Natural Gas Industry B最新文献

{"title":"Types of lithofacies in the Lower Cambrian marine shale of the Northern Guizhou Region and their suitability for shale gas exploration","authors":"","doi":"10.1016/j.ngib.2024.09.006","DOIUrl":"10.1016/j.ngib.2024.09.006","url":null,"abstract":"<div><div>The lithofacies and thermal maturity of the over-mature Lower Cambrian marine shale in the Northern Guizhou Region, and their impacts on reservoir properties in this shale were analyzed by combining geochemistry, mineralogy, and gas adsorption methods. Ten lithofacies were identified, and the dominant lithofacies in the studied shale are lean-total organic carbon (TOC) argillaceous-rich siliceous shale (LTAS), medium-TOC siliceous shale (MTSS), and rich-TOC siliceous shale (RTSS). Since the gas generation potential of organic matter was weak, meso- and macro-pores were compressed or filled during the thermal evolution stage with a vitrinite reflectance (<em>R</em>_O) range of 3.0%–4.0%. The controlling factors for methane adsorption capacity in the shale samples are significantly influenced by TOC content rather than thermal maturity. Among the RTSS, MTSS, and LTAS samples, RTSS exhibits the highest favorability for preserving hydrocarbon gas, followed by MTSS. The shale types in this study play a significant role in determining the properties of shale reservoirs, serving as an effective parameter for evaluating shale gas development potential. The RTSS and MTSS with a <em>R</em>_O range of 2.0%–3.0% stand out as the most favorable target shale types for shale gas exploration and development.</div></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142538252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental study on the diffusion process of natural gas from buried pipelines to underground confined spaces","authors":"","doi":"10.1016/j.ngib.2024.09.002","DOIUrl":"10.1016/j.ngib.2024.09.002","url":null,"abstract":"<div><div>In recent years, leakage from buried gas pipelines has been a frequent occurrence around the world. Leaked gas can quickly diffuse and accumulate in adjacent confined spaces, such as inspection wells, sewage pipes, and heat pipeline trenches, posing serious threats to people's lives and property in the event of fire. In this study, a large-scale experimental system was conducted to better understand how methane diffuses after an unintended leak from an underground pipe and how long the methane may take to dissipate in the soil and the adjacent underground confined space. A theoretical analysis is conducted of the seepage characteristics of methane gas in soil, and the experimental results indicate that the variation of methane concentration over time in soil and underground confined spaces is directly related to the distance between the test points and the leak holes. With an escalation in the gas flow rate, methane concentration progressively elevates within the same leakage time, demonstrating a decreasing augmentation rate. Once the air source has been cut off, the gas concentration in the underground confined space will maintain a stable state for a period time after reaching the peak value. Additionally, the time required to reach the lower and upper limits of dangerous concentration has an exponential relationship with the diffusion distance. Fitting curve equations have been drawn in all experimental scenarios.</div></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142538258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fracture features and fault influence on gas accumulation in the Longmaxi Formation in Changning block, southern Sichuan Basin","authors":"","doi":"10.1016/j.ngib.2024.09.007","DOIUrl":"10.1016/j.ngib.2024.09.007","url":null,"abstract":"<div><div>The Lower Silurian Longmaxi Formation is a major horizon for shale gas development in the Changning block in Sichuan Basin. In this study, the fracture features in the Longmaxi Formation in the Changning block were investigated through outcrop observation, core description, inclusion testing, and Fullbore Formation MicroImage logging. The results showed that tectogenetic shear fractures dominated the Longmaxi Formation, with maximum principal stress in the SSW, NW, and NE directions. According to fracture features and stress analysis, three phases of faults were generated by tectonic movements after the buried depth reached a maximum in the study area: phase 1 nearly EW-trending faults formed in the middle-late Yanshanian, phase 2 NE-trending faults formed from the end of the Yanshanian to the early Himalayan, and phase 3 NW-trending faults formed from the middle Himalayan to the present. According to the regression analysis of the tested shale gas production and faults, the faults with a throw of &gt; 200 m could have a great effect on gas production, and high-yield wells were generally located over 1 km away from faults. Based on the dissection of tectonic styles and typical wells drilled in the Changning block, three shale gas accumulation models were established: wide gentle syncline + internal smalxl fault, subdued anticline + large fault, and slope + internal fault. The study reveals the mechanism of fault influence on shale gas accumulation in the Longmaxi Formation in the Changning block and provides a reference for efficient shale gas production in the Sichuan Basin.</div></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142538253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A reverse biomarker-derived maturity trend in Triassic Yanchang Formation shales from the Ordos Basin in China","authors":"","doi":"10.1016/j.ngib.2024.09.008","DOIUrl":"10.1016/j.ngib.2024.09.008","url":null,"abstract":"<div><div>Organic-rich shales from the Triassic Yanchang Formation in the Ordos Basin in China are mainly derived from aquatic organisms with type II kerogen. A reverse maturity trend, derived from the commonly used biomarker maturity parameter Ts/(Ts + Tm) occurs in the depth profiles of the Chang 7₃ submember and the Chang 8 member. In contrast, maturity proxies derived from aromatic compounds show a normal sequence for more deeply buried Chang 8 samples exhibiting higher maturity levels, as expected. To explain the abnormal phenomenon, multiple controlling factors—including the paleoredox condition, water salinity, the clay mineral content and composition, biodegradation, the primary migration fractionation effect, and organofacies—are considered. It was found that organofacies BC (HI_o = 400-250) appear in the Chang 8 samples, while organofacies B (HI_o = 400-650) appear in the Chang 7₃ submember. The results suggest that variation in organofacies has a significant impact on Ts/(Ts + Tm) values, even for samples with the same kerogen type and similar source input, and is primarily responsible for the reverse maturity trend in the depth profiles.</div></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142538254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An experimental study of the effect of temperature on teeth breaking efficiency based on rock mechanical properties","authors":"","doi":"10.1016/j.ngib.2024.09.009","DOIUrl":"10.1016/j.ngib.2024.09.009","url":null,"abstract":"<div><div>To master changes in rock mechanical properties and the impact of high temperature on rock-breaking efficiency, the rock mechanical properties of granite, limestone, and sandstone under different temperatures and single-tooth static-pressure experiments were studied. The results show that the compressive strength, shear strength, internal friction angle, and elastic modulus of granite and limestone initially increased and then decreased as the temperature rose. The experimental temperatures were 25 °C, 100 °C, 200 °C, 300 °C, 400 °C, and 500 °C. The mechanical properties of granite reached the maximum at 200 °C, while those of limestone reached the maximum at 100 °C. The compressive strength, shear strength, and internal friction angle of sandstone gradually diminished, while the elastic modulus gradually increased at the abovementioned five temperature points. Among the samples of granite, limestone, and sandstone, the crushing-specific work of conical teeth, wedge teeth, and scoop teeth was smallest when the temperature was 300 °C. Compared to the normal temperature, the load of conical teeth, wedge teeth, and scoop teeth was reduced by 32.1%, 28.4%, and 22.9%, respectively, when they were pressed into sandstone. At the same temperature, the conical tooth had the highest rock-breaking efficiency, followed by the wedge tooth; the scoop tooth had the lowest efficiency. Conical teeth can be used to select the tooth shapes of bits to improve drilling efficiency. Optimizing the tooth profile and conducting research on rock-breaking efficiency under different temperatures and rocks have an important role in bit design and can greatly improve drilling efficiency.</div></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142538299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pore heterogeneity and evolution of the Lower Silurian Longmaxi shale reservoir in the Southern Sichuan Basin: Responses to sedimentary environment","authors":"","doi":"10.1016/j.ngib.2024.09.010","DOIUrl":"10.1016/j.ngib.2024.09.010","url":null,"abstract":"<div><div>As the cornerstone for evaluating the storage capacity of shale reservoirs and assessing the viability of shale gas exploitation, shale pores play a very important role in shale reservoirs. Based on drilling well and test data, deep learning, and artificial intelligence for image analysis, the types, characteristics, structures, and vertical heterogeneity of shale pores were studied. Additionally, we conducted a comprehensive investigation into the sedimentary environment characteristics and their influence on the heterogeneity of shale reservoir pores in the Longmaxi Formation using associated geochemical analyses. The results revealed that the sedimentary environment underwent significant changes in the Longmaxi Formation, characterized by a sea level fall, accelerated sedimentation rates, weakened reducing conditions, decreased palaeoproductivity, and increased terrigenous influx, which led to a decrease in the frequency of organic matter (OM) pores, paralleled by a gradual increase in inorganic pores. In the S₁l₁¹⁻¹, S₁l₁¹⁻², S₁l₁¹⁻³ sections of the Long11 sub-member, OM pores constitute the primary pore type. Conversely, in the S₁l₁¹⁻⁴ section and the Long12 sub-member, inorganic pores prevail as the primary pore type. Furthermore, the strongly anoxic sections are also pay zones that are not only enriched in OM but also concentrated with OM pores. The S₁l₁¹⁻¹ and S₁l₁¹⁻² sections are characterized by anoxic conditions, with total organic carbon (TOC) content exceeding 4% and abundant biogenic silica. Notably, an increased terrigenous influx adversely impacts the development and preservation of pores in the Long11 sub-member while exerting a dual effect in the Long12 sub-member. The increased terrigenous influx dilutes the OM and decreases the probability of intergranular pores and intragranular pores filled by OM. Moreover, more brittle mineral particles were deposited, which promotes the development and preservation of intergranular and intragranular pores.</div></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142538256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Generic layout optimization design methodology for China's loop-star natural gas field pipeline network","authors":"","doi":"10.1016/j.ngib.2024.09.005","DOIUrl":"10.1016/j.ngib.2024.09.005","url":null,"abstract":"<div><div>The layout optimization design of a natural gas gathering pipeline network is a multi-objective optimization problem because the extant theories are unable to meet the different decision preferences in scheme design, which restricts the intelligentization of gas gathering pipeline layout optimization. Currently, there are no generic design studies on the loop-star pipeline network. Therefore, this paper proposes a generic layout optimization model containing a large number of discrete and continuous variables, such as pipe connection relationships, pipe sizes, pipe length, and pipe specifications. In the solution section, drawing inspiration from the hormone regulation mechanism and local foraging rule in bionics, an improved particle swarm optimization algorithm based on hormone regulation (HRPSO) is proposed, and it obtains the favorable parameters range of the HRPSO algorithm. The results illustrate that the HRPSO algorithm exhibits convergence to the global optimum with a probability of 1. In comparison to manual design, the comprehensive costs of the optimized scheme are saved by 22.71% with the HRPSO algorithm. Compared to the four PSO variants in the paper, it can save costs by 5.38%, 4.95%, 4.09%, and 3.65%, respectively.</div></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142538259","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A novel EUR prediction model for fractured horizontal shale gas wells based on material balance theory","authors":"","doi":"10.1016/j.ngib.2024.09.003","DOIUrl":"10.1016/j.ngib.2024.09.003","url":null,"abstract":"<div><div>Accurately predicting the estimated ultimate recovery (EUR) of shale gas wells is key to formulating a shale gas reservoir development plan. However, in practice, determining the EUR remains challenging due to the complex dynamic characteristics of shale gas production, which first decreases rapidly and then slowly. In this study, based on material balance theory and equivalent seepage resistance theory and considering crucial factors including primary water, adsorption, and pore effects, a new production model for fractured horizontal shale gas wells is developed. The calculation process is designed by using Newton's iterative method. The shale gas well EUR prediction method is verified, and the factors influencing the EUR are analyzed. The results show that adsorption has a significant effect on production, especially on the Langmuir volume. Moreover, ignoring the influence of primary water, which exists in shale gas reservoirs in the form of bound water, results in an overestimation of the EUR. Furthermore, production positively correlates with the fracture half-length and the number of fractures, but the action mechanisms of these two factors differ. Unlike the number of fractures, which predominantly affects the initial stage of production, the fracture half-length has a more nuanced role. It is capable of altering the stimulated reservoir volume zone, thereby exerting influence over the entire production life cycle.</div></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142538314","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of rock strength degradation by fluid intrusion on borehole stability in shale","authors":"","doi":"10.1016/j.ngib.2024.09.004","DOIUrl":"10.1016/j.ngib.2024.09.004","url":null,"abstract":"<div><div>The interaction between shale bedding planes and fluids significantly weakens their structural integrity, profoundly affecting borehole stability in shale reservoirs. However, traditional analyses often overlook fluid intrusion from the borehole into the bedding planes, leading to an inaccurate understanding of the mechanisms behind shale deterioration and inadequate guidance for drilling engineering design. This study models the process of drilling fluid permeating bedding shale through fluid intrusion experiments. It evaluates how forces acting on the bedding plane and the drilling cycle affect strength evolution, deriving rules governing changes in the mechanical parameters of both the shale matrix and the bedding planes. We developed a borehole stability calculation model that incorporates bedding plane considerations by integrating the established rules for mechanical parameter changes. The model analyzes the effects of the bedding plane, well inclination angle, wellbore azimuth angle, bedding plane inclination angle, and drilling cycle on the collapse pressure and collapse area with different types of drilling fluids. The results indicate that the presence of bedding planes significantly influences borehole stability. Therefore, both matrix and bedding plane damage should be considered to accurately calculate the collapse pressure and area. The well inclination angle, wellbore azimuth angle, and bedding plane inclination angle also impact borehole stability. It is recommended that the horizontal section of the wellbore be drilled in the direction of the minimum horizontal in situ stress. As the drilling cycle extends, the collapse pressure gradually increases, with the largest increase occurring in the direction of the minimum stress. Additionally, the increase in collapse pressure is greater when using water-based drilling fluid than when using oil-based drilling fluid. These findings provide theoretical insights for drilling engineering design in bedding shale environments, aiming to enhance borehole drilling safety.</div></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142538313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fluid activity characteristics of shallow shale veins in the Wufeng–Longmaxi Formation in the Shixi syncline in northern Guizhou and their significance for shale gas preservation","authors":"","doi":"10.1016/j.ngib.2024.09.011","DOIUrl":"10.1016/j.ngib.2024.09.011","url":null,"abstract":"<div><div>Preservation conditions are key to enriching shallow shale gas. Therefore, the veins of two typical wells in the Shixi syncline in northern Guizhou as research objects. Based on core observation, vein thin-section observation, cathodoluminescence, calcite in situ U-Pb dating, fluid inclusion microthermometry, Raman spectrum shift, single well basin simulation, and C-O isotope geochemical analysis, the researchers clarified the characteristics of the veins and the differences in paleofluid activity, as well as their significance for shale gas preservation. The results showed that: 1) a small number of high-angle fractures had developed mainly in the Shixi syncline in northern Guizhou. The width of viens is small and filled primarily with early calcite-quartz and late calcite. The inclusions were mainly methane and brine. The proportion of brine inclusions in the SD1 well was greater than that in the SX1 well. The SD1 well has experienced more intense second-stage uplift and denudation, and the consequent gas loss is serious. 2) The results of the C-O isotope analysis showed that most of the vein-forming fluids were derived from marine carbonate rocks. The O₃b had obvious negative deviations of δ¹³C and δ¹⁸O, which were modified by exogenous or deep hydrothermal fluid. The C-O isotope difference between the vein bodies and the surrounding rock of the SX1 well was small, and the preservation conditions were better. 3) The difference in gas content in the Shixi syncline depends on the degree of damage to gas reservoir preservation conditions caused by burial depth and other factors. Shixi syncline is a wide and gentle syncline with central retention enrichment mode. Therefore, clarifying the development of shale veins, the characteristics of paleofluid activity, and their significance for shale gas preservation can lay a foundation for studying the enrichment mechanism of shallow shale gas and thus guide further exploration and development.</div></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142538255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}