Study on the Lost Circulation Mechanism of Polymer-Based Drilling Fluid Systems in Deep Fractured Shale

Zang, Yanbin; Chen, Zengwei; Wang, Yi; Zhang, Yan; Xu, Shengchi; Xie, Junyu; Chen, Wei

doi:10.3390/polym17212929

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Study on the Lost Circulation Mechanism of Polymer-Based Drilling Fluid Systems in Deep Fractured Shale

by

Yanbin Zang

¹,

Zengwei Chen

¹,

Yi Wang

¹,

Yan Zhang

^1,2,*

,

Shengchi Xu

³,

Junyu Xie

³ and

Wei Chen

³

¹

State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development, Beijing 100083, China

²

School of Petroleum Engineering, Yangtze University, Wuhan 430113, China

³

Research Institute of Geology, CNPC Xibu Drilling Engineering Company Ltd., Karamay 834000, China

^*

Author to whom correspondence should be addressed.

Polymers 2025, 17(21), 2929; https://doi.org/10.3390/polym17212929 (registering DOI)

Submission received: 26 September 2025 / Revised: 28 October 2025 / Accepted: 30 October 2025 / Published: 31 October 2025

(This article belongs to the Section Polymer Applications)

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Abstract

To elucidate the lost circulation mechanism in naturally fractured shale, this study employs fluid seepage theory and fracture deformation theory, assumes the polymer-based drilling fluid system behaves as a Herschel–Bulkley (H–B) fluid, and develops a calculation model for lost circulation pressure that comprehensively incorporates fracture geometry, fracture stress state, drilling fluid properties, and the pressure differential between the wellbore and the formation. Research shows that the lost circulation rate of drilling fluid increases with greater initial fracture width, fracture deformation index, fluid consistency coefficient, yield stress, and pressure differential between the wellbore and the formation, while it decreases with increasing fracture radial extension length, fracture roughness, drilling fluid density, and normal stress on the fracture surface. The initial fracture width, fracture radial extension length, and fluid consistency coefficient have a significant influence on the lost circulation rate of drilling fluid. In contrast, the effects of the fracture deformation index and dynamic yield stress are relatively minor, indicating that they are not the primary controlling factors of fracture-induced lost circulation.

Keywords: shale; drilling fluid loss; fracture-induced lost circulation; loss rate; polymer-based drilling fluid

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MDPI and ACS Style

Zang, Y.; Chen, Z.; Wang, Y.; Zhang, Y.; Xu, S.; Xie, J.; Chen, W. Study on the Lost Circulation Mechanism of Polymer-Based Drilling Fluid Systems in Deep Fractured Shale. Polymers 2025, 17, 2929. https://doi.org/10.3390/polym17212929

AMA Style

Zang Y, Chen Z, Wang Y, Zhang Y, Xu S, Xie J, Chen W. Study on the Lost Circulation Mechanism of Polymer-Based Drilling Fluid Systems in Deep Fractured Shale. Polymers. 2025; 17(21):2929. https://doi.org/10.3390/polym17212929

Chicago/Turabian Style

Zang, Yanbin, Zengwei Chen, Yi Wang, Yan Zhang, Shengchi Xu, Junyu Xie, and Wei Chen. 2025. "Study on the Lost Circulation Mechanism of Polymer-Based Drilling Fluid Systems in Deep Fractured Shale" Polymers 17, no. 21: 2929. https://doi.org/10.3390/polym17212929

APA Style

Zang, Y., Chen, Z., Wang, Y., Zhang, Y., Xu, S., Xie, J., & Chen, W. (2025). Study on the Lost Circulation Mechanism of Polymer-Based Drilling Fluid Systems in Deep Fractured Shale. Polymers, 17(21), 2929. https://doi.org/10.3390/polym17212929

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Study on the Lost Circulation Mechanism of Polymer-Based Drilling Fluid Systems in Deep Fractured Shale

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