Method for determining medium-and-large-radius track of two-dimensional small-pre-target-displacement horizontal well

Abstract

The invention relates to a method for determining a medium-and-large-radius track of a two-dimensional small-pre-target-displacement horizontal well. The method sequentially comprises the following steps that the position of a first target spot, the position of a second target spot and the position of a wellhead are determined, the displacement and the true vertical depth of the first target spot and the displacement and the true vertical depth of the second target spot are obtained, a third-part horizontal segment rail is determined, and the third horizontal segment track extends along a connecting line between the first target spot and the second target spot; a second-part angle-gain landing track is determined upwards with the first target spot as a terminal point, and the second-part angle-gain landing track comprises a first angle-gain circular-arc segment, an angle-holding linear segment and a second angle-gain circular-arc segment; a reverse angle-building track is determined with the wellhead as a starting point and the track midpoint as a terminal point, the reverse angle-building track comprises a plumb shaft segment, a reverse angle-building circular-arc segment, an angle-holding linear segment and an angle-dropping circular-arc segment, and the radius values of all the circular-arc segments range from 191 m to 286.5 m. According to the method for determining the medium-and-large-radius track of the two-dimensional small-pre-target-displacement horizontal well, the pre-target displacement is increased through reverse angle building, and the contradiction between the complex ground conditions and well location optimization of the horizontal well with the medium-and-large-radius track can be solved.

Description

technical field [0001] The invention relates to a medium-to-long radius trajectory of a horizontal well, in particular to a method for determining the medium-to-long radius trajectory of a two-dimensional small target distance horizontal well, and belongs to the technical field of petroleum drilling. Background technique [0002] In the field of oil drilling, horizontal wells are the fastest-growing and most widely used drilling technology in recent years. They have technical advantages such as greatly improving oil and gas recovery, accelerating capital recovery, and reducing costs. Horizontal wells are divided into five types according to the radius of curvature of the wellbore trajectory. ①Long-radius horizontal well, curvature radius R>286.5m, build-up rate K<20° / 100m; ②medium-long radius horizontal well, curvature radius R=286.5m-86m, build-up rate K=(20°-67°) / 100m; ③Medium and short-radius horizontal wells, curvature radius R=86m-28.65m, K=(67°-200°) / 100m; ④sho...

AI Technical Summary

Problems solved by technology

[0008] Compared with the prior art, the present invention has achieved the following beneficial effects: (1) The orbit of the present invention is determined by combining the forward direction and the reverse direction. Part of the reverse ramping track, that is, firstly find the midpoint of the track from the bottom up from the first target point, then determine the track to the midpoint of the track from the top down from the wellhead, and finally determine all the parameters of each section to make each section smooth connection; (2) By adding successively tangent reverse-increasing circular arc sections, reverse-inclining track-stabilizing straight-line sections, and declination-inclining circular arc sections to reach the midpoint of the track, the inclination angle is zero degrees, increasing the reverse displacement, making The displacement in front of the target reaches the appropriate displacement suitable for the medium-long radius orbit, and then connects with the horizontal track through the first inclination arc section, the inclination landing track stabilizing straight line section and the second inclination arc section that are tangent in sequence; (3) The borehole trajectory of the horizontal well with a small target front distance that could not be designed as a medium and long radius orbit is determined as a medium and long radius orbit, which overcomes the problem that the conventional Φ216 wellbore with a small target distance can not be applied to the medium and short radius drilling technology. (4) It avoids the need to move the wellhead position due to the small target front distance to become a long target front displacement horizontal well. Compared with the conventional target front displacement horizontal well, it increases the drilling footage, increases the construction difficulty and drilling cost; (5) avoids It was found that some wells gave up construction because the position of the mobile wellhead was too large due to site conditions, effectively solved the problem of determining the wellhead position of horizontal wells under complex ground conditions, and provided a new means for the development of complex small fault block oilfield reservoirs; ⑹The arc section The radius is between 191m and 286.5m. For the Φ216 wellbore, the build-up rate is low and the curvature is flat, which is conducive to the smooth running of the drilling tool and the drill string has a long life; (7) The bending stress and radial deformation of the casing string in the curved well section with medium and long radii Small, conventional casing completion methods can be used; (8) Compared with medium and short-radius horizontal wells, continuous deflection is not required, there is a straight line section for stabilizing the deflection, and the difficulty and risk of landing are small, the difficulty of trajectory control is small, and the risk of pipe sticking is small

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