bluuebunny/crossref_metadata_2025_split huggingface dataset:
Smart Water Flood in Carbonate Reservoirs: an Integrated Analysis Through Zeta Potentiometric and Simulation Studies
Authors: Srivastava Vivek Raj , Sarma Hemanta Kumar , Mitra Sujit , Gopal Giridhar , Gupta S. K. 
Published: February 2024

Abstract
Smart waterflooding (SWF) is the science of injecting water of reduced salinity or modified potential determining ions (PDI) concentration in petroleum reservoirs for a specific brine/oil/rock system to obtain higher oil recovery efficiency. The study validates the surface interactions by zeta potentiometric measurements, estimates oil recovery, and generates relative permeability by core flood simulation through laboratory inputs, using in-situ samples of oil, water, and rock samples from one of the Giant offshore fields of India.
The main emphasis of this paper is on 1) Varying the ionic composition of the injection water and reducing salinity for injection purposes; 2) Tuning the concentration of PDI (Ca+2, Mg+2 & SO4-2) ions after fixing a reduced salinity, the surface ionic chemistry between carbonates and water results in altering the rock wettability; 3) Surface charge of oil-saturated whole core samples of rock in the presence of various diluted and smart brines were estimated by zeta potential measurements;4) Smart water flood for incremental recoveries; 5) Single porosity simulation model to match oil recovery and pressure profiles obtained from smart water floods.
The main conclusions of the study are 1) Wettability alteration in the carbonate rock tested to a more water-wet state by tuning the ionic concentrations of injection brine; 2) Zeta potentiometric studies with low-salinity waterflood (LSWF) in carbonate reservoirs can achieve positive results by: Increasing the concentration of sulfate ion to increase the zeta potential of the rock surface to an optimum level above which the deposition of calcium sulfate will not become a problem;Tuning the concentration of divalent cations, preferably calcium, such that the value of zeta potential is close to zero. At this stage, a weak bond exists between the oil and the rock surface due to a weak negative charge on the oil and a weak positive charge on the rock surface;Increasing the hydrophobicity of oil by dilution of injected brine which seems to be responsible for increasing the zeta potential and detaching the oil from the rock surface. This is due to electrical double-layer expansion which is principally caused by reduced ionic strength.
3) Smart flooding experiments indicated an increase in the overall recovery factor; 4) A positive shift in the oil relative permeability curve towards the right.
The novelty of the paper is manifested by the following findings: Potential of PDI for carbonate reservoirs at a high-temperature range and an optimum concentration of PDI, at which maximum oil recovery is possible.Confirmation of Smart water flood effect in offshore carbonate reservoir through wettability alteration.A more efficient method as compared to sequential dilution.Underlying mechanisms of waterflooding involving the chemistry of injection brine in a carbonate system are investigated.
Pushing the Limits of Coiled Tubing Intervention in Mega-Reach Wells: A Success Story Offshore India
Authors: Mirani A. , Tripathi S. , Srivastav A. , Chandak R. 
Published: February 2024

Abstract
Coiled Tubing (CT) operating envelopes have become challenged by the increasing length of lateral sections in extended-reach wells. CT was deployed in a 3800 mMD, mega-reach, offshore well with a 2600 m lateral section and a Measured Depth (MD): Total Vertical Depth (TVD) ratio of 3.2 to perform fishing and sliding sleeve manipulation jobs. Customized CT intervention solutions designed to perform these job objectives are presented in this paper.
A tailor-made hourglass-type 1.75 in CT string was designed since the weight limitations of the rig crane prevented the possibility of lifting 2 in CT onto the platform. A customized Bottom Hole Assembly (BHA) with self-centralizing components and an Extended Reach Tool (ERT) was used to improve CT reach while maintaining the ability to pass through shouldered profiles in the completion jewelry. Laboratory tests on various lubricants yielded a suitable metal-to-metal Friction Reducer (FR) to use while running the CT to reduce drag, prevent lock-up, and further improve CT reach in the well.
The first objective of the CT intervention was to retrieve a wireline tractor stuck between two gas lift valves. The fishing BHA comprised a mechanical JDC type pulling tool and a customized bell guide to engage the top of the fish. A hydraulically activated downward impact tool with an ERT was included in the BHA to improve the achievable set-down weight at the target depth and increase the likelihood of engaging the fish. The fish was then successfully retrieved in under 24 hours. Once retrieved, sliding sleeves in the lower completion were now accessible for CT-based manipulation. The sleeve manipulation BHA comprised a mechanical BO type shifting tool with an ERT to perform selective profile manipulation. FR was pumped along the heel section of the wellbore to achieve a friction coefficient reduction of nearly 30%, which improved CT reach and maximum set-down at the BHA. The operation was complete once the sleeve manipulation was performed successfully and the well was put on production.
CT intervention in Extended-Reach (ER) wells is technically challenging and operationally complex. Furthermore, available literature and case histories on this topic are sparse. This paper presents key learnings from both the planning and execution stages that made this challenging job successful. It aims to serve as a reference for operators and service companies to plan, develop, and execute similar CT well intervention solutions.
Improvement of Flow Coefficient Estimation with Limited Well Test Data for Real-Time Condition Analytics of Choke Valve
Authors: Visawameteekul T. , Kam T. , Thamvechvitee P. 
Published: February 2024

Abstract
The study discusses a method for monitoring the internal condition of choke valves to predict sand erosion using flow coefficient (Cv). The method calculates the Cv of the choke valve by utilizing eight parameters and compares it to the newly manufactured value to generate warnings. However, the availability of spot-check well test data can significantly impact the model's efficiency if tests are performed infrequently. To address this issue, the Extended Cv monitoring method is proposed in this paper.
The main purpose of this study is to develop a model for estimating Cv value in the absence of well test data. This will enhance the present Cv monitoring system, which currently only monitors the valve when the well is being tested. This study aims to bridge a gap in the Cv monitoring approach by evaluating wellhead operational data and dynamic well test data instead of relying on only static well test data. The proposed supplemental data capture dynamic features and are collected continually, which allows us to analyze the internal status of choke valves in a continuous manner. Three representative wells from the Greater Bongkot South asset are chosen as showcases for the study. The study result indicates promising results for choke valve real-time condition monitoring.
The proposed method has been proven to enable online condition monitoring in the absence of well test data. By predicting valve condition, warnings can be generated to limit operation and prevent potential harm to plant integrity and personal safety. The Extended Cv monitoring method overcomes the limitation of the well test-based model, making it more efficient by utilizing continuously measured parameters data and employing machine learning techniques.
This paper provides a useful reference for future studies to forecast Remaining Useful Life (RUL) of choke valve. The method presented in this study has the potential for expansion to other wells and has the potential to be applied in other industries facing similar issues. Overall, this study provides a valuable contribution to the development of methods for monitoring and predicting the internal condition of choke valves to address the challenges of sand production in the oil and gas industry.
Performance Evaluation of Alkali Activated Kaolinite Clay as Oil and Gas Geopolymer Cement
Authors: Melia A. , Gbadamosi A. , Agi A. , Oseh J. , Junin R. 
Published: February 2024

Abstract
With the increasing awareness against global warming, it is imperative to substitute Portland cement that has been used in the oil and gas industry due to huge emission of carbon dioxide (CO2) associated with its production Recently, geopolymer cement has been identified as a suitable alternative because of its environmentally benign nature and can meet the specifications of oil and gas wells. The use of kaolinite clay, which comes from natural resource as the base material contributes to the environmental sustainability and makes the cementing material cost-effective. The aim of this research is to study the effect of several external exposures curing temperatures and hydration time on kaolinite clay based Geopolymer cement. Firstly, two samples were prepared under four different curing temperatures including ambient temperature (23°C), 40°C, 60°C, and 80°C. The strongest samples from four curing temperatures were taken and cured at three different hydration times of 24 h, 72 h and 120 h. To determine the acid resistance of the samples, they were soaked in acid solution for 24 h and 72 h, 3%/12% of HF/HCl. The result shows that geopolymer cement appeared to have higher compressive strength under higher temperature and acidic condition. Moreover, geopolymer cement has better mechanical properties compared to conventional cement. The outcome of this study is beneficial for ensuring environmental sustainability in oil and gas well cementing process.
Effect of Surfactants on Oil/CO2 Minimum Miscibility Pressure of Unconventional Liquid Reservoirs-Molecular Dynamics Simulation Study
Authors: Dong Zhenzhen , Hou Tong , Ma Xinle , Lin Keze , Li Weirong , Qian Shihao , Xu Haobin , Ma Xueling 
Published: February 2024

Abstract
CO2 flooding has been identified as an effective method for enhancing the recovery rate of unconventional oil and gas. However, in many oilfields, the miscibility pressure of CO2 with crude oil exceeds the oilfield pressure, preventing them from achieving miscibility. This impedes the desired recovery outcomes. Surfactants present a solution to this challenge, as they can reduce the miscibility pressure between CO2 and crude oil, thereby elevating the recovery rate. Yet, the microscopic dynamics of how surfactants modulate the MMP in CO2 flooding within ULRs remain under-explored.
This research aims to delve into this gap, using molecular dynamics to elucidate the underlying mechanisms and potential benefits of surfactant inclusion in CO2 flooding applications for unconventional reservoirs.
Our study, rooted in molecular dynamics, seeks to demystify these dynamics and understand surfactants’ role more profoundly. Delving into the CO2-n-decane system, we discovered that C12PO6 and SW320 significantly alter the interfacial width by forming a molecular film, which enhances CO2's solubility in crude oil. Notably, SW320 emerged as more potent than C12PO6 in this regard. Both C12PO6 and SW320 managed to reduce the MMP of the CO2-n-decane system by more than 15%. However, when it comes to cost-effectiveness, C12PO6 shows a compelling balance between performance and affordability. Further insights revealed that the structure of the C12PO6 surfactant plays a crucial role in determining its MMP reduction capacity. Intriguingly, the addition of low carbon alcohols, especially n-pentanol, enhances the C12PO6 surfactant's surface activity, underscoring its superiority over ethanol in reducing interfacial tension.
In essence, this research offers a microscopic lens to view the intricate dance of surfactants in CO2 flooding within ULRs. Our findings provide a robust framework for refining recovery strategies in unconventional reservoirs, potentially transforming the landscape of CO2 flooding methodologies to ensure more sustainable and efficient oil and gas extraction.
Adsorption Characteristics of CO2, CH4, H2S in Kaolinite Nanopores with the Implications for Carbon Sequestration
Authors: Qian Cheng , Hu Hao , Liu Chen , Liu Yueliang , Zhao Yang , Rui Zhenhua 
Published: February 2024

Abstract
The sequestration of carbon dioxide (CO2) in shale formation has dual benefits of reducing carbon emissions and enhanced oil recovery (EOR). CO2 purified from industrial waste gas is the main gas source for CO2 injection into oil reservoirs, but industrial waste gas may contain impurities such as hydrogen sulfide (H2S). Impurity gases may impair carbon storage and EOR via competitive adsorption. Consequently, it is worthwhile to evaluate the adsorption characteristics of CO2, CH4, and H2S within kaolinite nanopores and their implications on carbon sequestration and CH4 recovery. Drawing upon the kaolinite nanopores model, the impact of various surfaces on the adsorption characteristics of CO2, CH4, H2S, and their mixes was examined using the Grand Canonical Monte Carlo (GCMC) methods. Various factors, including temperature (293.15-383.15 K), pressure (0-20 MPa), pore width, and gas mole fraction, are investigated in the adsorption behaviors of the mixtures in the nano-confined space. The quantity of three molecules adsorbed enhances as pressure grows and falls with rising temperature. The rank of absolute adsorbed amount is H2S &gt; CO2 &gt;CH4. The interaction energies of kaolinite with CO2, CH4, and H2S at 20 MPa, 293.15 K are −1421.1138, −479.0825, −2528.245 kcal/mol, respectively, and Van der Waals energy is the main component of interaction energy. Compared to 1 nm hydrophobic pores, the loading of H2S, CO2, and CH4 in hydrophilic pores under 323.15 K and 20 MPa is 22.76%, 13.17%, and 11.57% greater, respectively. The adsorption of CO2 and CH4 are negatively impacted by H2S, and the adsorbed CO2 and CH4 are reduced by roughly 59.66% and 87.11%, respectively, at 25% (molar fraction) H2S. The nanoscale mechanism of gas adsorption in the clay mineral was disclosed from a molecular perspective, which theoretically supports the application of CO2 storage and EOR projects in shale reservoirs.
A Machine Learning Based Data Driven Approach to Obtain and Estimate Potential CO2 Storage Assessment Using Sub-Surface Data Through Relative Carbon Storage Index Parameter
Authors: Tan K. , Roy S. , Consoli C. , Sakimoto N. 
Published: February 2024

Abstract
In efforts to achieve net-zero greenhouse gas emissions (GHG) by 2050, realizing a carbon-netural and decarbonized society, the Japanese government has initiated various projects from developing geothermal energy and hydrogen fuel cells to carbon capture storage.
Domestic and overseas CO2 storage exploration projects include the search for deep saline aquifers, depleted hydrocarbon fields (through EOR or re-purposing for long-term carbon sequestration), and un-mineable coal seams. Since geological storage is the primary focus, attention will be concentrated in this first phase on basins with saline aquifers and depleted fields.
Funded through National Low Emissions Coal Initiative, the Petrel sub-basin had been found to be suitable for the geological storage of CO2. This basin had also been identified to be one of the potential basin storages through a regional site screening study to find prospective basin and potential storage resource calculation using the rapid and cost-effective screening fairway method which maximizes the use of any available data, and helps to high grade fairways for further assessment (Uren et al, 2022).
Automated Machine Learning for Lithology Prediction Derived from Seismic Data
Authors: Qaedi K. , Barker S. M. , Simanjuntak A. , Tan T. Q. 
Published: February 2024

Abstract
Lithology prediction is important for oil and gas exploration to understand the complex geological features. Machine learning techniques have shown great results in the quest to understand the complexities of seismic data. Developing an accurate machine learning model is a challenging task due to complex geological data that is limited and noisy data. The study presents Automated Machine Learning (AutoML) that can handle the intricacies of seismic data for lithology prediction. A dataset comprising 14 vertical well locations was utilized to extract seismic information along the wells and lithology data based on the gamma ray log. The extracted features serve as the input for AutoML, an automatic algorithm selection process that utilizes the Bayesian optimization algorithm to identify the best-performing model. The extracted features are used as inputs for AutoML, an automated algorithm selection process that employs Bayesian optimization to determine the best-performing model. The results indicate that the Ensemble model outperforms other algorithms, achieving an accuracy of 89%, specificity of 77%, precision of 82%, F1-score of 90%, and a Matthew Correlation Coefficient (MCC) of 79%. In conclusion, the application of a classification AutoML model has demonstrated a high level of efficacy in accurately predicting lithology derived from complex seismic data. This approach effectively captures the intricate relationships and patterns within the seismic data, enabling dependable lithology predictions.
Adaptive Strategy in Execution of Crown Plug Retrieval at the First Deepwater Subsea Workover Campaign
Authors: Sare Johanes , Binilang Ronald , Pande Batara , Herputra Shanni , Rossi Massimo , Rachmat Basuki , Prayogo Denny , Melly Recia Karina 
Published: February 2024

Abstract
A thorough planning and preparation is very critical to ensure a successful deep-water subsea workover campaign particularly the first one in the country. A reliable back-up plan played important role in this subsea operation where the hydraulic stroking tool with the support of other downhole robotic tools, that once a contingency became the main procedure due to the successful crown plug retrieval when the conventional solutions failed.
This paper will present the planning, process, execution and lesson learned during the operations.
Wireline intervention has always been prepared for various activities in recent subsea workover campaign including being the contingency of crown plug retrieval. The conventional way to retrieve crown plugs is using slick line jarring. If this method is not successful due to certain causes and equipment limitation due to water depth (ranging between 400 and 1500 meters), a hydraulic electric stroking tool will be run to pull out the crown plugs. This new advanced electric line stroking tool is a proven and reliable solution to remove the plugs that can apply axial force up to 100,000 klbs using bi-directional hydraulic ram. In addition to the stroking tool, a detail procedure was developed involving cleaning the landing string prior RIH and deploy suction tool on the top of crown plugs to make sure that GS pulling tool run with stroker able to latch on to the crown plug.
In this campaign, at the first well from three wells workover campaign, the slick line was deployed first. On the first and second attempt, after more than 25 times, the GS pulling tool failed to latch. It was believed the crown plug fish neck was full of debris. The suction tool was run to clean out the debris subsequently after confirming the crown plug was clean, the stroking tool was run and pulled out the upper crown plug in one stroke. The lower crown plug was also successfully retrieved with the same method. From being the contingency, now deploying the electric line stroking tool continued to the second and third wells as main activity with improved operational procedure by capturing the lessons learned from each well. The operator would have added more rig days for rigging up and down the coil tubing unit to retrieve the crown plugs. This emphasizing how significant to have a very well-planned contingency solutions and being agile to overcome the challenges in the deep-water.
CFD Simulation of Factors Affecting Gas Hydrate Particle Deposition in Gas Wells
Authors: Chen Shun , Dong Pingchuan , Zhang Youheng , Cheng Peizhai , Yang Bingtao 
Published: February 2024

Abstract
Hydrate deposition has significantly reduced production and generated associated financial losses. Gas hydrate wellbore deposition research mostly considers the cohesiveness of hydrate particles and their adhesion to pipe walls, but the virtual mass force, pressure gradient force, and other forces between particles are not taken into account.
This study improves the hydrate particle deposition model by taking into consideration the uneven distribution of hydrate particles in the wellbore caused by gravity. The momentum equation of the hydrate aggregate incorporates the pressure gradient force and virtual mass force. To predict the amount of hydrate deposition on the production tubing, the natural gas-water flow is simulated using an Eulerian-Lagrangian framework and the shear stress turbulence model. Lastly, a sensitivity analysis is executed to scrutinize the impact of a multitude of factors on the deposition quantity of hydrate aggregates on the production tubing. These factors encompass the Saffman lift force, virtual mass force, pressure gradient force, random collision, aggregation, fragmentation, and wall roughness.
The simulation results emphasize the significant role of the Saffman lift force in the deposition of hydrate particles. Neglecting this force leads to a substantial deviation from the actual results. As the particle flow rate and wall roughness increase, there is a marked increase in the amount of hydrate particle deposition. Conversely, an increase in particle density results in a decrease in the amount of particle deposition. Specifically, when the particle flow rate escalates from 2m/s to 4m/s, the average deposition amount surges by 81.9%. An increase in wall roughness from 0.1mm to 0.5mm results in a 15.8% increase in the average deposition amount. When the particle injection amount rises from 5e-7kg/s to 5e-5kg/s, the average deposition volume amplifies by a factor of 98. However, when the particle density increases from 900kg/m3 to 2000kg/m3, the average deposition volume diminishes by nearly 32%. These findings provide valuable insights into the dynamics of hydrate deposition. The results of this study will improve current understanding of the regulations governing hydrate deposition in gas wells and contribute to the safety of wellbore flow. They also have significant implications for the prevention and management of gas hydrate wellbore.
A Novel Hydraulic Fracturing Method to Enhance Stimulation Effect for Continental Shale Oil Reservoir
Authors: Zhang Lufeng , Guo Xusheng , Wang Xinliang 
Published: February 2024

Abstract
Horizontal well fracturing is a fundamental means of shale oil development. Due to the tight reservoir and difficulty in replenishing energy, horizontal well fracturing generally results in low production capacity, rapid decline, and low recovery rates. To accelerate shale oil development, it is necessary to develop fracturing technologies that increase production and recovery rates. The integration of terrestrial shale oil sources and reservoirs or the specific components in crude oil makes the reservoir more prone to oil wetting or complex wetting, which is not conducive to the extraction of crude oil. The extraction of movable crude oil can lead to rapid energy attenuation. The development direction of fracturing is to use tens of thousands of cubic meters of fracturing fluid to achieve deep matrix modification and energy replacement. In light of this, this paper proposed a new nano-emulsion fracturing fluid to enhance the stimulation effect. Based on the laboratory experiments, the interfacial activity, adsorption performance, wetting inversion, and spontaneous ambition of nano-emulsion were systematically evaluated.