At this month’s convention, “The Future of Egypt’s Brownfield Development,” Egypt Oil & Gas will host a workshop dedicated to the latest advancements in technology and current case studies related to brownfield development in Egypt.
Session 1: Introduction to Brownfields: From Logistics to Economics
Most of Egypt’s existing oil wells are considered brownfields, which are defined as mature oil fields in a state of declining production, or reaching the end of their productive lives, and typically over 30 years old. Session 1 of the workshop will include a presentation from EGPC and Transglobe, “Definitions of Brownfields, Egypt Statistics and Work Flows,” and an overview of brownfield development and challenges by Gaffney Cline.
A case study presented in Session 1 by Sherif Shawky, Mohammed el-Khayat, and Bronislav Vago of Suez Oil Company, “Maximizing the recovery of a major brownfield,” examines the successful mitigation of production decline at the Zeit Bay field, which began its natural downturn in 1988. The complex geological structure, heterogeneous horizons, strong aquifer, and an expanding gas cap have presented challenges in modeling the reservoir as well as limited drilling options.
The case study discusses “the ultimate need to maximize oil production prior to gas cap blowdown,” which Sherif Shawky explains as a gas injection process “during the oil production stage to maintain the reservoir pressure as long as possible and in turn maximize oil recovery.” This gas injection can originate from other fields, or in the case of Zeit Bay, as re-injection from the associated gas of the same field. At some point, oil production through this process ceases to be economically feasible, and the oil field transitions to mainly a gas field. “The later gas production scheme is called the ‘Gas-cap Blow-down’ stage. Sometimes ceasing gas injection earlier, or starting gas production may negatively affect oil rate,” informs Shawky.
New production data from newer formations was gathered using Pressure Transient Analysis (PTA), and has ultimately improved reservoir characterization at Zeit Bay, adds Shawky. Other wells are scheduled to have similar successes during the coming financial year, the paper said.
Rigless operations at Zeit Bay have proven to be cost-effective and have increased the economic value of the field, resulting in significant drops in cost per barrel. “Rigless operation cost is usually higher than wireline operation,” explains Shawky, yet “cost-per-barrel is usually lower in case of rigless operations.” As such, it is more economical to proceed with a rigless operation if the cheapest wireline operation is not accessible.
Also presented in Session 1 is a case history of Khalda Petroleum Company’s Western Desert Khalda 2 concession, which has been in production since the early 1970s and undergoing successful rejuvenation, having nearly doubled oil production since 2010.
In a paper presented by Kuwait Energy Egypt, production decline and development of the mature fields of Kareem, Ayun, Shukheir Northwest, Ahmed, and West Ahmed is discussed, in addition to the positive outcome of water flooding in the Umm el-Yusr Field, and new resources having been identified through seismic stratigraphic studies.
Mahamed Ismael of Enap Sipetrol presents a field study of the Shahd-SE Field in the Western Desert, to illustrate the challenges presented by uncertain geological and engineering data for proper reservoir characterization.
Session 2: Integrated Reservoir Engineering and Water Flooding
One of the main topics discussed in Session 2 of the workshop is 3D reservoir modeling, which “attempts to incorporate all geological, petrophysical and reservoir engineering data inside a static structural framework,” informs Richard Vaughan, Head of Onshore Nile Delta at RWE Dea. “Rock types or sedimentary facies can be distributed in 3D space, based on well correlations and a conceptual depositional model, or directly input from seismic inversion property modeling,” Vaughan told Egypt Oil & Gas, who coauthored a case study of the Ras Fanar Field with Mohamad Ali of the Production and Reservoir Department at RWE Dea. These models have helped identify uncertainties or “heterogeneity” in the reservoir, which helps target un-drained “sweet-spots.”
On how RWE Dea has implemented 3D reservoir modeling, Vaughan noted that “The presence of thick salt and anhydrite deposits above the main producing reservoirs within Gulf of Suez absorb a significant amount of seismic energy. This usually limits the ability of geoscientists to derive reservoir properties directly from the seismic.” The Ras Fanar field is unique in that “the overburden is relatively thin, so that the evaluation seismic-derived reservoir parameters is more conducive,” he said.
Dr. Darius Shahsavari, P.E. of IPR Group of Companies, outlined three new enhanced oil recovery (EOR) methods in his paper, “Integration of Modern EOR Techniques for Application in Brownfields,” and discusses the evolving definition of EOR. These techniques are:
- Reservoir characterization via adaptive neural network analysis
- Hybridized surrogate reservoir metamodeling
- Smart well technology
“It will be shown that all three of these methods help to reduce uncertainties usually associated with conducting EOR operations at profitable levels,” Shahsavari wrote.
Another significant topic of the workshop is water flooding in brownfields. As Eng. Hussein Mohamed Abou Elleil of Qarun Petroleum Company noted, “it is a traditional phenomena in the oil sector that the associated water increases with time.” However, as their paper discusses, the Qarun fields experienced an accelerated increase in associated water that has proven to be a challenge to dispose of, and an environmental risk. Water disposal wells have been utilized to deal with excess water safely, as well as minimize costs. Their case study provides a complete comparison between various water disposal approaches, weighing operational and economic criteria.
A paper by Saber Mustafa and Ahmed Abd Hadi of the Suez Oil Company and Aly Gadallah of RWE Dea presents another case where 3D geomodeling of complex structures has proven to be an effective approach to reservoir management, in the Ras Budran field. In regards to field development and reservoir management, building coherent models of heavily tectonized areas-while a significant technological challenge-has had a substantial effect on increasing production and lowering operational costs, the paper said. Ras Budran, west of the Sinai coast of the Gulf of Suez, is representative of a field with a complex geological and geophysical structure. 3D geomodeling techniques have proven instrumental in understanding and characterizing formations, which has led to success in development and exploration of the field.
Saber Mustafa told Egypt Oil & Gas, “Building a 3D geological model of a complex structure requires a consistent interpretation which is matching with the well data.”
Some characterization techniques that have been implemented at Ras Budran include:
- Well correlation, used to detect well tops and creating reservoir zonations
- Dipmeter data and a vertical seismic profile (VSP), which is used in structural interpretation as methods for fault analysis, and also as a dip guide for the horizon interpretation
- Miocene thickness maps, for detecting the major boundary faults and proving that these faults have been rejuvenated during the syn-rift phase of the Gulf of Suez
- Pressure and production data, used to detect the sealing faults, which are not penetrated by wells
- Surface structure maps for structure calibration
“Geo-seismic interpretation, as a result, has unlocked new areas drilling, and has added a new reserve to the field,” Mustafa added.
In addition to the above technologies, presentations in Session 2 will discuss “Improving Sweep efficiency in the Gulf of Suez by Deep Conformance Control using a Thermally Activated Particle System” by the Gulf of Suez Petroleum Company, and “Formation micro Imager Log Facies Analysis & Depositional Environment Interpretation” presented by Enap Sipetrol.
Session 3 and 4: Improved Oil Recovery
TransGlobe is “looking towards tertiary EOR solutions to extract further value from the fields,” following a 350% production growth and 280% reserves growth in the West Gharib Concession. This increase in growth comes as a result of applying integrated subsurface modeling, as illustrated in their presentation “Deployment of Proven Technologies for Value Creation in Brownfield.”
In the Belayim field in the Eastern side of the Gulf of Suez, a combination of infill drilling (the process of adding new wells in an existing field within the original well) and excessive water injection has led to an increase in recovery, said Eng. Samir Sisistriss and Eng. Mustafa in their paper for the Belayim Petroleum Company. “In the past decade more than a hundred of deviated wells and tens of horizontal wells have been drilled in order to compensate for the effectiveness of water injection, where sweep efficiencies and recovery factors using conventional flood patterns are unsatisfactory. The interest in combining the water injection and drilling of infill wells has kept growing, extending the life of this mature field, and maintaining its production plateau, and achieving high recovery rate,” the paper said.
Hydraulic fracturing has increased the production rate of the Bah-I well in the Falak field of the Meleiha concession from 20 b/d to 400 b/d, according to Agiba Petroleum’s presentation. “The field was considered as a marginal field, producing from only one well with a low oil rate. After using hydraulic fracturing technique to develop this field, oil production rate increased to 3,000 b/d. Currently the field contains 11 wells as oil producer and four wells as injectors.” This technique has increased Agiba’s reserves by 288%.
Another method discussed in this session is the gas life method, “one of the most common methods of increasing production in oil fields,” according to a paper by Adham O. Hamshary, Petroleum Engineer at BP. This method consists of continuous injection of lift gas into the tubing, which “reduces bottomhole pressure and allows more oil to flow through the well.” Gas lift has produced positive results in the Shoav-Ali, a major field in southern Suez.
By Lily Leach