Open AccessResearch on Calculation Model of Horizontal Wellbore Shape with Non-uniform In-situ Stress
Author(s) -
Zhenning Yu,
Yu Fahao,
Ting Wei,
Dianju Wang,
Yue Wang
Publication year - 2020
Publication title -
iop conference series. earth and environmental science
Language(s) - English
Resource type - Journals
eISSN - 1755-1307
pISSN - 1755-1315
DOI - 10.1088/1755-1315/619/1/012059
Subject(s) - borehole , deformation (meteorology) , stress (linguistics) , geology , instability , geotechnical engineering , mechanics , position (finance) , geometry , physics , mathematics , philosophy , linguistics , oceanography , finance , economics
In horizontal Wells, non-uniform ground stress is the root cause of irregular borehole shape. The failure of caliper instrument in horizontal section leads to the failure of accurate evaluation of borehole shape, which makes it difficult to calculate the frictional resistance of tubing string in the later stage. This paper studies the borehole shape calculation model from the following two aspects: (1) in the aspect of diameter expansion caused by shaft wall collapse. By establishing coulomb-Mohr criterion in cylindrical coordinate system, the well wall collapse instability is judged, and the hole diameter expansion is evaluated by establishing the calculation model of the instability range. (2) Shrinkage caused by stress concentration. Firstly, the boundary position of formation deformation is determined. Secondly, the calculation model of borehole deformation is established by analyzing the stress characteristics of formation, which reflects the time effect of borehole deformation. Therefore, the establishment of borehole shape calculation model of horizontal well provides a basis for calculating the friction between the pipe string and the horizontal section.