Natural Gas Industry B最新文献

{"title":"Thoughts on the development of CO2-EGR under the background of carbon peak and carbon neutrality","authors":"Liehui Zhang ,&nbsp;Cheng Cao ,&nbsp;Shaomu Wen ,&nbsp;Yulong Zhao ,&nbsp;Xian Peng ,&nbsp;Jianfa Wu","doi":"10.1016/j.ngib.2023.07.007","DOIUrl":"10.1016/j.ngib.2023.07.007","url":null,"abstract":"<div><p>In September 2020, the Chinese government proposed the goals to reach carbon dioxide emissions peak by 2030 and achieve carbon neutrality by 2060 (“two-carbon goals”). This brings opportunities to the development and application of CO₂-enhanced gas recovery (CO₂-EGR) in China. To obtain an overall understanding of the development of CO₂-EGR under the two-carbon goals, this paper analyzes the significance, potential, status quo and challenges of CO₂-EGR, and makes suggestions on the development of CO₂-EGR in China. The research results are obtained as follows. First, the development of CO₂-EGR plays a crucial role in ensuring China's energy security, accelerating the construction of the clean energy system to promote energy transition and realizing the two-carbon goals as early as possible. Second, China should clarify a path for CO₂-EGR development, build a spatial layout of CO₂-EGR, and promote digital inclusion in CO₂-EGR, enhance the emission reduction role of CO₂-EGR in the multi-energy complementary system, boost large scale application of renewable energy and deep decarbonization in the traditional coal industry, which is difficult to reduce carbon emissions. Third, China should draw lessons from European and American tax credit and innovation funds policies to accelerate the construction of a CO₂-EGR policy support system. Fourth, China should carry out research on key CO₂-EGR technologies to accelerate the construction of a CO₂-EGR methodology and standard system and promote rapid and standardized development of the CO₂-EGR industry. It is suggested to establish a CO₂-EGR demonstration area in the Sichuan Basin and popularize it across China, so as to improve comprehensive economic benefits through the establishment of large-scale industrial clusters. It is concluded that the two-carbon goals bring opportunities to the development of CO₂-EGR in China, which will promote gas production and demonstration of CO₂ sequestration in gas reservoirs and have positive significance in ensuring energy security and realizing carbon peak and carbon neutrality in China.</p></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":"10 4","pages":"Pages 383-392"},"PeriodicalIF":3.3,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42527533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Life-cycle deliquification techniques and their application for deep shale gas reservoirs","authors":"Huali Zhang ,&nbsp;Jiaxiao Chen ,&nbsp;Changqing Ye ,&nbsp;Xiaotao Zhang ,&nbsp;Fan Yu ,&nbsp;Anqi Du","doi":"10.1016/j.ngib.2023.07.002","DOIUrl":"10.1016/j.ngib.2023.07.002","url":null,"abstract":"<div><p>Deep shale gas resources in the Sichuan Basin have great potential, and this is a major area for future shale gas exploration and development. Deep shale gas wells face problems with liquid loading throughout the production cycle. Regarding deliquification techniques, it is necessary to consider the requirements of gas wells over the full life cycle, as well as the main form of artificial lift used at different stages, to achieve economically efficient development. This paper divides the life cycle of a deep shale gas well into two stages: early production and middle/late production. Pressure-control production is conducted in the early stage of production, whereas investigations on critical liquid-carrying models, the flow distribution in the wellbore, and the main form of artificial lift are conducted in the middle and late stages of production. A recommended scheme of deliquification techniques over the full life cycle has been developed to guide the development and enhancement of artificial lift methods in deep shale gas reservoirs. As of March 2022, in the PetroChina Southwest Oil &amp; Gasfield Company managed-pressure production has been implemented in 14 wells in the early stage of deep shale gas production. In eight wells, plunger gas lift has been implemented in the middle and late stages of production. In seven wells, foam lift has been implemented. The abovementioned techniques are effective in increasing and stabilizing production and achieving deliquification in deep shale gas reservoirs.</p></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":"10 4","pages":"Pages 333-340"},"PeriodicalIF":3.3,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45979998","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterizing multi-scale shale pore structure based on multi-experimental imaging and machine learning","authors":"Jun Yao ,&nbsp;Lei Liu ,&nbsp;Yongfei Yang ,&nbsp;Hai Sun ,&nbsp;Lei Zhang","doi":"10.1016/j.ngib.2023.07.005","DOIUrl":"10.1016/j.ngib.2023.07.005","url":null,"abstract":"<div><p>An accurate and comprehensive understanding of shale pore structure is fundamental and critical for accurate reserves evaluation and efficient hydrocarbon development. Thus, by taking the shale of Paleogene Eocene Shahejie Formation in the Jiyang Depression, Bohai Bay Basin, as an example, the 2D and 3D multi-resolution images of the shale microstructure are obtained by multiple imaging technologies, including X-ray computed tomography, large-field scanning electron microscopy, scanning electron microscopy and focused ion beam scanning electron microscopy. By integrating image processing and machine learning algorithms, the shale pore structure is characterized at a single scale and multi scales. The results are obtained as follows. First, the shale pore space in the study area is mainly composed of microfractures, inorganic pores, organic matters and organic pores, and exclusively shows multi-scale characteristics. Second, there are various types of inorganic pores, and abundant dissolution pores; organic matters are distributed as strips and patches, and no organic pores are found in some organic matters. Third, pores with radius less than 20 nm account for 25%, those with radius between 20 and 50 nm account for 19%, those with radius between 50 and 100 nm account for 29%, those with radius between 100 and 500 nm account for 14%, those with radius between 500 nm and 20 μm account for 11%, and those with radius between 20 and 50 μm account for 2%. Fourth, the organic pores are less connected than the inorganic pores. The connectivity between organic pores and inorganic pores plays a crucial role in hydrocarbon migration, and microfractures control fluid flow channels. Fifth, pores with radius less than 50 nm are dominantly organic pores, those with radius between 50 and 500 nm are mainly organic and inorganic pores, and microfractures mainly contribute to the pores with radius more than 500 nm. It is concluded that a single imaging experiment cannot accurately and comprehensively reveal the multi-scale micro pore structure of a shale reservoir. Through integration of multiple imaging technologies and machine learning algorithms, the shale pore structure can be recognized and characterized at both single scale and multi scales. The proposed new method provides accurate and comprehensive information of multi-scale pore structures.</p></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":"10 4","pages":"Pages 361-371"},"PeriodicalIF":3.3,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45986446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhanced gas recovery: Theory, technology, and prospects","authors":"Xinhua Ma ,&nbsp;Dongbo He ,&nbsp;Yunsheng Wei ,&nbsp;Jianlin Guo ,&nbsp;Chengye Jia","doi":"10.1016/j.ngib.2023.07.008","DOIUrl":"10.1016/j.ngib.2023.07.008","url":null,"abstract":"<div><p>Research on the enhanced gas recovery (EGR) technology is urgently needed in most of China's major gas fields due to low recovery in their late development stages. To promote progress in ERG theory and technology, this paper establishes a unified and universal model for gas recovery evaluation, analyzes the key factors affecting the gas recovery, and expects the prospect of EGR. The results are obtained as follows. First, the production degree of reserves, pressure drawdown sweep efficiency and pressure depletion efficiency are key factors affecting the gas recovery, which is the product of the coefficients corresponding to these factors. Second, according to the development practice of Anyue Longwangmiao gas reservoir, Kela 2 gas field, Sulige gas field and Southern Sichuan shale gas, it is estimated that the recovery of conventional water-driven gas reservoirs and unconventional gas reservoirs (incl. tight gas and shale gas) can be improved by 6–15 percentage points by increasing the production degree of reserves, the pressure drawdown sweep efficiency and pressure depletion efficiency. Third, it is proposed that clarifying the EGR mechanism, developing new EGR methods, and promoting the field test of EGR technologies are directions for theoretical and technical researches. The study results provide a theoretical foundation for EGR. The EGR methodologies for different types of gas reservoirs provide technical support for improving gas recovery and stable production of existing gas fields, promote healthy and rapid development of natural gas industry in China and provide guidance for guaranteeing national energy security.</p></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":"10 4","pages":"Pages 393-405"},"PeriodicalIF":3.3,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46678289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical simulation of proppant transport from a horizontal well into a perforation using computational fluid dynamics","authors":"Tiankui Guo ,&nbsp;Xing Yang ,&nbsp;Hai Liu ,&nbsp;Ming Chen ,&nbsp;Zunpeng Hu ,&nbsp;Jilei Niu ,&nbsp;Yiman Shi","doi":"10.1016/j.ngib.2023.07.003","DOIUrl":"10.1016/j.ngib.2023.07.003","url":null,"abstract":"<div><p>With the increasing global demand for oil and gas, the development of unconventional resources such as shale gas is becoming ever more important. The key to developing unconventional oil and gas resources lies in horizontal wells with multistage fracturing technology. In the process of horizontal well segmentation fracturing, the distribution of the proppant among multiple clusters has a significant influence on the fracturing effect. However, the influence of various factors on the entry of proppant into the perforation and then into the fracture along the wellbore is unclear. In this paper, based on the flow characteristics of proppants in fracturing fluids, we investigate the wellbore–perforation proppant transport using a Eulerian multiphase flow model. The effect of different factors on proppant entry into the perforation in horizontal wells is studied. We first verify that the computational fluid dynamics model satisfies the accuracy requirements for studying the sand-carrying efficiency of proppants in a perforation cluster. Second, the effects of the proppant size, proppant density, fracturing fluid viscosity, perforation diameter, and fracturing fluid flow rate on the proppant transport efficiency are investigated. Finally, a mathematical model of the sand-carrying efficiency is established by multivariate nonlinear fitting. The results show that the proppant size has a more significant effect on proppant settling at low wellbore flow rates. Increasing the diameter of the proppant particles can accelerate proppant settling. Higher wellbore flow rates tend to reduce the sand-carrying efficiency, although using a low-density proppant can mitigate the effect of the wellbore flow rate. At low wellbore flow rates, increasing the perforation size makes it easier for the proppant to enter bottom perforations. Increasing the fluid viscosity helps to distribute the proppant evenly between perforations in different directions, but this effect diminishes as the flow rate increases. Finally, a formula for the wellbore sand-carrying efficiency is obtained and validated, providing a basis for optimizing the distribution of the proppant in the perforation. The results from this paper enhance our understanding of the sand and fluid feeding patterns of each perforation cluster and provide direction for improving the construction process and enhancing the fracture inflow capacity.</p></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":"10 4","pages":"Pages 341-351"},"PeriodicalIF":3.3,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43129720","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cellulose nanocrystals (CNCs) as a potential additive for improving API class G cement performance: An experimental study","authors":"Asad Elmgerbi ,&nbsp;Ibrahim Abou Askar ,&nbsp;Alexander Fine ,&nbsp;Gerhard Thonhauser ,&nbsp;Rahman Ashena","doi":"10.1016/j.ngib.2023.05.001","DOIUrl":"https://doi.org/10.1016/j.ngib.2023.05.001","url":null,"abstract":"<div><p>Integral cement sheaths are crucial for safe and economical hydrocarbon production throughout the well lifecycle. Cement additives tailor short- and long-term cement properties for various well conditions to ensure well integrity. Although various additives exist, the current trend in reducing the carbon footprint motivates the developing \"greener” additives that are environmentally friendly and made from renewable and sustainable sources such as cellulose nanocrystals (CNC). CNCs exhibit superior properties and have shown significant impact on cement slurry, including increased degree of hydration, strength, and altered properties. However, most studies on CNCs are intended for construction industry rather than hydrocarbon and geothermal well cementing. Investigating the use of CNCs as high-performance cement additives is therefore of interest due to their potential benefits. This study aims to determine the effect of CNC on vital well cement properties. The effects of CNC were determined using standard American Petroleum Institute (API) test procedures and equipment in an experimental approach. The experimental findings indicate that the addition of cellulose nanocrystals (CNC) at a concentration of 2 vol% resulted in a notable increase of 7% in viscosity, a significant decrease of 50% in free water, a remarkable reduction of 78% in cement shrinkage, and no discernible effect on slurry thickening time. Furthermore, the inclusion of a 0.2 vol% of CNC yielded a significant surge of 56% in compressive strength after 21 days and accelerated 500 psi strength development by 9%. However, the investigation revealed that a concentration of 1.5 vol% of CNC represents a threshold concentration or the turning point, beyond which the addition of CNC can negatively impact the studied cement properties.</p></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":"10 3","pages":"Pages 233-244"},"PeriodicalIF":3.3,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50181910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Intelligent safe operation and maintenance of oil and gas production systems: Connotations and key technologies","authors":"Laibin Zhang ,&nbsp;Jinjiang Wang","doi":"10.1016/j.ngib.2023.05.006","DOIUrl":"10.1016/j.ngib.2023.05.006","url":null,"abstract":"<div><p>Oil and gas production systems have the characteristics of high operation and maintenance risk and great accident influence. With the deep integration of informationization and industrialization, the development direction and necessary choice of the oil and gas industry is to develop the oil and gas production system into the interconnected, multi-domain interactive cyber-physical intelligent system. In order to avoid or reduce the complex, diverse and potentially unknown safety risks in the process of oil and gas production, improve the safety and reliability of oil and gas production system and increase the production efficiency, this paper analyzes the safety problems occurring in the intelligentization process of oil and gas production system and constructs a system from the perspective of operation and maintenance based on key elements of intelligent safe operation and maintenance technology, combined with the typical production scenarios in the oil and gas production industry. And the following research results are obtained. First, the connotation of intelligent safe operation and maintenance technology is clarified, the key elements and existing problems and challenges of intelligent safe operation and maintenance technology are analyzed, and the “1-2-3-4-5-6” intelligent safe operation and maintenance technology system of oil and gas production system is constructed, which empowers six key technologies with key elements of oil and gas production to realize the essential safety of oil and gas production system. Second, the intelligent safe operation and maintenance technology actively promotes the application and implementation of condition monitoring, health management, risk assessment, intelligent early warning technologies in typical production scenarios such as drilling and extraction, storage and transportation, refining and chemical industry in up, middle and down streams of oil and gas production. Third, in view of the characteristics of oil and gas production system under digital transformation, it is proposed to develop the intelligent safe operation and maintenance technology with the functions of intelligent decision-making, active prevention and comprehensive safety in the future to help the safe construction in the field of oil and gas production and promote the safe and healthy development of the oil and gas industry. In conclusion, the research on intelligent safe operation and maintenance technology system of oil and gas production system is conducive to the safe construction in the field of oil and gas production, which will not only provide technical support for the realization of trouble-free oil and gas production system, but also provide reference for the intelligent development of the world oil and gas industry.</p></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":"10 3","pages":"Pages 293-303"},"PeriodicalIF":3.3,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45731504","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Major advancement in oil and gas exploration of Jurassic channel sandstone in Well Bazhong 1HF in northern Sichuan Basin and its significance","authors":"Dongfeng Hu,&nbsp;Zhenxiang Li,&nbsp;Zhihong Wei,&nbsp;Jinbao Duan,&nbsp;Zhiwei Miao,&nbsp;Lei Pan,&nbsp;Chengyin Li,&nbsp;Hua Duan","doi":"10.1016/j.ngib.2023.05.004","DOIUrl":"10.1016/j.ngib.2023.05.004","url":null,"abstract":"&lt;div&gt;&lt;p&gt;In January 2023, Well Bazhong 1HF in the northern Sichuan Basin obtained high-yield industrial oil flow of over 100 cubic meters from the Jurassic channel sandstone for the first time, realizing a major breakthrough. In order to provide more support for further oil and gas exploration in this area, this paper analyzes the sedimentary and reservoir characteristics of the Jurassic Lianggaoshan Formation in Bazhong region of northern Sichuan Basin and their control factors based on the exploration achievements of Well Bazhong 1HF. Then, oil and gas reservoir characteristics and oil and gas sources are comparatively analyzed. Finally, the key technologies for the exploration of channel sandstone oil and gas with multi-stage vertical superimposition, lateral migration, thin reservoir and strong heterogeneity are researched and developed, and the next oil and gas exploration direction in the Lianggaoshan Formation of northern Sichuan Basin is pointed out. And the following research results are obtained. First, in the second member of Lianggaoshan Formation (“Liang 2 Member” for short) in Bazhong region, multi-stage underwater distributary sand bodies of delta front are developed with sandstone thickness of about 25 m and average porosity of 5.6%. The pore types are mainly primary intergranular pores and feldspar/debris intragranular dissolved pores, the pore throat structure is good, and the development of good-quality reservoirs is controlled by the sedimentary microfacies of underwater distributary channel. Second, the oil and gas reservoir of Liang 2 Member is a highly oil-bearing condensate gas reservoir/volatile oil reservoir, whose oil and gas is mainly sourced from the semi-deep lacustrine shale of Liang 1 and 2 Members. Third, channel sand bodies are superimposed and developed continuously in the upper part of Liang 2 and Liang 3 Members, and the source-reservoir configuration is good, with the characteristics of near-source hydrocarbon accumulation and overpressure hydrocarbon enrichment. Fourth, for the channel sandstones with multi-stage vertical superimposition, lateral migration, thin reservoir and strong heterogeneity, the reservoir prediction technology of “high-frequency sequence stratigraphy slice, seismic frequency decomposition and facies-constrained seismic waveform indication inversion” is developed to precisely characterize the “sweet spot” target of narrow channel sandstone, and the key fracturing technology of “dense cutting + composite temporary plugging + high-intensity proppant injection + imbibition and oil-increasing” is formed to realize the large-scale reconstruction of channel sandstone reservoir. In conclusion, the breakthrough of Well Bazhong 1HF in the exploration of Lianggaoshan Formation oil and gas in Bazhong region reveals the huge potential of Jurassic oil and gas exploration in the Sichuan Basin, and plays a positive role in promoting the exploration and development of the Jurassic channel sandstone oil ","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":"10 3","pages":"Pages 270-282"},"PeriodicalIF":3.3,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44243940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A new method to evaluate the effects of mechanical heterogeneity on fault architecture in sedimentary sequences","authors":"Yicheng Mou ,&nbsp;Wei Guo ,&nbsp;Yangwen Pei","doi":"10.1016/j.ngib.2023.03.001","DOIUrl":"10.1016/j.ngib.2023.03.001","url":null,"abstract":"<div><p>Geologists have long realized the important control of mechanical stratigraphy on fault nucleation, fault linkage and fault compartmentalization. However, uncertainties still exist concerning the mechanical heterogeneity of the stratigraphy because of difficulties in quantifying the mechanical stratigraphy. In this study, the average strength <span><math><mrow><msub><mi>S</mi><mrow><mi>a</mi><mi>v</mi><mi>e</mi></mrow></msub></mrow></math></span> of a section is calculated considering the strength and thickness of each individual layer. The strength difference <span><math><mrow><msub><mi>S</mi><mo>Δ</mo></msub></mrow></math></span> and normalized mechanical contrast <span><math><mrow><msub><mi>S</mi><mo>Δ</mo></msub><mo>/</mo><msub><mi>S</mi><mrow><mi>a</mi><mi>v</mi><mi>e</mi></mrow></msub></mrow></math></span> are defined for each individual layer in a section. A diagram of the normalized mechanical contrast <span><math><mrow><msub><mi>S</mi><mo>Δ</mo></msub><mo>/</mo><msub><mi>S</mi><mrow><mi>a</mi><mi>v</mi><mi>e</mi></mrow></msub></mrow></math></span> versus the normalized height <span><math><mrow><mi>H</mi><mo>/</mo><mrow><munderover><mo>∑</mo><mrow><mi>i</mi><mo>=</mo><mn>1</mn></mrow><mi>n</mi></munderover><msub><mi>h</mi><mi>i</mi></msub></mrow></mrow></math></span> can then be employed to effectively evaluate the vertical mechanical heterogeneity of the stratigraphy in a section. High-frequency fluctuations between negative and positive <span><math><mrow><msub><mi>S</mi><mo>Δ</mo></msub><mo>/</mo><msub><mi>S</mi><mrow><mi>a</mi><mi>v</mi><mi>e</mi></mrow></msub></mrow></math></span> values represent high mechanical heterogeneity, and vice versa. The scaled mechanical heterogeneity <span><math><mrow><msub><mrow><mi>M</mi><mi>H</mi></mrow><mrow><mi>s</mi><mi>c</mi><mi>a</mi><mi>l</mi><mi>e</mi><mi>d</mi></mrow></msub></mrow></math></span> can be used as an index to quantify the mechanical heterogeneity of the stratigraphy in sections with different scales. However, it is also important to realize that fault throw may promote or restrict the control of mechanical heterogeneity on faulting deformation. The mechanical heterogeneity may present limited control on the fault architecture, particularly when the fault throw is several times larger than the scale of the section. Increasing deformation rate may also minimise the control of the mechanical heterogeneity on the fault architecture.</p></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":"10 3","pages":"Pages 213-222"},"PeriodicalIF":3.3,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47226343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Determination of adsorption parameters in shale gas resource/reserve calculation: Case study of Wufeng Formation–Longmaxi Formation in the Sichuan Basin","authors":"Qun Zhao ,&nbsp;Tianqi Zhou ,&nbsp;Hongyan Wang ,&nbsp;Yiqiu Jin ,&nbsp;Shangwen Zhou ,&nbsp;Xianggang Duan","doi":"10.1016/j.ngib.2023.05.007","DOIUrl":"10.1016/j.ngib.2023.05.007","url":null,"abstract":"&lt;div&gt;&lt;p&gt;In the calculation of shale gas resources/reserves, isothermal adsorption parameters are mainly determined by dry sample data at the laboratory temperature, and the regression effect of total organic carbon content (&lt;em&gt;TOC&lt;/em&gt;) isothermal adsorption parameters is poor. Based on the physical significance of key parameters in Langmuir and Henry adsorption models, the problems in determining the isothermal adsorption parameters in the calculation of shale gas reserves/reserves are analyzed by taking the marine shale in the Upper Ordovician Wufeng Forming–Lower Silurian Longmaxi Formation in the Sichuan Basin as an example. Based on a large number of measured isothermal adsorption data, the effects of &lt;em&gt;TOC&lt;/em&gt;, temperature and water saturation on the shale gas adsorption parameters are analyzed. The influence model of &lt;em&gt;TOC&lt;/em&gt;, temperature and water saturation on isothermal adsorption parameters of shale gas is established, and a novel method for calculating the adsorption parameters of shale gas from under experimental conditions to original reservoir conditions is proposed. The results are obtained as follows. First, there are problems in the calculation of shale gas resources/reserves, such as poor and contradictory fitting relation between isothermal adsorption parameters and &lt;em&gt;TOC&lt;/em&gt;, difficulty in the conversion of Van't Hoff equation, and difficulty in direct application of water saturation (&lt;em&gt;S&lt;/em&gt;&lt;sub&gt;w&lt;/sub&gt;) in resource/reserves calculation. Second, the problem of poor direct fitting relation between Langmuir pressure (&lt;em&gt;p&lt;/em&gt;&lt;sub&gt;L&lt;/sub&gt;) and &lt;em&gt;TOC&lt;/em&gt; is solved by integrating the Langmuir adsorption model with the Henry adsorption model and by establishing a new parameter – Henry constant a for methane adsorption capacity of shale. Third, when &lt;em&gt;S&lt;/em&gt;&lt;sub&gt;w&lt;/sub&gt;&lt;40%, the Langmuir volume (&lt;em&gt;V&lt;/em&gt;&lt;sub&gt;L&lt;/sub&gt;) is linearly negatively correlated with Sw; when &lt;em&gt;S&lt;/em&gt;&lt;sub&gt;w&lt;/sub&gt;&lt;20%, a is constant relatively; by establishing the relationship between the normalized absolute adsorption capacity and &lt;em&gt;S&lt;/em&gt;&lt;sub&gt;w&lt;/sub&gt; (&lt;50%) under the pressure exceeding 30 MPa, the effect of &lt;em&gt;S&lt;/em&gt;&lt;sub&gt;w&lt;/sub&gt; on the isothermal adsorption capacity can be calculated. Fourth, the in-situ stress in the Wufeng Formation–Longmaxi Formation shale reservoir affects the adsorption capacity of shale. For shale reservoirs with the same &lt;em&gt;TOC&lt;/em&gt;, the higher the in-situ stress, the smaller the &lt;em&gt;V&lt;/em&gt;&lt;sub&gt;L&lt;/sub&gt; and a values. Under high pressure (&gt;30 MPa), the effect of &lt;em&gt;S&lt;/em&gt;w on the methane adsorption capacity of shale shows a similar trend, and the effect of water molecules on the adsorption capacity on shale pore surface is constant. It is concluded that the proposed novel method for determining the isothermal adsorption parameters of shale with different &lt;em&gt;TOC&lt;/em&gt;, temperature and water saturation conditions provides a technical support for the accurate calculation of shale gas resources/reser","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":"10 3","pages":"Pages 304-311"},"PeriodicalIF":3.3,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42956488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}