bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimizing TVD Surveys in ERD Wells Minimizes Anticollision Risk
Authors: Al Hajri Hezam , Al Ghazzawi Ayman , Al-Yousef Fouad , Azher Mohammed , Madhi Adel Bin , Al-Mutairi Yousef 
Published: October 2018

Abstract
Typical well surveys are made once per stand, producing a 95-ft survey database; however, numerous things can take place in that 95 ft of pipe. Small changes in continuous inclination and azimuth lay hidden between traditional static survey stations. Processing these real-time measurements, in combination with traditional surveys, generates a definitive 10-ft survey list, resulting in an enhanced geometrical representation of the wellbore position. This enhanced wellbore positioning becomes increasingly significant in areas with high-anticollision risk. This type of survey processing was implemented in extended-reach drilling (ERD) projects in the Middle East. A comparison between the 95-ft surveys and the processed high-resolution surveys showed changes to 10 ft in the true vertical depth (TVD) measurements. Such shift in the TVD is important because it can result in having to revise planned trajectories to further minimize anticollision risk arising from the nearby TVD proximity with offset wells. This paper will present data to quantify the enhancement in TVD positioning using advanced survey processing in ERD projects in the Middle East, and its impact on minimizing anticollision risk.
A New Robust Approach for Hole Cleaning to Improve Rate of Penetration
Authors: Al Rubaii Mohammed Murif 
Published: October 2018

Abstract
Hole cleaning evaluation and prediction presents a challenge in drilling industry. The optimization of hole cleaning can reduce the down time during drilling operations. Good hole cleaning means high rate of penetration and less drilling problems. In this paper, a robust hole cleaning model is presented. It is based on monitoring and controlling simultaneously the carrying capacity index (CCI) and the cuttings concentration in the annulus (CCA) to ensure perfect hole cleaning. The cost of drilling can increase tremendously if not enough attention is paid to ensure proper hole cleaning. The knowledge of the size of cuttings, size of annulus, flow pattern, and down hole fluid properties cannot be determined with high level of accuracy using hole cleaning indicators such as transport ratio, hole cleaning ratio or transport index. Cutting concentration in annulus (CCA) alone cannot reveal the drilling mud properties, while the application of CCI alone will not help in optimizing ROP to the desired limit. The drilling parameters and mud rheological properties in certain hole sections were collected and analyzed first to determine the effect of mud properties and drilling parameters on hole cleaning and ROP performance. The data selected are from the same hole size, formation type and mud type. The relationship between mud rheological properties and CCI was then evaluated to determine how strong they are. This step helps determine the significance of mud rheological properties on estimating CCI. CCI and CCA were then simultaneously monitored and controlled to ensure proper hole cleaning leading to optimization of the Drilling operations and reduction in the drilling time. The data analysis demonstrated a strong link between rheological parameters and CCI. The approach was then validated by trial testing it in the field. The results showed that efficient hole cleaning level was achieved, which facilitated improvement of rate of penetration. It was used to drill in challenging hole sections and improved the well drilling performance by more than 55%, mitigated stuck pipe incidents, and eliminated wiper trips, reaming trips, and pumping of sweeps. The new approach or hole cleaning model showed the importance of combining CCI and CCA to optimize the drilling operations and reduce the time. This is the first time to combine the two techniques for hole cleaning optimization. The new hole cleaning model will help the drilling engineers drill a clean, stable hole in short time, and hence reduce the total cost of the drilling operations.
Correlating Dielectric Dispersion Data and Wettability Index of a Carbonate Rock
Authors: Al-Ofi Salah Mohammed , Dyshlyuk Evgeny , Sauerer Bastian , Valori Andrea , Ali Farhan , Abdallah Wael 
Published: October 2018

Abstract
Petrophysical models are used to estimate formation water saturation and salinity from dielectric dispersion data. These models are sensitive to other attributes of the formation such as wettability. Previous studies, analyzing different parameters of dielectric petrophysical models have shown how the dielectric dispersion is qualitatively influenced by rock wettability. Such analysis requires prior knowledge of the water saturation. To date, there is no direct method to quantify wettability from dielectric data.
In this work, we discriminate the effects of water saturation and wettability on dielectric dispersion data. We conditioned a 1.5-inch-diameter dolomite plug with solutions of different concentrations of stearic acid. In each set of experiments, we imbibed water into the sample and measured the dielectric dispersion in a frequency range of 10 MHz to 1 GHz using a reflection coaxial probe. This method enables us to obtain several dielectric measurements on a rock at defined wettability states and at different saturation levels. Then, the inverted dielectric interpretation answers such as water-phase tortuosity (MN) are analyzed for each dataset to distinguish their sensitivity to saturation and wettability. After each set of experiments, we measured the wettability index of the sample using US Bureau of Mines (USBM) and Nuclear Magnetic Resonance (NMR) methods and correlated it with dielectric inverted parameters.
Our findings show that the inverted interpretation parameters from dielectric data correlate well with the wettability index from USBM. These parameters include MN, the grain aspect ratio for the bimodal model, and the depolarization factors of water and oil-matrix of the textural model. We aged the sample into three wettability conditions: neutral-wet, strongly water-wet, and strongly oil-wet. For extreme wettability conditions, we observed a consistent trend of dielectric interpretation parameters with wettability during water flooding independent from saturation. For the neutral wettability case, the inverted dielectric parameters are constant up to a water saturation of about 50% and then starts to change gradually. For the strongly water-wet case, we observed a similar trend for depolarization factor as found in the literature, in which the nonwetting phase depolarization factor is close to the spherical geometry.
Our study illustrates how the inverted dielectric dispersion petrophysical parameters can correlate with well-established laboratory measurement of the wettability index, such as USBM method, for a specific core plug. This correlation can aid in estimating the wettability index directly from dielectric dispersion data for cores with similar rock textures. Different rock textures may impose different correlations, and further work is needed to establish a dielectric correlation for each rock type in a reservoir for application to downhole formation evaluation.
What is the Optimal Trajectory of Sidetrack Horizontal Well for Bypassing Obstacles in Cluster Wells?
Authors: Zhiyue Wang , Deli Gao , Jianjun Liu , Degao Hu , Wenrui Wu 
Published: October 2018

Abstract
Trajectory design of sidetrack horizontal well is faced with bypassing obstacles in cluster wells which makes the design process more complicated. The obstacle is assumed to be drilled trajectory sections such as vertical section and directional section, then they are described as a part of cylinder and annulus. Trajectory type for bypassing obstacle is classified based on geometrical relationship between tangent line of sidetrack point, tangent line of target point and axis of obstacle. The objective function is minimizing the total trajectory energy and the constraints include the safety distance to obstacle and the maximum build rate and maximum turn rate. Teaching-learning Cuckoo Search algorithm has been proposed to solve the established model. Case studies have been carried out according to different trajectory type, the results indicate that the proposed method can obtain sidetrack trajectory with minimum trajectory energy, in the meanwhile, the trajectory can avoid collision with obstacle and the wellbore curvatures are appropriate, the new method avoid trial calculation, it is also applicable to other types of sidetrack well trajectory for bypassing obstacles.
Petrophysics of Source Rock Reservoirs: A Complete Workflow
Authors: Eid Mahmoud , Abedeen Ainul , Kurri Janardhan 
Published: October 2018

Abstract
Source rock reservoirs have complex mineralogies and pore systems–their porosity varies from low to moderate, and their permeability varies from low to ultra-low and is in the nano-darcy range. The petrophysical evaluation of these complex reservoirs using only conventional logging tool (quad combo) data is highly complex and uncertain as a result of the tools’ limitation. Obtaining better and more certain petrophysical results for these reservoirs require integrating data from the conventional logging tool with the high-tech tools [elemental spectroscopy, nuclear magnetic resonance (NMR), dielectric, and spectral gamma ray].
It is challenging to calculate accurate porosity and water saturation values of source rock reservoirs using conventional log data. The presence of kerogen and complex mineralogies, such as conductive minerals, increases the difficulty. Because these petrophysical outputs are important for reserve estimates, any calculation error of these components directly affects the hydrocarbon in-place estimates. To address this issue, a new workflow has been developed to integrate data from conventional logging and high-tech tools.
This paper demonstrates a workflow designed to characterize source rock reservoirs by integrating data from conventional logging and high-tech tools. Additionally, this workflow helps provide accurate petrophysical outputs that are used later to estimate the correct hydrocarbon in place. This workflow was tested in multiple source rock reservoirs in the Middle East region. This workflow also provides mechanical properties (including Poisson’s ratio, Young’s modulus, closure pressure, and brittleness) of source rock reservoirs. The integration of rock mechanics and petrophysical results helps identify sweet spots that can be selected for fracturing operations.
Geomechanical Studies on CO2 Sequestrated Rocks in an Aqueous Saline Environment
Authors: Tariq Zeeshan , Abdulraheem Abdulazeez , Elkatatny Salaheldin , Mahmoud Mohamed , Muqtadir Arqam , Murtaza Mobeen 
Published: October 2018

Abstract
In a quest to reduce the greenhouse gasses, geologic sequestration of carbon dioxide (CO2) in an underground hydrocarbon rock formation or aquifer is one of the most promising alternative to reduce the amount of CO2 release in an open environment. However, long-term storage of CO2 effects the geomechanical and geochemical properties of the host rock. In carbonate aquifers, water dissolves the injected CO2 gas forming carbonic acid which has the tendency to dissolve calcium compounds present in the formation. The dissolution of calcium is particularly worrying since it contributes to the matrix of the rock. Thus, the mechanical properties of the rock are altered, which left unattended could result and in compaction of the formation and surface subsidence.
This paper aims to study the degradation of the petrophysical and mechanical properties of two types of rocks namely limestone and sandstone due to the storage of supercritical CO2 for desired amount of time. Supercritical CO2 has low viscosity but high density and has ability to store in large amount within the same space and with the high pumping efficiency. Two different carbonate rocks and one sandstone rock were exposed to a CO2-brine solution at a pressure of 1200 psi and at 120 °C for durations ranging from 10 to 120 days. The mechanical properties were then examined by both static and dynamic mechanical tests along with the routine core analysis (RCA).
Results showed that long term CO2 storage affected the mechanical, acoustic and petrophysical parameters of rocks examined in this study, viz., Khuff limestone, Berea Sandstone, and ordinary limestone. The duration of solubility time brine-CO2-rock has a considerable impact on the petrophysical and mechanical parameters of the rock samples. Outcomes of this study also shows that the rock mechanical and petrophysical properties significantly affected when CO2 store for the longer period of time. CO2, rock, and brine interaction is dependent on time consequently the rock mechanical and petrophysical parameters changes are also time dependent. The potential candidate found for geological sequestration of CO2 studied is limestone because of its minimal rock properties altered.
A Stochastic Optimization Approach for Profit Maximization Using Alkaline-Surfactant-Polymer Flooding in Complex Reservoirs
Authors: Tariq Zeeshan , Mahmoud Mohamed , Al-Shehri Dhafer , Sibaweihi Najmudeen , Sadeed Ahmed , Hossain M. Enamul 
Published: October 2018

Abstract
In heterogeneous reservoir formations, water tends to have early breakthrough due to the overriding and viscous fingering during secondary recovery. The overall hydrocarbon recovery efficiency remains very low in gas and water flooding projects because of less viscosity and higher mobility of water and gas. Therefore, there is an underlying need for improving recovery through a suitable chemical enhanced oil recovery (EOR) method. After investigating the feasibility of alkaline, polymer, surfactant, surfactant-polymer, alkaline-polymer and alkaline-surfactant-polymer (ASP) flood, ASP was selected as a chemical EOR method in low permeability heterogeneous reservoirs. However, the performance of the ASP flooding was highly dependent on operational parameters. Thus, it was important to select these parameters with extensive care to increase the recovery along with the profitability. The relationship between the ASP flooding operational parameters and profitability (NPV) has not been yet understood fully.
In this research, the new stochastic optimization approach to optimize the ASP flooding operational parameters has been proposed. To gain the objective of this research, a numerical simulation study was carried out and Particle Swarm Optimization (PSO) was implemented as an optimization algorithm. The net present value (NPV) served as the objective function that has to be maximized among the compared flooding processes. The used operational parameters were location of production and injection well, number of injection cycles, oil production rate, ASP injection time, ASP injection rate, alkaline-surfactant and polymer concentrations, surfactant and polymer viscosities. Sensitivity study of these parameters shows significant impact on net present value and ultimate oil recovery. Results also confirm that NPV is increased significantly after the optimization of all flooding parameters by using Particle Swarm Optimizer.
The new optimized model was developed for designing the ASP as a chemical EOR method in low permeability heterogeneous reservoir. It can be served as a handy tool for reservoir engineer to select the best ASP flood parameters to achieve maximum NPV.
The Accelerated Development of Young Professionals in an Integrated Environment
Authors: Alnahas Mohammed , Hamam Hassan , Sudirman Sharizan 
Published: October 2018

Abstract
An integrated environment consists of professionals from various backgrounds of engineering and geosciences that carry out tasks conjointly through advanced integrated technologies. In the oil and gas industry, the aim is toward developing the optimized field development plan as well as solving complex subsurface challenges. Young Professionals are integrated within the experienced professionals’ team to work on challenging tasks to develop their learning curve.
The Young Professionals’ development plan starts in the integrated environment - of engineers and geoscientists - by assigning them to mentors who are subject matter experts. Spanning from core analysis to reservoir modeling, the Young Professionals work on different tasks in parallel to gain a well-rounded knowledge base in an optimized timeframe. The Young Professionals initially start with simple tasks such as data mining and basic log analysis, before integrating into the more challenging tasks of decision making in modeling.
In an integrated environment, the Young Professionals get exposed to various tasks and concepts, accelerating the learning and development that would take much longer in a silo-type environment. As an added value, the Young Professionals develop their soft skills to communicate with the team and share their opinions.
As the Young Professionals excel in the simple tasks, more challenging tasks from different backgrounds are given to them to challenge and expand their critical thinking methods. Over a relatively short period of time, Young Professionals’ critical thinking methods are developed and they start taking the lead in tasks and even come up with out-of-the-box solutions to overcome the many challenges of developing and optimizing an integrated reservoir study.
Integrated environments provide unique opportunities for Young Professionals to unlock their full potential. Experts from various disciplines carry out their tasks through the Young Professionals. The interactive environment is a key factor in exposing Young Professionals to different challenges, scenarios, and solutions, which help in enhancing their development.
Efficiency of Selected Terpene-Based and Conventional Solvents in the Dissolution of Asphaltene Deposits
Authors: AlAamri Jamal , AlDahlan Mohammed , AlDarwesh Sajjad 
Published: October 2018

Abstract
The need for more efficient, cost effective, relatively high flashpoint, and environmental friendly organic solvent is crucial. Due to safety and environmental effects of the conventional aromatic solvents, efforts are being focused to search for more natural based products.
A total of 14 terpene-based and conventional solvents have been examined to identify their dissolving power of asphaltene/organic sludge. The organic solvents vary in their compositions from xylene or conventional based solvents to the more environmental friendly compounds of terpene (green solvents). They also vary in their flash points from as low as 75°F tod as high as 200°F.
The organic scale/sludge samples have been studied by thermogravimetric analysis (TGA), FT-IR, ESI-MS and asphaltene analyses. The analysis showed the contents of asphaltene, functional groups, saturation level and weigh loss of both deposits. Dissolution tests were conducted on both organic deposits using 11 terpene-based solvents and 3 conventional solvents. Dissolution tests were conducted at room temperature and 50°C with soaking times of 3 and 24 hours.
The solubility of deposit A at most of the solvents was found to be lower than the solubility of deposit B due to variation in both deposits’ compositions. Even though the increase of the soaking time was found to be of positive impact, most of the dissolving occurred in the first few hours. This study results also revealed that the efficiency of the terpene-based organic solvents is a function of terpene concentration; however, increasing the terpene concentration would decrease the flash point, which is of a safety concern in warm climate countries, especially during high temperature seasons. The environmentally friendly terpene-based solvents displayed promising results and can be an alternative to conventional solvents.
Wettability Evaluation by Fast Field Cycling NMR Relaxometry
Authors: Gao Jun , Kwak Hyung T , Al Harbi Ahmad M 
Published: October 2018

Abstract
Wettability is an essential concept to understand oil trapping due to adhesion and capillary forces, and it depends on the fluid/rock molecular interactions within the thin liquid layer on the pore surface. The conventional methods for wettability determination exploit its macroscopic averaging effects during various displacement processes. These methods are sufficient for general categorization; however, they are not easy to be used in the wettability alteration study, which is one of the most import oil mobilization mechanisms for carbonate reservoir. The direct characterization of the microdynamics of liquid molecules on the pore surface would provide not only the measurement of wettability but also the understanding of how added materials affect fluid molecular dynamics and alter the wettability for oil mobilization. This study is to extend the application of the newly developed nuclear magnetic resonance technique and Fast Field Cycling (FFC) NMR relaxometry to more fluids and rock samples as the first stage for the above objectives.
NMR dispersion (NMRD) profile by FFC NMR is a low field magnetic resonance technique, which measures the longitudinal spin relaxation over a wide range of Larmor frequencies determined by magnetic field strength. The dependency of spin-lattice relaxation rate on Larmor frequency allows to identify the liquid molecular dynamic patterns on the pore surface and determine the respective correlation times. NMRD affinity or wettability index was obtained from the time scales of the molecular translation and chemical exchange based on the dipolar interactions in the proximity of the paramagnetic spins. Only limited NMRD results of fluid/rock systems and saturation states were reported currently. This work utilizes a wide bore FFC NMR relaxometer to obtain NMRD on more fluids and rock samples of different mineralogy and analyzes their NMRD features with spin relaxation models.
The current study obtains the NMRD curves and qualitative affinity/wettability estimation for different fluid/rock system, including brine, mineral oil, crude oil, sandstone, limestone, and carbonate reservoir rocks. The dynamic patterns of liquid molecules are evaluated through NMRD features for their adhesive degree one the pore surface. The comparison with supposed wettability property indicates that they correlate well, and the wettability states are better understood through their molecular dynamics.
The NMRD measurement and interpretation of various fluid/rock systems extend its application; the determination of microdynamic patterns and parameters explains different wettability states from the molecular level. This study set the foundation for its application extended to fluid/rock systems at various saturation states and wettability alteration monitoring and optimizing during different oil mobilization processes.