Egypt's Western Desert reservoirs are characterized to be tight clastic reservoir. In the early development stages only layers with high permeability were produced while tight formation was not considered economic due to application of conventional completion strategy resulting in very low production results. With the decline of Egypt's hydrocarbon production and increase in domestic demand of energy, economically production from these tight reservoirs is a great challenge to maintain production's annual decline. The prospective of these tight producing zones were discovered at a depth below 14,000 feet where the stress is extremely high (1.1 psi/ft) and the reservoir permeability conditions are low with range of 0.2 mD; being necessary in all cases to fracture stimulate each horizon to define the fluid and evaluate productivity. The extreme stress condition and high fracturing treating pressure, risk of premature screen out are one of the main challenges to perform fracture stimulations on these formations which exceeded the working capability of the available equipment in addition; it required significant amount of horsepower on location. Initially, the conventional fracturing treatment was conservatively designed in terms of treatment rate, polymer loading of fracturing fluid and proppant concentration to manage both risk and treatment proppant placement. However, this conservative approach impaired proppant-pack conductivity and the effectiveness of the fracture half-length However, premature screen-outs severely disrupted stimulation operations, leading to costly nonproductive time and deferred production. The poor results using these conventional fracturing techniques during initial exploration and development, the wells were deemed uneconomical. The recent advances in channel fracturing technology; enabled operators to unlock the potential of their toughest reservoirs to economically produce and unlock the enormous amount of hydrocarbons retained in the rock, prolong life of mature fields and achieve production targets. With the application of this technique, helps alleviate the risks of screenout and mitigates the proppant bridging buildup, as the proppant is added in pulses along with dissolvable fibers. These proppant pillars are suspended and held in place by fibers during the treatment. Once pumping is stopped, the fracture closes on the proppant pillars and the fibers degrades under effect of formation temperature. These pillars hold stable channels along the entire geometry of the fracture that provide open pathway for hydrocarbons to flow in near-infinite conductivity. Additionally, 40% less proppant was used and reducing pump rates, which lowered horsepower requirements by 30%. Results indicate that the channel fracturing technique has significantly impacted wells' performance and achieved the desired objectives over conventional fracturing methodologies. Positive features that were observed such as reduced net pressure increase estimates, elimination of near-wellbore screen-outs.
Hydraulic fracturing is frequently used to create enhanced wellbore connectivity to enable tight reservoirs to produce hydrocarbon. Many factors can be considered as risks to the success of fracturing operations. One of the risks arises in reservoirs that are close to a water-bearing zone. The risk of fracture growth into the water zone limits the stimulation options and eliminates the chances of using hydraulic fracturing treatment to improve well productivity, thereby restricting the well's future production and often resulting in lost recoverable reserves. In the Western Desert of Egypt, two wells were to be fracture stimulated with a risk of propagating into a nearby water zone. The productive pay of low-permeability reservoirs is separated from underlying water zones by a weak or no stress barrier. The proximity of the water zone to the hydrocarbon-producing zone varied from 20 to 40 ft, and containing the fracture height in such well conditions to prevent the fracture propagating into the underlying water zone becomes a serious challenge. This can jeopardize the post treatment well productivity. It therefore becomes necessary to prevent fracture height propagation from growing into the adjacent water zone.
This case study presents a novel hydraulic fracturing technique, applied for the first time in Egypt's Western Desert that controls fracture height growth in the absence of in-situ stress contrasts. This technique places an artificial proppant barrier below the pay zone, close to the water-oil contact, creating high resistance to fluid movement and restricting pressure transmission, thus arresting unbridled vertical height growth of fractures. These barriers are created prior to themain fracture treatment by pumping heavy proppant slurry at fracturing rates carried in a fracturing fluid loaded with high breaker concentrations. The high breaker concentration breaks the gel fast, thus allowing the proppant to settle quickly to the bottom of the created fracture. The results from the application of this newly applied dual fracturing treatment technique have been overwhelming, with a 12-fold increase in production with no increase in water production. The application of this technique resulted in an increase in the net pressure at the end of main fracturing treatment indicating fracture containment within the zones of interest. The minifracture analysis, stress profile calculation, fracture geometry characterization, and no water breakthrough after the treatment support the fracturing design.
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.
Ismail, Ahmed (Baker Hughes Incorporated) | Stockey, David (Baker Hughes Incorporated) | DiGiovanni, DiGiovanni (Baker Hughes Incorporated) | DiGiovanni, Anthony (Baker Hughes Incorporated) | Burch, Connie (Baker Hughes Incorporated) | El-Moniem, Mohamed Abd (Bapetco-Shell) | El-Desouky, Waleed (Bapetco-Shell) | El-Sawy, Ahmed (Bapetco-Shell) | Galal, Mohamed (Bapetco-Shell)
The ongoing drilling campaign for an operator drilling in Egypt's Western desert area involved drilling vertical and directional wells approximately 5,000- to 5,500-m deep. The application involved drilling through very hard and abrasive sandstones, and intercalations of shale, sand, silt and dense dolomite inter-beds of about 25,000 psi unconfined compressive strength (UCS). Historically, poly crystalline diamond compact (PDC) drill-bit showed inconsistent bit performance that included premature bit failure and low rate of penetration (ROP), resulting in costly bit trips to the surface.
New and improved bit technology was required to improve the penetration rate and footage to reduce bit trips to the surface and improve the overall drilling performance. An in-depth study of the formation properties, wireline logs, drilling parameters and bit dull analysis was performed. Detailed analysis identified this application can benefit from running cutters with a non- planar cutting face on a field-proven seven- blade PDC bit frame. The bit was run on a Rotary Steerable System (RSS) coupled with a positive displacement motor (PDM) on top of the BHA to further improve the drilling efficiency and overcome any challenges.
Upon deployment, the 8½-in bit design with the new 16-mm cutters with non-planar cutting structure combined with optimized depth-of-cut control, stability, hydraulics efficiency and balling prevention features led to improved performance when drilling the complex, hook-shaped well profile (where torque and drag were an issue in the past). Compared to field offsets, the bit drilled very smoothly and aided the operator in placing the well in the correct direction with minimum bit- torque caused from bit and formation interaction. Offset bits fail to achieve the required directional plan in the past because of the severe nature of drilling in the area.
This integrated solution resulted in a 15% improvement in the ROP as compared to the offsets and a 57% improvement in footage drilled. This performance replaced six drill bits, which were used to drill the same interval in the offset wells. The new innovative PDC cutter technology saved the operator at least USD 250,000 from the planned authority for expenditure (AFE) cost, as well as set two consecutive footage records. This paper outlines the problems in drilling this challenging area, the thought process behind using the various technologies incorporated in the PDC bit design and the keys to overall success.
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.
Moneim, M. A. (Shell Egypt) | Ahmad, M. F. (Shell Egypt) | Hanafy, O. (Smith Bits, a Schlumberger Company) | Fayez, S. (Smith Bits, a Schlumberger Company) | Eloufy, M. (Smith Bits, a Schlumberger Company) | Aguib, K. (Smith Bits, a Schlumberger Company)
Drilling the deep lithology column using PDC bits in the Obayied field of Egypt's Western Desert has been extremely difficult. The field's lithology column represents an amplification of all of the typical lithology characteristics in the Western Desert. The highly interbedded sandstone, siltstone, and shale—along with the variance of such interbedding across the field—has been a significant challenge for well planners and has adversely affected cost per foot. The application is characterized as predominantly abrasive and impact-intensive in the same section, hence challenging for PDC bit durability. To efficiently drill the 8½-in interval, a fundamental change in PDC bit design is required.
Considering these formidable challenges, service providers had to evolve PDC bits to meet the constant demand of improving performance and reducing costs. Focus was concentrated on balancing new technology developments and the willingness to invest on field trials. To accomplish these objectives in the Obayied field, the operator and the service provider identified two main problems—developing an in-depth understanding of rock strength characteristics of each individual formation in the deep rock column and its variance across the field, and developing PDC bits that can survive such a challenging rock column with improved durability and ROP.
Recently, a novel conical diamond element (CDE) with extreme impact- and abrasion-resistant characteristics has been developed. The CDE has been incorporated at bit center in a new and innovative PDC design, solving the traditional challenge of the inefficient characteristic of PDC bit central area. In addition, a field-wide rock strength study based on sonic and gamma rays logs provided the transparency required for better planning and risk management to resolve the operational inefficiencies traditionally seen in the Obayied field.
The new PDC bits utilizing the CDE technology has been deployed in Obayied and has reduced consumption to just 3–4 bits per section in 2014, whereas that number was 8–10 bits per section averaged in 2006. The new bit has also reduced the average number of days to drill the section from as low as 6 days to reach TD instead of 20 days. Performance gains were achieved both in ROP and footage totals in the most challenging formations, including Alam Al Buwaib, Upper Safa, and Lower Safa. The authors will discuss the benefits of this industry collaboration that achieved exceptional performance improvement leading to dramatic cost savings in the Obayied field.
Kamel, Osama (Khalda Petroleum Company) | Mansour, Mahmoud (Khalda Petroleum Company) | Ibrahim, Abdelshafy (Khalda Petroleum Company) | Reyad, Mahmoud (Khalda Petroleum Company) | Hanafy, Omar (Schlumberger Company) | Sherif, Mohamed (Schlumberger Company) | Aguib, Karim (Schlumberger Company) | El Sheikh, Omar (Schlumberger Company) | Bits, Smith (Schlumberger Company)
Recent manufacturing and hardfacing advances have produced a steel-body PDC bit (SB-PDC) capable of efficiently drilling interbedded formations at significant depth. These technological advances have increased the bit's resistance to abrasion/erosion and enabled a new style steel-body PDC bit to drill formations in Egypt's western desert previously drilled by matrix PDC bits. Field tests have confirmed the steel-body PDC bit can outperform matrix PDCs in a wide-range of interbedded applications that contain a heterogeneous mixture of shale, sand/siltstone, and limestone. The approach combines optimized cutting structure design and premium PDC cutters that enable the steel-body PDC bit to drill the abrasive sand/siltstone component. The bit can also efficiently drill shale and soft limestone due to its hydraulic efficiency which was a factor limiting performance improvement in previous designs. The bit solution employs: Cutting structure optimized using FEA-based modeling system Premium grade PDC cutters Next generation of abrasion/erosion resistant hardfacing material Hydraulically efficient bullet-shaped body type The new SB-PDC technology was deployed in a sequence of tests in different applications and fields in Egypt's western desert. The trials were run in different lithologies at different depths. Direct comparisons to relevant matrix PDC technology and other available steel-body bits clearly demonstrates the new-style steel-body PDC bit's value by setting new benchmarks and reducing cost/ft.
El Sherbeny, Wael (Baker Hughes) | Al-Baddaly, Hesham (Baker Hughes) | Rahal, Ayman (Baker Hughes) | Said, Mohamed (Baker Hughes) | Hardman, Douglas (Apache Corporation) | Henry, Todd (Apache Corporation)
Nanotechnology has become the buzz word of the decade! The precise manipulation and control a matter at dimensions of (1 – 100) nanometers have revolutionized many industries including the oil and gas industry. Nanotechnology applications have pierced through different petroleum disciplines from exploration, reservoir, drilling, completion, production, processing and finally to refining.
Nanoparticles are the simplest form of the structures with sizes in the nm range. In principle, any collection of atoms bonded together with a structural radius of less than 100 nm can be considered a nanoparticle.
The Tiny nature of nanoparticles results in some useful characteristics, such as an increased surface area to which other materials can bond in ways that make for stronger or more lightweight materials. At the nanoscale; size does matter when it comes to how molecules react to and bond with each other.
The filter cake developed during nanoparticles-based drilling fluid filtration is very thin, which implies high potential for reducing the differential pressure sticking problem and formation damage while drilling.
While drilling shales formations with nanodarcy (nD) permeability, Nanoparticles can be added to the drilling fluids to minimize shale permeability through physically plugging the nanosized pores and suppress the pressure transmission, hence Nanotechnology can provide a potential solution for environmentally sensitive areas where oil-based mud (OBM) historically used as a solution to stabilize shales.
Geotechnical challenges normally increase with increasing well inclination due to the highly faulted nature of many of the formations. Pressures and temperatures are typically not excessive but the complex interlayering of shales, sandstones siltstones and limestones results in multiple problems associated with borehole instability.
The Paper will reveal all lab work and field procedures for new Nanotechnology additive for wells that have an intercalated lithologies and tight reservoirs. Also paper will reveal the effectiveness of the nanotechnology additives to stabilize hole geometry that is demonstrated by comparison pre-nanotechnology wells and post-nanotechnology wells.
A review of the available data of the Obaiyed field was carried out by Bapetco as part of the 2002 FDP update and the last review of Oct.2004. The Obaiyed field is a complex field, characterized by large uncertainties in permeability distribution and accordingly connected GIIP. The objective was to produce an integrated diagenetic and sedimentological model that can be utilized in 3D reservoir modelling. The study has resulted in a comprehensive 3D model of an estuarine, incised valley depositional system. Geological, Petrographical, sedimentological and Reservoir Engineering data have been integrated to create model realizations reflecting extreme scenarios of the permeability distribution within the field in an attempt to define their connectivity. The majority of the sandstone were deposited as bars within the estuary. The occasional higher permeability layers correspond to petrographic differences in the sandstones that relate to depositional sub-environment. Rock samples have been taken from the Paleozoic/Mesozoic in order to assess the diagenetic history, its impact on reservoir quality, and potential petrographic criteria by using the following analyses:
• Rock composition, Thin section petrography, SEM-analysis, XRD;
• Clay Mineralogy and Illite crystalinity;
• Age dating and Age of diagenesis: K/Ar-dating of Illite/Kaolinite concentrates.
The permeability and saturation distribution are a function of the diagenetic history of the field, causing the Paleozoic sandstones, which underlie the Mesozoic Lower Safa, to have a markedly lower permeability and generally lower saturation.
The Obaiyed gas/condensate field presents the challenging combination of a complex subsurface and a short timeframe to fully develop the field and to deliver committed daily quantities. The field was discovered in 1992, subsequently 4 appraisal wells were drilled between 1994 and 1996. After issuing the initial FDP in 1996 a development campaign was started in 1997, first gas was produced in 1999.
After drilling 28 wells in the area subsurface uncertainties have been reduced significantly, the current updated FDP focuses on the development of reserves locked in the tight parts of the field as a means to maximize profitability of the field. Currently over 50% of the in-place gas is locked in tight gas sandstones in the Obaiyed field.
In order to rule out other causes of poor productivity, the formation damage is the mechanism responsible for poor productivity. As this can only be done by ensuring no damage during drilling
Over the next two years, drilling activity in Bapetco will be increased, mainly because of the upcoming drilling campaign to develop the NEAG field In Abu El Gharadig Area and Obaiyed Area. Initial development plan will comprise drilling of 8-10 development wells in both Areas.