bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Systematic and Comprehensive Approach for Characterizing Capillary Desaturation Curves in Low-Permeability Carbonate Rocks
Authors: Siyal Amaar , Ahmed Shehzad , AlAmeri Waleed , Al-Shalabi Emad W. 
Published: March 2023

Abstract
It is widely recognized that the determination of true residual oil saturation to water (Sorw) is a critical factor in predicting waterflooding performance and implementing enhanced oil recovery (EOR) methods. A particular EOR method will provide a high prospective result if there is an overestimation of Sorw. The concept of capillary desaturation curve (CDC) is used to determine how much amount of oil can be recovered, when implementing a certain EOR technique. The objective of this study is to determine the true residual oil saturation to water (Sorw) for low permeability Indiana limestone outcrops using the centrifuge technique under reservoir conditions and further generate their CDCs. In this work, three carbonate Indiana limestone outcrops with low permeability range (4-8 mD) and representative fluid samples i.e., field oil, formation water, and seawater, were utilized. The CDC was then characterized for carbonate rocks by further reducing Sorw using surfactant flooding where three anionic surfactant formulations with different IFT values were selected. A systematic approach was followed starting with conventional core analysis followed by special core analysis. For the CDC generation via surfactant flooding, three surfactant formulations having different IFT values were selected through a preliminary screening.
This study showed that there is no correlation between initial water saturation (Swi) and absolute permeability for the cores tested. In addition, variations in spontaneous oil recovery was noted among cores within the same range of rock permeability, which indirectly indicates the existence of heterogeneity within each rock. Furthermore, a true Sorw of 20-29% was achieved using the centrifuge method, which was confirmed during the surfactant flooding stage. Additionally, CDC studies indicated that a critical trapping number of 10-4 was achieved for the tested cores, which is higher than most of the reported values of 10−8 to 10−6 in the literature. Accordingly, the complete desaturation of mixed-to-oil wet carbonate rocks is quite challenging since it requires a further increase in trapping number, which could possibly be achieved using ultra-low IFT surfactants. This work presents a systematic and comprehensive approach for determining true Sorw and understanding microscopically trapped oil in carbonate rocks based on CDC. The produced results would be useful in EOR screening for future surfactant flooding pilots in carbonate rocks with low permeability.
An Integrated Experimental Method to Study Multistage Alternating Injection Acid Fracturing in Limestone Formation
Authors: Ren Yonglin , Wang Da , Feng Puyong , Chen Jun , Shao Shangqi , Zhang Wanchun , Cui Bo 
Published: March 2023

Abstract
Multistage alternating injection acid fracturing is one of the emerging acid fracturing techniques to stimulate the carbonate reservoirs. Nevertheless, the previous research on this technology mainly focused on numerical simulation, and there has been little experimental research on it. The etching behavior and mechanism of various acid types and different number of injection stages within the fracture is still unknown.
In this paper, we propose an integrated methodology to experimentally study multistage alternating injection acid fracturing. First, we introduce an innovative acid-etched fracture surface evaluation method to evaluate the acid-etched fracture both quantitatively and qualitatively based on etched fracture surface topography analysis, amount of rock dissolved and a newly defined acid etched channel propagation index, and design a multifunctional core acid etching system to satisfy the requirements of acid etching experiments. Then, we conduct a series of acid etching experiments to optimize the acid types and number of acid stages to create fracture under different core permeability. On the basis of the fracture evaluation, we analyze the mechanism by comparing the etching patterns using different types of acid and fracturing fluid with different number of injection stages. Finally, we further verify the validity of the acid-etched fracture evaluation method through laboratory experiments using a modified fracture conductivity test system to test the fracture conductivity under confining stress ranging from 10~40 MPa.
The following findings can be concluded from the experiment results: similar with previous digital research results, the experiment results show that the number of alternating injection acid stages only slightly influences fracture conductivity and hardly affects the fracture surface etching patterns. Nevertheless, different from previous numerical research results, this experimental study finds that the acid types can strongly affect both the fracture conductivity and etching patterns during alternating injection. Among the four alternating injection combinations, the low viscosity emulsion acid and chelating acid combination shows the lowest conductivity and the lowest channel propagation index, while the cross-linked acid and surfactant based acid combination achieves the highest fracture conductivity and the highest channel propagation index due to their high viscosity and self-diverting properties.
This experimental research provides an integrated experimental method to study multistage alternating injection acid fracturing and its results provide an insight into this technology.
Advanced Research and Development in Unconventional Use of Tracer Technology for EOR and IOR: The Gen Z Tracers
Authors: Chatterjee Monalisa , Toh Sean , Alshmakhy Ahmed , Bigno Yann , Hewitt Paul 
Published: March 2023

Abstract
Over the last few decades, tracers have provided crucial insights on fluid flow behavior assessing reservoir connectivity. For years, they had been viewed as mostly passive molecules that go with the flow of the injected fluid and uncover pathways between injectors and producers. The proposed paper sheds light on some interesting newer frontiers of tracer applications with unconventional uses to gain further flow insight from an oil and gas reservoir.
Although primarily developed for interwell applications, newer and more sophisticated genres of tracers have found their way to assist with well fluid flow behavior. Inflow tracer applications, used for phase flow diagnostics, have been around for a few decades now. However, with several parameters like physical space restrictions, temperature, solid support selection, multi-phase flow, initial surge and target concentrations at play, it was soon realised that an extended lifetime was needed to provide techno-economic benefits during reservoir monitoring. Microencapsulation of tracer molecules is one of the newer developed techniques that has shown significant extension to tracer life in controlled release tracer applications as well as improved dispersibility within fracking fluid. Newer synthesis mechanisms like microencapsulation have been developed to linearize inflow tracer release profiles that has led to a substantial increase in tracer lifetime. As the research and development progressed, newer tracers such as frac bead tracers were developed allowing long term fluid flowback monitoring in fracture stimulated wells.
In parallel, it is still an active field of investigation as to how tracers can be integrated with common downhole completion and topside equipment of a well to accurately detect early water breakthrough.
The paper discusses the advances in these target areas where chemistry is constantly being upgraded to suit end user needs. Novel applications and ‘out-of-the-box’ uses have been developed in the last couple of years where inflow tracers have found a modified use within the gas lift system in a well and integrated with the top-side flow arm of the well, eradicating the need for individual sampling of wells and detection of water breakthrough at an early onset, thus aiding timely decision making and improved recovery from the well. Real time analysis of tracers have attracted attention for quite some time now. The paper also discusses the latest development in this area and the challenges associated with real field applications.
While advancements in versatility of the tracer molecules have been published prior in literature, to the best of the authors’ knowledge, no work has been published to date that discusses the latest advances in unconventional uses of the tracer molecules aiding EOR and IOR processes.
Key Success Factor for High Power Laser Deployment: Strategy and Execution
Authors: Batarseh Sameeh , San Roman Alerigi Damian Pablo , Al Harith Abdullah 
Published: March 2023

Abstract
This paper presents the strategy and execution that led to the industry's first successful deployment of a high-power laser in the field. The development encompassed various aspects: administration, technical, lab-to-field transformation, and intensive research.
One of the primary success factors was identifying potential technologies and forecasting their evolution. High-power lasers were selected for the upstream applications because of their capabilities and successful use in almost every industry, ranging from medical to the military; it attracted the industry due to its unique features, such as precision, reliability, control, and accuracy. High-power lasers at the early stage (generation) were not applicable for downhole applications due to their relatively lower power levels. However, it has been utilized widely in several applications, such as sensing, measurements, and others. The objective of this program is to utilize the new generations of higher-power lasers in several upstream applications. The program is strategically designed to reduce the risk and increase success. In the initial stage, the work focused on the feasibility and characterization of intervening physics. The goal was to answer fundamental technical questions, such as "can lasers penetrate all types of rocks? What are the limitations? What is the effect of the laser on rocks?" The research spanned the last two decades, culminating in the development of the first field prototype of a high-power laser system.
The work proved that near-infrared multi-kilowatt lasers (hereon high-power lasers or HPL) could perforate and process any rock type at different conditions, including in-situ testing and liquid environments. The experimental plan was designed systematically and divided into phases, starting from fundamentals to advance. Prototype tools were designed, tested, and upscale for field deployment. All applications can be performed with the same HPL source -only the optical head needs to be changed.
High-power laser technology is an alternative to conventional methods of subsurface energy extraction, such as perforation, descaling, and drilling. It is cost-effective, compact, versatile, waterless, energy-efficient, and environmentally friendly, thus enabling sustainable field operations.
Hydrolysis-Promoted Polymerization of Furfuryl Alcohol: Selective Method for Mitigating Excess Water Production in Oil Wells
Authors: Cairns Amy J. , Saini Rajesh K. , Chang Fakuen F. 
Published: March 2023

Abstract
Water production during hydrocarbon extraction is a major problem for the upstream oil and gas industry. The challenge posed for operators is the increase in operational costs pertaining to separation, treatment, and disposal processes, amongst others. A wide assortment of scenarios can lead to unwanted water production from wells in hydrocarbon producing zones such as casing leaks, cusping, water breakthrough due to the presence of natural fractures or high permeability streaks, etc.
Methods of treatment are not a one-size-fits-all approach but range from being simple to more complex. To best mitigate the problem, particularly in the long-term, it is necessary to perform a thorough evaluation to understand the location and cause of the water production. Key existing solutions use mechanical devices, chemical methods, or combinations thereof to form a semi-to-impermeable barrier to prevent the flow of water from reaching the wellbore. While potentially very effective, the longevity of such methods is hindered by lack of efficiency, selectivity, stability, high cost and placement risks in relation to the completion type.
Here, we report on the development, formulation, and performance evaluation of a robust thermoset resin system that is inherently selective for blocking water -bearing zones in oil producing formations. The strategy behind this approach is based on acid-catalyzed polymerization of furfuryl alcohol. Specifically, use of judiciously selected acid-generating precursors, namely ester-containing compounds that are hydrophobic in nature. Under suitable reaction conditions, hydrolysis takes place at the interfacial boundary thereby releasing acid and directing blockage specifically to the water zone via resin formation.
The resin system has been formulated for application in carbonate or sandstone reservoirs with temperatures up to 150 ˚C and set times up to 48 h. In this study, an overview of our down-selection process for ester selection guided by static bottle test results and regained permeability data obtained under reservoir conditions using a coreflood apparatus will be discussed.
This chemical method for mitigating excess water production in oil wells is configured to selectively plug the water producing zones without affecting the oil producing zone. Instead, it is proposed that suitable chemical placement can be achieved by bullheading the treatment into the formation thereby reducing operational complexity and cost.
Laboratory Assessment of Rock Wettability Effect on Polymer Retention in Carbonates
Authors: Hernández-Morales Álvaro , Mushtaq Muhammad , Sebastian Anoo , W. Al-Shalabi Emad , AlAmeri Waleed 
Published: March 2023

Abstract
Polymer retention is one of the controlling aspects of an effective polymer flooding process. Very few studies discussed the effect of rock wettability on polymer retention, with no consensus on the outcome. While some studies described that oil-wet rocks have low polymer retention, others reported the opposite. This work investigates the effect of rock wettability on the retention of an ATBS-based polymer onto carbonates at high salinity and moderate temperature conditions. In this study, static and dynamic retention tests of an ATBS-based polymer onto high permeable Indiana limestone outcrops were conducted in both absence and presence of oil. These tests were conducted at 50 °C using representative crude oil and formation water (167,114 ppm) of Middle East carbonate reservoir conditions. For the two-phase dynamic tests, the cores were aged at 90 °C for different times (8 hours, 3 and 14 days) to create different wettability conditions, which were verified by Amott index to water. Then, polymer retention and in-situ rheology, including RF and RRF, were determined. Similar procedure was followed for dynamic single-phase tests, but without core aging. Furthermore, single- and two-phase static tests were conducted under identical experimental conditions to compare the retention values.
The results of Amott index to water showed that the selected aging times were suitable for creating different wettability conditions, where cores with longer aging times had a wettability more towards oil-wetting state. It was observed that three-days period of aging was enough to restore the wettability of Indiana limestone outcrops used in this study. Also, polymer dynamic retention was found lower in the presence of oil by about 35 to 47% as opposed to its absence. A further decrease in polymer retention by 14% was obtained for cores with a more oil-wetting condition resulting in a retention level of about 25 µg/g-rock. This is because oil-wet cores have a larger and effective surface area covered by the oil film, leading to a lower surface area left for polymer adsorption as opposed to cores with a wettability towards a more water-wetting state. On the other hand, single- and two-phase static adsorption tests showed non-comparable and very high retention values in the range of 305-337 µg/g-rock. This finding indicates that aging of the rock in such tests does not play a decisive role in obtaining representative polymer retention levels comparable to the dynamic tests. This study is one of the very few works that discuss the effect of rock wettability on polymer retention in carbonates. The study provides an essential insight into the inconclusive results in the literature by highlighting the role of wettability effect on polymer retention based on both static and dynamic retention tests.
Microfluidics for Carbonate Rock IOR: Some Lessons From Fabrication, Operation and Image Analysis
Authors: Duits Michael H.G. , Le-Anh Duy , Ayirala Subhash C. , Alotaibi Mohammed B. , Gardeniers Han , AlYousef Ali A. , Mugele Frieder 
Published: March 2023

Abstract
After successful implementation of Lab-on-a-chip technology in chemical and biomedical applications, the field of petroleum engineering is currently developing microfluidics as a platform to complement traditional core flooding experiments. Potentially microfluidics can offer a fast, efficient and low-cost method to screen many variables like flooding brine composition, reservoir temperature and aging history. We addressed this potential for the waterflooding of carbonate rocks. Using thermostated glass micro- models with rock-inspired ‘dual depth’ pore geometries as a basis, we explored i) introduction of calcite chemistry into the chip, ii) monitoring of changes in fluid composition and iii) quantification the residual oil from visualization. The development aspects of these efforts are the scope of the present paper.
Glass microchannels were functionalized by firmly attaching calcite nanoparticles to the inner surfaces and expanding them via seeded growth. Optical microcopy allowed to monitor the calcite distribution if the particles were not covered with crude oil (CRO). The calcite coating density could be steered, but also showed variability within the chip and between chips. Measurement of residual oil saturation (ROS) from optical microscopy is more challenging in the presence of calcite particles, due to their darker appearance. However, comparing the dynamic intensity of individual pixels with those in CRO- and brine-filled chips, allowed us to not only accommodate the calcite-induced optical differences, but also to find a correlation between calcite coverage and ROS. Our developed data analysis scheme, based on mask overlaying and image registration, also allows a sensitive monitoring of ROS, for both short (30 s) and long times (8 days) using low (2X) magnification Additionally captured high-resolution (10X) images reveal vital details underlying the global oil displacement. Implementation of more on-chip characterization tools could significantly contribute to a better mechanistic understanding of the IOR process. Non-invasive add-ons like Raman microscopy or chemically inert dyes could be implemented directly. Incorporation of electrode sensors will only be efficient if the chips can be re-used, which is currently not the case. This paper uses results from published works and unpublished data to reflect on the development of the microfluidics-for- testing IOR technologies. Our identification of possibilities and technical challenges in IOR on calcite- coated chips should be helpful in future designs of microfluidic research studies.
Real-Time Borehole Breakout Identification Utilizing Ultrasonic Amplitude Images in a Slim Borehole
Authors: Al Zayer Mohammed , Solial Ali , Taher Ahmed , Al Maimani Ali 
Published: March 2023

Abstract
Wellbore deterioration and breakouts can be mitigated by following proper drilling practices and drilling fluid optimization techniques. While conventional LWD tools can help in identifying borehole breakouts, advanced ultrasonic amplitude images can be utilized to identify borehole breakout intervals and additionally determine their widths to enable safe mitigating actions while drilling. Ultrasonic amplitude images depend on impedance contrast to reliably identify borehole shape and features.
Breakout identification depends on the contrast in properties between the formation and the mud, and historically density and photoelectric images have been used for this purpose. Using ultrasonic imaging tools, breakout can be identified using azimuthal variations in measured amplitude. The ultrasonic imager can be used to determine the orientation of breakout intervals with improved resolution compared to conventional tools, and the image can be transmitted to surface through mud-pulse telemetry. Pre-planning is critical to optimize the tool settings, including the firing voltage and frequency.
Pre-well modelling combined with real-time data is critical for drilling the well safely, and a pre-well geomechanics study provided an optimum mud-weight window based on offset-well analysis. The ultrasonic imager provided high-definition images for mud-weight optimization and gave insight into breakout width and direction in real time. In combination with other real-time measurements, the image was utilized to help stabilize the borehole and avoid hole deterioration by identifying the zones experiencing extensive wellbore damage. Time-lapse analysis provided critical information for understanding how such deterioration developed over time.
This is the first application of amplitude images in a slim borehole for real-time geomechanics. The data helped with optimizing the mud weight and provided critical information for optimizing the completion design and anticipating problematic intervals. The acquired data was further utilized to study the effectiveness of pumped bridging material and together with time-lapse data will provide critical information to improve future wells in similar environments.