bluuebunny/crossref_metadata_2025_split huggingface dataset:
First Application of LWD NMR and Quadrupole Sonic Measurements Derived Formation Evaluation in a Carbonate Reservoir in Sichuan Basin, China
Authors: Jia Chang Qing , Wang Yue , Zhang Jun Liang , Zhang Qiang , Zhang Jing , Zhao Zuo An , Wu Jin Long , Zhao Xian Ran , Li Kai Xuan , Zhang Hong Liang , Liu Yan Mei , Zhang Lei 
Published: February 2024

Abstract
Natural gas production in the Sichuan Basin has been increasing in recent years with double-digit growth. Exploration and development of complex carbonate reservoirs ensures production growth. A major challenge is that the target Triassic Feixianguan Formation is characterized by extremely high sulfur. Use of radioactive source measurements such as density and neutron, are prohibited, for the sake of safety, giving rise to uncertainty in the interpretation of lithology and porosity. It is necessary to introduce source-less measurements as substitutions for the formation evaluation.
This paper discusses a novel application of logging-while-drilling (LWD) nuclear magnetic resonance (NMR) and quadrupole sonic measurements for formation evaluation of this carbonate reservoir. The LWD NMR offers simultaneous measurement of T1 and T2, and the joint inversion of T1-T2 data provides real-time answers of the porosity, permeability, and pore structure of the reservoir. The LWD quadrupole sonic tool not only acquires formation compressional, shear, and Stoneley slowness, but also provides unique insight into high angle fracture identification. The integration of NMR and sonic measurements reveals the potential of the carbonate reservoir in the Triassic Feixianguan Formation.
A case study is presented from a carbonate reservoir of Triassic Feixianguan Formation in the PetroChina SouthWest Oil and Gas Company. The lithologies of Feixianguan Formation are composed of dolomite and calcite. Mineralogy is successfully estimated by integration of NMR porosity and formation compressional slowness. The NM-derived effective porosity of the dolomite reservoir ranges from 2-20%, and the permeability ranges from 0.01-1000 mD. The well is drilled using oil-based mud, so the NMR free fluid T2 cutoff could be higher than the default 100 ms. Factor analysis based on the NMR T2 data indicates the free fluid T2 cutoff to be 210 ms in the dolomite reservoir. The pore structure of the dolomite reservoir is dominated by macro pores. The integration of NMR free fluid volume, crossover of compressional and shear slowness, and fracture analysis based on Stoneley data proves effective and robust in potential zone identification.
This paper discusses integration of LWD NMR T1-T2 logging and quadrupole sonic measurements in the carbonate formation evaluation. It helps operator to understand the potential of the reservoirs. The gas production of the well that adopts the technology breaks the gas field production record. The workflow can also be applied to other high-sulfur reservoirs in China.
Research and Practice on Bottom Water Breakthrough Governance Strategy of Heavy Oil Reservoir Based on Heat-Gas-Agent Synergistic Huff and Puff
Authors: Liu Dong , Liao Hui , Zheng Wenqian , Wu Tingting , Tian Cong 
Published: February 2024

Abstract
Bohai is rich in heavy oil reservoirs with edge and bottom water. The existence of bottom water will lead to rapid water cut increase and worsen thermal recovery performance, so it is long-term undeveloped. And this poses a great challenge to the thermal recovery, of which it is also a worldwide industry problem. Therefore, it's of great significance to take effective control measures in time and realize the efficient development of bottom water heavy oil reservoirs.
The research shows that thermal chemical technology can better improve thermal recovery. Combined with experimental and numerical simulation research, this paper has carried out some very significant explorations. Firstly, the experiments of different chemical composite thermal media were carried out and the enhanced-effect mechanism was clarified, that is viscosity reducer reducing viscosity, gas dissolved& reducing viscosity, gel and foam's plugging effect, surfactant reducing oil-water interfacial tension. Meanwhile, through numerical simulation the thermal and chemical mechanism was characterized by relative permeability interpolation method with experimental results taking into account.
The above research shows that it is feasible to control water channeling in bottom water heavy oil reservoirs by thermal composite huff and puff technology, which strengthens confidence of thermal recovery and development of offshore bottom water heavy oil reservoirs, and also opens a new way for the development of offshore bottom water heavy oil reservoirs. Firstly, hot water or steam can reduce the viscosity of crude oil, and viscosity reducer can further reduce viscosity. Gel and foam can block bottom water channeling and improve thermal efficiency. At the same time, the surfactant can reduce oil-water interfacial tension and reduce crude oil viscosity through emulsification effect. Secondly, the thermal-gas-agent characterization method finely characterizes the synergistic mechanism of each component, which lays a foundation for the development and implementation of composite huff and puff plan. Thirdly, through the combination of hot water and heat-resistant foam plugging, obvious effect of precipitation and oil increase was achieved in two horizontal wells of LD2 bottom heavy oilfield. After the measures, the daily oil rate increase from 10 m3 to 40 ~ 70 m3, the water cut reduced from 74% ~ 92% to 1% ~ 10%.
LD2 is the first bottom water heavy oil oilfield developed by thermal recovery. The successful pilot test of hot water chemical combined huff and puff in two horizontal wells of LD2 oilfield has opened a new development mode and strengthened the confidence of developing offshore bottom water heavy oil. Therefore, 18 new horizontal thermal wells are designed, expecting to increase recoverable reserves of 327 million tons, which is of great significance for offshore thermal development.
Interpreting Screening of Appropriate Carbonate Reservoir for Low Salinity Water Flood EOR in Giant Indian Offshore Fields
Authors: Srivastava Vivek Raj , Mitra Sujit , Gopal Giridhar , Gupta S. K. 
Published: February 2024

Abstract
In offshore giant carbonate reservoirs low pressure, high salinity, and high temperature make popular liquid-based EOR a challenge. But tuning injection water salinity/ ionic composition can increase both microscopic and macroscopic displacement efficiency in carbonates screened based on temperature, wettability, and potential determining ions (PDI). The study includes an analysis of major offshore fields of India and highlights key factors that showed a positive impact of low salinity water flood (LSWF).
The main emphasis of this paper is on 1- Screening of carbonate reservoir offshore fields based on spontaneous imbibition and wettability index experiment; 2- Core flood displacement experiment for proper evaluation of LSWF effect based on incremental recovery; 3- Optimization of salinity on carbonate core samples in both tertiary and secondary mode water flood; 4- Relative permeability curve generation for both high salinity seawater (HSSW) and Optimized low salinity water (OLSWF) water through single porosity core model simulation based on laboratory experiment inputs and 5- Pilot area simulation to quantify the benefit of OLSWF on a field scale.
The main conclusions of the study are 1- Wettability index and spontaneous imbibition (SI) experiments indicate a potential low salinity effect; the presence of clays, formation, and injection brine composition, presence of potential determining ions determines the impact of oil recovery for screening of fields; 2- Displacement studies indicated an incremental recovery of (5.6-15.9% HCPV) respectively over seawater flooding owing to a reduction of salinity; 3- Salinity optimization study reduce the potential risk of incompatibility between injection water and the initial crude-oil/brine/rock system. Rock-fluid compatibility studies confirm 25% seawater (SW) salinity as optimum salinity with maximum incremental recovery with diluted versions of seawater having a salinity range from 33640 ppm to 336 ppm; 4- Relative permeability curve generated for both high salinity seawater (HSSW) and optimized low salinity water (OLSWF) water with the help of 1D Core flood simulation. The oil recovery profile was used to generate a reasonable match between experimental and simulation results. Residual oil saturation decreases by about 10 saturation units under low salinity flooding in imbibition mode; 5-Simulation Study envisages incremental oil gain of 1.37 MMt over the base case with incremental oil recovery of 1.5%.
The originality of the paper lies in the finding of the potential of LSWF for offshore carbonate reservoirs at high-temperature ranges along with its confirmation by a shift in the relative permeability curves through the wettability alteration phenomenon. The positive outcomes serve as guidelines for carbonate reservoir screening and the science of rock fluid interactions at the pore scale in LSWF.
Unified Fracture Design Optimisation Under the Fracture Height Migration of the Oligocene Formation, White Tiger Field
Authors: Huu Truong Nguyen , Quynh Mai Duong Thi 
Published: February 2024

Abstract
Many hydraulic fracturing treatments have been carried out for producer wells selection with low permeable formation in the primeval sedimentary of the White Tiger field to increase the permeability of the reservoir and increase the fracture conductivity, leading to an increase the productivity index. Several treatments recorded a higher fracture growth in comparison with the effective reservoir thickness, resulting in poor proppant distribution within the fractured reservoir, and shorter propped length, and narrower propped width, resulting in poorer propped fracture conductivity. In this study, the optimally designed the optimal propped length and propped width using Unified fracture design (UFD) in combination with symmetrical fracture height evolution with a pseudo-three-dimension model (p-3D) for three-layered formation under the constraint of maximum proppant distribution per unit fracture area created, or optimum dimensionless productivity index for the low permeability reservoir. Results for a single well production fracturing case in the upper Oligocene formation have been obtained with such fracture height migration of 124.1 ft, pay zone thickness of 120 ft, propped fracture half-length of 298 ft, propped fracture width of 0.18 in, propped fracture conductivity of 660 mD.ft, the highest percentage of proppant placement in the pay zone at 96.7% by 125,710 lbs of proppant size 16/30 of Sintered Ball Bauxite (SBB), mass of propped used 130,000 lbs, effective reservoir-reservoir efficiency is 125,710 lbs. In addition, the sensitivity analysis of in-situ stresses and fracture toughness of the overlying layers and the underlying layers under treating pressure influenced by fracture height migration have been discussed.
Carbon Dioxide Gas Adsorption on Eagle Ford Shale for Assessing CO2 Storage Potential
Authors: Adnan N. , Amir M. B. Shaiful , Mohshim D. F. , Aji A. Q. Mohd 
Published: February 2024

Abstract
Shale formations have the potential to store a considerable amount of CO2 through gas adsorption in the shale matrix. This work aims to investigate the effects of total organic carbon content, pressure and temperature on adsorption capacity of Eagle Ford shales. This study involved the determination of void volume of two shale samples (EF A and EF B) with varying TOC and the determination of their CO2 adsorption capacity at varying pressure of 2 MPa – 10 MPa and varying temperature of 40°C and 60°C. The study employed a volumetric approach to examine the CO2 gas adsorption on shale samples. Results indicated that shales with higher TOC content have higher CO2 adsorption capacity, making shale formations with more organic matter to be potential candidates for CO2 storage. Overall, TOC, pressure and temperature played a significant role in CO2 adsorption capacity of the shale samples.
Optimisation of Well Location for Water Gas Alternating Flooding in Deepwater Carbonate Reservoirs Based on Artificial Intelligence
Authors: Li Yunbo , Wang Ze , Sun Hao , Yu Yang , Liu Zhangcong , Yang Zhaopeng 
Published: February 2024

Abstract
A deep-water offshore oil field belongs to a carbonate reservoir with a depth of over 2000 meters, and is developed using large well spacing water gas alternating (WAG) flooding. Compared with onshore oilfields, single well investment in deepwater oilfields is high, and in order to achieve the goal of high production with thin wells, the requirements for well location deployment are higher. At the same time, the presence of heterogeneity in carbonate reservoirs further increases the difficulty of well layout. Therefore, optimizing the well location for the development of water gas alternative flooding in deep water carbonate reservoirs to achieve optimal cumulative production and economic benefits is a challenge.
Optimization of well locations based on numerical simulation usually requires engineers to spend a lot of time and energy. With the rapid development of artificial intelligence (AI) technology, using machine learning algorithms to optimize well locations may be a fast and reliable solution. The research started with data processing. Firstly, data related to well location optimization parameters are collected and pre-processed, such as data filling and data normalization. Pearson algorithm is used to judge the importance of feature parameters according to correlation, and finally the interference between features is reduced by dimensionality reduction algorithm. After data processing, a reservoir agent model is established based on XGBoost (eXtreme Gradient Boosting), the Sparrow Search Algorithm (SSA) is used to optimize the hyperparameters of the model, and SSA-XGBoost is used to optimize the well location of deepwater carbonate reservoirs in multiple rounds.
The results clearly show that AI is a powerful tool for optimizing well placement in deepwater carbonate reservoirs. SSA-XGBoost model scored 0.99 in the training set decision coefficient, 0.96 in the test set decision coefficient, and 0.83 in the verification set decision coefficient, which has higher prediction accuracy compared with other machine learning algorithms.
This study provides a technical method for the location optimization of WAG flooding Wells in deep water carbonate reservoirs
Numerical Simulation on Interaction Between the Supercritical CO2 and Water-Rock in Tarim Basin
Authors: Zhang Youheng , Dong Pingchuan , Chen Shun , Chen Yiwei , Cheng Peizhai , Yang Bingtao 
Published: February 2024

Abstract
Climate change is related to human survival and long-term development. In the context of global carbon neutrality, carbon dioxide capture, utilization, and storage play a key role in carbon emission reduction. Supercritical CO2 appears weakly acidic when dissolved in water. After contact with the reservoir, the carbonate rock in formation will react with the CO2 aqueous solution, which will lead to the process of original mineral dissolution and secondary mineral precipitation, and affect the seepage process. The numerical simulation method is used to study the CO2-water-rock reaction time and storage capacity in structural and stratigraphic trapping, residual trapping, solubility trapping, and mineral trapping. Solubility trapping utilizes CO2 to dissolve in the aqueous phase at a certain pressure/temperature to achieve the purpose of storage. It largely depends on pressure, temperature, and surface area in contact with water bodies. Residual trapping uses the effect of the relative permeability curve from displacement to suction to trap the non-wetting phase. The mineral trapping of Anorthite, Calcite, and Kaolinite after CO2 injection under the initial condition of PH=7 was simulated. Comparison of water-rock reactions under four different storage methods. The results show that, during the simulation process, anorthite gradually dissolved, kaolinite gradually precipitated, and calcite initially dissolved and then precipitated. In the early stage of CO2 injection and reaction, more than 90% of CO2 is stored by structural and stratigraphic trapping and residual trapping, and there is a small amount of solubility trapping. The contribution rate of mineral trapping is about 0. With time, the amount of CO2 stored by solubility trapping and mineral trapping gradually increases, the concentration of CO2 dissolved in formation water and the concentration of Ca2+ and Mg2+ increase significantly, the dissolution rate of formation rock increases, and the mineral trapping rate of CO2 also increases. It will take decades or even hundreds of years to realize the permanent storage of CO2. This provides theoretical support for long-term and safe storage of CO2 in reservoirs and prediction of storage methods and has certain guiding significance.
Wellbore Strengthening for Highly Depleted Formations: Controlling Particle Size Distribution in Drilling Mud
Authors: Illiani Nur , Nordin Khairul Annuar , Rincon Marco T. , Barbeau Francky , Sany Ramzan 
Published: February 2024

Abstract
A field development located offshore Peninsular Malaysia targets the northern Malay Basin oil-bearing sandstone reservoir. However, the reservoir shows reduced pore pressure due to hydrocarbon depletion, which is naturally coupled with a decreased fracture gradient. In addition to geomechanics constraints, the well design involves highly deviated and Extended Reach Drilling (ERD) wells aimed at reaching untapped hydrocarbon reserves. The abnormal pressure regime and the typical constraints of highly deviated and ERD wells demand an innovative well design that incorporates a two-pronged approach to control Equivalent Circulating Density (ECD) as well as hole stability issues due to severe depletion. One of the strategies adopted was the design of a Low ECD Non-Aqueous Drilling Fluid (Low ECD NADF) aimed at reducing ECD while drilling without sacrificing optimal hole cleaning ability. Additionally, the specially designed Low ECD NADF was treated with Wellbore Strengthening Material (WBSM) to penetrate the severely depleted reservoir section. This specially-designed drilling fluid proved successful in both controlling ECD and increasing wellbore hoop stress across the depleted sands, preventing losses during drilling, casing running, and cement operations. The paper outlines the geomechanical data analysis guiding the WBSM design, computer-assisted predictions of hydraulically induced rock fractures using dedicated software for dynamically induced fracture size prediction, and laboratory testing iterations refining the WBSM package. Field application of the Low ECD NADF system included the use of Permeability Plugging Test (PPT) and Particle Size Distribution (PSD) analyses. Additionally, surface solids control equipment manipulation, including strategic shale shaker control, allowed the maintenance of WBSM treatment at optimal fracture pluggability at a minimum cost throughout the drilling of the depleted zone.
Production Enhancement Through Profile Modification (PM) of Injection Water Using Deep Penetrating Cross-Linked Polymer Gel in a Mature Carbonate Field in Offshore India - A Success Story
Authors: Sutaria Ishaq , Gupta VK , Daksh Pd. Vikrant , Nagiresu B. , Saklani Diksha 
Published: February 2024

Abstract
India's most gigantic oil field Mumbai High (MH) is an offshore mature carbonate field situated North West of Mumbai city in the Arabian sea of Western India. The field has a vast production history and is currently in mature stage of production with increasing water production. Several steps were taken to reduce the water cut and increase production for maximizing recovery from this mature carbonate field mainly driven by water injection. Most prominent reason for increasing water cut is presence of active high permeability conduits causing premature breakthrough of injection water. The early water breakthrough via matrix/dual porosity pathways from injectors is leading to water recycling between injectors and producers leading to unwanted high water production. Moreover most of these injectors are completed in multiple layers with very limited PLT/ILT data. To cater to this problem Profile Modification (PM) technology with deep penetrating polymer gel system was adopted on a large scale in a unique manner to improve the sweep efficiency and enhance production. This involved comprehensive analysis of performance of injectors and their nearby producers coupled with extensive laboratory studies to optimize the chemical formulation to come up with a tailored made chemical formulation best suited for the target reservoir. To ensure best results in terms of reducing the quantum of produced water, each job plan has been customized depending on reservoir parameters such as temperature, salinity, injectivity, injection history, depth of the target zone and permeability. Jobs were executed successfully in 31 injectors in a specific sequence targeting both the high permeable channels as well as the matrix/medium permeability zones so as to achieve uniform sweep across all layers. This approach resulted in substantial incremental oil gain and reduction in water cut in offset producers. This paper summarizes the candidate selection, chemical optimization studies, execution methodology, production response pre and post job and lessons learnt. This water management practice can be considered as one of the most efficient methods for addressing the problem of increasing water production from mature offshore carbonate fields under water injection in India and globally.
Rosmari Marjoram Offshore Platform Bespoke Skirted Mudmat Design
Authors: Abdullah Hafizzi , Sian Hoo Chee , Chen Ng Yong , Jalil Ashiq 
Published: February 2024

Abstract
Offshore Platforms are typically installed at a flat seabed area. However, the site selected for Rosmari Marjoram Offshore Platform (RMP) location has widespread presence of pockmarks, resulting in an uneven seabed where the conventional mudmat design is not feasible and this typically requires seabed preparation work (e.g rockfill) which is costly and has residual risk to pile and conductor installation. This is where engineers ingeniously deal with challenges by tailoring a mudmat shape that will ‘fit’ the unlevelled seabed around Rosmari Platform location to address the risk to jacket on-bottom stability during installation. This paper intends to highlight the unique challenges and complexity of Rosmari Marjoram Offshore Platform (RMP) jacket foundation design, and how the team successfully address the issues.
The ‘Bespoke’ skirted mudmat foundation option was proposed whereby the sizes and shapes of the skirted mudmat baseplates were ‘tailor-made’ to conform with the flat portions of the seabed. Assessments were done thoroughly which concludes that adequate bearing and sliding stability during jacket on bottom.