SPE Drilling & Completion
Volume 24, Number 3, September 2009, pp. 398-403

Summary

Conditions leading to the plugging of perforations in wells and pore throats in porous formations are investigated experimentally. Accurate correlations are developed for the effect of pore throat to particle size ratio on flowing fluid conditions and plugging time leading to particle bridging. It is demonstrated that the critical pore throat to particle size ratio vs. particle-volume fraction Reynold's number can be correlated satisfactorily using an exponential function, and the dimensionless plugging time vs. reciprocal particle-volume fraction yields an exponential-type correlation. Such empirical correlations can be used to determine and alleviate the conditions that induce perforation and pore plugging by migrating particles in petroleum reservoirs. These correlations reveal that the critical pore-to-particle diameter ratio below which plugging occurs may be greater than the unit physical limit.

Introduction

Plugging of perforations in wells and pores of porous formations occur frequently during various operations of oil and gas industry, including water flooding, drilling, perforation, and workover. Particles migrating at sufficiently high concentrations with a particle to hole size ratio may form bridges across and narrow down the perforations and pore throats, reducing the flow rate through reservoirs. This may cause severe damage to the productivity of the oil and gas wells. Hence, the operational conditions need to be adjusted to avoid the plugging of pores and perforations by suspended particles.

The mechanism of pore-throat plugging in porous formations is of interest in geotechnical engineering and the petroleum industry. Pore-throat plugging can occur by size exclusion or by the jamming of fine particles during fluid flow. Migration and entrapment of fine particles during flow in petroleum reservoirs can lead to clogging and decreased oil productivity. The pore throats control the rate of flow through the interconnected pore space inducing a gate or valve effect (Chang and Civan 1991).

© 2009. Society of Petroleum Engineers

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History

• Original manuscript received: 27 August 2008
• Revised manuscript received: 16 November 2008
• Manuscript approved: 8 December 2008
• Published online: 6 August 2009
• Version of record: 28 September 2009