Sichuan Area Research Articles

Numerical Simulation on the Influence of the Distribution Characteristics of Cracks and Solution Cavities on the Wellbore Stability in Carbonate Formation

The development of cracks and solution cavities in carbonate reservoirs can notably reduce the rock’s mechanical properties, leading to a severe wellbore collapse problem during drilling operations. To clarify the influence of the characteristics of cracks and solution cavities on the wellbore stability in the Dengying Formation carbonate reservoir in the Gaoshiti–Moxi area of Sichuan, the mechanical properties of carbonate rock were analyzed. Then, the influences of the attitude and width of cracks, the size and quantity of solution cavities, and their connectivity on wellbore stability were studied using FLAC3D 6.00 numerical simulation software. Our results show the following: (1) The cracks and solution cavities in the Dengying Formation carbonate rock cause significant differences in the rock’s mechanical properties. (2) The equivalent drilling fluid density of collapse pressure (ρc) considering the effects of cracks and solution cavities is 6.4% higher than without these effects, which is in good accordance with engineering practice. Additionally, cracks play a more significant role than solution cavities in affecting the wellbore stability. (3) When the orientation of a crack is closer to the direction of maximum horizontal stress, and the dip angle and width of the crack increase, the stress and deformation at the intersection of the crack and wellbore gradually increase, and correspondingly, ρc also increases. (4) The stress and displacement of various points around the solution cavities gradually increase with the increases in diameter and quantity of solution cavities, and ρc also increases. (5) Compared with the situation where cracks and solution cavities are not interconnected, the stress disturbance area around the wellbore is larger, and ρc is greater when cracks and solution cavities are interconnected.

Using Resistivity Structure to Study the Seismogenic Mechanism of the 2021 Luxian Ms6.0 Earthquakes

Over the past few years, there has been a noticeable change in the occurrence of seismic disasters in Sichuan, China. The focus has shifted from Western Sichuan to the previously more stable Southeastern Sichuan. The recent Ms6.0 earthquake in Luxian, Southeastern Sichuan, on 16 September 2021, has once again captured the interest of scholars, who are closely examining the seismogenic environment and potential seismic hazards in the region. We conducted a magnetotelluric (MT) array survey in the Luxian earthquake area to explore the deep seismogenic environment of the 2021 Luxian Ms6.0 earthquake zone and understand the potential effects of industrial extraction on seismic activities. Here are the insights we obtained: Underneath the anticline in the Luxian Ms6.0 earthquake area, there is a structure that mainly exhibits high resistance. On the other hand, beneath the syncline, a structure with medium to low resistance is observed. The epicenter of the mainshock was identified near the intersection of high- and low-resistance media within the Fuji syncline area. Smaller aftershocks that followed the mainshock were mainly concentrated in the low-resistance layers at depths of 3–5 km in the Fuji syncline area. MT survey results have confirmed the existence of a detachment zone in the shallow crust near the epicenter of the Luxian Ms6.0 earthquake. It is believed that this detachment layer played a significant role in the seismogenic process of the Luxian Ms6.0 earthquake. During different stress conditions, this layer became active and caused the compression and faulting of a hidden fault below, resulting in the Luxian Ms6.0 earthquake. After the main earthquake, a series of smaller aftershocks with varying focal mechanisms occurred as the stress fields continued to release. It is important to note that the Luxian Ms6.0 earthquake highlights the ongoing high stress levels in the southern region of the Sichuan Basin. This emphasizes the need for continued monitoring and consideration of potential seismic hazards in the southern Sichuan area.

Characterization of key aroma-active compounds in Zanthoxylum schinifolium by sensory evaluation and multiple instrumental analyses

The aroma characteristics of Zanthoxylum schinifolium from four different production areas in Sichuan were identified and compared. Aroma components were analyzed via sensory evaluation, gas chromatography–olfactometry–mass spectrometry (GC–O–MS), and comprehensive two-dimensional gas chromatography-olfactometry-mass spectrometry (GC × GC–O–MS). The results revealed that minty, spicy, woody, fresh, citrus, and herbal notes could be perceived, with the Jinyang sample exhibiting the most significant aroma profile. Compared with GC–O–MS, GC × GC–O–MS offers advantages in identifying aroma-active compounds, and it can identify more types and quantities of aroma-active compounds. In this study, 40 aroma-active compounds from seven different classes were identified via GC × GC–O–MS. Through aroma extraction dilution analysis (AEDA), 14 aroma-active compounds were quantitatively analyzed, and odor activity values (OAVs) were calculated. Additionally, orthogonal partial least squares discriminant analysis (OPLS-DA) was employed to identify four aroma-active compounds with variable importance in projection (VIP) scores greater than 1, indicating their potential as identification markers. This study enhances our understanding of the sensory characteristics and aroma-active compounds of Zanthoxylum schinifolium.

Cytological analysis of flower development, insights into suitable growth area and genomic background: implications for Glehnia littoralis conservation and sustainable utilization

BackgroundGlehnia littoralis F. Schmidt ex Miq., an endangered plant species with significant medicinal, edible, and ecological value, is now a central concern for conservation and sustainable utilization. Investigating the physiological and ecological mechanisms leading to its endangerment and elucidating its genetic background constitutes the foundation for conducting in-depth research on G. littoralis.ResultsOur observations have revealed a significant degree of floral sterility in wild populations of G. littoralis. The inflorescences of G. littoralis are classified into three types: completely fertile, completely sterile, and partially fertile compound umbels. Moreover, the flowers of G. littoralis can be categorized into fertile and sterile types. Sterile flowers exhibited abnormalities in the stigma, ovary, and ovules. This study is the first to discover that the presence or absence of a giant cell at the funiculus during the initiation of ovule primordium determines whether the flower can develop normally, providing cytological evidence for female sterility in G. littoralis. Conversely, both fertile and sterile flowers produced normally developed pollen. Field observations have suggested that robust plants bear more fertile umbels, while weaker ones have fewer or even no fertile umbels, indicating a close relationship between flower fertility and plant nutritional status. Our model correctly predicted that the eastern coastal regions of China, as well as prospective areas in Neimenggu and Sichuan, are suitable environments for its cultivation. Additionally, Using flow cytometry and genome survey, we estimated the genome size of G. littoralis to be 3.06 Gb and the heterozygosity to be 4.58%.ConclusionThe observations and findings presented in this study were expected to provide valuable insights for further conserving its genetic resources and sustainable utilization of G. littoralis.

The polymorphism analysis and therapy vaccine target epitopes screening of HPV-35 E6 E7 among the threaten α-9 HPV in Sichuan area

High-risk human papilloma virus (HR-HPV) persistent infection is closely associated with the development of cervical cancer and squamous intraepithelial lesion (SIL).The α-9 HPVs, which is predominantly composed of HR-HPV types, account for 75% of HR-HPV infection in Sichuan. The oncoproteins E6 and E7 of HPV play a crucial role in tumor initiation and progression. Notably, HPV-35 is the only HR-HPV type within the α-9 genus that is not included in the nine-valent HPV prophylactic vaccine. Cervical cell samples obtained from Sichuan were collected for HPV detection and genotyping. Among the 406 HPV-positive samples, 31 HPV-35 were detected, 24 HPV-35 E6 and 26 E7 were successfully amplified and sequenced, five nucleotide mutations in E6 and three in E7 were detected, T232C, T434G of E6 (W78R, I145R) and C67T, G84T of E7 (H23Y, L28F) were non-synonymy mutation. PAML 4.8 server was used to detect positive selection sites of HPV-35 E6, E7, and E6 is W78R. Phyre2 were used to predict and analyze protein structures, W78R made influences on protein structure. IEDB were used to screen epitopes vaccine target for HPV-35 affection therapy, and 5 HPV-35 E6 and 3 HPV-35 E7 most potential epitopes were obtained, the most potential peptides for therapy vaccine design were 79-91YRYSVYGETLEKQ, 45-60FACYDLCIVREGQPY, 124-135RFHNIGGRWTGR of E6; 3-19GEITTLQDYVLDLEPEA, 38-47TIDGPAGQAK, 70-88VQSTHIDIRKLEDLLMGTF of E7 and W78R mainly decreased the epitopes affinity.Conclusions Amino acid substitution in the positive selection sites of HPV-35 E6 and E7 genes have been found to influence protein structure and to decrease the overall affinity of antigen epitopes. This observation aligns with the evolutionary significance of positive selection site, which may confer advantages to the virus by making infected cells more challenging for the immune system to detect, thereby enhancing HPV’s adaptability to the host environment. The polymorphism analysis of HPV-35 E6, E7 contributes to the enrichment of α-9 HPV data in Sichuan China, which is instrumental in improving the effectiveness of clinical detection. Furthermore, these findings provide a relevant theoretical foundation for the prevention and treatment of HPV-related diseases.

Biostratigraphy of the early Cambrian small skeletal fossils from the Niuniuzhai section of southern Sichuan in China

The Niuniuzhai section in Leibo County, southern Sichuan, China, is part of the western carbonate platform of the Yangtze Block. The section is crucial for correlating early Cambrian successions in the eastern Yunnan and southern Sichuan areas. A comprehensive biostratigraphic analysis of small skeletal fossils (SSFs) from this section identifies three SSF assemblages: (1) the oldest from an interval of uncertain age affinity in the middle and upper Dahai Member of the Zhujiaqing Formation; (2) the Watsonella crosbyi Assemblage Zone (Zone Ⅲ) in the upper Dahai Member of the Zhujiaqing Formation; and (3) the Sinosachites flabelliformis–Tannuolina zhangwentangi Assemblage Zone (Zone IV) in the middle Shiyantou Formation. These SSF assemblage zones in the Niuniuzhai section correlate well with sections from eastern Yunnan and southern Sichuan, indicating a coherent Terreneuvian succession on the the Yangtze Platform and in other continents.

Why do aging households in agriculture prefer land abandonment to transfer? Evidence from hill plots in Sichuan, China

AbstractIncreased aging of the agricultural population may lead to a reconfiguration of land elements, but existing studies have not analyzed this on a plot level. China's vast hilly and mountainous regions will have a more serious impact on agricultural aging, but this context has still not received enough attention. Based on primary data from 2602 plots and 1080 farm households in the hilly areas of Sichuan, using human capital theory and instrumental variables approach, it is found that aging in agriculture will promote the abandonment of plots in the hilly areas, especially those that are remote, small in size and poor condition. Aging in agriculture will inhibit the out‐migration of plots in the hilly areas, and aging increases the abandonment of plots. In addition, this paper finds that the imperfect development of the land transfer market in hilly areas and the strong farmers' land endowment effect are the main reasons limiting land transfer. However, the inhibitory effect of the endowment effect diminishes with age. This study helps to rationally view the value of abandoned land and provides a new research perspective for parcel redistribution.

Current Situation and Influencing Factors of Caregivers' Pressuring Feeding Style in Infants of 6-11 Months Old in Rural Areas of Sichuan Province

Objective To investigate the status and influencing factors of pressuring feeding style among caregivers in remote rural areas of Sichuan province. Methods Multistage sampling was conducted to select infants of 6-11 months old who had received complementary food and their caregivers in remote rural areas of Sichuan province.A questionnaire was used to collect sociodemographic characteristics of infants and their caregivers,pressuring feeding behaviors,feeding environment,and caregivers' negative emotions.Quantile regression was employed to analyze the factors influencing pressuring feeding among caregivers of infants. Results A total of 1358 pairs of infants and their caregivers were included,with the pressuring feeding behavior score of 11 (8,14).Parity was the protective factor for caregivers' pressuring feeding (β25=-1.17,P<0.001;β50=-1.40,P=0.002;β75=-2.18,P<0.001).Whether infants played with toys while eating (β25=1.00,P<0.001;β50=1.20,P=0.003;β75=1.42,P<0.001) and whether infants watched TV/mobile phones (β25=0.50,P=0.048;β50=1.07,P=0.004) were the risk factors.At the 75th percentile,caregivers' negative emotions were the risk factor for pressuring feeding (β75=0.94,P=0.015).Caregivers' education background (β25=0.83,P=0.034;β50=0.87,P=0.021) and family income (β75=1.09,P=0.012) were also significantly associated with pressuring feeding scores at different quartile points. Conclusion Pressuring feeding behaviors of caregivers in remote rural areas of Sichuan province need to be improved.Based on the characteristics of infants and their families,guidance should be carried out to improve the feeding environment and the mental health of caregivers,thereby promoting reasonable feeding behaviors among caregivers of infants in rural areas.

Exploration of the passivation effect of different types of passivators on cadmium contaminated soil

The problem of excessive cadmium in farmland soil in China is severe, and it is of great significance to explore suitable passivators for specific polluted soils. Three typical and representative commercially available passivators were selected as the test agents, and simulated the natural production process of irrigation and drainage in farmland soil. Through soil cultivation experiments, the remediation effects of different types of passivators and water management on Cd contaminated farmland soil in a certain area of Sichuan were explored. The results showed that the passivator agent 1# based on organic matter reduced the soil pH value, the passivator agent 2# based on alkaline substance and the passivator agent 3# based on clay mineral could increase the soil pH value in different degrees, and the passivator agent 2# was better than the passivator agent 3#. Under flooding condition, soil pH value can be increased. The three passivator agents can increase the content of soil organic matter in different degrees, and the maximum increase rate was 35.2% under 8%. The three passivator agents can reduce the available Cd in different degrees, and the maximum reduction of passivator agents 1#, 2# and 3# was 61.8%, 67.1% and 46.4% respectively. The correlation analysis showed that the flooding state was conducive to the decrease of available Cd. Under the action of passivator agent 1# , the correlation between available Cd and pH was weak, and there was a strong negative correlation between Cd and organic matter (R=0.9922). Under the action of passivator agent 2#, available Cd had a strong negative correlation with pH (R=0.8702) and a weak negative correlation with organic matter (R=0.4041). Under the action of passivator agent 3#, available Cd was strongly negatively correlated with soil pH value and organic matter.

A Study on the Strategy of Modern Border Governance in the Qing Dynasty -- A Brief Discussion on the Governance Strategy of Zhao Erfeng during his tenure as the Resident Minister in Tibet

In the late Qing Dynasty, in order to consolidate the southwest border and resist the invasion of British colonizers. The central administrative group of the Qing Dynasty carried out a series of governance and business activities on the Xichuan border. In this series of activities, Zhao Erfeng, who was then the Minister of Border Affairs of Sichuan and Yunnan, was known as the "Zhao Butcher". He cruelly suppressed the national movement with iron and blood methods, and implemented strategies such as land reform and new policies, which greatly changed the form of border areas in Sichuan. This article aims to explore the development process of modern ethnic relations and border governance by exploring Zhao Erfeng's governance period, extracting the ruling ideas of Qing rulers towards ethnic border areas, and exploring the development process of modern ethnic relations and border governance.

Research on Inheritance and Innovation under the Perspective of Non-legacy Brand Revitalization

Su embroidery is a kind of folk handicraft popular in the area of Sichuan, and it is regarded as the first of the “Four Famous Embroideries of China”. Su embroidery carries a strong cultural imprint, has a deep historical heritage, and is listed in the National Intangible Cultural Heritage Protection Catalog. In the process of inheritance and development of Su embroidery technology, through the analysis of the challenges faced by Su embroidery technology in the current market to find the market positioning, strengthen the optimization of Su embroidery technology to enhance and promote the brand, explain the innovative use of multimedia technology in the digital creation of the brand, to enrich the propaganda channels of Su embroidery technology, to set up the brand's degree of memory and cognition, and to effectively convey the brand information, to achieve multi-dimensional publicity effect, making its cultural connotation well preserved. The cultural connotation can be well preserved and promoted, which has a positive effect on the inheritance and development of Su embroidery craft.

Technical study on the early twentieth century’s embroidered women waistcoat in Gyalrong Tibetan area in Sichuan, China

In the early twentieth century, traditional handicraft was challenged by the latest technology in China. It is reflected by ethnic costumes combining new and old, as in the waistcoat of this study. This waistcoat made at Gyalrong Tibetan area in Sichuan, China, displays unique local features in terms of its brilliant colors and comprehensive craftsmanship. This study employs techniques such as optical microscopy, infrared spectroscopy, scanning electron microscope and high performance liquid chromatography-mass spectrometry to investigate various aspects of this waistcoat, including its fabrics and dyes. The results showed that the waistcoat was primarily made of cotton and silk, with a bamboo paper layer, and that silk as well as twisted gold and silver threads were employed for the embroidery. Various embroidery techniques were applied, with patterns, color combinations, and characteristics being consistent with those of Tibetan and Shu (蜀) embroidery. In terms of dyeing technology, a wide range of colors were achieved through multi-step dyeing processes using natural dye stuffs like pagoda bud, and synthetic dyes like magenta. These findings indicates that modern technologies were well integrated into traditional garment manufacture in the early twentieth century in China.

An analysis of the development path of ethnic villages under the protection of traditional Jiarong culture

Most of the villages in the north-west ethnic areas of Sichuan are located within a culturally rich zone. However, during the process of village modernization, the protection and inheritance of traditional culture are often overlooked. This study has investigated the construction techniques and spatial components of traditional villages in Lixian, Sichuan Province, from the perspective of cultural inheritance. It analyzes and synthesizes representative design language and proposes a design concept that combines spatial perspective and cultural inheritance to conduct research on design paths aimed at strengthening functional positioning, optimizing spatial layout, improving village style, and improving infrastructure. The objective is to establish a research path to maintain the village-style during post-disaster process reconstruction and village development, thus protecting the unique local architectural culture and achieving comprehensive village development. In addition, we explored issues such as the lack of architectural style and the lagging development of human settlements, aiming to promote rural revitalization and integrated urban-rural development in this area.

Comparative Study on Flow Characteristics in Deep Marine and Marine-Continental Transitional Shale in the Southeastern Sichuan Basin, China.

Permeability is a significant characteristic of porous media and a crucial parameter for shale gas development. This study focuses on deep marine and marine-continental transitional shale in the southeastern Sichuan area using the gas pulse decay testing method to systematically analyze the gas permeability, stress sensitivity, and gas transport mechanisms of shale under different pressure conditions and directions. The results show that the porosity and gas permeability of the deep marine shale are greater compared to those of the marine-continental transitional shale. The elevated fluid pressure in the deep marine shale offers superior conditions for the preservation of nanopores, while the high quartz content provides advantageous conditions for fluid transport in nanopore channels. The permeability and stress sensitivity of the deep marine shale are greater than those of the marine-continental transitional shale, and the stress sensitivity is greater in the perpendicular bedding direction than in the parallel bedding direction, possibly related to the mineral composition of shale and the compaction it has undergone. The flow mechanism of the deep marine shale is transition flow and Knudsen flow, while that of the marine-continental transitional shale is transition flow. The deep marine shale possesses smaller nanopore sizes and a higher quantity of micropores, which create advantageous conditions for gas transport within nanopores. During the process of extracting shale gas, the extraction of gas causes a decrease in pore pressure and an increase in effective stress, resulting in a reduction in permeability. However, when the pore pressure reaches a specific value, the enhanced slippage effect leads to an increase in permeability, which is advantageous for gas extraction. In the later stage of shale gas well production, intermittent production plans can be developed considering the strength of the slippage effect, leading to a significant improvement in production efficiency.

Late Permian radiolarian Neoalbaillella caridroiti assemblage from the Loufanggou, Guangyuan-Shangsi area, Sichuan Province, China

A well-preserved Lopingian (Late Permian) radiolarian assemblage including Neoalbaillella has been recovered from the Loufanggou 2 section of the Dalong Formation in northern Sichuan, China. The assemblage consists mainly of spherical radiolarians with spongy tests, such as Entactinaria and Spumellaria. Albaillellaria and Latentifistularia are relatively rare in the assemblage. The occurrence of Neoalbaillella caridroiti nov. sp., Neoalbaillella antaixiangi Yao and Kuwahara and Albaillella triangularis Ishiga, Kito and Imoto indicates that the Loufanggou 2 section may be correlated with the Neoalbaillella optima assemblage zone. Until now, only Neoalbaillella caridroiti nov. sp. and Neoalbaillella antaixiangi were known to occur in the northern Sichuan area. This limited occurrence indicates the possibility that the Dalong Formation depositional basin in northern Sichuan Province was a geographically limited area, and the radiolarian assemblage shows its provincialism.

Establishment of Reference Range for Serum Concentration of Vitamin A and Vitamin E in Southern Sichuan Area of China

Establishment of Reference Range for Serum Concentration of Vitamin A and Vitamin E in Southern Sichuan Area of China

Optimal and Multi-View Strategic Hybrid Deep Learning for Old Landslide Detection in the Loess Plateau, Northwest China

Old landslides in the Loess Plateau, Northwest China usually occurred over a relatively long period, and their sizes are usually smaller compared to old landslides in the alpine valley areas of Sichuan, Yunnan, and Southeast Tibet. These landslide areas may have been changed either partially or greatly, and they are usually covered with vegetation and similar to their surrounding environment. Therefore, it is a great challenge to detect them using high-resolution remote sensing images with only orthophoto view. This paper proposes the optimal-view and multi-view strategic hybrid deep learning (OMV-HDL) method for old loess landslide detection. First, the optimal-view dataset in the Yan’an area (YA-OP) was established to solve the problem of insufficient optical features in orthophoto images. Second, in order to make the process of interpretation more labor-saving, the optimal-view and multi-view (OMV) strategy was proposed. Third, hybrid deep learning with weighted boxes fusion (HDL-WBF) was proposed to detect old loess landslides effectively. The experimental results with the constructed optimal-view dataset and multi-view data show that the proposed method has excellent performance among the compared methods—the F1 score and AP (mean) of the proposed method were improved by about 30% compared with the single detection model using traditional orthophoto-view data—and that it has good detection performance on multi-view data with the recall of 81.4%.

Epidemiology and Clinical Characteristics of Cerebral Alveolar Echinococcosis in the Tibetan Region of Sichuan, China.

This study aimed to examine the epidemiology and clinical characteristics of cerebral alveolar echinococcosis in the Tibetan region of Sichuan, China. A retrospective analysis of hospitalized cases of cerebral alveolar echinococcosis from six medical units in the Garze Tibetan Autonomous Prefecture, Sichuan Province, from January 2016 to June 2021 was conducted. The study focused on the characteristics, clinical presentation, and imaging features of the disease. Of 119 cerebral alveolar echinococcosis patients, 76 were male and 43 were female. Occupationally, 62 were farmers, 46 were herdsmen, nine were monks, and two were students. The mean age was 43.9 (± 13.9) years. The primary clinical manifestations were dizziness, headaches, and epilepsy. The incidence of cerebral alveolar echinococcosis was most concentrated within 4 years after the diagnosis of hepatic alveolar echinococcosis (77/119, 64.7%). There were 86 cases (72.3%) with multiple intracranial echinococcosis lesions, with an average size of 2.0 cm × 2.5 cm. The imaging features showed that the lesion was mainly concentrated in the anterior circulation blood supply area, and the lesion had multiple aggregated small vesicular structures as its unique imaging feature. Among 98 follow-up cases, 62 could live independently (63.3%); 18 deaths were recorded (18.4%), with an approximate 5-year survival rate of 81.6%. Regular examination of patients with first diagnosis of hepatic alveolar echinococcosis without a combination of echinococcosis in other parts of the body can help monitor and prevent the occurrence of cerebral alveolar echinococcosis, improve the understanding of cerebral alveolar echinococcosis in Tibetan areas of Sichuan.

The association between the deviation from balanced time perspective on adolescent pandemic mobile phone addiction: the moderating role of self-control and the mediating role of psychological distress.

Few studies have examined the impact that the deviation from balanced time perspective (DBTP) had on mobile phone addiction during the COVID-19 normalization prevention and control phase. Therefore, this study sought to determine the associations between DBTP, depression and anxiety, self-control, and adolescent mobile phone addiction. The moderated mediating model was tested using the SPSS PROCESS model. The sample was 1,164 adolescents from different regional areas of Sichuan, China. From February to March 2020, participants completed the Zimbardo time perspective inventory (ZTPI), the brief symptom inventory for physical and mental health (BSI-18), the self-control scale (SCS), and the Chinese version of the mobile phone addiction index (MPAI). The DBTP was significantly and positively correlated with mobile phone addiction, depressive and anxiety symptoms mediated the relationship between DBTP and mobile phone addiction, self-control moderated the indirect effect of DBTP on mobile phone addiction, and as the level of self-control increased, the effect of DBTP on anxiety and depression and the effect of depression and anxiety on mobile phone addiction weakened. During the COVID-19 pandemic, DBTP and lower self-control were risk factors for higher mobile phone addiction in adolescents. Therefore, guiding adolescents to balance their time perspective and enhance their self-control could strengthen their psychological well-being and reduce addictive mobile phone behaviors. This research was supported by "Youth Fund of the Ministry of Education" (18YJCZH233): "Research on the plastic mechanism of decision-making impulsiveness of anxious groups in the context of risk society."

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.