bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Scalable Numerical Solution Method for Fine Scale Compositional Simulation
Authors: Wang Baohua , Xu Mingyuan , Li Qiaoyun , Li Hua , Jia Han , Fan Tianyi , Wu Shuhong 
Published: February 2024

Summary
Nonlinear iteration is a very important part of reservoir numerical simulation. If the iteration steps can be reduced, the speed of the iteration and the reservoir numerical simulation will be helped greatly. In this study, a self-equilibrium Newton method has been explored for nonlinear system of compositional simulator, which is composed of inexact Newton method, non-negative constraint line search method of molar concentration and automatic time step selection method. Furthermore, a multilevel preconditioning operator and domain decomposition method are adopted to realize parallel computation of the simulation. Comparison with traditional methods, numerical tests indicate that the self-equilibrium Newton method can improve the overall efficiency of the nonlinear system of the component model.
How to Use Expansion Rubber to form an Adaptive Sealing Layer to Solve Severe Loss——Materials, Effects and Theory
Authors: Cui K. X. , Li D. Q. , Liu J. H. , Li F. , Tu Y. L. 
Published: February 2024

Abstract
During oil and gas drilling, severe loss from fractured formations is often encountered, which significantly increases drilling costs. The main reasons for failure plugging operations are twofold: firstly, it is difficult to achieve effective matching between the sizes of the plugging particle material and the fracture; Secondly, underground fractures are actually in a dynamic process of size change, leading to repeated losses, however, it is an important feature that has been seriously ignored before.
This paper introduces a key material with great potential to solve the above problems—adaptive smart expansion rubber. A detailed analysis was conducted on the composition and function of the material, and water absorption equilibrium swelling evaluation experiments were conducted to investigate the strength changes and expansion force of the material before and after expansion. Furthermore, the sealing effect of the material on fractured layers was further evaluated.
The evaluation results demonstrate that the expansion rubber exhibits higher strength both before and after expansion, surpassing traditional water-absorbing expansion gel particles. The material can expand by a volume ratio up to 750% and generate at least 50kPa of support stress after expansion. The evaluation of the plugging experiments indicates that the material can effectively enter the interior of the loss layer and successfully solve the loss. The plugging effect increases with the increase of water absorption and expansion time. This paper further proposes a new theory of adaptive sealing, which means that the expansion rubber can enter multi-scale fractures through elastic deformation under the differential pressure, and support the fracture wall surface through continuous expansion, thereby adapting the fracture size and sealing fractures.
This paper fully utilizes this smart material to improve the success rate of primary plugging and reduce the rate of repeated losses, saving plugging time and cost, which has important reference value.
PTA Application in Carbon Capture and Storage – Challenges, Diagnostics, Modeling
Authors: Idorenyin E. H. , Al-Abdulwahab I. M. 
Published: February 2024

Abstract
This paper documents pressure transient analysis (PTA) aspects of carbon capture and storage (CCS), from design considerations through modeling while also highlighting attendant challenges. CO2 injection in porous media has expanded in utility and increased in popularity following global consensus on decarbonization. To this end, CCS is unarguably a viable decarbonization option for the petroleum industry. However, it requires a reliable understanding of the subsurface in terms of quality, integrity, and capacity. In this study, we expatiate on the place of PTA analysis in long-term CO2 storage in porous media.
This work focuses on CO2 injection in saline aquifers; nonetheless, findings here can be easily adapted to depleted oil and gas systems. We first discuss CO2 injection-falloff test design vis-à-vis expectations from PTA-driven formation description. This is followed by an overview of analysis techniques that guarantee reliable estimate of injectivity and robust characterization. We then demonstrate the use of transient modeling to obtain a first-level evaluation of storage capacity in addition to improved characterization. The challenges encountered are also discussed.
Our findings show that knowledge of potential storage sites is indispensable in successful CO2 sequestration. A properly designed and carefully implemented well test remains a viable window to acquiring representative dynamic data which, upon analysis, provides valuable information about the storage media. Diagnostics and modeling must be supported with accurate description of the injection fluid as well as the in-situ formation fluid, otherwise the results may be in serious error.
This paper provides guidance toward best practices on the design, diagnostics and modeling of CO2 injection-falloff tests for the purpose of robust formation description and long-term CO2 sequestration.
A New Numerical Well-Test Model Using an Analytically Modified Embedded Discrete Fracture Model
Authors: Zhou Biao , Chen Zhiming , Song Zhigang , Zhao Xurong , Wang Bin , Olorode Olufemi 
Published: February 2024

Abstract
In the past few decades, multi-stage hydraulic fracturing technology has emerged as a crucial tool for the commercial development of unconventional oil and gas resources. Accurately characterizing transient flow near fractures is a critical concern for many researchers. Currently, discrete fracture models (DFMs) are primarily used to analyze the pressure transient behaviors of multi-stage fractured horizontal wells (MFHWs). Although discrete fracture models can accurately capture transient flow around fractures, they require a substantial number of grids to ensure computational precision, which in turn leads to higher computational costs. Conversely, standard embedded discrete fracture models (EDFMs) based on pseudo-steady-state assumptions, while computationally efficient, struggle to precisely depict the early transient flow around fractures. To narrow this gap, we proposed a new numerical well-test model for analyzing the pressure transient behaviors of MFHWs using structured Cartesian grids and an analytically modified EDFM (AEDFM).
We have made modifications to the transmissibility between the matrix and fractures by multiplying it with a transient factor. Furthermore, we have validated the accuracy and efficiency of our proposed model through comparisons with results from analytical models and standard well-test software. This demonstrates the significance of our proposed model in accurately capturing transient flow around fractures and reducing computational costs. Additionally, we conducted research on the pressure transient behaviors of a MFHW under different parameters and further evaluated the significance of the proposed modifications based on the results. The results indicate that, compared to the standard EDFM, the AEDFM can effectively match the early nonlinear pressure drop near fractures. This study may potentially provide a powerful tool for the precise analysis of pressure transient behaviors in MFHWs, while also significantly reducing computational costs.
New Mechanical Solutions for Isolating Severe Losses in High Temperature Wells
Authors: Zhan Guodong David , Yao Yang , Guo Huijuan , Aljohar Abdulwahab 
Published: February 2024

Abstract
In recent years, with the development of China's oil and gas exploration to deeper layers, the number of deep & ultra-deep wells has been increasing year by year. The casing layer sequence in the well structure design reaches 6 - 7 layers, which has tended to the design limit, but the handling ability is still insufficient in the face of sudden complex formations. Complications such as severe loss and different pressure systems in the same formation are encountered during drilling, resulting in early casing, which may not achieve the exploration target in the end. The open hole clad technology based on high performance solid expandable tubular is focus on solving difficult problems that weak and complex formation and severe drilling loses which cannot be effectively plugged or controlled.
This paper studies the open hole clad technology based on high performance solid expandable tubular in exploration wells by using the methods of indoor test and field trials. The operation principle and technical characteristics of open hole clad technology are introduced in detail. And the test of expansion tubular performance, expansion cone performance and thread sealing strength were carried out to study the expansion tubular operation process. Then aiming at LZ1 exploration well with complications such as severe loss and different pressure systems in the same formation are encountered during drilling, the open hole clad technology field experiment was carried out, and the clad effect of expansion tubular were analyzed.
The research results showed that: (1) the indoor tests of expansion tubular performance, expansion tubular cone performance and thread sealing strength verified the reliability of expandable tubular open hole clad technology which can effectively deal with the severe drilling loses on the safe drilling in exploration wells. (2) LZ-1 exploration wells have successfully created conditions for safe drilling in the target formation of LMX group by using Φ219mm expandable tubular to clad the complex formation. Through the method of mechanical seal, the sudden complex situation is solved, and the equivalent density of bottom hole is more than 2.1 g/cm3 after rapid plugging of complex strata, which make sure the drilling of the lower formation was smooth.
The ability to seal complex formations with severe losses using open hole clad technology based on high performance solid expandable tubular can be used to solve the complications such as severe loss and different pressure systems in the same formation in exploration wells, making sure the drilling of the lower formation was smooth.
Advanced Paleocurrent Analysis Over the Permo-Carboniferous, Methods to Reveal Its Complex Depositional History, Saudi Arabia
Authors: Al-Masrahy Mohammed A. , Lahmar Hakima Ali , Elaraby Abdelmoniem , Amer Aimen 
Published: February 2024

Abstract
The Permo-Carboniferous deposits in Saudi Arabia display a high-level of lateral and vertical heterogeneity resulting in a complex facies architecture. Such settings can be challenging to decipher using basic techniques that depend solely on openhole logs leading to inconsistent interpretation. The aim of this paper is to examine the role of local tectonics in the formation and alternation of subsurface depositional systems and associated hydrocarbon reservoirs in the area under investigation. This is accomplished through a multidisciplinary data integration approach involving core, borehole images, openhole logs, and seismic data. Specific objective includes reconstructing the paleogeography of the study area, which will grant better understanding of reservoir behavior on both vertical and lateral scales. The results of this paper suggest that deposition of the Permo-Carboniferous section at the study area is represented by low-sinuosity braided channels controlled by a preexisting Hercynian reactivated structure that served as a proxy of deposition. Detailed analysis of the paleocurrent data in the southern region of the field reveals three breaks in the sedimentary record. The basal events show variations in the paleocurrent orientations, suggesting deposition occurred over a preexisting terrain. The second event was characterized by a flat paleotopography associated with a period of tectonic stability and dominant unimodal NW sediment paleoflow. During this event, local lacustrine facies were developed in the SW part of the study area. The last event is marked by a SSW change in the paleocurrent flow and changes in lithofacies composition. It is postulated that the dramatic changes in paleocurrent directions are attributed to the reactivation of an earlier Hercynian paleostructure that could have supplied the area with new sediments. In contrast, the northern region of the field displays a consistent southerly paleocurrent flow, suggesting that the northern region was tectonically stable. This work reveals, for the first time, in detail the interaction between sedimentation and tectonism over the Permo- Carboniferous section in the study area. Such an approach can be adopted in other fields, ultimately leading to a systematic paleogeographic reconstruction mosaic of the region.
Geophysical Investigations of a Subsurface Structural Anomaly, Gullebi Field, Ghadames Basin, Libya
Authors: Shahlol Abdelhamed , Elmaslil Abraheem , Owonifaari Foluso , Alzaruk Ahmad 
Published: February 2024

Abstract
Gullebi Field lies in the southwestern part of Concession NC7A in the central Ghadames Basin. The field is characterized by a northeast-southwest reverse fault named the Gullebi Fault. The fault extension is about 45 km and is the conduit for the main hydrocarbon accumulation of the Devonian reservoirs. Based on available seismic data and other geophysical methods that were used in the past for hydrocarbon exploration in the field, there was evidence of a structural complexity—a radial rim faulting system with a deep depression surrounding a central dome. This domal structure has an average circular depression ranging from 152 to 305 m deep. The total width of the anomaly is about 13 km in diameter, while the radius of the dome is about 3 km.
To investigate the structural complexities of this anomaly, Arabian Gulf Oil Company (AGOCO) conducted a new airborne gravity and magnetic survey over the entire area of the NC7A concession addition to the existing seismic data within the concession. Based on the results of all geophysical methods used for this investigation, two hypotheses were established to identify the origin of this anomaly. The first cause could be the possibility of an igneous or volcanic intrusion that originated from the basement. The second theory assumed the anomaly was generated by possible meteorite impact that created synclinal rims around the domal structure. In this paper we present the geophysical assessment of seismic, gravity, and magnetic analyses and mapping conducted in the area to enable the geological interpretations to be more feasible.
Pressure Transient Analysis (PTA) Enables a New Approach for Building Robust Reservoir Permeability Distribution for Miscible Gas Injection Development
Authors: Al Hinai Nasser , Agarwal Pankaj , Dmitrii Smirnov , Fanis Khayrutdinov , Al Kaabi Saqer , Siyabi Rashid , Al Jabri Iman , Al Kindi Ilyas , Amira Harrasi , Alyaqadhan Al Hinai , Quraini Aiman , Alkhattab Mahrooqi , Hadhrami Abdullah 
Published: February 2024

Abstract
Accurate estimation of oil recovery and optimization of reservoir performance requires realistic estimates of permeability distribution. This paper presents an approach to build different modeling realizations for testing possible reservoir behavior during miscible gas injection (MGI) and UR range for MGI development. Multiple geological realizations were built for nine Area-H carbonated reservoirs to bracket the permeability distribution range away from well control, which is a major uncertainty impacting production behavior and history match.
Two main factors that affect ultimate recovery and production forecasts are property distribution and permeability range. Therefore, different geological and dynamic model realizations were built to test the reservoir behavior during MGI, which helped to make reliable estimates of production profiles and UR. Full-field reservoir models were constructed for multiple geological realizations, and permeability distribution results showed that using permeability-thickness (KH) and high-perm model methods increased confidence by preserving high-permeability streaks and introducing higher heterogeneity. Fewer changes were required to calibrate the full-field reservoir model to actual pressure data with KH than with conventional core-based permeability. High-permeability streak models provided faster gas breakthrough, higher GOR, and lower UR than conventional and KH-matched models. High-contrast permeability models provided a higher confidence estimation of faster gas breakthrough and oil recovery. High-permeability streaks and high-contrast models can mitigate the negative influence of enhanced reservoir heterogeneity on field production performance forecast. As a result, robust ranges of production profiles and promise would help the project forecast robustness check against low case realizations and upfront planning on potential mitigation/recovery options in case of heterogeneity indies thief zone behavior leading to faster gas breakthrough.
A new approach is presented that helps to estimate realistic production forecasts and UR ranges for gas injection development projects. It allows testing models for different subsurface realizations and generating robust project economics. The methodology given in this study can show a good practice for the characterization of heterogeneous reservoirs for MGI flooding development, especially for capturing the downside as an alternate geological realization.
Polyaromatic Hydrocarbon-Based Host-Guest Complex for Heavy Oil Viscosity Reduction
Authors: Chen Shaohua , Wang Jinxun , AlSofi Abdulkareem M , AlOtaibi Mohammed B 
Published: February 2024

Abstract
Polyaromatic hydrocarbons (PAHs) were known to interact with the micro-aggregates of asphaltene compound in heavy crude oil. This study aims at designing, synthesizing, and applying a water-soluble self-assembled viscosity reducer (SAVR) bearing PAHs to efficiently reduce the viscosity of heavy oil through the formation of host-guest complex. The synthesized SAVR product was composed of two chemical components A and B. In an emulsion comprising heavy oil and the SAVR, the PAH groups from the hydrophobic part (component A) strongly interacted with the asphaltene in heavy oil via π-π stacking and hydrophobic association to solubilize these components, the hydrophilic part (component B) of the SAVR self-assembled with component A via host-guest complex to improve the solubility of the entire SAVR in an aqueous environment. The collapse of the asphaltene component results in a decrease of the viscosity of heavy crude oil. The SAVR products were compatible with high-salinity water, and able to form stable oil-in-water (O/W) emulsions with heavy oil. The SAVR formulation exhibited high effectiveness in heavy oil viscosity reduction, the viscosity of heavy oil was decreased by 80% at a 1:1 mass ratio of A:B and an oil-to-water ratio of 7:3. At the heavy oil-water interface, the oil bulk was found to gradually disperse in the aqueous phase containing SAVR in the form of small oil droplets. This new chemical formulation has great potential in heavy oil displacement from a reservoir or treating produced heavy oil, ultra-heavy oil, oil sands, etc. Since the viscosity of the heavy oil can be substantially reduced, the oil can be more easily produced and transported for further processing in an economical and efficient manner.
Experimental Investigation of Liquid, Supercritical CO2, CH4, and CO2/CH4 Mixture to Improve Oil Recovery
Authors: Enab Khaled , Elizondo Thomas , Elmasry Youssef , Flores Leonel , Addo-Mensah Alfred 
Published: February 2024

Abstract
This study investigates the efficiency of injecting CO2 and CH4 in improving oil production from black oil reservoirs. While prior research highlights the effectiveness of these gases in enhancing oil recovery factors, comparing their performance in bulk interaction to their performance in the porous medium is scarce. Furthermore, the impact of the physical state of the injected CO2—liquid, gas, or supercritical— on oil extraction mechanisms still needs to be explored. Hence, our study aims to bridge this gap through a comprehensive experimental analysis of gas-oil interactions in the bulk phase and within porous media. The bulk gas-oil interactions were investigated using a visual Pressure Volume Temperature (PVT) cell.
In contrast, the gas-oil interaction within the porous media was investigated using a coreflooding experimental approach. The proposed investigation is designed to evaluate the influence of the permeability on the gas-oil interactions and the effect of the physical state of the injected fluid —liquid, gas, or supercritical — on the gas miscibility in oil. Since viscosity reduction and oil swelling are the primary mechanisms for miscible gas Enhanced Oil Recovery (EOR), this study focuses on the efficiency of different injected gases and the physical state of CO2 on the swelling factor, saturation pressure alternation, and viscosity reduction. The swelling factor and saturation pressure curves were measured when different molecular percentages of gas above the minimum miscible pressure were mixed with oil. The viscosity reduction effect was calculated by comparing the viscosity of the oil produced from the coreflooding experiment to the viscosity of the original oil. The oil minimum miscible pressure (MMP) of each considered gas in the oil sample was determined based on the oil composition determined by Gas Chromatography (GC) analysis.
The results showed that the CO2/CH4 mixture outperformed CO2 liquid, supercritical, and CH4 in coreflooding experiments. Additionally, the coreflooding experiments proved liquid CO2 (Cold) performed better in improving oil recovery than supercritical CO2. However, the bulk PVT analysis revealed a higher swelling factor for supercritical than liquid CO2, which suggests supercritical CO2 outperforms other gases, including cold CO2. In contrast, the viscosity of the produced oil when supercritical CO2 was injected was lower than that of all other gases. The observed variation in CO2 performance indicates the significant role of CO2 physical state of CO2 in the oil extraction mechanism. The conclusion of this study provides a better understanding of the performance of different gas injection strategies in conventional reservoirs, which brings insights into optimizing gas injection into depleted oil reservoirs that contain dead oil.