Study of wellbore curvature during drilling in the Gogerendag field

During the drilling process, the borehole curves for several reasons. Both techno-technological factors and natural factors lead to this. Natural factors include inclined bedding of rocks, alternation of rocks of different hardness, layering, fracturing, presence of caverns and shear planes, and anisotropy of rocks, which means that their properties are not the same both along and across the bedding. The loss of straightness of the bottom of the drill string while creating axial load on the bit, its rotation, use of bent tubing and drill string bottom hole assembly (BHA) layout are technical and technological factors. During the initial drilling period, the well deviates from the vertical due to non-horizontality of the rotor table and non-centredness of the derrick. Two components can determine any wellbore curvature. The first is the azimuth angle or zenith angle, which shows the deviation of the well axis from vertical. The second is the curvature angle. This is the angle between the vertical plane passing through the north end of the magnetic arrow and the vertical plane lying on the axis of the warped borehole. The borehole curves in one plane at constant azimuth, whereas at variable azimuth the borehole curves in space. Investigation of well warp patterns during drilling in the Gogerendag field is the focus of the research study. The focus of the study is to assess the quality of well construction and wellbore verticality assurance. Based on the study, the author offers recommendations and results to prevent wellbore distortion. Keywords: curvature; wellbore; drilling tool; layout; pendulum; zenith angle; conductor.