Using of the Drill Bit with Combined Action Significantly Reduce Well Construction Time in Belarus Republic

Abstract

The history of drilling for oil in the Republic of Belarus began in the mid-1960s (Sosnok A. 2016), when the first industrial oil inflows were received in the Rechitsky district of the Gomel region, from wells No. 6 and No. 8. In the years that followed, local and international experience was leveraged to actively drill and develop the region’s oil deposits, using advanced technologies suited to the complex geological conditions of the Pripyat trough. The new century is calling for innovative approaches to solve well construction problems currently facing Belorusneft Production Association (PA). The need to improve drilling, completions, and production methods has led to the introduction of modern technology, with sweeping changes in all aspects of well construction. In 2019, exploration and production drilling in Belarus entered a new stage of development, in which reducing well construction time via the use of new, improved technologies became one of the highest priorities. A few decades ago, due to the complex geological structure that characterized Belarus deposits, drilling was carried out mainly by the rotary-turbine method. This method used roller cone and impregnated bits, which demonstrated quite good results; however, they did not compare to the performance of modern-day polycrystalline diamond compact (PDC) bits. In line with Belorusneft’s phased rig fleet refurbishment around 2016, PDC drill bits were introduced and deployed across all of the operator’s oilfields to handle "aggressive" hydraulic parameters in the Pripyat oil and gas basin. At the same time, there was a gradual transition from use of the turbine drilling and rotary bottom hole assembly (BHA) to BHAs that include a hydraulic positive displacement motor (PDM) and rotary steerable system (RSS). The volume of drilling with the newly configured BHA increased from 14 percent in 2016 to 83 percent by the end of 2019 Distribution of drilling volumes for Belorusneft, by year, by drive type. The increase of PDC bit usage was one of several factors that helped raise the run length per bit and the rate of penetration (ROP) to a new level. As shown in Table 2, due to the introduction of modern drilling technologies, the average ROP increased by more than 2 times since 2016, and amounted to 7.64 m/hr in 2019. With this higher ROP, it was possible to increase the total volume of drilling in 2019 by more than 1.5 times compared to 2016, without increasing the total number of drilling rigs. Average ROP and total drilling volumes for Belorusneft, by year. This paper describes the main challenges encountered in Belarus when drilling with Halliburton PDC bits, and the solutions delivered by the evolving bit design improvements. It includes the introduction of combined rock failure action bits with a higher penetration rate and, accordingly, associated cost savings. The paper also reveals the advantages of using these new bits when drilling wells in the complex geological conditions of the Pripyat sag basin. The Republic of Belarus is one of the first countries in the Eastern hemisphere to test and confirm the high efficiency of innovative bit design for drilling intercalating heterogeneous rocks of wells with different profiles, compared to ordinary PDC bits of conventional design.