Sains Malaysiana 43(5)(2014): 807–812

A Numerical Study on Fracture-Plugging Behaviour of Granular Lost Circulation Materials

(Kajian Berangka Tingkah Laku Tampalan Retak Bahan Tak Teratur Bergranul)

GUI WANG* & XIAOLIN PU

State Key Laboratory of Oil & Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Xindu, Chendu, Sichuan, P. R. China

Diserahkan: 4 April 2013/Diterima: 3 September 2013

ABSTRACT

A distinct element approach has been introduced for simulating the plugging performance of granular lost circulation materials (LCM) in a fracture. This approach solves the fully coupled fracture walls, fluid and particles system in an interactive environment. The effects of the particle shape, size distribution and concentration on the fracture-plugging performance of the granular LCM have been investigated using the three-dimensional particle flow code (PFC3D). The simulated results showed that the irregular granular LCM could plug a fracture width larger than the sieving granulation by single-particle bridging type. The particle size distribution (PSD) of LCM dominates the plugging depth and efficiency in a fracture and there exists an optimum concentration for maximum effect of LCM additives.

Keywords: Fracture; lost circulation material; numerical simulation; plugging

ABSTRAK

Pendekatan elemen berbeza telah diperkenalkan bagi mensimulasi prestasi tampalan bahan tak teratur (LCM) bergranul dalam retakan. Pendekatan ini menyelesaikan masalah dinding retak berganding penuh, bendalir serta sistem zarah dalam persekitaran interaktif. Kesan bentuk zarah, pengagihan saiz dan kepekatan terhadap prestasi tampalan retak LCM bergranul telah dikaji menggunakan kod aliran zarah tiga dimensi (PFC3D). Keputusan simulasi menunjukkan bahawa LCM bergranul yang tidak sekata boleh menampal retak yang lebih besar daripada penyaringan penggranulan mengikut jenis penyambung satu zarah. Taburan saiz zarah (PSD) daripada LCM menguasai kedalaman tampalan serta kecekapan dalam retak dan wujud kepekatan optimum untuk kesan maksimum aditif LCM.

Kata kunci: Bahan tak teratur; retak; simulasi berangka; tampalan

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*Pengarang untuk surat-menyurat; email: wanggui@126.com