangxi karst area, Beijing suburban mountainous areas, etc., played a lot of fruitful wells, solved the difficulties of millions of people and livestock and production of water to play an important role in poverty alleviation and enrichment.

2.2.2.2 Multi-media reverse circulation drilling technology

The so-called reverse circulation drilling means that the circulating medium in the drilling process is in the opposite direction of the circulation of the conventional drilling method, and the reverse circulation drilling generally adopts the double-wall drilling tools, and the circulating medium is mainly divided into two kinds of compressed air and liquid. During the drilling process, the circulating medium reaches the bottom of the hole through the double-walled air tap, double-walled active drill pipe, double-walled drill pipe inside and outside of the pipe ring gap, drive the bottom of the hole rock-breaking apparatus to break the rock, and carry the rock core and rock chips through the center channel of the drill pipe to reach the surface of the rock core or rock sample collection device.

Because of the unique double-wall drilling tool structure of reverse circulation drilling, the required geological samples can be obtained without raising the drilling tool in the hole, which determines that this method has the following advantages: high time utilization, high drilling efficiency, low labor intensity, good well washing effect; hole bottom cleaning, long life of the drill bit, and realizing the simultaneous drilling and sampling, which achieves the goal of high-quality and high-efficiency.

Based on the different circulation media, reverse circulation drilling technology is mainly divided into air reverse circulation and hydraulic reverse circulation.

(1) Air reverse circulation continuous sampling drilling

With a variety of drilling tools combination (Figure 2.4), it can be adapted to a variety of stratigraphic conditions (Table 2.1) for coring or sampling continuous drilling, and it can satisfy the geological requirements for coring; it is especially suitable for drilling construction of hydrological geological exploration holes in arid and water-scarce areas, etc.

Figure 2.4 Schematic diagram of the combination of air reverse circulation drilling tools

Because the circulating medium is air, it won't block the water channel, no pollution to the water quality, and won't lose the aquifer; in the process of drilling, it can be judged according to the degree of wetness of the rock samples to determine whether it enters the aquifer; with the increase in the depth of the aquifer, the amount of water returning to the hole gradually increases, and the amount of water returning to the hole tends to be stabilized after passing the aquifer, so that it can be roughly judged whether it is entering the aquifer. After passing through the aquifer, the amount of water returned tends to stabilize, so that the location of the aquifer can be roughly judged, and the size of the water can be qualitatively judged. For example, Ningxia Errenshan-Jinchangzi mining area was originally designated as a poor water area (5m3/24h), with air reverse circulation drilling more than 20 holes, not only the holes in the water, and the amount of water gushing up to 20-30m3/h. Another example, in Zhoukoudian, Beijing Institute of Prospecting and Mining Engineering yard drilling with the conventional method of hundreds of meters deep did not find groundwater, the air reverse circulation drilling method, but found a richer up to the standard of potable water groundwater.

Table 2.1 Combination of Drilling Tools and Adaptation to Stratigraphy

(2) Hydraulic Reverse Circulation Continuous Core Drilling Technology

Taking the liquid as the circulating medium, the double-walled drilling tools are used to realize the continuous upward and downward return of the core. This drilling technology uses cemented carbide and diamond bits as rock breaking tools, and drills by rotary grinding and coring. It is mainly used for drilling in 2 to 4 level overburden strata, coal strata and more complete medium and hard rock strata. Practice has proved that hydraulic reverse circulation continuous core drilling technology for hydrogeological survey, geological mapping, geochemical exploration, coal field core drilling and environmental protection and other drilling construction, has a high drilling efficiency and better geological results. In more than 300 meters drilling construction in Yantai, Shandong Province, the monthly efficiency of the integrated table reaches more than 1,300 meters, and the time utilization rate reaches 75%.

2.2.2.3 Rope core drilling technology

Rope core drilling technology is a kind of widely used geological core drilling technology, which is widely adaptable to the stratum. 1973, the Institute of Exploration for the first time successfully developed rope core drilling tools for core drilling, and then gradually developed a variety of series of products, including: hydrological water wells rope core drilling tools series, hard "slippery" strata, heavy rope coring tools for deep holes, rope coring tools for soft and broken strata and coal strata, and rope coring tools for plastic three-layer pipes and overrun pipes, etc. At the same time, the Institute has also developed its own drill bits and reamers, which have greatly improved the technological level of China's diamond drilling. drilling technology level in China.

The application of rope core drilling technology can reduce the number of lifting and lowering of drilling tools, increase the pure drilling time, reduce the abrasion of the core and the chance of falling off in the middle of the process, and the core taking rate reaches 90% to 100%; it can prolong the life of drilling bits, etc.; it is regarded as "four highs, three lows, and two goods", i.e., high quality of project, high utilization of time, high efficiency of drilling, and high life of drilling bits. It is known as "four high, three low, two good", i.e. high project quality, high time utilization rate, high drilling efficiency, high bit life, low accident rate, low labor intensity, low consumption of equipment and materials, good geological effect, good economic benefits.

In order to meet the new round of geological survey geological drilling needs and further improve the comprehensive level of China's geological drilling and the use of a new type of drilling technology - combined drilling technology came into being, the air reverse circulation continuous sampling, hydraulic reverse circulation continuous coring and rope coring drilling technology organically combined with a set of The drilling can be completed with a set of drilling rods and auxiliary apparatus, which achieves the drilling according to the location, meets the geological requirements, improves the drilling efficiency and reduces the drilling cost. The technology can be better used for hydrogeological hole exploration and solid mineral exploration; at the same time, the Institute is also continuing to develop the use of rope coring supporting drilling tools for deep holes in complex strata.

2.2.2.4 Liquid impact rotary drilling technology

Liquid submerged hammer drilling technology is based on rotary drilling to add a use of flushing fluid-driven liquid submerged hammer, which can produce a certain amount of impact energy and frequency of the load, which can greatly improve the efficiency of more than 5 levels of stratigraphic drilling, to overcome the diamond drilling "slippery" problem, in the rock core, and to improve the efficiency of drilling. It can greatly improve the drilling efficiency in formations of more than 5 levels, overcome the problem of diamond drilling "slipping", and extend the return footage in broken formations where the core is easy to be clogged. The Institute has developed more than 30 specifications of six series of hydraulic submerged hammers, such as positive-acting series, double-acting series, rope coring series, hydrological and water well drilling series, and liquid and gas dual-use series, and is still developing hydraulic hammers for deep wells and spraying reverse series of hydraulic hammers, etc. The Institute has also developed a series of hydraulic hammers for deep wells, which are used for the drilling of deep wells.

Scientific drilling on the Chinese mainland is a national key project, and its implementation will be an excellent opportunity to comprehensively test and improve the level of China's drilling technology from the point of view of drilling technology. The construction of its 2,000m pilot and main holes adopts the advanced technology with Chinese characteristics: screw motor/liquid-actuated hammer/diamond core drilling process method. The YZX127 hydraulic hammer developed by the Institute has become an indispensable drilling apparatus for the main hole of CCSD, and played a leading role in the drilling of the main hole.

In summary, the Institute of Exploration has taken the lead in the research of hydraulic percussion rotary hammer technology since 1958, and through the unremitting efforts of several generations, while making new breakthroughs in theory and technology, it has actively carried out the transformation and application of scientific and technological achievements, so as to further expand the field of its application. In recent years, the hydraulic impact rotary drilling technology has been applied to groundwater exploration, water wells and geothermal, oil and gas wells, geological core drilling, underwater blasting and engineering geological survey and other fields, and in the popularization and application of good benefits.

2.2.2.5 Controlled Directional Branch Hole Drilling Technology

Controlled directional drilling technology is to use the bottom of the hole motor and the necessary curved joints or curved shells to control the direction of drilling along the designed trajectory to reach the predetermined target area, the drilling technology can be drilled at different depths of a main hole in different directions to drill a number of branch holes, which can greatly improve the efficiency of the drilling and cost savings, improve the drilling comprehensive utilization rate.

At present, the controlled directional branch hole drilling technology has been successfully applied in solid mineral exploration, and the directional drilling docking well technology is also widely used in salt mines, underground coal bed gasification and other fields, which can drill 6-9 branch holes in one main hole, and can realize the docking of two boreholes 500m apart at a depth of 3,000m below the ground, and the Institute of Exploration has successfully completed more than 30 pairs of docking wells by using this technology. The exploration institute has successfully completed more than 30 pairs of docking wells using this technology, and in 2002, the exploration institute completed a docking well as deep as 2,787m in Hubei, which is the largest docking well in China. The successful application of this technology has brought good social and economic benefits to the society and production units.

Controlled directional multi-branch hole drilling technology for the development of geothermal and hydrological water well drilling, etc., can better expand the collection area of geothermal wells and water wells, enriching the amount of water; in the water wells on the verge of depletion, the implementation of radial horizontal wells can be carried out in the same main wells in order to increase the rate of wells and extend the life of the wells, so that the dead wells to come back to life; the buttressing of connecting wells can be converted from the underground dry thermal rock into Geothermal heat, in order to give full play to the effective role of underground energy, for the benefit of the people.