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Journal of King Saud University – Engineering Sciences (2011) 23, 49–66

King Saud University

Journal of King Saud University – Engineering Sciences
www.ksu.edu.sa www.sciencedirect.com

REVIEW

Potential implementation of underbalanced drilling technique in Egyptian oil fields
K.A. Fattah
a

a,*

, S.M. El-Katatney b, A.A. Dahab

b

Petroleum and Natural Gas EngineeringDepartment, College of Engineering, King Saud University, P.O. Box 800, Riyadh 11421, Saudi Arabia b Petroleum Engineering Department, Faculty of Engineering, Cairo University, Egypt Received 20 October 2009; accepted 10 February 2010 Available online 7 December 2010

KEYWORDS Underbalance drilling; Drilling fluids; Drilling cost; Hole problem

Abstract The need to increase productivity and to reducedrilling damage favors the use of underbalanced drilling (UBD) technology. In highly depleted reservoirs, extremely low-density fluids, such as foams or aerated mud, are used to achieve circulating densities lower than the pore pressure. In such cases, the induced modification of the in situ stresses has to be supported mainly by the rock, with little contribution from the drilling fluid pressure.The application of underbalanced drilling depends on the mechanical stability of the drilled formation, among other factors. In general, poorly consolidated, depleted formations are not suited for that technology. In this paper, 23 UBD worldwide cases have been analyzed; two of which are from Egyptian fields and the others are from Iran, Algeria, Kuwait, Oman, Texas, Mexico, Indonesia, Canada,Libya, Middle East, Qatar, Saudi Arabia and Lithuania. From these analyses, the reasons of failure or success have been stated. The reasons of success included depleted reservoirs and highly fractured carbonates formation while, the reasons of failure include over pressurized shale, highly tectonic stress areas, and downhole failures. The main attractive application of this technology was proposed tobe only in the reservoir section, and the target was to prevent the reservoir damage and hence increase the productivity and recovery factor.

* Corresponding author. E-mail address: kelshreef@ksu.edu.sa (K.A. Fattah). 1018-3639 ª 2010 King Saud University. Production and hosting by Elsevier B.V. All rights reserved. Peer review under responsibility of King Saud University.doi:10.1016/j.jksues.2010.02.001

Production and hosting by Elsevier

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K.A. Fattah et al.
A proposed underbalanced drilling program is developed based on these analyses to be used in the three main regions in oil and gas producing Egyptian fields. The aerated mud was selected as a drilling fluid to drill the reservoir section in Western Desert and Gulf of Suez region whereas the single phase fluid was selectedas a drilling fluid in the Nile Delta region.
ª 2010 King Saud University. Production and hosting by Elsevier B.V. All rights reserved.

Contents 1. 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Studied cases. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1. Case 1: gulf of Suez area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2. Case 2: western desert gas field area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3.Case 3: Iranian oil field . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4. Data analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Proposed UBD program to be implemented in Egyptian fields . . . . . . . . . . . . . . ....