With the development of drilling technology and the search for effective methods to increase oil recovery, drilling of horizontal wells became widespread. The world's largest companies began to massively implement this technology. The permanent increase in the complexity of geological conditions in the drilling areas, the involvement in the development of reservoirs with difficult recoverable reserves, technological and economic reasons stimulate horizontal drilling in the Russian Federation. The volume of drilling activities in Rosneft Oil Company over the past ten years has increased several times, including the volume of horizontal drilling. While increasing volume of horizontal drilling, the wells design is changing (multi-lateral, multilateral), the diversity of Geology is increasing and the variability of LWD tools is rising. In the context of increasing the volume of horizontal drilling, company needs systematization and classification of wells according to the degree of complexity for geosteering in order to more efficient allocation of resources while drilling (project documents, personnel, services, etc.) and improve the efficiency of horizontal wells.
The authors propose to implement in oil and gas industry a new parameter for horizontal wells Geosteering Difficulty Index (GDI). The method for its determination, as well as the classification of wells on the complexity of geosteering, is shown. An example of optimization of the services used on the basis of the presented classification is given, which as a result, will reduce unproductive costs and increase the economic efficiency of drilling horizontal wells.
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