Experimental Study on the Effect of Drilling Fluid with Different Mix Designs for Bore Hole Collapse Prevention

Chung-Sik Yoo; Jung-Hyuk Choi; Yun-Su Han

doi:10.7843/kgs.2014.31.1.15

All Issue

2015 Vol.31, Issue 1 Preview Page Next Page

Experimental Study on the Effect of Drilling Fluid with Different Mix Designs for Bore Hole Collapse Prevention 시추 안정액 배합설계에 따른 공벽 붕괴방지 효과에 관한 실험적 연구

31 January 2015. pp. 15-24

PDF XML

Abstract

This paper presents the results of a reduced-scale physical model investigation into the effect of drilling fluid with different mix designs for bore hole collapse prevention. The bore hole collapse prevention mechanism for the bentonite based drilling fluid was first discussed together with the effect of conditioning with different additives on engineering characteristics of bentonite based drilling fluid. Reduced-scale model tests were then carried out considering field procedures for cases with a decomposed granitic soil with 20% fines and a sand with various drilling fluids with different mix designs. The results indicated that the addition of polymer to the bentonite based drilling fluid decreases the amount of drilling fluid injected, the drilling fluid infiltration thickness and increases the final depth of excavation. Also revealed is that the effect of polymer on the performance of drilling fluid is more pronounced in the decomposed granite soil with 20% fines than the sand. Practical implications of the findings from this study are discussed in great detail.

Keywords

Drilling fluid

Reduced scale model test

Bentonite

RCD pile

Slurry wall

본 논문에서는 지반 시추시 공벽붕괴 방지를 위해 적용되는 시추 안정액(drilling fluid)의 다양한 배합설계에 따른 공벽붕괴 방지 효과에 대한 실험적 연구 결과를 다루었다. 이를 위해 먼저 벤토나이트 계열 안정액의 공벽 붕괴 방지 메카니즘을 검토하였으며 아울러 벤토나이트계 안정액의 배합(conditioning)에 따른 안정액의 성능지표 변화에 대한 실험결과를 간략히 기술하였다. 또한 지반시추(굴착) 및 안정액 투입을 간략히 모사하는 토조 장치를 구축하여 세립분이 20% 포함된 화강풍화토 및 모래지반을 대상으로 다양한 배합으로 조성된 벤토나이트계 안정액에 대한 실험을 수행하고 안정액 투입량, 수평 침투범위, 굴착가능 깊이 등을 측정하여 공벽붕괴 방지 효과를 고찰하였다. 그 결과 벤토나이트에 폴리머를 추가할 경우 안정액 투입량 및 수평 침투범위가 굴착가능 깊이가 증가하는 것으로 나타났으며 폴리머의 공벽유지 기능 향상 정도는 모래층보다 화강풍화토 지반에서 보다 뚜렷하게 발휘되는 것으로 검토되었다. 본 논문에서는 도출된 연구결과가 실무적 차원에서 지니는 의미에 대한 내용을 기술하였다.

References

1.Kwon, Y. H., Jun, S. K., Baek, S. J., and Ariyama, M. (1999), “A Study on the Mix Design for Stabilizing Liquid of Slurry Wall”, Korean Concrete Institute Spring Conference, pp.457-462.

2.Nguyen, T. B., Park, M., Lim, J., Choi, H., and Han, S.I. (2011), “Characteristic of Bentonite Filter Cake Vertical Cutoff Walls Evaluated by Modified Fluid Loss Test”, Journal of KGS, Korean Geotechnical Society, February, 2011, Volume 27, No.2, pp.53-62.

3.Hong, W. P., Lee, M. K., and Lee, J. H. (2006), “Model Tests on Ground Deformation during Trench Excavation for Diaphram Walls”, Journal of KGS, Korean Geotechnical Society, December, 2006, Volume 22, No.12, pp.77-88.

4.American Petroleum institute RP 13B-1 (1990), “Recommended Practice Standard Procedure for Field Testing Water - based Dilling Fluids”.

5.American Petroleum Institute 13A (2010), “Specification for Drilling Fluids Materials”.

6.Fritz, P., Hermanns, S., and Heinz, R. (2002), “Modified Bentonite Slurries for slurry Shields in High Permeable Soils”, 4^th International Symposium on Geotechnical Aspects of Underground Construction in Soft Ground, pp.33-39.

7.JBAS (1977), “Japan Bentonite Manufacturers Association Standard”.

8.Lal, M. (1999), “Shale Stability: Drilling Fluid Interaction and Shale Strength”, Proceedings of SPE Asia Pacific Oil and Gas Conference, Society of Petroleum Engineers, pp.1-10.

9.Maidl, B., Herrenknecht, M., Maidl, U., and Wehrmeyer, G. (2012), Mechanized Shield Tunnelling 2^nd Edition, Wiley-Blackwell.

10.Wang, X. and Sterling, R. L. (2007), “Stability Analysis of a Borehole Wall during Horizontal Dirctional Drilling”, Tunnelling and Underground Space Technology, Vol.22, pp.620-632.

11.Yoo, C. and Choi, J. H. (2014), “Development of Bore Hole Collapse Prevention Methodology using Drilling Fluild”, Report to Hyundai Heavy Industries.

Information

Publisher :The Korean Geotechnical Society
Publisher(Ko) :한국지반공학회
Journal Title :Journal of the Korean Geotechnical Society
Journal Title(Ko) :한국지반공학회 논문집
Volume : 31
No :1
Pages :15-24
Received Date : 2014-10-14
Revised Date : 2014-12-02
Accepted Date : 2015-01-08
DOI :https://doi.org/10.7843/kgs.2014.31.1.15

Journal of the Korean Geotechnical Society ISSN:1229-2427(Print) 2288-646X(Online) 한국지반공학회 논문집

All Issue