Latin America-Caribbean Petrobras and CNPC have signed a memorandum of understanding in Beijing to begin negotiations on a strategic partnership, Petrobras has reported. The companies agreed in the document to jointly evaluate opportunities in Brazil and abroad in key areas of mutual interest. Petrobras, the Brazilian national oil company, said in a news release on its website that partnerships will represent an important strategy in its 2017–2021 business plan because of the potential benefits of risk sharing, increasing investment capacity, technological exchange, and strengthening corporate governance. YPF, Total, Wintershall, and BP have announced a USD 1.15-billion joint investment to increase shale gas production in Argentina. The provincial government in Neuquén, where the resource-rich Vaca Muerta Shale is located, has agreed to split the Aguada Pichana area into two parts and combine it with the Aguada de Castro area.
OMV has discovered natural gas and condensate at well 6506/11-10 in License PL 644B offshore Norway. The company-operated well targeted the Cretaceous Hades prospect and the Jurassic Iris prospect directly beneath it. The preliminary results showed a discovery of 20 million to 115 million recoverable BOE for Hades and 20 million to 130 million recoverable BOE for Iris with "very good" reservoir properties, OMV said. The project venturers are reviewing the discovery data to decide upon potential appraisal drilling. OMV has a 30% working interest in License PL 644/644B, with other interests held by Statoil (30%), Faroe Petroleum (20%), and Spirit Energy (20%).
The primary purpose of using traditional friction reducers in stimulation treatments is to overcome the tubular drag while pumping at high flow rates. Hydraulic fracturing is the main technology used to produce hydrocarbon from extremely low permeability rock. Even though slickwater (water fracturing with few chemical additives) used to be one of the most common fracturing fluids, several concerns are still associated with its use, including usage of freshwater, high-cost operation, and environmental issues. Therefore, current practice in hydraulic fracturing is to use alternative fluid systems that are cost effective and have less environmental impact, such as fluids which utilize high viscosity friction reducers (HVFRs), which typically are high molecular weight polyacrylamides. This paper carefully reviews and summarizes over 40 published papers, including experimental work, field case studies, and simulation work. This work summarizes the most recent improvements of using HVFR’s, including capability of carrying proppant, reducing water and chemical requirements, its compatibility with produced water, and environmental benefits in hydraulic fracturing treatments. A further goal is to gain insight into the effective design of HVFR based fluid systems.
The findings of this study are analyzed from over 26 field case studies of many unconventional reservoirs. In comparing to the traditional hydraulic fracture fluids system, the paper summaries many potential advantages offered by HVFR fluids, including: superior proppant transport capability, almost 100% retained conductivity, cost reduction, minimizing chemicals usage by 50%, less operating equipment on location, reducing water consumption by 30%, and fewer environmental concerns. The study also reported that the common HVFR concentration used was 4gpt. HVFRs were used in the field at temperature ranges from 120°F to 340°F. Finally, this work addresses up-to-date challenges and emphasizes necessities for using high viscosity friction reducers as alternative fracture fluids.
Yang, Junjie (Baker Hughes, a GE Company) | Karam, Pierre (Baker Hughes, a GE Company) | Cozyris, Kristian (Baker Hughes, a GE Company) | Hustak, Crystal (Baker Hughes, a GE Company) | Doherty, James (Riley Exploration – Permian, LLC) | Allen, Carmen (Riley Exploration – Permian, LLC)
As a well-known tight oil dolomite reservoir in Texas, San Andres formation has attracted broad attention about horizontal drilling and development strategy. To optimize the oil recovery and asset’s economics, the aim of the study was to use an integrated approach to understand reservoir heterogeneity and performance, determine optimal landing zone and its impact on production, understand fracture geometry using different pumping schedules, and the optimal cluster spacing. In addition, the potential benefit of a refrac and infill drilling program was also investigated.
To tackle the optimization problem, an integrated reservoir modeling workflow was developed. Starting with a 1-D geomechanical model which captures the in situ stress profile and rock mechanics, hydraulic fracture modeling was developed to history match the treatment process, and therefore a comprehensive fracture geometry can be estimated. In the interim, a geological model with populated reservoir properties was established based on the offset data including petrophysical logs, imaging logs and cores. After calibration, the dynamic reservoir model was built to test multiple sensitivity runs for an optimized field development strategy.
Geological modeling separated the field into two models to study the variation of properties on the east and west side. The east section shows a higher porosity and lower saturations. Those water saturations increase below the main pay zone indicating a potential water source. In addition, special core analysis shows a strong oil-wet nature of the reservoir rock. In the east section, sensitivity runs included infill development and variations in landing depth. It is noted that the production is not sensitive to landing zone because fracture geometry is primarily controlled by vertical stress profile. In the west section, sensitivity runs included refrac, infill drilling, and a greenfield development plan with variations on well spacing and completion design. The observation shows tighter well spacing or cluster spacing accelerates the oil production in early time, while yielding similar long term oil recovery and shows a combination of refrac and infill drilling yields a 21% incremental oil production beyond the base case.
This study provides valuable information about the workflow to develop tight oil plays by describing a detailed case study. The result also sheds light on the optimized field development strategy for analogous fields.
Development of stress sensitive reservoirs, especially in challenging environment, is raising awareness that geomechanics is a vital aspect of reservoir management. Understanding reservoir geomechanical behavior becomes more and more important for petroleum industry. A significant changes in formation pressure caused by depletion will induce deformation and stress/strain changes in the reservoir and the surrounding formation, understanding in-situ stresses and how stress changes in and around the reservoir due to depletion is important in a multidisciplinary approach to reservoir characterization and management. These changes in stresses/strain affect the reservoir as well as the overburden and underburden formation, which directly affect drilling and stimulation operations strategies. Reservoir compaction, shear casing and well damage, cap-rock integrity, fault reactivation and sand production can occur during reservoir depletion. To address these issues, 3D geomechanical models have been developed (which describe the state of stresses in the reservoir and overburden).
Alcorn, Zachary P. (University of Bergen) | Fredriksen, Sunniva B. (University of Bergen) | Sharma, Mohan (University of Stavanger) | Rognmo, Arthur U. (University of Bergen) | Føyen, Tore L. (University of Bergen and SINTEF Industry) | Fernø, Martin A. (University of Bergen) | Graue, Arne (University of Bergen)
A carbon-dioxide (CO2) -foam enhanced-oil-recovery (EOR) field pilot research program has been started to advance the technology of CO2 foam for mobility control in a heterogeneous carbonate reservoir. Increased oil recovery with associated anthropogenic-CO2 storage is a promising technology for mitigating global warming as part of carbon capture, utilization, and storage (CCUS). Previous field tests with CO2 foam report various results because of injectivity problems and the difficulty of attributing fluid displacement specifically to CO2 foam. Thus, a comprehensive integrated multiscale methodology is required for project design to better link laboratory- and field-scale displacement mechanisms. This study presents an integrated upscaling approach for designing a miscible CO2-foam field trial, including pilot-well-selection criteria and laboratory corefloods combined with reservoir-scale simulation to offer recommendations for the injection of alternating slugs of surfactant solution and CO2, or surfactant-alternating-gas (SAG) injection, while assessing CO2-storage potential.
Laboratory investigations include dynamic aging, foam-stability scans, CO2-foam EOR corefloods with associated CO2 storage, and unsteady-state CO2/water endpoint relative permeability measurements. Tertiary CO2-foam EOR corefloods at oil-wet conditions result in a total recovery factor of 80% of original oil in place (OOIP), with an incremental recovery of 30% of OOIP by CO2 foam after waterflooding. Stable CO2 foam, using aqueous surfactants with a gas fraction of 0.70, provided mobility-reduction factors (MRFs) up to 340 compared with pure-CO2 injection at reservoir conditions. Oil recovery, gas-mobility reduction, producing-gas/oil ratio (GOR), and CO2 utilization at field pilot scale were investigated with a validated numerical model. Simulation studies show the effectiveness of foam to reduce gas mobility, improve CO2 utilization, and decrease GOR.
As long as Stokes law or low viscosity Newtonian fluids have been available, common knowledge within the industry has been that whenever these fluids are utilized during the hydraulic fracturing process, very rapid settling of any conventional proppant occurs. Over the years, there have been occasional jobs pumped where the larger sized proppant was the initial proppant pumped, followed by the smaller meshed sand, ceramic or bauxite materials. Little attention was paid to this differing sort of treatment, due to the belief in piston like displacement of proppant regardless of fluid type. Commonly curable resin-coated sand was always pumped in the very last slurry stage of a fracturing treatment, in the common hopes of controlling any potential sand production from the near wellbore area when operations were concluded and flow back operations were initiated to bring the well on line. In reality, with typical over flush volumes, any resincoated sand pumped during a slick water treatment will travel far away from the wellbore.
Germany’s DEA Deutsche Erdoel AG has agreed to acquire privately held Sierra Oil & Gas, interest owner in six blocks in Mexico, including the giant Zama discovery. Sierra holds a 40% nonoperated interest in the 465-sq-km Block 7 containing much of the shallow-water Zama discovery, where appraisal drilling is under way. Zama is estimated to hold 400–800 million BOE of recoverable resources with estimated peak output of 150,000 BOE/D. Production is expected to start up by 2022–2023. Talos Energy is operator and Premier Oil is the other partner.
Huang, L., X. Dong, and T. E. Clee, 2016, A scalable deep learning platform for identifying geologic features from seismic attributes: TLE. Jin, L., M. Sen, T. Hong, and P. Stoffa, 2007, Joint estimation of porosity and saturation by combining a rock physics model and constrained pre-stack seismic waveform inversion: SEG Annual meeting San Antonio.