bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intelligent Prediction of Acid-fracturing Performance in Carbonates Reservoirs
Authors: Eliebid Mohammed , Hassan Amjed M. , Mahmoud Mohamed , Abdulraheem Abdulazeez , Elkatatny Salaheldin 
Published: October 2018

Abstract
Acidizing joint hydraulic fracturing is a widely used technique to increase the fracture conductivity in carbonate reservoirs stimulation. Predicting acid fracturing performance for optimum fracturing job design requires a detailed understanding of acid-rock reactions, rock strength and the stress applied to the rock and their effect on the fracture conductivity. The available models have many prediction limitations to acidized fracture conductivity with closure stress. Artificial intelligence is suggested to obtain a more precise prediction for acid-fracture conductivity. Artificial neural network (ANN) and adaptive network- based fuzzy inference system (ANFIS) are used to develop intelligent models capable of delivering an accurate design to acid-fracture conductivity. Published experimental data from the literature is used to train the models. 70% of the data was used for training and 30% was used in testing. The results showed that both ANN and ANFIS models outperformed the currently available models. ANFIS subtractive clustering with 0.4 cluster radius showed the best match to experimental data with 1.36% average percentage error and 0.998 R2.
Cement Evaluation Challenges
Authors: Gowida Ahmed H. , Ahmad Zainaddin , Elkatatny Salaheldin , Mahmoud Mohamed 
Published: October 2018

Abstract
Cement Evaluation Logs are generally used to evaluate the quality of the cement sheath behind the casing or liner before a well test or production operation is performed in the well. In many countries, regulatory authorities require that cement evaluation logs be done in every well after cementing operations to investigate the presence and quality of the cement sheath. The main objective of the cement evaluation process is to evaluate the hydraulic isolation of the cement sheath. The main principle of cement bond log (CBL) tools is to send an acoustic signal inside the casing and measuring the acoustic impedance of the cement between the casing and the formation. The interpretation and processing of these measurements are sometimes complicated and difficult to understand because CBL can be affected by the downhole conditions and the input parameters for processing. Therefore, it is important to understand how the log is processed before planning for any remedial action based on the apparently poor cement quality obtained from the log. Also, there are some challenges such as lightweight cement, the presence of micro-annulus, and eccentricity of the tool itself may affect the measurement and the relating remedial action to solve the problem.
Conventional cement evaluation tools are useful in most scenarios, but in more challenging operations, there is a pressing need for more advanced cement evaluation techniques to increase the confidence of the measurements for the evaluation of wellbore integrity. This paper demonstrates ultrasonic cement evaluation tools principles and examples for evaluating the quality of the cement bond. Also, the most common challenges and conditions which affect the sonic signal and lead to falsely indication of effective cement integrity. The processed case studies highlight the confidence of the cement isolation identified using these tools and evaluation techniques and their impact on the upcoming remedy actions.
Feasibility Study of 3000m Horizontal Section of Jiaoye 2-5HF Horizontal Extended-reach Well in Fuling Shale Gas, China
Authors: Li Xin , Gao Deli , Hu Degao , Zheng Youheng , Liao Rugang 
Published: October 2018

Abstract
The accurate prediction and improvement of the maximum measured depth (MMD) of horizontal extended-reach well (ERW) play a major role in improving the economic benefits and avoiding drilling risks of horizontal ERW in Fuling shale gas, China. In this study, a model to predict the MMD of horizontal ERW is presented, and the MMD of Jiaoye 2-5HF well in Fuling Shale Gas is determined. The MMD prediction model is established based on the dynamic pressure balance of bottom hole and the restriction of drilling pump. Considering the bearing capacities of drilled formation and drilling pump, this paper predicts the MMD, especially the horizontal-section limit of Jiaoye 2-5HF well in Fuling shale gas based on the extended-reach limit theory, determining whether it can meet the drilling need of 3000m horizontal section. The results show that the well's MMD is 6928m, and the horizontal- section limit is 3985m according to the casing programme and drilling parameter of Jiaoye 2-5HF, which can meet the drilling need of 3000m horizontal section. The MMD first increases and then decreases with the increase in drilling fluid flow rate. In addition, the Jiaoye 2-5HF well cannot meet the drilling need of 3000m horizontal section when the drilling fluid flow rate is greater than 38L/s or the rated pressure of drilling pump is less than 23.5MPa. Furthermore, the constraint conditions for the extension ability of horizontal ERW under different drilling parameters are not the same, and the MMD values are also different. Therefore, it is necessary to calculate separately. This work provides a practical tool for predicting the Jiaoye 2-5HF horizontal well's MMD in Fuling shale gas. The study is significant to avoid drilling hazards, maximize reservoir contact and obtain good economic benefits of Fuling shale gas in China.
Measure the Effectiveness of Frac Sleeves Integrity in Multi-Stage Completions using Multi-Finger Caliper and Acoustic Flow-Analyzer
Authors: Saada Mahmoud , Ismail Moustafa , Lu Yanjie , Zhang Wenting , Rourke Marvin , AbdelMoula Mongi 
Published: October 2018

Abstract
With the increased demand of Hydrocarbons, the industry trend to continually develop the unconventional reserves and/or maximize the HC production; different wellbores are accordingly drilled and completed with multi-stage completions. Frac Sleeve in Multi Stage completion tend to show several integrity issues. Multi-finger caliper tool has a proven capability of assessing the wellbore obstructions and internal corrosive damage to tubulars.
Gathering appropriate logging data is important for monitoring well-head and annuli pressures. Evaluating the Frac sleeves integrity whether are closed or open as well as to look for deformation within the sleeves are of client's objectives to confirm its conditions. We will combine the caliper data with passive noise detection tools to confirm and understands the fluid flow behavior in the well-bore and behind casing. Same combination is used to assess the injection sweep efficiency and anisotropy.
Caliper 3D visualization and advanced noise detection processing software were used to quickly and precisely understand the condition of the Frac sleeves in several wells for the sake of injection assessment and for future remedial actions to the recommended sleeves. Also, through comprehensive analysis, caliper logs have been used to assess scale buildup, paraffin or other mineral deposits in the wellbore which could coat the perforations, casing, tubulars, valves, pumps and downhole equipment.
The proposed paper will summarize field results and data gathered from several passes across the Frac sleeves. Using the logging data, we will measure the effectiveness and integrity of the Frac Sleeve for the purpose of injection/production assessment.
A Numerical Analysis for Acid Bullheading Treatment in Oil and Gas Wells Using Lattice Boltzmann Method
Authors: Alruwaili Khalid M. , Noui-Mehidi Mohamed N. 
Published: October 2018

Abstract
Acid bullheading is a well-known treatment for removing downhole scale and formation damage in oil and gas fields. The treatment is performed by using a controlled percentage of hydrogen chloride, and is normally operated under restricted wellhead pressure for health, safety, and environment (HSE) and well integrity purposes. These constraints sometimes prevent the treatment to be more effective in removing formation damage and improving injectivity and/or productivity of oil and gas wells. The present work is related to a fundamental study of fluid invasion in different types of formation with regard to the designed acid bullheading setups. The results are compared and analyzed based on a numerical investigation for the same geometrical and dynamical parameters to assess the efficiency of the fluid invasion designed process. The new treatment design utilizes the concept of cyclic pressure by fluctuating the injection velocity. In this paper, a mathematical formulation of fluid flow invasion in a porous medium is presented using a lattice Boltzmann numerical analysis. This method uses a mesoscopic approach to solve the flow problem instead of using Navier-Stokes equations and giving good numerical accuracy. It mimics different formation porosities, injection velocities, and procedures over time. A qualitative comparison between constant and variable injection velocities was performed under a fixed period of time. The new simulation code visually demonstrates the growth of fluid invasion in the investigated domains and highlights clear differences between the two cases of continuous and cyclic injections. This approach presents a new design in matrix stimulation that could effectively optimize oil and gas treatment operations.
Well-Placement Optimization in a Novel Heavy Oil Recovery Process Using In-Situ Steam Generated by Thermochemicals
Authors: Moussa Tamer , Patil Shirish , Mahmoud Mohamed , Elkatatny Salaheldin 
Published: October 2018

Abstract
Determination of optimal well locations plays an important role in the efficient recovery of hydrocarbon resources. However, it is a challenging and complex task because it relies on reservoir, and fluid and economic variables that are often nonlinearly correlated. Traditionally, well placement optimization (WPO) has been done through experience and use of quality maps. However, reservoir management teams are beginning to appreciate the use of automatic optimization tools for well placement that will yield the largest financial returns or highest net present value (NPV). In addition, the performance of a reservoir is time and process dependent, therefore well placement decisions cannot be based on static properties alone. On the other hand, well placement optimization requires a large number of simulator runs in an iterative process, and thus several runs to reach the maximum achievable NPV. Therefore, there is a real need for automatic well placement approach that uses highly efficient optimization method, which can improve the result quality, speed of the convergence process to optimal result and thus decrease the time required for computation.
The objective of this work is to determine the optimal well locations in a heavy oil reservoir under production using a novel recovery process, in which steam is generated, in-situ, using thermochemical reactions. Self-adaptive differential evolution (SaDE) and particle swarm optimization (PSO) methods are used as the global optimizer to find the optimal configuration of wells that will yield the highest NPV. Comparison analysis between the two proposed optimization techniques is introduced. The CMG STARS Simulator is utilized in this research to simulate reservoir models with different well configurations.
Comparison of results is made between the NPV achieved by the well configuration proposed by the SaDE and PSO methods. The results show that SaDE performed better than PSO in terms of higher NPV after ten years of production while under in-situ steam injection process using thermochemical reactions. This is the first known application where SaDE and PSO methods are used to optimize well locations in a heavy oil reservoir that is recovered by injecting steam generated in-situ using thermo-chemical reactions. This research shows the importance of well placement optimization in a highly promising and novel heavy oil recovery process. This also is a step forward in the direction to eliminate the CO2 emissions related to thermal recovery processes.
Hybrid Carbonated Low Salinity Waterflood in Calcite-Cemented Sandstone: Effects of Low pH and Salinity on Oil Production and CO2 Storage
Authors: Lee Ji Ho , Hong Eun Ji , Kim Guan Woo , Lee Kun Sang 
Published: October 2018

Abstract
Hybrid carbonated low salinity waterflood (CLSWF) introduces synergetic effects of oil viscosity reduction and wettability modification. The technology injecting CO2-saturated low salinity water is a hybrid design of low salinity waterflood (LSWF) and carbonated waterflood (CWF). Coupled with geochemical reaction and equation of state (EOS) modeling, this study proposes compositional simulation of the CLSWF process. In a comparison to LSWF to quantify the synergetic effects, CLSWF introduces enhanced wettability modification effect due to geochemical reactions of ion-exchange and mineral dissolution. The low pH and salinity conditions during CLSWF dissolve significant calcite mineral to increase Ca2+ molality. It results in more cation-exchange and enhances wettability modification following LSWF mechanism. CO2 is transported from CO2-saturated low salinity water to oil during CLSWF. This interphase transport of CO2 reduces oil viscosity improving mobility ratio. As a result, additional oil production with 6% and improved injectivity are observed in CLSWF. In addition, CLSWF introduces CO2 storage effect. Despite of the interphase transport of CO2, significant CO2 is remained in water and captured in reservoir. Therefore, the novel CLSWF is shown to be a promising technology securing both enhanced oil production and CO2 storage.
High Efficiency Static Mixer Technology for Crude Desalting
Authors: Alhajri Nasser A. , White Ramsey J. , Oshinowo Lanre M. 
Published: October 2018

Abstract
A high-efficiency static mixer was installed at the inlet of a desalter vessel at a Saudi Aramco gas-oil separation plant (GOSP) under an initiative to field trial new technologies to enhance crude quality of low water and salt content, and to optimize wash water consumption used in the desalting. This paper describes a high-efficiency static mixer assessment through Computational Fluid Dynamics (CFD) modeling and an extensive field trial. The technology, which is the first of its kind implemented in Saudi Aramco, is a compact wafer style mixer with a specially designed orifice plate. Enhanced turbulent mixing of wash water with wet crude oil improves desalting efficiency, resulting in lower desalter outlet salt-in-crude concentration and/or reduced wash water consumption. The compact design of the mixer and the restricted lengths of upstream and downstream straight run piping requirements makes this mixer ideal for installation in congested areas without the adequate space for conventional spool static mixers. The high- efficiency static mixer produced a 17% reduction of wash water consumption after installation downstream the conventional mixing valves and upstream the desalter inlet at the Saudi Aramco facility while maintaining the salt-content at 5-6 pounds per thousand barrels of crude oil. A total saving of more than 8½ million gallons of wash water was achieved during the nine month field trial. Further analysis by Saudi Aramco, including CFD modeling, identified the potential to improve mixer performance and gain further reductions in wash water rates by optimizing the mixer location.
Recent Advances in Foamed Acid Fracturing
Authors: Karadkar Prasad , Bataweel Mohammed , Bulekbay Aslan , Alabdrabalnabi Mohammed 
Published: October 2018

Abstract
Foamed acid fracturing is gaining importance in maximizing flowback recovery and is particularly applicable when reservoir energy is not sufficient to effectively flow back the well. Laboratory studies and field implementations during the 1980s showed application of foamed acid in addressing three fundamental issues of acid fracturing such as reactivity control, fluid loss control, and conductivity generation but it was evaluated at low temperature and in shallow wells. Recently, foamed acid has been successfully utilized to energize reservoirs to enhance flowback recovery and restore production after treatment. This paper summarizes literature reports from the last 30 years, showing improved use of foamed acid for acid fracturing.
Foamed acid offers additional benefits such as retardation, deeper conductivity generation, reduced water consumption, and improved acid diversion. Foamed acid laboratory studies from literature such as foam stability, rheology, reaction kinetics, fluid loss, diversion characteristics, and dynamic acid etching is reviewed. Comparison of CO2 and N2 foamed acid is documented in this paper to define fluid selection criteria for a typical foamed acid treatment. Foamed acid rheology at different quality is also summarized in this paper from previous studies.
The dissolution of carbonate rock is controlled by reactivity, which is greatly reduced after foaming for the same acid strength and temperature. Foamed acid having 50-60 quality could retard 60-70% acid reactivity. Excessive fluid loss is one of the challenges in acid fracturing. Conventionally, fluid loss is mitigated by using synthetic polymers to viscosify acid that controls leakoff by depositing a low permeability filter cake on the face of formation leading formation damage concerns. Foamed acid does not build filter cake and showed excellent leakoff control. Proper reactivity and fluid loss control regulates conductivity generation in acid fracturing. Conductivity generation depends on kinetic parameters — such as acid type/strength, temperature, reaction time, and flow regime. These parameters affect the amount of rock removed during the acidizing process. Case histories from different regions where recent application of foamed acid is documented show placement strategies and lessons learned. A horizontal well in one case study was treated with N2 foamed acid to achieve a 2.5 fold increase in production. N2 and CO2 foam was used as foam diverter in acid fracturing, and the productivity index increased to 38% with the use of N2 foam while in other fields the productivity index increased to 3.25 fold with the use of CO2 foam.
Laboratory studies available in the literature are not adequate to design foamed acid treatment for high-temperature, high-pressure wells. This paper summarizes published literature showing improved use of foamed acid for acid fracturing.
Real-Time Monitoring and Evaluation of Actual Vs. Simulated Torque and Drag In Deviated, Long Lateral, Open-Hole Gas Wells
Authors: Hashmi Ahmad Atef , Duran Roberto , Kadura Ahmad , Vega Roberto 
Published: October 2018

Abstract
This paper describes the implementation of a system for evaluating actual torque and drag when running multistage fracturing (MSF) completion equipment in long, open-hole (OH) lateral sections. The process uses an important evaluation tool to compare with results from simulated scenarios, which helps with real-time decision making when actual parameters differ from those simulated.
Torque and drag (T&D) were simulated using different friction coefficients. Actual torque and drag data collected while performing a previous reaming trip were combined with caliper logs to evaluate the running-in-hole (RIH) of the OH MSF completion equipment. Real-time monitoring of the actual run and continuous evaluation provided important information that helped in avoiding sticking, as well as the high-circulating-pressure scenarios that led to loose OH laterals in similar previous wells. Using the evaluation tool significantly increased the success rate of running the OH MSF completion equipment in gas wells.
The torque-and-drag simulations enabled ease of operation when running the OH MSF completion equipment to the target depth. Various techniques are presented that were used in the torque and drag simulations to accurately predict real-time parameters and properly anticipate downhole variables while running in hole. Logging data from a caliper run performed on the OH formation were uploaded into the torque-and-drag software, which enabled a more realistic simulation. This helped to pass through expected tight spots and washouts in the OH. Additionally, the previous reaming trip provided valuable data concerning friction-factor coefficients; a torque-and-drag simulation of the reaming trip was performed, and the differences in parameters while running in hole were monitored. The friction factors were adjusted to match the actual parameters of the reaming trip, and those same friction factors were then used to simulate the OH MSF completion. This technique provided a more suitable reference in terms of expected parameters.
Running OH MSF completion equipment in a long, lateral OH poses significant risks for sticking or decreased circulating capability, particularly in wells drilled in the minimum stress direction. Adding the evaluation process to the existing real-time monitoring system allows for predicting adverse scenarios before they become irreversible; thus, the modeling increases the likelihood of successful system deployment, which, in turn, allows for a quicker turnaround to production.
A Theoretical and Practical Comparison of Capacitance-Resistance Modeling With Application to Mature Fields
Authors: Temizel Cenk , Salehian Mohammad , Cinar Murat , Gok Ihsan Murat , Alklih Mohamad Y. 
Published: October 2018

Abstract
With the advances in data-driven methods, they have become more widely-used in analysis, predictive modeling, control and optimization of several processes. Yet, as it is a relatively new area in petroleum industry with promising features, the industry overall is still skeptical on use of data-driven methods as it is a data-based solution rather than traditional physics-based solutions. In this sense, in order to shed light on the background and applications in this area, this study comparatively evaluates one of the methods used in waterflood surveillance and optimization called capacitance-resistance model illustrated on two types of mature fields with high and low-perm characteristics.
Data-driven methods serve as a robust tool to turn data into knowledge. Historical data generally has not been used in an effective way in analyzing processes due to lack of a well-organized data where there is a huge potential of turning terrabytes of data into knowledge. A capacitance-resistance model is built to identify the well connectivities between the wells and then carry that knowledge to better reservoir management through optimization of injection and production in two different sets of data.
In CRM modeling, analysis of injection/production data at associated injectors and producers reveals the connectivities and further optimization leads to optimum injection values. Steps and the methodology of building a CRM model using real data is illustrated to exemplify the whole process in a comparative way between two mature reservoirs. We introduce the concept of application of spatial constraints in terms of injection-producer maximum influence radius to accelerate and improve the solution where knowledge of radius of influence for an injector is known by historical data and experience.
The theoretical and practical information is supported with mature field examples to investigate the factors affecting the performance of vertical wells in tight and intermediate-permeability reservoirs along with the outline of the major challenges and how to solve them. This study also illustrates the challenges of application of CRM on a tight reservoir in the order of 0.1md and comparison of the application of the method on a more intermediate-perm reservoir. Field data used in this study is from publicly available, open access source, Division of Oil, Gas & Geothermal Resources (DOGGR) website - http://www.conservation.ca.gov/dog