History of Science and Engineering Annotation << Back HISTORY AND FEATURES OF DEVELOPMENT OF TECHNOLOGY AND TECHNOLOGY OF TILT-DIRECTIONAL DRILLING OF OIL AND GAS WELLS IN THE XX CENTURY I.D. Mukhametgaliev, A.Kh. Agliullin, R.A. Ismakov, Ch.T. Mukhametgalieva The article considers the stages of development downhole drilling equipment for for drilling directional technology wells in the period from the 20s of the XX century to the latest time. The purpose of the article is to summarize the scientific and practical experience that contributed to the birth and development of the production sector of drilling in the directed wells. This work is the second part of a series of articles, consisting of three parts, which are devoted to the coverage of the stages of development of drilling directed wells (DDW) and the main technical and technological problems being solved. Under the modern high-tech service for technological support of drilling, a long of evolutionary and revolutionary process is hidden, where primitive devices have been transformed into complex mechanisms and sensors for deflecting the well axis in a given direction and measuring parameters for building a well route. The aspects of DDW development discussed in the article touch on key issues that have made this production sector one of the mainstays in the drilling business. As the results of historical research work, the article presents a pyramid of events by degree of importance at the stage of development of inclined drilling. Among the key historical episodes of the formation of the DDW were seven events from the first mention to the latest time. Keywords: directional drilling; downhole inclinometers; downhole whipstock; electric drill; impact-rod drilling; toolface; turbo drill. DOI: 10.25791/intstg.08.2020.1205 Pp. 39-50.