Research Status of hydraulic hammer at Home and Abroad

Hydraulic percussion rotary drilling is a major reform of existing rotary drilling and a new drilling method after modern diamond drilling. It makes good use of the weaknesses of hard rock, such as high brittleness, low shear strength and poor impact resistance, and is an effective drilling technology to solve the problems of low drilling efficiency and poor drilling quality in hard rock and some complex rock formations.

The idea of using the residual liquid energy of mud pump and cooling bit to drive hydraulic hammer to realize hydraulic percussion rotary drilling began in 1887. The drilling method invented by German Walter Buschman was patented in Britain, but it was still in the experimental stage in the United States, the former Soviet Union and some countries in Eastern Europe until the 1960s, and some products were initially used. Gulf Oil Company and Shell Oil Company have studied this problem with the main purpose of applying it to oil drilling and eliminating sticking. Large diameter, hammer weighing 300kg, low impact frequency. Two kinds of hydraulic DTH hammers have been developed and tested by Panmei Petroleum Company, and they are mainly planned to be used in oil and gas drilling. Its representative is the positive-acting Bashinger hydraulic hammer (outer diameters are 178mm and 279mm), but these hydraulic hammer studies have stopped because they can't adapt to the mud environment in the above drilling field. The former Soviet drilling technology research institute developed BBO 5A reaction hydraulic hammer, which used a drill bit with a diameter of 145mm to drill to 2200m in oil drilling, but the spring in the structure was easy to be damaged and needed to be improved. The most effective research on geological and mineral drilling abroad is the Soviet Union. From 1900 to 1905, the research on hydraulic percussion rotary drilling technology began, but it was not until 1970 that it was gradually applied to production practice, during which it took about 70 years. There are г-7 and г-9 in hydraulic hammer, with diameters of 59mm and 76mm respectively. In the early 1980s, two kinds of wire rope coring hydraulic hammer with diameters of 59mm and 76mm were developed, both of which were positive-acting. However, due to no breakthrough in adapting to mud environment and life, the research and use were stopped in the early 20th century. In 1960s, Hungary developed five kinds of double-acting hydraulic DTH hammers with diameters ranging from 48mm to 160mm, which are characterized by being assembled on a special trailer, equipped with corresponding pumps, desanders, coring tools, drill bits and accident handling tools, being able to transport flexibly and serving multiple drilling rigs in construction mines or construction sites. When the drilling rig encounters hard stratum and needs percussive rotary drilling, it can dispatch a full set of auxiliary machinery for construction in time, and then it can be flexibly dispatched to the hole sections of other machinery for service. This hydraulic drilling equipment in Hungary is not only used for geological mine drilling, but also for water well drilling and engineering construction drilling. Like the former Soviet Union, it stopped because of mud adaptability and life problems. WH- 120N double-acting hydraulic hammer was developed by Japanese Li Gen company in the 20th century. It is a double-acting hydraulic hammer with a cylindrical slide valve. Its biggest feature is that it uses gas-liquid mixture as working medium, with an outer diameter of 120mm, a length of 883 ~ 1 138mm, a mass of 65kg and a pumping capacity of 30. G-DrillAB Branch, a member of LKAB Group, a Swedish iron ore producer, and SDS Company of South Australia also developed a high-pressure hydraulic hammer named Wassara in 1990s, which is planned to be mainly used for mine exploration. Its working principle is to use pressure water to control the up and down position of the variable diameter cylindrical valve, so as to change the channel where the water flow acts on the piston and make the piston reciprocate up and down. The working pressure of the hydraulic hammer can reach 18 MPa, and it has been drilled to the aperture of 105 ~ 120mm, and the hole depth is 40 m. According to the introduction, it has high requirements for the construction period, but it has extremely high requirements for the washing liquid, and the clean water has to be filtered by the filter of 100 micron, so it is difficult to popularize it in production. In 2002, DOE (British Ministry of Environment) tested the performance of its SDS series and Novtek's N series hydraulic hammer. Since then, there has been no new research progress on these two kinds of hydraulic hammer.

The compound hydraulic hammer (with positive valve function and double impact hammer function) of Kloster University in Germany has achieved some results through a large number of laboratory experiments, but it has not been successfully applied to practice. Generally speaking, there are many and extensive researches on hydraulic hammer abroad, but it has not been applied in industry.

Through the above summary, the research of hydraulic DTH hammer technology was in the leading position in the world in the 20th century, but it stopped at the end of last century because it could not effectively solve the problems of mud adaptability and low life of dynamic seal pair (Table 2. 1).

Table 2. 1 Statistics of some foreign hydraulic DTH hammers

In China, the research began with 1958. Firstly, a special test-bed was established in the experimental station of Zhoukoudian Exploration Technology Research Institute in Beijing. 1963, on the basis of extensive data collection, the Atlas of Impact Rotary Drilling was edited to introduce foreign related documents, which were distributed to many units with geological exploration tasks, laying a foundation for later development. 1965 The Institute of Exploration Technology of the former Ministry of Geology has successively designed seven kinds of hydraulic hammer with different structures, among which six YZ-2 sets were trial-produced in a polymetallic mine in Hunan on 1966, with the maximum drilling depth of 430m, which achieved good results and attracted wide attention in the industry. From 197 1, the Ninth Geological Brigade of Liaoning Bureau of Geology and Mineral Resources and the former Changchun Institute of Geology and other units began to study an original SC-89 and JSC-75 jet hydraulic DTH hammer, and won the science and technology award in 1982. It is a hydraulic DTH hammer that has been actually applied in China. Since 1975, except for the extensive development of hydraulic DTH hammer in geological system in China, almost all other brother departments with core drilling tasks have studied this drilling technology, and almost all of them have been positively praised in production practice. This advanced drilling technology has been gradually recognized and developed steadily in geological drilling, oil and gas drilling and various projects. Its technical core-hydraulic DTH hammer is gradually becoming a main branch of downhole power drilling tools.

Figure 2. 1 Main hydraulic hammer types developed by China.

At the end of 1970s and 1980s, China's research on hydraulic hammer entered its heyday, and the departments of geology, metallurgy and coal developed various types and specifications of hydraulic hammer for small-bore coring drilling, including positive-acting, double-acting, reactive and composite hydraulic hammer, with more than 30 kinds (Figure 2. 1). See Table 2.2 and Table 2 for the hydraulic hammer of some industries. The cumulative footage has exceeded several million meters, and good economic benefits have been achieved. Comprehensive statistics can improve drilling efficiency by more than 30% ~ 50%, at the same time, it can obviously improve drilling quality and core recovery rate, extend footage and reduce material consumption. In the construction of Anhui 32 1 Geological Team, YZ-54 directly created the largest coring drilling depth in China, which reached1000.66 m. hydraulic hammer was widely used in the field of geological coring drilling in China and the Soviet Union, and the completed workload once reached one million meters. According to the literature, the maximum application depth of coring drilling in the Soviet Union reached 2000 meters.

In 1990s, hydraulic hammer ZC-800, YQ- 150, YQ- 178, YS-2 19 and SYC- 178 were developed in China. At the same time, the energy utilization rate and the improvement of single impact work of hydraulic hammer are further studied. The former Changchun Institute of Geology made an in-depth study on jet hydraulic hammer, and its main method was to increase the single impact work by increasing the stroke of the hammer. The research focus of the two institutions has developed to meet the needs of large-diameter omni-directional drilling, and both have made some progress. However, due to the sharp decline in the workload of geological exploration in China, the research investment in hydraulic hammer has slowed down, and these achievements have not been well applied and further improved. Most other institutions that initially conducted research on hydraulic hammer have stagnated due to market and financial reasons (Table 2.2).

Table 2.2 Main technical parameters of common hydraulic DTH hammers

At the same time, hydraulic hammer percussive rotary drilling technology has received unprecedented attention in the field of oil drilling, but it is still in the development stage. Representative results are as follows:

SYZJ hydraulic DTH hammer developed by Beijing Petroleum University: hydraulic hammer with double valves and double functions was developed in cooperation with Hebei Comprehensive Team of the Ministry of Geology and Mineral Resources. Hydraulic hammer is used in interval 2308 ~ 235 1m (43m). The formation is mudstone and siltstone, which improves the drilling efficiency by 63%. In mudstone, it improves the drilling efficiency by 2 1% and reduces the well deviation.

Hydraulic hammer of YSC 178 jet in Dezhou Petroleum Drilling Research Institute: 3643 ~ 376 1m interval of Qugu 3 well in Shengli Oilfield, with footage 1 18m, effective time of 67h, efficiency 1.76m/h, which improves the mechanical efficiency by 40%.

Jet-suction hydraulic hammer, Tong 17 well in southern Sichuan, limestone, interval 2787 ~ 28 1 1m, footage 24m, drilling time 14.68h, and mechanical efficiency increased by 40%. In addition, Xi Petroleum Institute and Baoji Petroleum Machinery Factory have also carried out this kind of research work on hydraulic hammer.

Some foreign countries also introduced hydraulic hammer from China for research: Smith International Co., Ltd. of the United States commissioned the former Changchun Institute to jointly develop two sets of YSC- 178 jet hydraulic hammer, which were tested in the autoclave at the headquarters of Smith Company of the United States in May, 1998. 1988, the jet hydraulic hammer was simulated in the autoclave of the former Institute of Deep Drilling and Oil Production (IET) of Kloster University of Technology, West Germany, and it still worked stably under the confining pressure of 40MPa. After the actual drilling test, the efficiency was improved by 0.6 ~ 1 times. However, due to the cooperation between its scheme and KTB drilling scheme in Germany, its research work could not be followed up in time due to the change of construction scheme, which led to the cancellation of well entry test and the subsequent in-depth experimental research could not be continued.

Therefore, by the end of the 20th century, the research of hydraulic DTH hammer mainly focused on theoretical research, and there was no big breakthrough in production application and product industrialization progress, especially in oil and gas drilling in large diameter deep wells, which did not reach the level of industrial application. The reason is that the continuous working life of hydraulic DTH hammer can't match the working time of roller bit in oil drilling, that is, the life of parts in hydraulic hammer can't meet the actual needs of drilling.

2 1 century, the research and application of hydraulic DTH hammer entered a new development period. In particular, Chinese mainland Scientific Drilling Project CCSD 1 is used as a platform to show the overall drilling level and strength of China, and a number of drilling technologies including hydraulic DTH hammer are pushed to the forefront of deep drilling and tested. Hydraulic hammer's research has been improved several times, and the world's first composite drilling technology with China characteristics (screw motor/hydraulic hammer/diamond coring technology) has achieved remarkable results. From August 5438, 2006 to October, 2005, CCSD/KOOC-0/Well YZX/KOOC-0/27 hydraulic hammer * * * was constructed 505 times, with a cumulative footage of 3526.3m and a well depth of 5/KOOC-0//KOOC-0/8.2. The pipeline integrity rate is over 95%. The core recovery rate is over 90%, which has achieved good results, significantly improved the economic and technical indicators of drilling construction, and showed the adaptability of hydraulic DTH hammer to deeper and deeper holes. This is also the latest world record of hydraulic DTH hammer coring drilling, which has achieved remarkable results. This technology has become the primary characteristic drilling technology of scientific drilling engineering in mainland China, and it has been highly praised in the process of international exchange, causing great repercussions.

At the same time, according to the successful experience of YZX 127 hydraulic hammer, the Institute of Exploration Technology developed YZX series of high-efficiency hydraulic hammer, forming a series of products, as shown in Table 2.3. Compared with the traditional hydraulic hammer, the high-efficiency series hydraulic hammer has a simple structure, and the number of sealing pairs is reduced from 4 to 2, which effectively reduces the jamming probability of moving parts. The structural adjustment parameters were reduced from five to three, the original fixed throttle ring in hydraulic hammer was cancelled, the water cushion effect during anvil striking was reduced, and the impact energy output of hydraulic hammer was increased by 25% ~ 50% under the same input energy. At the same time, this series of hydraulic hammer has the advantages of stable operation and simple operation. Even if it doesn't work for special reasons, it won't cut off the waterway as quickly as the traditional hydraulic hammer, which can ensure that the conventional rotary way is used to drill this round or complete the service life of the roller bit in the well. This advantage greatly improves the reliability of hydraulic hammer's on-site safe use, which has obvious practical significance.

Through the scientific and reasonable diversion design of hydraulic hammer, hydraulic hammer has an adjustable porous diversion structure, which better solves the contradiction between the working pump quantity in hydraulic hammer and the pump quantity used in the drilling site (the difference is 50%), and alleviates this problem to some extent. Through the test of three kinds of lower piston consolidation methods, the problem of replacing the important wearing parts of hydraulic hammer in the field is well solved, which greatly facilitates the use in the production site and saves the cost.

Table 2.3 Structural Performance Parameters of YZX Series Hydraulic DTH Hammer

According to the change of domestic drilling market, in order to meet the needs of large-scale application of small-diameter wire-line coring in the new round of national geological survey, the Institute of Exploration Technology, on the basis of successfully developing high-efficiency series hydraulic hammer, combined hydraulic hammer drilling technology with wire-line coring technology with high drilling efficiency, timely developed a new generation of SYZX series wire-line coring hydraulic hammer (Table 2.4).

Table 2.4 Main performance parameters of SYZX rope coring hydraulic hammer drilling tool

This type of hydraulic hammer has achieved good drilling results: the aging time is generally increased by more than 30% to several times, the return footage is increased by more than 25%, and the cost is reduced by more than 15%. It overcomes the shortcomings of hydraulic hammer in previous research, such as complex structure, many wearing parts and poor working reliability, and makes this series of rope coring hydraulic hammer have obvious advantages in adaptability, working stability, wearing parts life and many other aspects.

Generally speaking, hydraulic hammer technology, which has made great progress, can better adapt to drilling conditions through coring drilling. The main reason is that the quality of flushing fluid for coring drilling is more guaranteed, and the continuous working time of coring drilling is shorter (generally within 10h). In addition, coring and drilling provide opportunities and time for ground maintenance in hydraulic hammer.