Submit an Article
Become a reviewer
Aleksander V. Lyagov
Aleksander V. Lyagov
Professor, Ph.D., Dr.Sci.
Ufa State Petroleum Technological University
Professor, Ph.D., Dr.Sci.
Ufa State Petroleum Technological University
Ufa
Russia

Articles

Geotechnical Engineering and Engineering Geology
  • Date submitted
    2022-08-10
  • Date accepted
    2023-02-28
  • Online publication date
    2023-04-28
  • Date published
    2024-02-29

Selection of the required number of circulating subs in a special assembly and investigation of their performance during drilling of radial branching channels by sectional positive displacement motors

Article preview

The task of sludge removal to the surface during construction of directional and horizontal wells and strongly curved radial channels is relevant. For stable operation of technical system “Perfobore”, it is proposed to use a circulating sub that ensures efficient cleaning of channel wellbore from the drilled rock. Two schemes of technical system “Perfobore” are considered, consisting of two seven-meter coiled tubing, a positive displacement motor, a bit and one circulating sub in the first scheme and two subs in the second scheme. For each of the schemes CFD modeling was implemented to determine values of pressure and speed. It was found out that the use of two circulating subs in the assembly is more efficient. In order to confirm the numerical experiment, bench tests were carried out. It was determined that the designed circulating sub can eject up to 25 % of pumped drilling fluid. The bench tests of full-size technical system “Perfobore” for drilling 14-meter channels with two circulating subs showed that the axial load on positive displacement motor produced by hydraulic loader was 3000 N and pressure drop depending on flow rate was 1.5-2.0 MPa. This allows the motor to operate at maximum power.

How to cite: Lyagov I.А., Lyagov A.V., Isangulov D.R., Lyagova А.А. Selection of the required number of circulating subs in a special assembly and investigation of their performance during drilling of radial branching channels by sectional positive displacement motors // Journal of Mining Institute. 2024. Vol. 265. p. 78-86. EDN ZBPWKU
Oil and gas
  • Date submitted
    2019-07-10
  • Date accepted
    2019-08-30
  • Date published
    2019-12-25

Methodology for calculating technical efficiency of power sections in small-sized screw downhole motors for the «Perfobur» system

Article preview

With an increase in the share of old and low-yield wells and for the efficient exploitation of fields, it is necessary to include low-capacity formations into production. There are many wells where sidetracking and hydraulic fracturing are difficult due to the close proximity of the gas cap and underlying water caused by geological and technological reasons, and the use of existing secondary drilling-in technologies is not effective due to the extensive colmatated zone or annular circulation. Relevance of radial drilling technologies is growing, which allows drilling-in of the formation with a network of extended channels to establish high-quality hydraulic communication between the formation and the well without affecting the permeability of the formation. In contrast to radial drilling technologies using hydraulic washing, technical system (TS) «Perfobur» uses small-sized screw downhole motors (SDM) and rock cutting tools for channel construction. For efficient milling of production casing and destruction of rock, the hydraulic downhole motor must have high torque, and for the possibility of drilling with a high rate of angle gain, it must have short power section. Existing Russian and foreign SDM have limited number of standard sizes and do not meet the requirements specified for the development of the downhole module of TS «Perfobur». The paper discusses the development of universal small-sized sectional screw downhole motors for milling casing strings and drilling a network of branched channels of super-small diameter and radius of curvature as a part of the TS «Perfobur». Methodology proposed in the article for selecting optimal configuration of the SDM power sections allows constructing small-sized sectional downhole motor that meets the technical requirements and has improved characteristics compared to standard SDM.

How to cite: Lyagov I.A., Baldenko F.D., Lyagov A.V., Yamaliev V.U., Lyagova A.A. Methodology for calculating technical efficiency of power sections in small-sized screw downhole motors for the «Perfobur» system // Journal of Mining Institute. 2019. Vol. 240. p. 694. DOI: 10.31897/PMI.2019.6.694