Horizontal well landing evaluation method based on shaft position uncertainty

Abstract

The invention discloses a horizontal well landing evaluation method based on shaft position uncertainty, which comprises the following steps of: S1, simplifying an error source of a shaft position uncertainty error model, selecting an error source related to an error ellipsoid high side radius, and calculating and designing a well track error ellipsoid high side radius; s2, calculating the target hitting probability based on shaft position uncertainty according to the high side radius of the error ellipsoid; s3, taking the critical point with the target hitting probability of 100% to calculate the critical marker bed depth, where the marker bed selection range is between the calculated critical marker bed depth and 100 m away from the landing point. According to the horizontal well landing evaluation method, the defects in the field of shaft position uncertainty measurement in the prior art are overcome, the shaft position uncertainty existing in the well drilling process is calculated, and the horizontal well landing precision is improved.

Description

technical field [0001] The invention relates to the technical field of drilling, in particular to a horizontal well landing evaluation method based on the uncertainty of the wellbore position. Background technique [0002] There are two key stages in the geosteering process of horizontal wells, namely the build-up section and the horizontal section. Among them, the safe and accurate landing in the build-up section is related to whether the horizontal section can be drilled smoothly in the reservoir, and determines the level of drilling encounter rate in the reservoir, which is a key step for the success of horizontal well drilling. If the landing is deviated, the reservoir will not be drilled, the construction period will be prolonged, and the investment cost will increase. Therefore, making the well trajectory safe to land is the main task and goal of the build-up section. However, there is always an error in the well trajectory of the horizontal well. Therefore, determini...

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Problems solved by technology

[0004] The purpose of the present invention is to provide a horizontal well landing evaluation based on the uncertainty of the wellbore position in view of the problem that the existing landing method does not consider the uncertainty of the wellbore position caused by the measurement error, resulting in low precision of the wellbore trajectory landing method, used to improve the accuracy of the horizontal well into the target

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