Africa (Sub-Sahara) Sonangol's deepwater Orca-1 well encountered oil in the presalt layer of Block 20/11 in the Cuanza basin offshore Angola. The well reached a measured depth of 12,703 ft. Initial well tests saw flow rates of 16.3 MMcm/D of gas and 3,700 BOPD. Cobalt International Energy (40%) is the operator, with partners Sonangol Research and Production (30%) and BP Exploration Angola (30%). Asia Pacific Premier Oil's Kuda Laut-1 well in Indonesia's Tuna production sharing contract has encountered 183 net ft of oil-bearing reservoir and 327 net ft of gas-bearing reservoir. Following evaluation operations, the well will be sidetracked to drill the Singa Laut prospect in an adjacent fault block. Premier is the operator (65%), with partner Mitsui Oil Exploration Company (35%).
Ibrahim Mohamed, Mohamed (Colorado School of Mines) | Salah, Mohamed (Khalda Petroleum) | Coskuner, Yakup (Colorado School of Mines) | Ibrahim, Mazher (Apache Corp.) | Pieprzica, Chester (Apache Corp.) | Ozkan, Erdal (Colorado School of Mines)
A fracability model integrating the rock elastic properties, fracture toughness and confining pressure is presented in this paper. Tensile and compressive strength tests are conducted to define the rock-strength. Geomechanical rock properties derived from analysis of full-wave sonic logs and core samples are combined to develop models to verify the brittleness and fracability indices. An improved understanding of the brittleness and fracability indices and reservoir mechanical properties is offered and valuable insight into the optimization of completion and hydraulic fracturing design is provided. The process of screening hydraulic fracturing candidates, selecting desirable hydraulic fracturing intervals, and identifying sweet spots within each prospect reservoir are demonstrated.
This paper was prepared for presentation at the Unconventional Resources Technology Conference held in Houston, Texas, USA, 23-25 July 2018. The URTeC Technical Program Committee accepted this presentation on the basis of information contained in an abstract submitted by the author(s). The contents of this paper have not been reviewed by URTeC and URTeC does not warrant the accuracy, reliability, or timeliness of any information herein. All information is the responsibility of, and, is subject to corrections by the author(s). Any person or entity that relies on any information obtained from this paper does so at their own risk. The information herein does not necessarily reflect any position of URTeC. Any reproduction, distribution, or storage of any part of this paper by anyone other than the author without the written consent of URTeC is prohibited. Abstract 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.
With the increase of Egypt's domestic demand for energy, economical production from unconventional reservoirs is a great challenge to maintain production's annual decline. This has spurred interest in the development of unconventional resources, such as tight reservoirs and shale gas, particularly because of the enormous success in North America that brought unconventional resources to the forefront of the discussion on the future of energy. The country has launched studies to evaluate, explore and appraise several prospects for unconventional gas in Shoushan-Matrouh and Abu Gharadig basins. Exploratory pilot data wells were drilled and completed in the appraisal program for collecting the required data to evaluate the reservoirs qualities, demonstrate the availability of reserves, and identify optimal technology to maximize productivity and set the foundation for future development of these unconventional plays. Logs, core testing, and analysis service data were performed on or collected from these wells. Laboratory testing was conducted to understand the complex mineralogy and variable rock fabric. Geomechanical rock properties derived from advanced petrophysical analysis of newly acquired high-definition triple-combo full-wave sonic logs and core samples were combined to develop sophisticated models. These understandings helped reduce uncertainty and the lessons learned from this work and presented in this paper helped define completion and stimulation technologies for horizontal wells.
This objective of this paper is to review of the results and share lessons learned related to the recent appraising activities of unconventional plays in Egypt's western desert, evaluate these unconventional resources to unlock their potential. In addition, this paper present the challenges of development, highlight the best strategies required for field development to capitalize on the promising potential of these reservoirs through an integrated advanced workflow. The results from this study will shed light on the results of recent unconventional gas exploration and appraisal activities, which indicate that the western desert of Egypt holds substantial resources of unconventional gas. This unconventional gas can help to change the slope of production rates in the country positively and set the foundation for future development of these plays.
Abouzaid, Ahmed (Baker Hughes) | Thern, Holger (Baker Hughes) | Said, Mohamed (Baker Hughes) | ElSaqqa, Mohammad (Khalda Petroleum Company) | Elbastawesy, Mohamed (Khalda Petroleum Company) | Ghozlan, Sherin (Khalda Petroleum Company)
The evaluation of logging data in shaly sand reservoirs can be a challenging task, particularly in the presence of accessory minerals such as glauconite. Accessory minerals affect the measurements of conventional logging tools, thus, introducing large uncertainties for estimated petrophysical properties and reservoir characterization. The application of traditional Gamma Ray and Density-Neutron crossover methods can become unreliable even for the simple objective of differentiating reservoir from non-reservoir zones.
This was the situation for many years in the glauconite-rich Upper Bahariya formation, Western Desert, Egypt. Formation evaluation was challenging and the results often questionable. Adding Nuclear Magnetic Resonance (NMR) Logging While Drilling (LWD) data in three wells changed the situation radically. The NMR data unambiguously indicate pay zones and simplify the interpretation for accurate porosity and fluid saturation dramatically. Key to success is NMR total porosity being unaffected by the presence of accessory minerals. NMR moveable fluid directly points to the pay zones in the reservoir, while clay-bound and capillary-bound water volumes reflect variations in rock quality and lithology.
Although the NMR total porosity is lithology independent, the presence of glauconite affects the NMR T2 distribution by shifting the water T2 response to shorter T2 times. This requires an adjustment of the T2 cutoff position for separating bound water from movable hydrocarbons. A varying T2 cutoff was computed by comparing NMR bound water to resistivity-based water saturation. The calibrated T2 cutoff exhibits an increase with depth indicating a decreasing amount of glauconite with depth throughout the Upper Bahariya formation. Based on these volumetrics, an improved NMR permeability log was calculated, now accurately delineating variations in rock quality throughout the different pay zones. In addition, viscosity was estimated from the oil NMR signal. The estimated values match the expected values very well and illustrate the potential of NMR to indicate viscosity variations.
Many of these results are available today already in real-time by transmitting NMR T2 distributions to surface while drilling. Besides the application for formation evaluation, the data can be used to initiate optimized side-tracking and completion decisions directly after finishing the drilling operations.
Most of Egypt's Western Desert reservoirs are characterized to have low permeability and heterogeneous, poor rock quality. In the early development stages only layers with high permeability were produced, while the low-permeability, low-porosity layers were not considered economic.
As these high-permeability layers became more mature and declined in production, tight layers became the operator's alternative choice to unlock the enormous amounts of hydrocarbons still present in these rocks and achieve economical production targets from these marginal fields. Hydraulic fracturing technology enabled us to unlock the potential of these challenging layers that were previously considered uneconomical.
Hydraulic fracturing is now a common practice, even pushing extremes such as deeper, high-temperature and high-pressure wells in the Western Desert. The incremental production gains from these challenging layers have encouraged operators to invest. Currently, hydraulic fracturing is routinely conducted for all new production and injection wells and is reconsidered for the old wells.
Completion practices, candidate selection criteria, perforation and design strategies, and workflows were revised to address these new challenging conditions and reservoir complexities with hydraulic fracturing technology. For example, vertical completions were replaced by horizontal multistage fracturing completions to increase the reservoir contact. State-of-the-art software was used to simplify decisions on fracture initiation points across heterogeneous reservoirs. Different technologies, alternative to conventional perforating, were introduced to enhance the proppant placement, post-fracturing production, and operational efficiency. This paper provides a review of hydraulic fracturing in Egypt's Western Desert. The hydraulic fracturing technique has been used to develop mature fields and challenging formations of Egypt since the early 1990s. More than 1,000 treatments targeting low- to medium- permeability rocks were pumped in Khalda Ridge. Correlation between mechanical properties, reservoir properties, essential fracturing design, completions, and operational parameters were established over time to help other operators that intend to apply hydraulic fracturing to their assets. Case histories are also provided, demonstrating different fracturing techniques for extreme conditions. In this paper we detail the progress related to completion practices and technologies to revive the mature fields of Egypt.
Egypt's Western Desert contains a series of basins underlain by organic-rich shales that provide the source for conventional hydrocarbon. The primary objectives for exploring the gas-rich shale plays and unconventional reservoirs in the Western Desert were to evaluate the Middle Jurassic Khatatba source rock reservoir qualities, demonstrate the availability of reserves, and identify optimal technology to maximize productivity of unconventional low-permeability reservoirs, stimulation, and testing strategies.
In 2014, a vertical exploratory data well was drilled and completed in the appraisal program before the completion of horizontals in this formation. Logs, core testing, and analysis service data were performed on or collected from this well. A stimulation model was built, which integrated petrophysical and geomechanical data. This model was used to aid the completion and stimulation design, including fracturing fluids and proppant selections. One-stage hydraulic fracturing was implemented, and the well was then flowed back and produced.
The Khatatba Shale was systematically studied in this work. Various methods were used to understand this source rock. A geological study identified the lithostratigraphic section of the Khatatba Shale formations by collecting core samples. Core tests measured total organic carbon (TOC), brittleness, and sensitivity to fluid. These understandings helped reduce uncertainty during hydraulic fracturing operations. A successful hydraulic fracturing treatment was performed for this formation, which showed that low-viscosity fracture fluid can be used as the treatment fluid to carry proppant into the formation. During fracturing, near-wellbore (NWB) multiple fractures can be an issue. From an operational point of view, there might be options better than performing high-rate fracturing treatments. The lessons learned from this work and presented in this paper helped define completion and stimulation technologies for horizontal wells.
This paper presents hydraulic fracturing treatment of the first shale gas well in Egypt for the Khatatba formation. Lessons learned about geochemical, rock mechanical, and petrophysical properties of this shale formation and their effects on hydraulic fracturing and production formed the basis for subsequent development of various shale plays in Egypt and worldwide.
The characterization of geomorphic features such as fault plane geometries and slickensides can reveal intricacies of fault displacement as well as the forces that formed the fault. Fault plane geomorphic features such as grooves, ridges, and steps, which are normally observed in outcrops, are apparently scale independent and can be extracted by detailed fault interpretation on 3D Seismic data. Strain not only affects the fault plane, but also extends into the rock volume (Matonti et al., 2012) and can be inferred in different ways through direct observation of features in the rock (Van der Pluijm and Marchak, 2004). This study proposes that strain can also be inferred by observation of features within the fault plane geomorphology and that given the proper conditions, these geomorphic features can be interpreted within seismic data.
A fault is a fracture on which slip develops primarily by brittle deformation processes. Faults control the distribution of economic resources by controlling the permeability of rocks and sediments, properties which, in turn, control fluid migration (Van der Pluijm and Marshak, 2004). Faults surfaces play important roles in the petroleum system, functioning as hydrocarbon migration pathways or as structural seals (Metwalli and Pigott, 2005). Very few comprehensive structural studies have been conducted utilizing advanced seismic attribute analysis combined with fault plane geomorphology. Of these studies, even less have been made available to the general public. Fault characterization is a crucial issue in reservoir exploitation, because faults can behave either as hydraulic seal or as conduit.
This research is focused on data from a producing Middle Eastern oil field. The Middle East accounts for an estimated 47.9% of the world’s proven oil reserves (BP, 2014). Many of the world’s giant and super-giant fields have been discovered in Middle Eastern countries. There are 47 supergiant fields (proven and probable recoverable reserves > 5,000 MMboe) and 194 giant fields (500-5,000 MMboe proven and probable reserves) that have been discovered within the Middle Eastern counties that line the Eastern Tethyan Margin (Marlow et al., 2014). Due to confidentiality agreements, disclosure of the exact field or location is restricted.
Ghanima, Ahmed (Bapetco) | El Bendary, Ahmed (Bapetco) | Taha, Ahmed (Bapetco) | Farag, Yasser (Bapetco) | Gamal, Ahmed (Bapetco) | Abbas, Sabry Aboel (Bapetco) | Samantray, Ajay (Bapetco) | Ibrahim, Haitham (Bapetco)
Histrorically, Upper Safa is considered to be the source rock of the gas and condensate accumulated in Lower Safa stratum in Obaiyed Field. Both of Upper and Lower Safa units are parts of Khatatba formation "Jurassic age, Western Desert coulumn, Egypt". The integration of all petrophysical and geochemical data indicated that, there is a rich organic Carbon embedded in the formation with a high britteleness ratio. As a result of the opportunity identification, there is an operational scope being studied now to proceed with a haydrulic fracturing stimulation targeting the sweet intervals "Intervals of high TOC and high Britteleness ratio" aiming to maximize the whole gas and condensate production of the field. This paper is summarizing the opportunity identification process and results using available petrophysical and geochemical data.
Six wells had been used in this study where there is a complete set of well and continuous petrophysical data exist in all of them supported by geochemical analysis reports. Specific interpretation techniques were utilized to identify the opportunity from the logs. The property of Total Organic Carbon was estimated from logs using standered DeltaLogR Passey Technique and then verified using measured data. The rock briteleness property was estimated from avilable acoustic sonic logs "Compressional and Shear slowness". The type of Kerogen and level of Maturity were recognized from geochemical sources. The data integration provided a well identification of the shale gas opportunity.
As a part of complete assessment study of unconventional resources, a dedicated subsurface team was formed in order to evaluate the connectivity of Upper Safa, estimate the in place volumes and define the development options. The team also proposed on short term scale performing a vertical hydraulic fracturing in one of the sweet wells in order to prove the evaluation concept and increase total field production.
The success of this project is measured by three aspects: first, proving the presence of commercial shale gas plays in Upper Safa unit, second, maximizing the gas and condensate production from the field and finally, on the long term scale, unlocking commercial unconventional gas resource for future generations in Western Desert, Egypt.
Soliman, Mamdouh (National Research Institute of Astronomy and Geophysics) | Massoud, Usama (National Research Institute of Astronomy and Geophysics) | Mesbah, Hany S.A. (National Research Institute of Astronomy and Geophysics) | Ragab, El-Said A. (National Research Institute of Astronomy and Geophysics)
The phenomenon of seawater intrusion is a very common and widespread environmental problem present in the majority of Egyptian coastal aquifers and showed its negative effects on all crops up on the coasts. This work was conducted at Ras El Hekma Gulf, which is about 70 km east of Matrouh city and occupies the northwestern Mediterranean coastal zone between latitudes 31° 06` and 31 ° 15` N and longitudes 27 ° 40` and 27° 54`E. Groundwater is the sole source for water supplies in the study area due to its remoteness from surface water channels. Therefore, it is vitally important to maintain this available resource to sustain our domestic and agricultural developments in this promising area.This paper refers to the investigation of seawater intrusion into the coastal aquifers at the study area using electrical resistivity tomography (ERT) and transient electromagnetic (TEM) soundings. In this concern, DC resistivity and TEM data have been measured along lines parallel and perpendicular to the Mediterranean coast line. Integrated interpretation of these data sets has effectively succeeded in identification of the subsurface litho-stratigraphic succession and revealed that the groundwater occurrences have been affected by the seawater invasion at different depth levels with variable extents.