Before the production technology of PDC was mature, or a period of time before the development of PDC drill bits, some manufacturers replaced natural large-grain diamonds with cemented carbide-free polycrystalline synthetic diamond to manufacture surface set drill bits. The shape of polycrystals has a cylindrical, triangular block, disc and rectangular, block-shaped and other ends of the cone, such as GE's Geoset, Fomset, De Beers' Syndax3 and Zhengzhou Sanmo Institute's TSP, their common feature is that they have high thermal stability, that is, they can withstand high temperatures of 1000 °C ~ 1100 °C, and can be directly sintered to the crown of the drill bit carcass composed of tungsten carbide powder and unbonded metal as drill teeth, crushing and cutting formation.
In 1969~1975, Zhengzhou Sanmo Institute produced several JR20SN-2 polycrystals of different diameters, which were first used for the manufacture of pregnanced drill bits and reamers for diameter protection, drilling into the formations below grade 7 of the mine, and then using 6×6mm polycrystals to manufacture oil scraper bits, and carried out tests in Shengli Oilfield, taking drilling into the same well depth of 2400m as an example, compared with cemented carbide scraper bits, each well can save 1.1~12,000 yuan and save 78% Compared with the cone bit, the polycrystalline scraper bit saves more than 50% of the cost, and the drilling time is reduced by 5~8 days. In addition, the geological core drill bit and reamer made of 1.8×5mm polycrystalline and the 2.5×5mm polycrystal are used for metallurgy, coalfield and geological pregnancing drill bit, and the effect is similar to that of natural diamond.
In the early 80s of the 20th century, before the PDC independently developed by China was not successful, 6×6mm polycrystals were used in a large number of core bits for oil and gas drilling and watermelon peel comprehensive drilling bits. Triangular massive polycrystals have also been used extensively in the manufacture of medium-hard to hard formations (e.g., limestone, dolomite), coring or full drill bits in slightly abrasive formations. Since the large-scale production of domestic PDC in the 90s, polycrystalline synthetic diamond has gradually withdrawn from the drilling market and has been fully replaced by PDC.
The R&D and application of PDC bits for oil and gas drilling have gone through a long time, the impact resistance of PDC in the early stage is not high, there is a stratification phenomenon, coupled with the problems in the design and manufacture of the drill bit and the risk of oil and gas drilling, the cone bit manufacturers that occupy a large share of the drilling market are not so positive, so the research and development and application of PDC bits have encountered great difficulties and resistance.
In 1973~1975, the United States used the 8.38×2.8mm PDC (Compax) produced by GE and the diamond layer was 0.5mm thick to be welded to the cemented carbide tooth post and then installed on the steel drill bit for testing. However, considering the structure and performance characteristics of PDC and the fact that most of the oil and gas formations are soft, medium and hard formations, drill bit manufacturers focus on the application of PDC in the oil drilling market with significant market prospects. The Drilling Research Center at Tulsa University in the United States was involved in the initial design of the planar PDC bit and conducted a pivotal test of the PDc itself. During this period, GE conducted trials of four PDC drill bits in South Texas, Colorado, Utah, and Upper Michigan, exposing some problems in the design and manufacture of PDC teeth and drill bits.
In December 1976, GE launched the Stratapax, a series of PTC products for drill bits, which improved performance, made them more impact-resistant, and more conducive to fixing to the drill bit body. At the same time, Diamant B0art has also conducted some successful PDC bit trials in the Persian Gulf and North Sea salt rocks, and East.man Christensen in the North Sea.
After the above-mentioned preliminary exploratory test, from the end of the 80s to the present, the PDC manufacturing plant has carried out a series of improvements and innovations to the PDC, so that the performance of the PDC has been greatly improved, and the major drill companies with the energy market boom, crude oil prices continue to hit new highs, they and oil companies together actively developed a series of new PDC bits, improve the use of the effect and expand the field of use.
Since the 90s, from the perspective of drill bit hydraulics, the phenomenon of drill bit mud bag in shale has been successfully controlled by improving the drilling mud, which has made a breakthrough in solving the problems existing in the shale interlayer. The biggest development of PDC drill bit is that Amoco company found that the most important reason for drill bit damage is caused by the rotation deflection (gyration) of the drill bit, and then developed the anti-drill bit deflection design technology, each drill bit manufacturer from the perspective of drill bit design on the tooth structure, cutter wing structure, drill bit profile shape, etc., a series of anti-deflection design technology, the degree of rotation deflection is reduced to the minimum. In addition, Eastman Christensen commercialized Amoco's anti-sway products by using a stabilizing bit working device that allows the PDC to reduce the severe deflection loads that cause it to break while drilling, and officially launched the anti-rotational deflection bit, which is more advantageous for drilling in multi-layered (heterogeneous interbedded) rock formations. In addition, the shape of the crown of the drill bit has also changed from a flat shape to a watermelon peel shape with 3~8 blades or even more blades (spiral).
Another reason for the continuous improvement and innovation of PDC drill bits is the development and application of more modern and complex computer data modeling systems (CAD/CAM), combined with laboratory validation, to increase the certainty of successful application of drill bits. In China, the development of PDC bit because of the impact of PDC localization, relative to the United States about 15 years later, in the mid-80s of the 20th century, Jianghan Drill Bit Factory, Dagang Switchboard Factory Drilling Research Institute and Beijing University of Petroleum and other units began to develop PDC bits, in 1985 Sichuan Shi-Christensen diamond bit company and in 1990 Xinjiang Emperor Ace Drill Bit Tool Company was established after the introduction of foreign mature PDC bit technology and follow-up new technology, and the use of GE, The quality of PDC produced by DeBeers and USS is stable and reliable, and the drill bits they manufacture have excellent performance in drilling, which has paved the way for the development and application of PDC bits in China and showed the bright prospects of PDC bits in the oil and gas drilling market. However, due to the high cost and high price of drill bits, its application is mainly promoted in oilfield and offshore oilfield drilling in Xinjiang.
In 1988, Zhengzhou Sanmo Institute independently developed a very low-cost PDC put on the market, accelerated the pace of localization of China's PDC bits, and successively appeared Jianghan Drill Bit Factory Drilling Research Institute, Dagang Petroleum Switchboard Factory, Shengli Oilfield Drilling Institute, Daqing Petroleum Administration Bit Factory and a number of PDC bit manufacturing plants, completely localized PDC bits in Daqing Oilfield, Zhongyuan Oilfield, Dagang Oilfield, Shengli Oilfield, Liaohe Oilfield, Jilin Oilfield and other areas have been promoted and popularized.
Due to the early 90s of the 20th century, the performance of domestic PDC is not satisfactory and the design and manufacturing level of some drill bit manufacturers is relatively low, the drilling effect is not ideal, until Zhengzhou Xinya Composite Superhard Materials Co., Ltd. was put into production, and unremitting research and innovation were carried out in PDC manufacturing technology, the specifications of the products were consistent with foreign products, and the quality and reliability of the products were improved, so as to basically meet the technical requirements of domestic and foreign drill bit customers for drilling soft and hard formations, and the company was mainly committed to the development of drill bits suitable for hard formationsPDC for drill bits in difficult-to-attack formations such as interlayers and deep wells. In addition, in terms of drill bit manufacturing, in addition to Sichuan Shiyi Christensen diamond bit company, Xinjiang Emperor Ace drill bit tool company, and a number of high-quality drill bit manufacturing companies have emerged: such as Chengdu Baiste diamond bit company, Wuhan Yistar tool company, Chengdu Dipu diamond bit company and Sichuan Sichuan stone diamond bit company. It is believed that in the near future, the use effect and application field of domestic PDC drill bits will progress rapidly with the improvement of PDC quality and the improvement of drill bit design and manufacturing level.
