Oil Exploitation Research Articles

Effect of Low-Temperature Plasma-Modified Carbon Fibers on Impact Load Damage of Low-Density Oil-Well Cement.

After large-scale exploitation of conventional oil and gas resources, most remaining resources are in highly depleted zones, where the fracture pressure of the formations is greatly reduced. Low-density oil-well cement prevents wellbore and formation fractures by reducing annular liquid column pressure and is one of the most commonly used cements in the oil and gas industry. However, cement sheaths made of low-density oil-well cement can be easily damaged due to the impact load generated during the well completion process. Incorporating carbon fibers into the cement matrix can effectively enhance the performance of cement sheaths. To ensure that carbon fibers can be closely combined with the cement matrix, low-temperature plasma modification technology was used in this study to pretreat the fibers. The mechanical properties of low-density oil-well cement incorporated with unmodified or modified carbon fibers were studied in detail under an impact load. The results of X-ray photoelectron spectroscopy revealed that the content of hydrophilic groups on the surface increased from 18.3 to 60.3% after the plasma treatment. The impact test results showed that the peak strengths of the cements cured at 60 °C for 14 days with 0.3% unmodified and modified carbon fibers could reach 37.01 ± 1.7 and 62.27 ± 1.7 MPa, respectively, under the impact load, i.e., an increase of 68.25% after the carbon fibers were treated with low-temperature plasma. Similarly, the absorbed energy increased from 15.59 to 44.31 J, and the energy absorption rate increased from 25.98 to 73.85%. Low-temperature plasma modification provided hydrophilic functional groups on the surface, significantly improving the interfacial bonding between the carbon fibers and cement matrix. The strengthened interaction was beneficial to extending the bearing time under the impact load and demonstrated a positive influence on the mechanical properties related to the impact resistance.

Operation failure of risk analysis on floating storage and offloading

The need for petroleum in daily life is increasing. The oil comes from the seabed, so it is necessary to have adequate facilities during the exploration and exploitation of crude oil. The process of distributing crude oil to FSO is assisted by the Product Transfer System pipeline. In this process there is a possibility of failure that occurs form several factors, namely tools, weather and sea conditions, and human. In this study, the analysis of the risk of operational failure during loading-unloading of crude oil is discussed. The analysis was carried out using the HAZOP Analysis and Bow-Tie Analysis methods. HAZOP Analysis for hazard identification, and Bow-Tie Analysis for finding the appropriate mitigation. From this method, an overview of the risks than can occur can be obtained so that the risk control required by FSO can be implemented. From the results of this study, it was found that there are 41 potential hazards on the process of loading-unloading crude oil FSO, with the highest risk is inadequate quality of the transfer equipment components with the likelihood rank is 4 and severity rank is 4. The results of Bow-Tie visualization of dominant risk found five causes, namely corrosion, inadequate material quality, eroded material, service life, and material degradation, and five consequences, namely property damage, delayed operational activities, oil spills, environmental damage due to oil spill, and corrosion occurs on the product transfer equipment.

Anisotropic dynamic permeability model for porous media

Based on the tortuous capillary network model, the relationship between anisotropic permeability and rock normal strain, namely the anisotropic dynamic permeability model (ADPM), was derived and established. The model was verified using pore-scale flow simulation. The uniaxial strain process was calculated and the main factors affecting permeability changes in different directions in the deformation process were analyzed. In the process of uniaxial strain during the exploitation of layered oil and gas reservoirs, the effect of effective surface porosity on the permeability in all directions is consistent. With the decrease of effective surface porosity, the sensitivity of permeability to strain increases. The sensitivity of the permeability perpendicular to the direction of compression to the strain decreases with the increase of the tortuosity, while the sensitivity of the permeability in the direction of compression to the strain increases with the increase of the tortuosity. For layered reservoirs with the same initial tortuosity in all directions, the tortuosity plays a decisive role in the relative relationship between the variations of permeability in all directions during pressure drop. When the tortuosity is less than 1.6, the decrease rate of horizontal permeability is higher than that of vertical permeability, while the opposite is true when the tortuosity is greater than 1.6. This phenomenon cannot be represented by traditional dynamic permeability model. After the verification by experimental data of pore-scale simulation, the new model has high fitting accuracy and can effectively characterize the effects of deformation in different directions on the permeability in all directions.

Reliability Analysis of a Four-legged Jacket Offshore Platform: A Case Study

Offshore oil and gas exploration and exploitation requires reliable infrastructure. One crucial issue to consider is the reliability of the structure. Structural designs generally use deterministic or fixed values in their calculations. However, the factors involved in the design process may be random variables, such as environmental loads, materials, dimensions, and operational conditions, which may vary. Therefore, when calculating the reliability of a structure, these random variables must be treated with the science of statistics and probability. This research uses probabilistic and statistical methods via the Monte Carlo method to analyze the reliability of offshore jacket structures. The jacket platform is destined for the four-legged Java Sea around Gresik, Indonesia. The research results show that the Jacket platform has a high level of reliability for operating loads of K = 0.9883 and extreme loads of K = 0.9963 based on reliability analysis using the Monte Carlo Simulation method. Although the reliability figure does not exceed 1, this can be taken as a sign that the Jacket platform is declared safe in the analyzed situations. This reliability analysis ensures that the jacket platform is reliable and safe in dealing with the various environmental conditions and loads encountered during its operational life.

Influences of different alkaline and acidic diagenetic environments on diagenetic evolution and reservoir quality of alkaline lake shales

Thin section and argon-ion polishing scanning electron microscope observations were used to analyze the sedimentary and diagenetic environments and main diagenesis of the Permian Fengcheng Formation shales in different depositional zones of Mahu Sag in the Junggar Basin, and to reconstruct their differential diagenetic evolutional processes. The diagenetic environment of shales in the lake-central zone kept alkaline, which mainly underwent the early stage (Ro<0.5%) dominated by the authigenesis of Na-carbonates and K-feldspar and the late stage (Ro0.5%) dominated by the replacement of Na-carbonates by reedmergnerite. The shales from the marginal zone underwent a transition from weak alkaline to acidic diagenetic environments, with the early stage dominated by the authigenesis of Mg-bearing clay and silica and the late stage dominated by the dissolution of feldspar and carbonate minerals. The shales from the transitional zone also underwent a transition from an early alkaline diagenetic environment, evidenced by the formation of dolomite and zeolite, to a late acidic diagenetic environment, represented by the reedmergnerite replacement and silicification of feldspar and carbonate minerals. The differences in formation of authigenic minerals during early diagenetic stage determine the fracability of shales. The differences in dissolution of minerals during late diagenetic stage control the content of free shale oil. Dolomitic shale in the transitional zone and siltstone in the marginal zone have relatively high content of free shale oil and strong fracability, and are favorable “sweet spots” for shale oil exploitation and development.

Corrosion behavior of Si-DLC film in simulant solutions containing CO2-H2S-Cl−

Tubing and casing failure due to corrosion is a common problem in the oil industry. The Si-DLC film deposited by plasma enhanced chemical vapor deposition (PECVD) technology is expected to protect the pipeline during oil and gas exploitation. Corrosion tests were carried out in different Na2S·9H2O concentrations and temperatures in order to evaluate the corrosion resistance and stability of Si-DLC film. The results show that the Si-DLC film significantly improves the corrosion resistance of the SS304 substrate. There is no significant change on the surface of Si-DLC film with the increase of temperature, and the XPS spectrum and Raman spectrum of DLC film after corrosion possess no obvious change, which indicates that Si-DLC film possesses a great high temperature stability. The Si-DLC film is denser and it possesses excellent protective effect on the substrate compared to the corrosion product layer. The as-deposited Si-DLC film possesses excellent corrosion resistance in CO2-H2S-Cl− environment and this study provides a promising protective material for the inner surface of the pipeline during oil and gas exploitation.

Dynamics of the surface carbonate system in oil fields with a high concentration of wells on the northwestern South China Sea shelf

Oil exploitation may pose adverse effects on marine ecosystems, but its impacts on surface carbonate dynamics remain unknown. In a carbonate system with low air-sea ∆pCO2, such as the South China Sea (SCS), human activities may affect the pCO2 distribution patterns and potentially alter CO2 sink or source at the surface. This study investigates the surface carbonate system in two oil fields, namely the Wenchang Oil Feld and Enping Oil Feld, located on the northwestern SCS (NWSCS) shelf. In Enping Oil Field, although there is a slight increase in surface pCO2 due to probable total alkalinity (TA) consumption from CaCO3 precipitation, strong biological production makes the plume water a strong CO2 sink. Similarly, the biological processes dominated the pCO2 variability in Wenchang Oil Feld, exhibiting high values in its central area. In NWSCS, the influence of shelf water was observed during both cruises. And the pCO2 drawdown caused by the decreased sea surface temperature (SST) and CO2 outgassing outweighed their increases via enhanced vertical mixing, leading to a pCO2 drawdown from September to October within this water mass. More importantly, there were no significant disparities observed in carbonate parameters at stations along transects with and without wells, and the observed parameter values in this study fell within the range reported previously on the nSCS shelf with similar controlling processes. Thus the impact of oil exploitation on carbonate dynamics is negligible, and the characteristics of the carbonate system in oil field are primarily governed by natural processes such as the mixing of plume water and basin water, CaCO3 precipitation and the changes in SST. The provided data establish a crucial baseline for detecting future alterations in carbonate chemistry within oil fields, and the rapid fluctuations in sea surface pCO2 highlight the need for higher spatiotemporal resolution observation.

Fertility Assessment of Nun River Floodplain Soils in Bayelsa State, Southern Nigeria for Agricultural Productivity

Following massive crude oil exploitation in Bayelsa State, arable land is shrinking and a food crisis, looming. To stop this trend, information on soil fertility status and management strategies becomes important for policy development. This paper assesses fertility status of the Nun River floodplain soils in Bayelsa State using newly developed indices for sustainable agricultural productivity and food security. Nun River plain alluvial soils of different landforms were collected from the genetic horizons of nine profiles, and analysed for physicochemical characteristics and soil fertility assessed using soil fertility index. (SFI) and soil evaluation factor (SEF). ). Silt-sized particles dominated Odi (ODI), Koroama (KRM) and Niger Delta University (NDU 1) soils, except in NDU2 and NDU3, pH was moderate to slightly acidic (5.64–6.30), available P, low to high (0.6–22 mg/kg), organic C (0.31–5.35%), and total nitrogen (0.01–0.45%) low to high while calcium dominated the exchange complex. Correlation between Organic matter and total N (r = 0.366, p ‹ 0.001) and available P (r = - 0.310, p ‹ 0.01) was highly positively, suggesting that organic matter dictates availability of N and P. The SFI values were higher (p ‹0.05) than SEF except in NUD2 and NDU3, pH, organic matter and available phosphorus contributing more. Of paramount importance is conservation of organic matter as the accumulation of biomass greatly improved physical properties and fertility of the soil.

Reversible phase separation of CO2 responsive microemulsion: Judgment on whether and how regulated by ratio of ion to responsive surfactant concentration

CO2 responsive microemulsion is a promising solvent with diverse applications in various fields including oil exploitation, material synthesis, and metal recovery. The implementation of reversible phase separation becomes important in enabling the reuses of CO2 responsive microemulsion and facilitating the separation of products in these applications. Earlier reports have established that changes in ion concentration within CO2 responsive microemulsion result in reversible phase separation. Ion in CO2 responsive microemulsion is derived from protonation of CO2 responsive substance which is commonly used as surfactant. An increase in ion concentration leads to a decrease in surfactant concentration. In microemulsion, adsorption of surfactants and ions at the oil–water interface is correlated with interface performance, which influence the ability to achieve efficient phase separation. Interfacial tension (IFT) is an important parameter for interface performance. In this work, ratio of ion to CO2 responsive surfactant concentration was defined as ∮. The relationship between IFT and ∮ was investigated through a combination of experiments and molecular dynamic simulation to explore mechanism of reversible phase separation. The results of present study indicated that ∮ was found to play a vital role in either inhibiting or promoting the formation of hydrogen bond network by hydrophilic groups in surfactants. The changes of hydrogen bond network resulted in increase or decrease in IFT, leading to reversible phase separation. This relationship between IFT and ∮ was used as a theoretical guidance to optimize N2/CO2 bubbling time to achieve reversible phase separation. The optimization improved the efficiency of CO2 responsive microemulsion in extracting active components from Rehmannia glutinosa Libosch. leaves, and enhanced sustainability of the microemulsion. The findings of this study could be used to advance the scientific understanding of reversible phase separation, offering theoretical guidance for green and efficient utilization of CO2 responsive microemulsion in extraction of natural products. Ultimately these results could encourage the broader applications of CO2 responsive microemulsion across diverse fields.

Simulation of collision behaviour between droplet and solid surface in liquid phase environment

AbstractProcesses involving dispersed immiscible fluids occur across the traditional onshore and offshore crude oil development phases, including oil exploitation and production, gathering and transportation, and station and field processing. The stabilities of such processes are deeply influenced by the collision and film drainage between separated phase interfaces. Due to factors such as gravity as well as buoyancy and resistance, droplets usually collide with the wall at a relatively high speed and experience one or several rebounds before gradually stabilizing and staying on the surface. Though work related to this aspect has raised significant attention, further research on the force‐deformation behaviour between microsized (r ≈50 μm) droplets and solid surface under the influence of the above factors is still lacking and strongly demanded. In this paper, under the comprehensive influence of flow driving, an emulsified water droplet colliding with a solid surface in silicon oil is modelled. The dynamic behaviour of the droplet was analyzed by coupling the Stokes–Reynolds drainage equation, the generalized Young–Laplace equation, and the force situation of the deformable droplet. Furthermore, the effects of interfacial tension, collision velocity, and viscosity of continuous phase on the collision characteristics of droplet were analyzed, and it was found that these factors could significantly change the collision characteristics of droplet.

Spatial political economy: The ideology of Nature, State–space and the oil commodity frontier

In this article, a spatial political economy approach is used to examine the development of global capitalism through an analysis of the expansionary movement of commodity frontiers. It surveys the early history of oil exploitation in Chile and offers a close analysis of Patagonia’s constitution of its oil commodity frontier as Cheap Energy. It is argued that focusing on the internal relation of space and Nature can enhance our understanding of capitalism as an emergent and dynamic totality grounded in particular places where value is extracted. The article sheds new light on the spatialities of Import Substitution Industrialisation in Latin America using the case of Chile and its development agency, Corfo, and reveals how the capitalist ideology of Nature was wrought as a state project. The political economy of scale in this context is examined by analysing the central role of state and class relations in the environment-making process of capital accumulation. The article advances a new understanding of State–space within uneven and combined capitalist development. The spatial political economy lens allows for a fresh understanding of past history, which may help us understand the current ‘green’ energy transition by means of the production of space and Nature.

Assessment of methane emissions from oil, gas and coal sectors across inventories and atmospheric inversions

Emissions from fossil fuel exploitation are a leading contributor to global anthropogenic methane emissions, but are highly uncertain. The lack of reliable estimates hinders monitoring of the progress on pledges towards methane reductions. Here we analyze methane emissions from exploitation of coal, oil and gas for major producing nations across a suite of bottom-up inventories and global inversions. Larger disagreement in emissions exists for the oil/gas sector across the inventories compared to coal, arising mostly from disparate data sources for emission factors. Moreover, emissions reported to the United Nations Framework Convention on Climate Change are lower than other bottom-up and inversion estimates, with many countries lacking reporting in the past decades. Finally, comparison with previous global inversions, revealed a strong influence of the prior inventory on the inferred sub-sectoral emissions magnitude. This study highlights the need to improve consensus on the methodological inputs among the bottom-up inventories in order to obtain more consistent inverse modelling results at the sub-sectoral level.

Verification and Validation of Rotating Machinery Using Digital Twin

Abstract Rotating machinery has extensive usage in industrial applications, either as leading equipment (power plants) or as auxiliary equipment (oil and gas exploitation). These highly complex systems demand expensive maintenance programs due to the high costs of eventual shutdown. Consequently, critical fault diagnosis and prognosis are essential during the operation of those systems. Fault identification and classification demand robust verification of codes and calculations and a discerning validation of numerical models used for rotating machinery. Hence, verification and validation (V&amp;V) are an essential initial service for a digital twin (DT), offering some advantages in this application. In this context, the following research question is proposed: Does V&amp;V using DT improve data access and reduce the effort of data exchange? The following objectives are created to address the research question: perform a code verification, conduct the calculation verification, validate the models using two different validation approaches, and demonstrate easy access to asset data. For this study, two identical hydrodynamic bearings and a noncentral disk were considered, representing a laboratory experimental setup. The validation metric requirement is promisingly satisfied for the disk and bearings according to validation Approaches 1 and 2. Furthermore, validation Approach 2 generates even more successful results than approach 1. Accurate estimation and reliable interpretation of the numerical model outcomes encourage the application of DT for future fault diagnosis and prognosis.

Application of GIS and RS in Petroleum Exploration

As the world’s demand for energy continues to increase, the efficiency and accuracy of exploration and exploitation of oil and gas resources have become increasingly important. The development of GIS and RS technologies has provided unprecedented convenience and opportunities for the exploitation of oil and gas resources. GIS and RS technologies have played a revolutionary role in pinpointing potential oil and gas fields, evaluating exploration risks, and monitoring the environmental impacts of exploitation activities. This paper focuses on the application of GIS and RS technologies in the field of oil exploration, focusing on the application of novel data sources such as LiDAR, high-resolution remote sensing imagery, UAV, and satellite remote sensing technologies, and the role of these technologies in assessing the environmental impacts of oil exploitation. This paper concludes that GIS and RS technologies not only enhance the accuracy of oil and gas field detection but also play a non-negligible role in environmental protection. Accurately detecting changes in surface water and groundwater helps to identify and prevent the occurrence of pollution that may be caused by exploration activities at an early stage. The significance of this paper is not only to improve the efficiency and accuracy of oil exploration but also to promote environmental protection and sustainable development.

Experimental and model analysis of the effect of pore and mineral characteristics on fluid transport in porous soil media

The fluid transport in porous media is a critical property for oil and gas exploitation, construction engineering, and environmental protection. It is profoundly influenced by pore geometry and mineral properties. Currently, the Kozeny–Carman equation serves as the permeability prediction equation for porous media, established on the circular pores model. However, it fails to fully account for the impact of pore shape and mineral properties of the soil, leading to significant deviations between predicted and measured soil permeability results. In this paper, based on scanning electron microscope image and mercury intrusion porosimetry, the pores were divided into circular pores and narrow slit pores according to the ratios of pore area and circumference. Then, the quantitative expression of the two types of pores and their connectivity and tortuosity were given, and the circular and narrow slit composite pore model was used to describe the soil pore. Subsequently, the electrostatic potential of pore water was calculated by the Poisson–Boltzmann equation to consider the adsorption effect of minerals on pore water. Combined with the Navier–Stokes equation, the permeability prediction equation considering pore geometry, pore connectivity, and tortuosity and mineral properties was established. Finally, the experimental results illustrated that the theoretical prediction results were in good agreement with the experimental results. The proposed permeability prediction equation proves valuable for assessing and predicting the fluid transport in porous media.

Inclination Build Rate of a Point-The-Bit Rotary-Steerable Tool

The combination of a rotary-steerable system (RSS) and power screws has become the main drilling tool for the efficient exploration and development of unconventional oil and gas. However, the application of point-the-bit (POB) rotary-steerable tools in directional drilling subjects spindle bearings to continuous alternating stress, which can lead to fatigue failure. In this study, numerical analysis and simulation are employed to guide the engineering application of rotary-steerable tools, particularly in the field of oil and gas exploitation. The structural composition and steering principles of rotary-steerable tools are analyzed. The influence of the structural parameters of the spindle on the deflection capacity of the tool is analyzed, and the optimal structural parameters are selected. Based on the results, the recommended distances between the various components of the tool could be obtained. Moreover, the maximum deflection capacity increases with torque when the WOB (weight-on-bit) is constant. Similarly, at constant torque, the maximum deflection capacity increases with the WOB. Overall, the WOB has a greater influence on the maximum deflection capacity than torque. To ensure the safe operation of the spindle, the WOB and torque must be within 200 kN and 20 kN·m, respectively. The findings of this study provide valuable insights into the safe application of POB rotary-steerable tools.

Geological Science and the Making of Colonial Oil Frontiers on the East Coast of Sumatra, 1890-1930

In the early 20th century, the Dutch Empire emerged as a prominent oil producer internationally, with the Netherlands East Indies leading the way in petroleum production. The colonial petroleum industry’s success was bolstered by scientific and technological advancements that streamlined the oil exploitation process. Geology played a critical role as a scientific tool that facilitated the conquest of landscapes and crude oil control along Sumatra’s east coast. The study of geology supported the colonial oil politics, leading to a new era of oil mining exploitation through robust economic partnerships between the Dutch colonial government and private oil companies. This paper aims to explore the link between Dutch colonial scientific agency and the establishment of an oil extraction territory that transformed the natural environment and social conditions on the east coast of Sumatra, from Aceh to Palembang.

Predicting production flow rates using artificial neural network – HST field case

Oil production flow rate prediction is a critical aspect of oil and gas exploitation operations. Currently, flow rate forecasting is often estimated using theoretical or empirical models. Theoretical and empirical models have limitations. This study applies an Artificial neural network (ANN) for prediction flow rate. The study considered 256 datasets collected from six wells in the HST Field, Cuu Long basin. The predicted results obtained from the ANN model with eight neurons and back-propagation algorithm achieved high predictability with a strong correlation coefficient of 0.964 and a low RMSE of 32.612 bbl/d. Therefore, the developed ANN models have been promised as an effective tool in production flow rate forecasting in oilfields. Keywords: Artificial neural network; backpropagation algorithm; flow rate prediction; multivariate regression method; gas-lift.

Victimhood Self-construal, Irony of Tears and Melancholy amid Wealth: Critical Assessment of Select Literary and Visual Metaphors on the Niger Delta Environmental Despoilment

Studies on self-construal indicate that man is propelled by what happens around him to react in a certain manner and this reaction, we suggest is a human universal common and a representation of conscious purposive response to concomitant environmental and circumstantial realities. This purposive response encapsulates messages, which an observer articulates and interprets; hence, our study is about deepening our understanding of the factors and variables responsible for victimhood self-construal projected in select texts on the Niger Delta environmental despoilment. Drawing from the theories of eco-criticism, victimhood, and self-construal, this study utilizes an interpretive approach to discuss select instances of victimhood portrayals in the poem ‘Delta Blues’ by Tanure Ojaide, in the drama Hangmen also Die by Esiaba Irobi and in the film Blood and Oil, directed by Curtis Graham. The study examines the primary reason, which is the dispossession of livelihood by environmentally destructive oil exploitation, adduced by the Niger Delta inhabitants to understand how it generates variables that instigate victimhood self-construal. Our observation is that in the texts the inhabitants’ victimhood self-construal can be described as purposive, the propelling variable is their concomitant environmental realities and the texts as communication media have different encumbrances and advantages regarding their efficacy and utility for advocacy.

Book Review of A Brief History of Oil: From Technological Progress to Changing the World

In order to explore the connection between oil and economy, society and politics, and grasp the future development trend of the oil field, Vaclav Smil introduced the development history of oil from the perspective of economy, society and politics, and then discussed the problems encountered by human beings in oil exploration, production, transportation, refining and sales, and introduced the huge creativity gradually accumulated by human beings in the process of extracting and processing oil, which made crude oil the world's most important source of energy. A Brief History of Oil: From Technological Progress to Changing the World is a book by Vaclav Smil, which consists of 12 chapters in 5 parts. It mainly covers the advantages and disadvantages of oil; The composition of oil and the geological conditions of its extraction; The improvement of oil exploitation technology and the discovery of super-large oil fields; Discovery of recoverable crude oil, development of oil fields, the management of extraction, refining and transportation; Finally, it concludes with reflections on the future of oil under the new pattern of energy strategy. The feature of this work is to obtain analytical data by examining the relationship between petroleum and society, economy and politics, to provide support for the optimization of petroleum system, and to provide scientific reference for scientists, educators, and managers engaged in the petroleum industry.