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Most of the Egypt's Western Desert plays are characterized as tight reservoirs. In early development stages, only the high permeability layers called “conventional reservoirs” were produced. The unconventional, challenging layers were not considered economical because of the high stimulation costs. As the high-permeability layers became more mature and showed a sharp decline in production, the tight layers/zones were targeted by operators to unlock the enormous amount of hydrocarbons and to achieve the economical production targets from these marginal fields. The government has launched a number of studies to evaluate, explore, and appraise several prospects of unconventional reservoirs. Gas shales were characterized within the Khatatba source rock in the Shoushan basin and a tight carbonate reservoir was observed in the Abu Gharadig basin. A total of six vertical and two horizontal exploratory wells were drilled and completed via multistage hydraulic fracturing in the appraisal stage of the program for collecting the required data. The pilot data were used to evaluate the reservoir quality, to demonstrate the availability of reserves, to identify the optimal technology for maximizing productivity, and to set foundations for the future development of these plays.
This paper presents the previous results of field trials and shares some lessons related to the recent appraising and development activities of unconventional plays in Egypt. The properties of these unconventional resources have been reviewed to unlock their potential. In addition, the best strategies of field development were highlighted to capitalize the promising potential from these reservoirs through an advanced workflow. This study sheds light on the recent unconventional gas appraisal and development activities. The results indicate that Egypt holds substantial resources of unconventional gas that can play a key role in positively changing the country's production.
Developing unconventional resources and unlocking the enormous amounts of hydrocarbons are gaining more interest. Achieving economical production targets is of key importance, particularly because of the increase in Egypt's domestic demand for energy and production's annual decline from the more mature, high permeability layers. Also, the enormous success in North America's production brought unconventional resources to the forefront of discussion on the future of energy. Five vertical and two horizontal exploratory wells have been drilled and completed via multistage hydraulic fracturing in the Apollonia tight carbonate. Another vertical exploratory well has been drilled and completed in the Middle Jurassic Khatatba source rock with one-stage hydraulic fracturing. Then the well has been flowed back. The goal of this appraisal program was to collect the required data and to set the foundation for the future development of these plays. Laboratory core testing was conducted to understand the complex mineralogy, reservoir characterization, and variable rock fabric. Geological and geochemical studies were conducted to identify the lithostratigraphic section of the Khatatba source rock and to measure the total organic content (TOC), the Rock Eval pyrolosis, and the thermal maturity of hydrocarbon and gas content. Geomechanical rock properties, derived from the advanced petrophysical analysis of newly acquired high-definition triple combo, full-wave sonic logs and core samples testing, were used to determine the rock elastic properties (the Young's modulus and the Poisson's ratio), brittleness and fracturability, and the natural fractures existence (Salah et al., 2016a). Understanding of all of these characteristics helped in reducing uncertainty during hydraulic fracturing operations. Moreover, a stimulation model, which integrated petrophysical and geomechanical data, was built. This paper reviews the findings of the recent activities within unconventional plays in Egypt and summarizes the formation properties, reservoir characteristics, and the flow back analysis of these wells. The lessons learned can form a basis for the subsequent development of various unconventional plays in Egypt.
Conventional oil and gas discoveries are becoming rarer, and increasing the need to develop unconventional tight resources. Understanding the complex mineralogy, variable rock fabric, and mechanical properties poses the greatest challenge in finding and producing these resources. Once the reservoir is properly understood, appropriate drilling, completion, and production strategies can be applied to successfully convert it into economic reserves. The key challenges in unconventional and tight gas plays are the understanding where, over vast geographical areas the regions of the reservoir with the highest combination of Reservoir Quality- RQ and Completions Quality- CQ are located. In many North American plays, the sweet spots were found only through extensive drilling of hundreds-and even thousands-of wells. In Egypt, operators need to find the sweet spots much faster than a trial-and-error approach. To do that, understanding reservoir heterogeneity is paramount.
Two vertical wells were drilled in Western Desert of Egypt in appraisal program for collecting the required data to explore one of the unconventional reservoirs discovered recently. Reservoir is planned to be appraised and developed with the help of multi-stage horizontal wells. Laboratory testing, which included scanning electron microscopy and X-ray diffraction were conducted to determine mineralogy and potential damage mechanisms. Fracturing fluid chemistry was tested and optimized using core plugs. Geomechanical rock properties derived from advanced petrophysical analysis of newly acquired high-definition triple-combo full-wave sonic logs and core samples were combined with geological parameters and potential treating schedules to develop sophisticated fracture simulation models. These models were then refined with in-situ reservoir data obtained from Mini Fall-Off (MFO) analyses to derive the final fracturing treatment design. The stimulation model was built using a three-dimensional (3D) geological model with multidisciplinary inputs, including formation properties, in-situ stresses, and completion parameters.
This paper describes the workflows followed with the heterogeneity analysis to study the data collected from these two vertical wells. Petrophysical and mechanical properties were used to describe RQ and CQ vertically across the reservoir to select the target layers. The main objective of the study is to plan approaching horizontal wells’ lateral placement for the best performing fracturing completions across these target layers identified with the help of integrated advanced workflows.
Van Steene, Marie (Schlumberger) | Povstyanova, Magdalena (Schlumberger) | Semary, Mahmoud Gamal (Schlumberger) | Mathur, Anil Kumar (Schlumberger) | Ali, Aziza (Schlumberger) | Edelman, Jeffery Mark (TransGlobe Energy Corp) | Maghrabia, Karim Mohamed (PetroDara)
Copyright 2013, Society of Petroleum Engineers This paper was prepared for presentation at the SPE Offshore Europe Oil and Gas Conference and Exhibition held in Aberdeen, UK, 3-6 September 2013. This paper was selected for presentation by an SPE program committee following review of information contained in an abstract submitted by the author(s). Contents of the paper have not been reviewed by the Society of Petroleum Engineers and are subject to correction by the author(s). The material does not necessarily reflect any position of the Society of Petroleum Engineers, its officers, or members. Electronic reproduction, distribution, or storage of any part of this paper without the written consent of the Society of Petroleum Engineers is prohibited. Permission to reproduce in print is restricted to an abstract of not more than 300 words; illustrations may not be copied. The abstract must contain conspicuous acknowledgment of SPE copyright. Abstract The Nukhul reservoirs of Egypt's Eastern Desert typically have low porosity, low permeability, and relatively heavy oil.