Gas Development Research Articles

The Transformation of Biomass to Bio-nature Gas, Principles and Future Development Trends

The Transformation of Biomass to Bio-nature Gas, Principles and Future Development Trends

Design of Fluid Control Valve Opening Control System

Technical problems such as the limited control times and time of existing fluid control valves and the inability to accurately control the control opening limit the long-term economic development of deep shale gas. This design is mainly based on PID control algorithm to control the opening of fluid control valve. It has the advantages of unlimited control times, high control precision and strong reliability.

SERS-Based Hydrogen Bonding Induction Strategy for Gaseous Acetic Acid Capture and Detection.

Surface-enhanced Raman scattering (SERS) can overcome the existing technological limitations, such as complex processes and harsh conditions in gaseous small-molecule detection, and advance the development of real-time gas sensing at room temperature. In this study, a SERS-based hydrogen bonding induction strategy for capturing and sensing gaseous acetic acid is proposed for the detection demands of gaseous acetic acid. This addresses the challenges of low adsorption of gaseous small molecules on SERS substrates and small Raman scattering cross sections and enables the first SERS-based detection of gaseous acetic acid by a portable Raman spectrometer. To provide abundant hydrogen bond donors and acceptors, 4-mercaptobenzoic acid (4-MBA) was used as a ligand molecule modified on the SERS substrate. Furthermore, a sensing chip with a low relative standard deviation (RSD) of 4.15% was constructed, ensuring highly sensitive and reliable detection. The hydrogen bond-induced acetic acid trapping was confirmed by experimental spectroscopy and density functional theory (DFT). In addition, to achieve superior accuracy compared to conventional methods, an innovative analytical method based on direct response hydrogen bond formation (IO-H/Iref) was proposed, enabling the detection of gaseous acetic acid at concentrations as low as 60 ppb. The strategy demonstrated a superior anti-interference capability in simulated breath and wine detection systems. Moreover, the high reusability of the chip highlights the significant potential for real-time sensing of gaseous acetic acid.

Advances in Drilling and Completion Fluid Technologies for Protecting Oil and Gas Reservoirs: Research Progress and Development Trends

Abstract The exploration and development of oil and gas reservoirs present significant challenges in achieving objectives such as increased reserves, enhanced production, and improved efficiency. The protection of reservoirs has been internationally recognized as a crucial technology for enabling high output with minimal investment, specifically due to the susceptibility of the drilling and completion phases to severe damage. The resulting harm significantly reduces oil and gas production and may cause drilled wells to become nonproductive, thereby hampering oil and gas field discoveries. Over the past half-century, scholars have extensively researched and developed four generations of temporary plugging-based technologies for oil and gas reservoir protection, including shielding temporary plugging, fine temporary plugging, temporary plugging with physiochemical film, and biomimetic temporary plugging. These advancements have progressively enhanced the effectiveness of reservoir protection. However, the increasing depth and complexity of oil and gas exploration and development have rendered previous technologies inadequate in providing sufficient protection, resulting in amplified risks to drilling safety such as circulation loss, sloughing, obstruction, drill pipe sticking, and blowouts. To overcome these challenges, the development of drilling and completion fluid technologies capable of forming a liquid casing during drilling has emerged as a novel solution for safeguarding oil and gas reservoirs. The successful implementation of this technology on a large scale enables the efficient development of untapped oil and gas resources, marking a breakthrough in reservoir protection. It also identifies future research directions and has practical implications for field technicians and scientific professionals.

Research on the Characteristics of Shale Three-axis Compression Sound Emission Features

In the shale gas development, the lack of stability caused by the transformation of the reserve layer is an important engineering problem to be solved. This article is based on the compression test and sound launch technology. The impact of rock destruction, crack type, and the process of sound launch features during compression. The results show that: The bell counting count of sound transmission is volatile and there is a gap. On the eve of the stress peak, the bell counting count rapidly increased to the maximum value; the energy is small in most of the time, the energy increases when the crack expansion, and the broken damage occurs in the rock -sample. At the same time, the energy released is the most.

A novel well log data imputation methods with CGAN and swarm intelligence optimization

Well log data plays a vital role in decision-making, resource assessment, production optimization, and environmental management of oil and gas development. However, when exploring and developing deep and ultra-deep oil and gas, the performance of logging equipment is greatly challenged by high temperature, high pressure, and high corrosion wellbore conditions. Log data often needs to be completed or corrected. Data imputation technology has become a powerful tool to fill the missing in well log data. A well log data imputation method based on deep learning is proposed. The proposed method combines conditional generative adversarial networks (CGAN) with swarm intelligence optimization algorithms. The seismic layer velocity is used as a constraint to guide CGAN to generate well log data that matches geological features. Establish an objective function based on multiple conditions to evaluate the quality of generated samples. The swarm intelligence optimization algorithm is used to minimize the objective function. The case study shows that the proposed method obtains pseudo samples that meet specific scenarios and perform better than other algorithms. The proposed method provides a new approach for deep learning algorithms in sequence data prediction.

Intelligent Inversion Analysis of Drilling Gas Kick Characteristic Parameters and Advanced Predictions of Development Trends

Summary Gas kicks are a common and complex occurrence in oil and gas exploration and development. Obtaining the characteristic parameters promptly and accurately after a gas kick occurs is of utmost importance. The kick characteristic parameters are essential foundational data for accurately understanding the multiphase flow state within the wellbore, analyzing kick development trends, and formulating well-killing design. Traditional methods for determining gas kick characteristic parameters often involve trial estimation, a process that can introduce significant arbitrariness. Alternatively, using specialized equipment for measurement and analysis is an option, but it can be time-consuming and limited by technology and cost constraints. This paper proposes an intelligent inversion method for kick characteristic parameters based on surface logging data, including standpipe pressure and mud pit volume. First, a gas kick simulation model is developed based on wellbore multiphase flow theory. This model can accurately simulate the changes in surface logging parameters that occur when a gas kick occurs. Next, the particle swarm optimization algorithm is used to optimize the kick parameters, such as the gas-influx index and pore pressure, in conjunction with the gas kick simulation model. The optimization evaluation criterion is the Fréchet distance, which is used to identify the calculated curve that is most similar to the actual logging parameter change curve. Subsequently, kick trends can be predicted using the simulation model based on these kick parameters. The case analysis demonstrates that the method proposed in this paper can rapidly acquire the gas kick characteristic parameters based on the early change characteristics of logging parameters. It effectively simulates and reproduces the true distribution of wellbore fluids, enabling advanced prediction of kick development. This approach helps in preparing preventive measures in advance, reducing the risk of accidents, and minimizing financial losses.

Study on the Effect of Cations on the Surface Energy of Nano-SiO2 Particles for Oil/Gas Exploration and Development Based on the Density Functional Theory.

Although nano SiO2 exhibits excellent application potential in the field of oil and gas exploration and development, such as drilling fluid, enhanced oil/gas recovery, etc., it is prone to agglomeration and loses its effectiveness due to the action of cations in saline environments of oil and gas reservoirs. Therefore, it is crucial to study the mechanism of the change in energy between nano SiO2 and cations for its industrial application. In this paper, the effect of cations (Na+, K+, Ca2+, and Mg2+) on the surface energy of nano SiO2 particles is investigated from the perspective of molecular motion and electronic change by density functional theory. The results are as follows: Due to the electrostatic interactions, cations can migrate towards the surface of nano SiO2 particles. During the migration process, monovalent cations are almost unaffected by water molecules, and they can be directly adsorbed on the surface by nano SiO2 particles. However, when divalent cations migrate from a distance to the surface of nano SiO2 particles, they can combine with water molecules to create an energy barrier, which can prevent them from moving forward. When divalent cations break through the energy barrier, the electronic kinetic energy between them and nano SiO2 particles changes more strongly, and the electrons carried by them are more likely to break through the edge of the atomic nucleus and undergo charge exchange with nano SiO2 particles. The change in interaction energy is more intense, which can further disrupt the configuration stability of nano SiO2. The interaction energy between cations and nano SiO2 particles mainly comes from electrostatic energy, followed by Van der Waals energy. From the degree of influence of four cations on nano SiO2 particles, the order from small to large is as follows: K+ < Na+ < Mg2+ < Ca2+. The research results can provide a theoretical understanding of the interaction between nano SiO2 particles and cations during the application of nano SiO2 in the field of oil and gas exploration and development.

Prediction of igneous lithology and lithofacies based on ensemble learning with data optimization

Igneous rocks are widely developed in various Mesozoic and Cenozoic continental and marine basins. Igneous reservoirs are the key reservoirs for current oil and gas development. Accurate prediction of lithology and lithofacies is a prerequisite for the effective exploration of igneous reservoirs. Igneous lithology and lithofacies are complex and correlated. The existing single-label igneous rock identification methods only consider the prediction of individual properties, and less consideration is given to the correlation of reservoir properties. Therefore, lithology and lithofacies prediction based on conventional logging data is regarded as a typical class-imbalanced multilabel classification problem when considering both attribute correlation in algorithms and evaluation metrics. To solve this problem, an ensemble method of data optimization combined with multigrained cascade forest (CF) is used in this study to develop a new multilabel lithology and lithofacies prediction model based on data from nine conventional logs in the eastern depressional reservoirs of the Liaohe Basin, and satisfactory results are obtained. The imbalance problem of the conventional logging data sets is first solved by using K-means and synthetic minority oversampling technique methods; then, the model is trained by scenario transformation and stripping with multigrained CF; and next, a multilabel classification evaluation index with multiple perspectives is introduced. The differences between the model and typical intelligent algorithms such as CF, adaptive boosting, random forest, and support vector machine are compared in simulated wells, and the new model is found to have obvious advantages. The model is finally applied to an actual well, and the accurate prediction results illustrate that the new model designed and trained for the class imbalance multilabel classification problem in this paper has application value in the lithology and lithofacies multilabel prediction of igneous rocks and also provides a theoretical basis for more complex multilabel reservoir evaluation using machine learning in the future.

Overpressure origin and evolution during burial in the shale gas plays of the Wufeng-Longmaxi formations of southern Sichuan basin

Identifying the origin, evolution and distribution of overpressure poses a significant challenge in shale gas reservoir, particularly in the deeper layers and zones of the Wufeng-Longmaxi Formations. To uncover the origin mechanism and reconstruct the evolution process of overpressure, samples are collected from the Wufeng-Longmaxi Formations in the southern Sichuan Basin. Subsequently, a combination of multi well-logging methods is employed to comprehensively identify the origin mechanism of overpressure. Additionally, forward numerical simulation and Laser Raman inversion validation are utilized to reconstruct the evolution process of overpressure during burial. Results show that: (1) Hydrocarbon generation pressurization is identified as the dominant origin mechanism of overpressure in the Wufeng-Longmaxi shale gas reservoir, employing a combination of well-logging methods, the revised Bowers method, and a velocity-density intersection chart. (2) The Wufeng-Longmaxi shale undergoes three main pressurization processes, including kerogen generation oil pressurization, crude oil cracking gas pressurization and kerogen cracking gas pressurization. Hydrocarbon generation pressurization correlates closely with factors such as organic matter abundance and type, original hydrogen index, kerogen mass fraction and transformation rate, oil cracking rate and retention coefficient. (3) The pressure coefficient of kerogen generation oil pressurization and gas cracking pressurization reaches 1.73 and 2.78, respectively. The contribution of crude oil cracking gas pressurization (75.6 MPa) is significantly greater than kerogen generation oil pressurization (37.8 MPa). (4) The density of methane inclusions (0.290–0.319 g/cm3) is corroborated through both Laser Raman spectroscopy and homogenization temperature analysis. The paleo pressure is recovered as 90.3–193.5 MPa, with a corresponding pressure coefficient spanning from 1.39 to 2.98. This study not only contributes to the advancement of the shale gas accumulation theory, but also provides valuable insights to guide the further exploration and development of marine shale gas within the intricate tectonic setting of the Sichuan Basin.

A review of surfactants as synergists in the field of enhanced oil recovery

The efficient development of oil resources is significant for alleviating the increasingly serious contradiction between oil supply and demand and ensuring national oil security. Surfactant flooding technology is one of the essential methods to enhance oil recovery and has been widely used in oil and gas development. The screening and development of traditional surfactants for oil displacement are mainly focused on reducing interfacial tension based on the theory of capillary number while ignoring the emulsification effect of surfactants. For different types of residual oil/remaining oil, the main contradictions faced by the target reservoir should be thoroughly analyzed to clarify whether the performance of surfactants used for oil displacement is mainly to reduce interfacial tension or strong emulsification capacity, and then screen surfactants suitable for reservoir characteristics and crude oil properties. In this article, the principle and application of surfactant flooding technology are reviewed from two aspects of interfacial tension and emulsification performance, the interrelationship between interfacial tension and emulsification capacity is explored, and the evaluation indicators and existing problems of surfactant used for oil displacement are analyzed in detail. Most of the evaluation methods for emulsification in the past were based on water extraction rate. A method for evaluating the emulsification ability of surfactants to crude oil is introduced. It is expected to provide scientific guidance for the screening and development of surfactants for oil displacement.

Applicability evaluation of plunger lift technology in shale gas wells

The accumulation of liquid in gas wells is a common problem in the later stages of shale gas production. The plunger lift is currently one of the most economically effective methods for removing accumulated liquid in gas wells, but its applicability is not yet clear. This article analyzes the production characteristics of gas wells on-site and summarizes the key indicators for evaluating the plunger lift technology, including casing pressure changes, production changes, liquid column plunger height, tubing-casing pressure differential changes, and differential size of pressure relief. Combined with numerical simulation methods, a complete set of evaluation systems for judging, classifying, and evaluating the effectiveness of plunger lift technology is established, and an evaluation method for the applicability of plunger lift technology is proposed. Taking well Ning 216-H4 as an example, a comprehensive evaluation is made on whether the gas well is suitable for plunger lift based on the height of the liquid column above the plunger, the production effect under pressure, and the overall shut-in time. This method has important guiding significance for the further promotion and application of plunger lift technology in deep wells, directional wells, and horizontal wells to achieve efficient development of natural gas.

Development of a greenhouse gas - air pollution interactions and synergies model for Korea (GAINS-Korea)

This study aimed to create Greenhouse Gas - Air Pollution Interactions and Synergies (GAINS)-Korea, an integrated model for evaluating climate and air quality policies in Korea, modeled after the international GAINS model. GAINS-Korea incorporates specific Korean data and enhances granularity for enabling local government-level analysis. The model includes source-receptor matrices used to simulate pollutant dispersion in Korea, generated through CAMx air quality modeling. GAINS-Korea's performance was evaluated by examining different scenarios for South Korea. The business as usual scenario projected emissions from 2010 to 2030, while the air quality scenario included policies to reduce air pollutants in line with air quality and greenhouse gas control plans. The maximum feasible reduction scenario incorporated more aggressive reduction technologies along with air quality measures. The developed model enabled the assessment of emission reduction effects by both greenhouse gas and air pollutant emission reduction policies across 17 local governments in Korea, including changes in PM2.5 (particulate matter less than 2.5 μm) concentration and associated benefits, such as reduced premature deaths. The model also provides a range of visualization tools for comparative analysis among different scenarios, making it a valuable resource for policy planning and evaluation, and supporting decision-making processes.

Shale brittleness evaluation under high temperature and high confining stress based on energy evolution

Deep and ultra-deep shale gas reservoirs are crucial targets for future natural gas development. Extensive research has shown the shale brittleness is closely associated with the hydraulic fracture network quality. However, the shale brittleness may be altered in deep reservoirs due to the high temperature and high geo-stress. At present, commonly used shale brittleness evaluation methods cannot distinguish the differences in energy evolution caused by different mineral components in shale rock. In order to distinguish this difference, this study innovatively proposes a shale brittleness evaluation method that considers mineral composition based on energy evolution. A high-temperature triaxial compression experiment was carried out on the Longmaxi Formation shale, its fracture mode was analyzed, and the brittleness of the shale was evaluated based on this innovative method. The results indicate that with increasing confining stress, the shale fracture mode transitions from brittle tensile-shear multi-crack penetrating fracture to brittle-plastic shear single-crack fracture, and the brittleness of shale shows a decreasing trend. Under low confining stress, the shale brittleness decreases with temperature. Under high confining stress, temperature is the non-main controlling factor of shale brittleness. This study provides valuable guidance for the design and optimization of hydraulic fracturing in deep shale reservoirs.

Quantitative characterization of the brittleness of deep shales by integrating mineral content, elastic parameters, in situ stress conditions and logging analysis

Deep shale reservoirs (3500–4500 m) exhibit significantly different stress states than moderately deep shale reservoirs (2000–3500 m). As a result, the brittleness response mechanisms of deep shales are also different. It is urgent to investigate methods to evaluate the brittleness of deep shales to meet the increasingly urgent needs of deep shale gas development. In this paper, the quotient of Young’s modulus divided by Poisson’s ratio based on triaxial compression tests under in situ stress conditions is taken as SSBV (Static Standard Brittleness Value). A new and pragmatic technique is developed to determine the static brittleness index that considers elastic parameters, the mineral content, and the in situ stress conditions (BIEMS). The coefficient of determination between BIEMS and SSBV reaches 0.555 for experimental data and 0.805 for field data. This coefficient is higher than that of other brittleness indices when compared to SSBV. BIEMS can offer detailed insights into shale brittleness under various conditions, including different mineral compositions, depths, and stress states. This technique can provide a solid data-based foundation for the selection of ‘sweet spots’ for single-well engineering and the comparison of the brittleness of shale gas production layers in different areas.

Developing Characteristics of Shale Lamination and Their Impact on Reservoir Properties in the Deep Wufeng–Longmaxi Formation Shale of the Southern Sichuan Basin

The deep shale of the Wufeng–Longmaxi Formation in the southern Sichuan Basin has high gas potential. The development characteristics of lamination could significantly impact reservoir property. Samples were investigated using microscopic observation, element analysis, organic petrology analysis, mineralogy analysis, and pore structure analysis to determine the types of laminae and laminasets, clarify the formation conditions of argillaceous lamina and silty lamina as well as their relationships with the sedimentary environment, and explore the influence of laminae on shale reservoir property. Results indicate that the Wufeng Formation shale exhibits weak development of laminae due to bioturbation, while the Longmaxi Formation shale develops continuous, parallel, and plate-like laminae. Compared with light silty lamina-rich shale, dark argillaceous lamina-rich shale usually develops in an anoxic reduction environment, with higher total organic carbon content, porosity, pore volume, specific surface area, and more developed organic matter pores, which can provide greater space for shale gas adsorption and storage. Shales in the middle section of the Longmaxi Formation are characterized by the development of silty-argillaceous interbedded type laminaset, which have good reservoir performance, making them the primary target for deep shale gas exploration and development.

Impact of investments on labour productivity in the chemical and petrochemical industry of the Republic of Kazakhstan

Relevance. Currently, the petrochemical and chemical industries are one of the main areas in the international economy. That is why it is important to choose effective alternative networks by promoting investments in factories to achieve certain indicators in the field of labour. The relevance of this topic is conditioned by the fact that labour productivity in the modern environment plays a crucial role in the activities of various industries. Purpose. The purpose of the study is to assess the correlation of investment and labour productivity in the chemical and petrochemical industry of the Republic of Kazakhstan. Methodology. The study used several methods of scientific research, specifically: correlation and regression analysis. Results. As a result, it was possible to explore the areas of activity responsible for the development of the chemical and petrochemical industry, namely: the development and production of oil, associated (petroleum) and natural gas, the production of chemical and petrochemical products, the production of coke and refined petroleum products, the development of rubber and plastic products. This allowed establishing the level of impact of investments on labour productivity of each of the above-mentioned sub-sectors. In addition, statistical data were investigated, based on which indicators were established reflecting the features of interaction between such components as investment, industrial development, and the improvement of professional personnel. The factors that qualitatively affect the efficiency of external market conditions for corporations are disclosed. Conclusions. The research shows that investments in chemical products, coke, and refined petroleum are more effective than those in crude oil and natural gas production. The practical value of the study is revealed in the possibility of using the results when developing development plans for specific chemical and petrochemical enterprises in the Republic of Kazakhstan, by attracting a specific type of investment. Keywords: energy efficiency; capital; infrastructure; productivity factors; innovation

Reservoir characteristics and formation model of Upper Carboniferous bauxite series in eastern Ordos Basin, NW China

Through core observation, thin section identification, X-ray diffraction analysis, scanning electron microscopy, and low-temperature nitrogen adsorption and isothermal adsorption experiments, the lithology and pore characteristics of the Upper Carboniferous bauxite series in eastern Ordos Basin were analyzed to reveal the formation and evolution process of the bauxite reservoirs. A petrological nomenclature and classification scheme for bauxitic rocks based on three units (aluminum hydroxides, iron minerals and clay minerals) is proposed. It is found that bauxitic mudstone is in the form of dense massive and clastic structures, while the (clayey) bauxite is of dense massive, pisolite, oolite, porous soil and clastic structures. Both bauxitic mudstone and bauxite reservoirs develop dissolution pores, intercrystalline pores, and microfractures as the dominant gas storage space, with the porosity less than 10% and mesopores in dominance. The bauxite series in the North China Craton can be divided into five sections, i.e., ferrilite (Shanxi-style iron ore, section A), bauxitic mudstone (section B), bauxite (section C), bauxite mudstone (debris-containing, section D) and dark mudstone-coal section (section E). The burrow/funnel filling, lenticular, layered/massive bauxite deposits occur separately in the karst platforms, gentle slopes and low-lying areas. The karst platforms and gentle slopes are conducive to surface water leaching, with strong karstification, well-developed pores, large reservoir thickness and good physical properties, but poor strata continuity. The low-lying areas have poor physical properties but relatively continuous and stable reservoirs. The gas enrichment in bauxites is jointly controlled by source rock, reservoir rock and fractures. This recognition provides geological basis for the exploration and development of natural gas in the Upper Carboniferous in the study area and similar bauxite systems.

Prediction of total gas content in low-resistance shale reservoirs via models fusion — Taking the Changning shale gas field in the Sichuan Basin as an example

The low-resistivity phenomenon appeared during the development of shale gas in the Changning area of southern Sichuan. The accurate prediction of GAST is crucial in formulating optimal development plans for low-resistivity shale reservoirs. A series of formulas such as Archie in traditional electrical logging is no longer applicable to the characterization of gas-bearing properties of low-resistivity shale reservoirs. In this paper, we propose a fusion model for predicting the total gas content of low-resistivity shale reservoirs using conventional logging and total gas content data of core analysis. The model combines three popular machine learning models: random forest, extreme gradient boosting tree, and deep neural network. First, rock physics logging knowledge and the Spearman coefficient method are used to select suitable logging data types as the input of three models. Second, three models are trained by using the selected logging and core gas content data to achieve optimal performance. Finally, based on the stacking model fusion strategy, the three are fused to obtain a fusion model with better generalization performance. The experimental results show that the average absolute errors of the fusion model in predicting the total gas content of low-resistance wells and ultra-low resistance wells are 0.025 and 0.023 respectively, and the R2 coefficients reach 0.952 and 0.964. The fusion model effectively predicts the gas content of low-resistivity shale reservoirs and has high application value.

MODELING of Water Saturation in Shallow Sandstone Oilfield

3D geological modeling technology has achieved visualization of underground reservoirs in oil and gas fields, and has been widely applied in oil and gas field development. 3D geological modeling includes structural modeling and attribute modeling, and strata and faults can be completed based on data from oil and gas field exploration and development. The porosity and permeability in the geological attribute model can be established based on logging interpretation conclusions and other relevant data, The establishment of a saturation model has always been a difficulty in 3D geological modelling. As the water saturation, is different from porosity and permeability of an oil field. Saturation is distributed under the control of factors such as gravity and capillary force, and cannot be established through spatial simulation interpolation. Instead, the influence of factors such as gravity and capillary force should be considered. This article takes the shallow sandstone M oilfield in Kazakhstan as an example, and establishes the J function of the oilfield by combining the capillary pressure experiment of the core well, in order to establish an oilfield saturation model.