bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel Janus Carbon Nanofluids from Waste Plastics as Sustainable Nano-Agents for Enhanced Oil Recovery: Scale-Up Synthesis and Performance Evaluation
Authors: Wang Wei , Chang Sehoon , Gizzatov Ayrat , Thomas Gawain 
Published: October 2023

Abstract
This research reports a new type of useful nanomaterials from waste plastics, Janus carbon nanofluids, and demonstrate potentials of the Janus carbon nanofluidsas high-effective alternative nano-agents for EOR application at reservoir condition. A novelsustainable cost-effective method has been developed to scale-up synthesis of Janus carbon nanoparticles (JC-NPs) from the waste plastic feedstock by combined pyrolysis, chemical functionalization and pulverization processes, which allow to produce the JC-NPs in mass quantity in industrial scale. The Janus nanostructures have been characterized and confirmed by multiple techniques including scanning electron microscopy (SEM), Langmuir-Blodgett (LB) curve, contact angle and interfacial tension (IFT) measurements. Unique dual properties of nanoparticulate and surfactant-like behavior of the JC-NPs have been observed and confirmed. Formulated as nanofluids in brine suspension, the JC-NPs can be directed and assembled at interfaces of rock/fluid or water/oil. Contact angle measurement has shown that the JC-NPs remarkably alternate the wettability of rock surface, and interfacial tension measurements have shown that the JC-NPs can lower the IFTs between brine and crude oil at simulated reservoir conditions. With low concentration of the JC-NPs in nanofluid formula, EOR performance tests have been performed to evaluate the efficiency of the nanofluids for oil replacement in carbonate reservoir with a microfluidic device, and the results have demonstrated that the Janus nanofluids at low concentration could remarkably promote the oil replacement in simulated carbonate reservoirs. The waste plastic conversion appears as an attractive way to produce useful, valuable Janus carbon nanomaterials to decrease the carbon footprint and contribute to the transition toward a resource-efficient chemical industry.
Application of Compressible Carbon in Cement to Mitigate Cement Pore Pressure Reduction and Improve Zonal Isolation
Authors: Wu Q. , O'Donnell B. J. , Stiles D. A. , Benton J. , Freysteinson J. , Johnson K. , Zhou C. , Robin R. J. , Koester S. 
Published: October 2023

Abstract
A quality cement job is essential to ensure long-term zonal isolation in oil/gas and carbon storage wells.This may be affected by the cement hydration process, where water is consumed causing pore pressure reduction, and shrinkage, which increases the risk of fluid/gas invasion, formation of micro-annuli and even the risk of shear bond strength reduction.This paper presents the application of compressible carbon particles as a cement additive to mitigate cement pore pressure reduction and improve zonal isolation. Cement formulations with compressible carbon were designed and evaluated using API standard tests and industry-wide recognized tests to ensure they met functional requirements for well cementing such as: mixability, thickening time, rheology, compressive strength development, fluid loss and free water.The concept is as follows:when cement is pumped into an annulus, the compressible carbon particles will compress under hydrostatic pressure.When the cement is hydrating, the compressible carbon will expand to mitigate the porepressure reduction.To validate the proof-of-concept, a benchtop high-pressure high-temperature (HP/HT) setup and a pilot-scale test setup were developed. A cement formulation with 9% compressible carbon by volume was found to be stable and have controllable performance properties such as thickening time, fluid loss and free water.A control slurry without compressible carbon was designed and tested for comparison.Both the benchtop and pilot-scale tests demonstrated that adding compressible carbon into the cement formulation mitigated the pore pressure reduction during cement hydration.This may reduce the risk of fluid/gas invasion that could result in migration in the set cement.Comparing the cement containing carbon to the control system without carbon, the gas permeability was reduced. The bond strength obtained from shear bond tests improved significantly, which may reduce the risk of debonding and be an indication of the reduction of shrinkage.Additionally, a better hydraulic seal was found in one test, but further investigation is needed.Similar mechanical properties such as compressive strength and tensile strength were measured for both cements with and without compressible carbon.The data showed adding compressible carbon does not have a negative impact on the hardened cement properties.In fact, adding compressible carbon decreased Poisson's ratio slightly. This paper will present the results of proof-of-concept testing for the novel application of compressible carbon in cement to improve zonal isolation by mitigating pore pressure reduction.It will also present new benchtop and pilot-scale experimental setups to measure pore pressure changes during cement hydration.
An Innovative Solution to Regain Well Integrity and Deepening Gas Injection Point - Maximizing Production and Rectifying Multiple Tubing Leaks with a Low-Cost Solution
Authors: Mamat Muhamad Aasif , Zayani Sirag , Alham M. , Johan M. , Kadir Masran , Rahman Saim , Ogueri Chidi , Thian Kelvin , Zafuan N. , Hamid Ali Abdul , Zamudin Budi Kastulani , Arifin Akram , Low Y. Peng 
Published: October 2023

Abstract
Multiple tubing leaks have become one of the major issues in brownfield operations especially on wells that have already exceeded their original production lifetimes. This integrity issue becomes more challenging when the leaks occur close to the tubing hanger due to the space constraints in fixing them.
In addition, high water cut wells with low reservoir pressure require continuous artificial lift where tubing integrity is crucial to allow the injected gas reach to the target injection depth. Conventionally, tubing packoffis used to isolate tubing leaks occurring in short intervals while longer ones require coiled tubing straddle with higher installation complexity. However, some wells need deeper injection than the initial completion design. The wells might not be able to flow efficiently without deepening the gas lift point to optimize production to the full extent.
In finding the solution to all three issues; multiple tubing leaks, low reservoir pressure and the requirement for deeper gas lift point, multiple solutions have been proposed and evaluated. Traditionally, workover is considered the best method to replace degraded tubing and to deepen gas lift mandrels.
This paper discusses an innovative and low-cost solution which has been proposed and successfully executed in a dual strings completion. A conventional coiled tubing straddle is installed in the long string as Coiled Tubing Gas Injection Straddle (CTGIS) for gas lifting and the short string is used for oil production. This system replicates the barrier envelope as per the production casing annulus during gas lifting operations and also deepens the lifting point through a sliding sleeves door (SSD). Injected gas mixes with liquid through the SSD from the long string allowing continuous flow from the short string. This low-cost and quick solution enables the well to be restored to production.
This paper includes the gas injection straddle system that consists of engineering design, installation and testing, resulting in a two-fold incremental increase in the production rate and costing only one-tenth of recompleting the well. This has increased the chance of success to restore most idle wells with tubing leaks and opens the door to enhance the existing production.
Application of Inflow Tracers to Complement Production Logs in a Carbonate Field
Authors: Urdal J. , Habib M. A. , Mikalsen T. , Chowdhury S. , Cleveland K. O. , Huseby O. , Bergo C. , Pride S. 
Published: October 2023

Abstract
The use of classical production logging tools (PLT) for the purpose of inflow profiling has occurred for decades in the Greater Ekofisk Area (GEA) wells. Recently, several of the newly drilled wells have been completed with inflow tracer (IFT) technology to trial an alternative means of acquiring an inflow profile. The results and lessons learned from employing both methods on the 2/7-S-35 well in the Eldfisk field are shared in this paper.
The IFTs are directly installed on the outside of the reservoir liner adjacent to each sleeve. The initial acid stimulation is key for releasing and displacing the tracers into the reservoir. Upon production start, the tracers are flowed back continuously with the produced fluids and sampled at surface. The samples are analyzed, interpreted, and a continuous inflow profile for the well is generated.
The inflow profiles derived from both IFT and PLT methods revealed differing results in the subject well. The most notable deviation was in the bottom of the well (Hod formation) where the PLT spinner did not show flow while the IFT showed a significant flow contribution (30% of total). Upon closer analysis of the PLT run, the temperature sensor data suggested flow from the bottom of the well which conflicted with the spinner sensor data. Overall, the IFT data and PLT temperature sensor data confirmed flow from the Hod formation which was also consistent with performance from offset analog wells.
Both methods offer an inflow profile solution at a similar cost but come with their own strengths and weaknesses. Careful design and application are recommended to increase the chances of capturing a representative inflow profile for a given well. The novelty of this paper is in the implementation of the patented rate-dependent method for generating IFT-based continuous inflow profiles for the subject well. The IFT provided a more credible inflow profile than the PLT and this data supported the decision to drill a dedicated well to further explore the Hod formation potential in the Eldfisk field.
Risk Analysis on Geological and Geomechanical Uncertainties - Learnings from CO2 Sequestration Modelling of a Saline Aquifer in Central Alberta, Canada
Authors: Wang Xiaoqi , Gillrie Mitchell , Chen Zan , Chen Suzy 
Published: October 2023

Abstract
The Government of Alberta has entered into evaluation agreements with 25 hubs to investigate permanent CO2 sequestration options, including deep saline aquifers. There is a rush of optimistic claims from numerous organizations on how much CO2 they are planning to dispose, yet it remains unclear how this will be achieved. In this study, practical models were constructed for the Basal Cambrian Sandstone (BCS) to evaluate its CO2 storage capacity from regulatory, geological and geomechanical perspectives.
Field data was collected from the Quest carbon capture and sequestration (CCS) facility, operated since 2015. A geomechanics module, integrated with a dual-permeability fluid model, was utilized to investigate the input variables of the storage formation and associated caprock, such as permeability, Young's modulus, Poisson's ratio, and Biot coefficient, etc. Barton-Brandis model was adopted to investigate CO2 leakage paths through natural fractures in the caprock. An extensive history match was performed and forecast cases were conducted to assess CO2 plume migration, trapping mechanisms, and pressure distribution throughout the life span of the project and over one hundred years after shut-in of CO2 injection.
The results have shown that the amount of CO2 disposal could be over four times the original designed capacity if the injection wells can be operated at maximized injection rate while still maintaining injection pressure below the regulated pressure limit. In addition, the CO2 storage potential can be significantly impacted by geological and geomechanical uncertainties, including ambiguities in structural and petrophysical interpretations, characterization of natural fractures, etc. For example, injection pressure that is higher than the minimal effective stress could lead to failure in the caprock. The changes of natural fracture permeabilities are modelled with the effective stress of surrounding rock matrix and the extent of CO2 leakage into the caprock is studied. The results showed that when reactivated, the natural fractures, especially those near the injectors, substantially increased the amount of CO2 leakage into the caprock. When this happens, it could potentially impose a risk to both storage capacity and safe containment of the sequestered CO2. Finally, proxy functions were developed for correlating the calculated CO2 storage capacity and risk factors. This provides a simplified analytical approach for further risk mitigation.
This study performed a comprehensive quantification of regulatory, geological, and geomechanical risks in a CCS project with real-world data. It provides an exemplary workflow of risk assessment, both numerically and analytically, to guide exploration, planning, operations, and monitoring of future CCS projects.
Optimization of Well Diagnostics and Repair
Authors: Yugay A. , Zhukin A. , Vorozhikhin S. , Girgis F. , Alkarbi M. A. 
Published: October 2023

Abstract
Well Integrity discipline is all about barriers. Double barrier envelope policy is a well integrity requirement well-known worldwide. This can be found in international standards: API RP90 (1 & 2), Norsok D10, ISO 16530 (1 & 2). This policy applies to wells with positive pressure at surface capable to flow naturally. Primary barrier envelope consists of well equipment which is in direct contact with produced or injected media. Secondary barrier envelope will be exposed to well media in case of primary barrier element failure. This paper focuses on such kind of wells that have a positive pressure at surface and fall under double barrier policy.
Any failure in primary barrier envelope (means - completion) is easily repairable during workover by simply re-completing the well with new completion. This can be done almost unlimited number of times, as long as there is a place to set the packer. Failure in secondary barrier envelope (means - casing) can be done as well, but not that easy and limited amount of time. In some cases, especially for onshore wells it might be economically more reasonable to drill the new well rather than to deal with complicated workover. Depending on the Company policy, casing integrity can be restored in sections using casing patches or the entire length can renewed by running and cementing casings of smaller diameter. Obviously, in both cases it impacts the size of the completion and cannot be done multiple times.
Once the primary barrier element fails, it will result in sustained annulus pressure (SAP) appearance. SAP wells create a risk of external leak to surface (or subsurface) in case of secondary barrier element, such as wellhead, casings, or different accessories failure.
Experimental Investigation Using Low-Frequency Distributed Acoustic Sensing for Propagating Fractures with Shear and Normal Stresses
Authors: Reid T. , Zhu D. , Hill A. D. 
Published: October 2023

Abstract
Low-frequency distributed acoustic sensing (LF-DAS) at a far field observation well is a diagnostic tool for hydraulic fracture propagation using measured values of strain. To understand subsurface conditions with shear and normal stresses, a laboratory-scale hydraulic fracture experiment was performed to simulate the LF-DAS response to fracture propagation with embedded distributed optical fiber strain sensors under these conditions. The objectives of this research are to generate hydraulic fractures of known geometry when shear and normal stresses are present, measure the strain response along distributed fiber sensors embedded in the sample, and use the results to enhance the interpretation of LF-DAS data measured at observation wells.
The experiment has been performed on a uniaxially-compressed, transparent cube made of epoxy with a radial initial flaw angled non-perpendicular to the applied stress. The epoxy cube is 8-in in each dimension. Fluid was injected into the sample to generate a fracture with shear and normal stresses along the plane of the fracture. These experiments used distributed high-definition fiber optic strain sensors with tight spatial resolutions. The sensors were embedded at four different locations, serving as observation/ monitoring locations. Pressure and fracture propagation were also recorded. The measured strains were compared to experiments with purely normal stress components to understand how the zero-strain and zero-strain rate methods for fracture geometry can be applied to the studied case when shear stress on the fracture plane is introduced.
The experimentally derived strain and strain-rate waterfall plots from this study with shear and normal stresses exhibit a narrowing region of extension surrounded by compression as the fracture approached and intersected a fiber optic cable. However, unlike the experiments with purely normal stress on the fracture plane, the introduction of shear stress has created an asymmetrical strain signature over the fracture plane. The dominant strain response on one side of the fracture plane suggests the existence of a shear stress on the plane of the fracture. This information can be used in the field to reveal the stress status during fracture propagation and more realistically evaluate the fracture front.
Novel Hybrid Degradable Plugs to Enable Acid Fracturing at High Temperature High Pressure Conditions
Authors: Zhao L. , Ren J. X. , Yuan M. , Liu Y. , Liu H. L. , Zhou C. J. , Wang S. W. , Ren G. F. , Cheng P. 
Published: October 2023

Abstract
Current commercial dissolvable plugs have been found unsuitable when we hydraulic fracture extremely HTHP wells, especially with acid. Dissolvable alloys, the most popular materials, react too intensively in acid environment, and nearly all types of commercial protective coatings have been tested unsatisfactory due to inevitable defects/holidays. Additionally, they suffer from recrystallization issues that prevent plugs from dissolving. Thermoplastic Polyglycolic Acid (PGA) may have a significantly low degradation rate in acid, but its temperature rating is too low.
To address this issue, we developed a new kind of fiber-enhanced degradable polymer composite material based on thermosets, which offers high strength and temperature rating, as well as low dissolving rate in acid conditions. Thanks to synergic effect from degradable metal slip design, a novel hybrid dissolvable plugs has been developed afterwards, which can not only hold pressure in HTHP condition and dissolve readily afterword, but most importantly can be dissolvable readily with acid (mainly through dissolving of metallic slips) if plug is stuck or set prematurely during installation process, a requirement crucial to our clients to develop wells suffering from deformative casing issues. Advanced degradable thermoset developed in this work offers temperature rating above 150℃ due to its highly cross-linked molecular structure. It exhibits extremely high strength (20~30 ksi [138-207 MPa] in tensile) at elevated temperature, and its dissolving rate in acid (15% HCl) is marginally higher than that in brine water during 2 hrs. of acid fracturing operation. Novel hybrid plug, with cone made from this new material and slips from traditional dissolvable alloy, is rated to hold pressure above 9000 psi (62 MPa) at 120℃ in acid fracturing condition, and degrades totally within 2 weeks, successfully meeting field requirement for HTHP wells. In case of premature set, this hybrid plug can be uninstalled reliably within hours through dissolving its dissolvable metal slips via acid.
To the best of our knowledge, it is the first report of degradable thermoset composite material in downhole plug application, and the first totally degradable hybrid plug working at HTHP condition in our industry. This study could not only benefit oil and gas industry to hydraulic frac HTHP reservoir inaccessible before, but also provides a new functional material that should be potentially used in development of other advanced tools in applications including drilling, completion, work over, etc.
Simulation-Assisted Diagnosis of GOR Evolution in Carbonate Reservoir, Offshore Abu Dhabi, Undergoing Miscible Gas Injection
Authors: Khan M. N. , Mogensen K. , Altaf B. , Menchaca T. Felix , Allouti A. 
Published: October 2023

Abstract
A major reservoir, Reservoir A, in an offshore carbonate field in Abu Dhabi underwent a thorough development-concept selection process. The subsurface evaluation recommended miscible gas injection-based development as the most optimal process, and the reservoir is undergoing the miscible gas injection operation. Over the course of production, ‘Reservoir A’ is experiencing a gradual GOR increase. The GOR evolution could be the result of different physical mechanisms, such as production below bubble point, gas coning, or miscible gas breakthrough. In the latter case, it is not clear whether reservoir dispersion has smeared out the miscible displacement front to a point where miscibility is lost. The key objective of this work was therefore to develop a diagnosis methodology using numerical simulation to interpret the GOR response.
A 2D numerical, fine-gridded simulation with a producer-injector pair was set up to explore the following scenarios: (a) production below bubble point; (b) gas coning from the gas cap; (3) a perfect miscible displacement; (4) a perfect immiscible displacement; (5) a miscible displacement that turns immiscible due to dispersion; (6) a combination of the above. The key output parameters tracked included GOR and its derivative and the flowing bottom pressure at the producer. The different runs were then compared against each other and with the measured GOR response.
A fit-for-purpose surveillance strategy was adopted to help assess the effectiveness of the overall development strategy. Recently, tracer test results confirmed the arrival of gas production down the horizontal wellbore. GOR evolution trends were captured using the inline multiphase flowmeters. The comparison of simulation-based type curves with the evolving GOR trend along with the other subsurface attributes shows an initial indication of the production of swelled oil, followed by the injection gas breakthrough. This paper showcases the effectiveness of the proposed technique and the initial results of the analysis.