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ORIGINAL RESEARCH article

Front. Earth Sci.

Sec. Solid Earth Geophysics

Volume 13 - 2025 | doi: 10.3389/feart.2025.1533309

This article is part of the Research Topic Advances in Petrophysics of Unconventional Oil and Gas View all 9 articles

Trajectory optimization of ultra-short sidetrack horizontal wells in marginal reservoirs

Provisionally accepted
Yanjiao Jiang Yanjiao Jiang 1*Jian Zhou Jian Zhou 1Jiaqi Zhang Jiaqi Zhang 1Zhihua Guo Zhihua Guo 1Dan Liu Dan Liu 2Xueying Li Xueying Li 1Jinbiao Gao Jinbiao Gao 1
  • 1 Northeast Petroleum University, Daqing, China
  • 2 Daqing Oilfield Co., Ltd., Daqing, China

The final, formatted version of the article will be published soon.

    The thin thickness of the sand body and the low oil recovery in the marginal reservoirs of the X area in D oilfield pose significant challenges. Using ultra-short radius horizontal wells is effective for substantially increasing production and designing reasonable well trajectory parameters is crucial for realizing the potential of oil reservoirs. Based on the actual geological system and the rock physical characteristics of the reservoir, and using the theory of oil-water two-phase seepage, a three-dimensional numerical simulation model is established for ultra-short horizontal wells in edge reservoirs to analyze the impact of horizontal well parameters on production. The simulation results show that the production increases with a longer horizontal section length, a greater entry distance, and larger angles between the well and mainstream flow line. The numerical results reveal that the optimal horizontal well length is 200 m, the optimal well orientation is 120°-150° to the main flow line, and the preferred range of entry distance is 50-70 m. For thin layers, horizontal wells located in the middle of the layer are optimal. Based on a coupled analysis of fluid flow in the horizontal wellbore and fluid seepage in the reservoir, a reasonable theoretical length of the horizontal well section is determined, and its reliability is verified with examples. The theoretical analysis is consistent with the simulation results. This study elucidates the influence of drilling trajectory parameters on thin-layer oil marginal reservoirs, and the determination of optimal parameters improves the scientific basis of trajectory design. These findings provide an important reference for residual oil dredging strategies.

    Keywords: marginal reservoir, Ultra-short sidetrack horizontal well, numerical simulation, Well location optimization, Productivity evaluation

    Received: 23 Nov 2024; Accepted: 25 Mar 2025.

    Copyright: © 2025 Jiang, Zhou, Zhang, Guo, Liu, Li and Gao. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Yanjiao Jiang, Northeast Petroleum University, Daqing, China

    Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.

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