Well Trajectory Modelling Considering Torque and Drag

Jihoon Kim; Junhyung Choi; Doyoung Kim; Taeil Park; Daesung Lee

doi:10.14481/jkges.2023.24.1.51

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2023 Vol.24, Issue 1 Preview Page

Well Trajectory Modelling Considering Torque and Drag 토크와 드래그를 고려한 시추궤도 모델링 연구

1 January 2023. pp. 51-60

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Abstract

Unlike the vertical drilling in the directional drilling should be minimized torque and drag in the well trajectory that avoided problems such as drillstring transformation, casing wear and key-seating. These torque and drag magnitude is determined by variations such as the well trajectory geometry, drilling mud, drillstring type and kick-off point. Therefore, it is essential to consider these variations for designing directional well trajectory. In this study, it was selected well trajectory by the most common build-hold type well and calculated torque and drag on each section by Analytical friction model. Analysis indicates that torque and drag could be minimized by using high lubricity drilling mud, kick-off point appropriate according to the well geometry and possible minimize dogleg severity. The results of this study is useful to minimize torque and drag from directional well trajectory design.

Keywords

Torque and drag

Analytical friction model

KOP

Friction factor

Well trajectory optimization

수직 시추와 다르게 방향성 시추작업에서 발생하는 드릴스트링(drill string) 변형, 케이싱(casing) 마모, 키 씨팅(key seating) 등의 문제를 방지하기 위해서는 시추 궤도 내에서 발생하는 토크(torque)와 드래그(drag)가 최소화되어야 한다. 토크와 드래그의 크기는 시추 궤도 형태, 이수(mud), 드릴스트링의 종류 그리고 킥오프 지점(KOP, kick-off point)과 같은 매개변수들에 의해 결정되기 때문에 시추 궤도 설계 과정에서 고려하여 설계하여야 한다. 본 연구에서는 가장 일반적인 방향성 시추 궤도인 빌드-홀드(Build-hold) 형태의 시추 궤도에 킥오프 지점이 각기 다른 시추 궤도를 선정하였고, 분포하중 모델(analytical friction model)을 이용하여 각 구간 내에서의 분포하중을 계산하여 궤도 전체에 대한 토크와 드래그를 계산하였다. 또한 매개변수에 따른 분석 값을 비교하여 분포하중이 최소로 발생하는 최적의 시추 궤도를 선정하였다. 분석결과 분포 하중을 최소화하기 위해서는 윤활성이 높은 이수를 사용, 궤도 형태에 따른 알맞은 킥오프 지점과 가능한 최소의 도그-래그를 지정하여 설계하는 것이 효과적임을 알 수 있었다. 이러한 결과는 분포하중을 최소화하기 위한 모든 방향성 시추 궤도 설계에 사용된다.

키워드

토크와 드래그

방향성 시추

시추궤도

킥오프 지점

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Information

Publisher :Korean Geo-Environmental Society
Publisher(Ko) :한국지반환경공학회
Journal Title :Journal of the Korean Geo-Environmental Society
Journal Title(Ko) :한국지반환경공학회 논문집
Volume : 24
No :1
Pages :51-60
Received Date : 2022-12-13
Revised Date : 2022-12-15
Accepted Date : 2022-12-26
DOI :https://doi.org/10.14481/jkges.2023.24.1.51

Journal of the Korean Geo-Environmental Society ISSN:1598-0820(Print) 2714-1233(Online) 한국지반환경공학회 논문집

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