Natural Gas Industry B最新文献

{"title":"Investigation of plugging performance and enhanced oil recovery of multi-scale polymer microspheres in low-permeability reservoirs","authors":"Wendong Wang ,&nbsp;Xincheng Guo ,&nbsp;Penghui Duan ,&nbsp;Bo Kang ,&nbsp;Da Zheng ,&nbsp;Atif Zafar","doi":"10.1016/j.ngib.2023.04.001","DOIUrl":"10.1016/j.ngib.2023.04.001","url":null,"abstract":"<div><p>Advanced water injection has become an effective method for developing low-permeability reservoirs. However, after a period of high yield from fracturing, the injected water flows rapidly along high-capacity channels, which greatly reduces the sweep efficiency of reservoirs. In this work, the plugging process by microspheres and nanospheres from the fracture to the matrix was simulated through core experiments. The plugging performance of multi-scale microspheres (microspheres and nanospheres) on the core matrix was evaluated by measuring the plugging rate and other parameters. Enhanced oil recovery after synergistic plugging with multi-scale microspheres was used as the evaluation index, a sensitivity analysis of injection parameters was performed, and the best combination of injection parameters was optimized by orthogonal experiments. The experimental results showed that the plugging performance of nanospheres is mainly reflected in the filling of the core matrix, while the plugging performance of microspheres is mainly reflected by retention at the injection end of the core (as opposed to the fractured end face). The plugging rate of nanospheres reached 78.83%, which is much higher than the 30.28% rate achieved with microspheres. The maximum oil recovery after plugging was 19.12%, which corresponds to the following combination of injection parameters: total injection of 0.6 pore volume (PV), injection ratio between nanospheres and microspheres of 2:1, injection rate of 1.5 mL·min⁻¹, and aging time of 6 days. Among the injection parameters, the injection ratio between nanospheres and microspheres had the greatest influence on the recovery of waterflooding after plugging, followed by the total injection of multi-scale microspheres. The injection rate and aging time had little effect.</p></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47330032","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":"Improved Joule Thomson equation of supercritical CO2-rich natural gas in separation system","authors":"Saripudin ,&nbsp;Tutuka Ariadji ,&nbsp;Sanggono Adisasmito ,&nbsp;Leksono Mucharam ,&nbsp;Doddy Abdassah","doi":"10.1016/j.ngib.2023.05.002","DOIUrl":"10.1016/j.ngib.2023.05.002","url":null,"abstract":"<div><p>The rapid expansion of supercritical gas technology for high-content CO₂ separation from natural gas is a promising avenue of research. However, CO₂-rich natural gas cools immediately after being separated and expands when the CO₂ dew point is reached in the absence of a refrigerant system. In our previous study, supercritical expansion experiments using various CO₂ compositions revealed that the Joule–Thomson equation gives a significant absolute average error value of 16.28%. This paper describes corrections to the Joule–Thomson expansion equation under supercritical conditions with various CO₂ concentrations. The results show that the trend of the expansion coefficient is highly dependent on the CO₂ composition. Using an improved Joule–Thomson equation of state over a CO₂ range of 25%–45% mol, the expansion coefficient tends to fall immediately when a rapid expansion occurs. For a supercritical fluid, the specific heat Cp depends on temperature, pressure, and density changes. The Van der Waals expansion coefficient profile is simulated using MATLAB, resulting in a correction factor of 1.17–1.32 being applied to the Cp value for CO₂ concentrations of 25%–40% mol, whereby the absolute average error tends to zero. For CO₂ concentrations of more than 40%, the Joule–Thomson equation cannot be applied because the expansion coefficient exhibits significant errors compared with the experimental data. The expansion coefficient does not directly determine the performance of supercritical expansion, but does affect the vapor fraction. Integrated production systems based on supercritical expansion are expected to produce an annual profit of around US$18 million from turbine expansion and US$489 million from the production of sweet gas with a purity of 96.6% and less than 2% mol CO₂.</p></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49285606","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":"Study on seepage model of Multiple Horizontal wells with complex fracture networks in tight Reservoir Based on boundary element method","authors":"Zongxiao Ren ,&nbsp;Zhan Qu ,&nbsp;Shuaihu Jia ,&nbsp;Guiyi Zhang ,&nbsp;Chaobo Fan ,&nbsp;Tian Feng ,&nbsp;Zhongxing Ren","doi":"10.1016/j.ngib.2023.05.003","DOIUrl":"10.1016/j.ngib.2023.05.003","url":null,"abstract":"<div><p>Horizontal well and volume fracturing technology are the key technologies to develop unconventional reservoirs. Tight reservoir is belonging to multi-scale seepage mediaafter fracturing, and theflow of fluid in it is extremely complicated. In this paper, based on the boundary element method (BEM), the seepage model of horizontal wells with complex fracture networks in irregular boundary reservoir is established for the first time. The model takes into account the influence of irregular reservoir boundary, dual media, complex fracture network and interference of multiple wells on horizontal well seepage. Using this model, the sensitivity analysis of wellbore storage coefficient, skin factor, fracture permeability and interporosity transfer coefficient is carried out. The model expands the application scope of BEM in the field of seepage simulation of unconventional oil and gas reservoirs and provides theoretical guidance for the development of tight oil reservoirs.</p></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46208725","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":"Development model and identification of evaluation technology for Wufeng Formation–Longmaxi Formation quality shale gas reservoirs in the Sichuan Basin","authors":"Dazhong Dong ,&nbsp;Feng Liang ,&nbsp;Quanzhong Guan ,&nbsp;Yuqiang Jiang ,&nbsp;Shangwen Zhou ,&nbsp;Rongze Yu ,&nbsp;Yifan Gu ,&nbsp;Surong Zhang ,&nbsp;Lin Qi ,&nbsp;Yan Liu","doi":"10.1016/j.ngib.2023.02.001","DOIUrl":"10.1016/j.ngib.2023.02.001","url":null,"abstract":"<div><p>In 2012, China's first national shale gas demonstrations areas were set up in the Sichuan Basin. After 10 years' construction and practice, the giant marine shale gas area of 10 × 10¹² m³ level is built up in the Sichuan Basin, and shale gas steps into a new stage of large-scale benefit exploration and development. In order to systematically summarize the achievements in shale gas exploration and development and provide guidance and reference for the exploration and development of deep shale gas and shale oil &amp; gas in other areas, this paper systematically summarizes the main characteristics, development models and key identification and evaluation technologies for quality reservoirs of Wufeng Formation–Longmaxi Formation shale gas by analyzing the electric property, lithofacies, reservoir parameters and microscopic porosity of key wells in the basin. And the following research results are obtained. First, biogenetic siliceous shale, calcareous shale and mixed shale are main lithofacies types in quality shale gas reservoirs, and they are formed in the environment of semi-deep and deep water continental shelf. Their lateral distribution is controlled by the paleogeomorphology and their vertical development is influenced by provenance, redox condition and paleo productivity. They are 25–90 m thick. Second, in the quality shale gas reservoirs develop organic pores, inorganic pore and microfractures (including lamina/bedding fractures), among which, organic pore is one of the main reservoir spaces and microfracture is not only indispensable reservoir space, but also production pathway. The reservoir space of shale gas is overall micro-nano pore, and macropores play an important role in shale gas enrichment. Third, three development models of quality reservoir are established, including sedimentary type, diagenesis type and reworking type. The sedimentary type is the foundation. Multiple quality reservoirs are developed in the high U/Th interval of graptolite belt at the bottom of Longmaxi Formation, and their thickness is mainly controlled by paleogeomorphology and especially greater in the depression area. The diagenesis type is divided into three forms, i.e., syngenetic-early diagenetic rigid support, middle-late diagenetic mineral-organic matter transformation, and overpressure relief compaction. The reworking type is dominated by quality reservoirs with microfractures. Fourth, the core technologies for identifying and evaluating quality shale gas reservoir include large-size core and rock slice observation, high-accuracy rock mineral identification, experimental gas content test and simulation, SEM microscopic characterization, 3D microscopic pore reconstruction, comprehensive geophysical interpretation and prediction and big data analysis. In conclusion, nearly 10 years' research and practice achievements in demonstration area construction can deepen the understanding on domestic quality shale gas reservoirs, pr","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42534086","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":"Research progress in natural gas hydrate reservoir stimulation","authors":"Man Huang ,&nbsp;Lianghong Wu ,&nbsp;Fulong Ning ,&nbsp;Jiaxian Wang ,&nbsp;Xiaofeng Dou ,&nbsp;Ling Zhang ,&nbsp;Tianle Liu ,&nbsp;Guosheng Jiang","doi":"10.1016/j.ngib.2023.01.005","DOIUrl":"10.1016/j.ngib.2023.01.005","url":null,"abstract":"<div><p>Natural gas hydrate (hereinafter referred to as hydrate) is a kind of future energy with great potential. At present, the apparent factor hindering commercial hydrate development is the unqualified gas production rate, so it is necessary to research stimulation means from the perspective of hydrate exploitation method, and reservoir stimulation technology is particularly important. After systematically reviewing hydrate reservoir stimulation theories and technologies, this paper divides the field of reservoir stimulation into three directions, i.e., hydraulic fracturing, near-well stimulation and chemical stimulation, summarizes the main research results, problems and challenges in these three directions, and carries out discussion and prospect. And the following research results are obtained. First, rapid progress has been made in the research of hydraulic fracturing and it results have verified the fracability of hydrate deposits. It is revealed that the fracturing mechanism of hydrate deposits is similar to the tensile failure of rocks. It is indicated that fractures can still make contribution to permeability improvement after they closed under confining pressure, which is beneficial to secondary opening. In addition, the effects of in-situ stress and fracturing fluid on fracturing behaviors of hydrate deposits are analyzed, the numerical model of fracturing process is established, the mechanisms of hydraulic fractures to improve the depressurization and heat injection effects of hydrate reservoirs are analyzed, and the improvement effects of hydraulic fractures, as high-permeability channels on gas production rate and other key production indexes are clarified. Second, the research of near-well stimulation reveals the washout mechanisms and laws of high-pressure water jet on hydrate deposits. It is verified by numerical simulation that water jet slotting, circumferential grouting column and stratified split grouting can effectively improve the production performance, but the research is in the stage of establishing gas production model to evaluate the stimulation effect and the feasibility and effectiveness needs verifying. Third, as for chemical stimulation, the potential of CO₂ caprock reconstruction and methanol huff and puff to improve the production performance of hydrate reservoirs is explored, and the feasibility of CO₂ caprock reconstruction and storage is analyzed. In conclusion, to deal with current problems and challenges, it is necessary to strengthen the construction of the reservoir stimulation theory and technology system with hydraulic fracturing as the leading role, near-well reservoir stimulation as the auxiliary and chemical stimulation as the supplement, so as to accelerate the industrialization process of hydrate resources.</p></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44533824","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":"Research status and development trend of key technologies for enhanced geothermal systems","authors":"Liang Gong ,&nbsp;Dongxu Han ,&nbsp;Zheng Chen ,&nbsp;Daobing Wang ,&nbsp;Kaituo Jiao ,&nbsp;Xu Zhang ,&nbsp;Bo Yu","doi":"10.1016/j.ngib.2023.01.011","DOIUrl":"10.1016/j.ngib.2023.01.011","url":null,"abstract":"<div><p>Enhanced geothermal system (EGS) is a primary method to develop geothermal resources stored in hot dry rock (HDR), but it faces several key problems, such as unreasonable hydraulic fracture networks at high reservoir temperature, unclear multi-scale and multi-field coupling regularity, low heat extraction efficiency caused by the flashing flow in geothermal wells, and low thermoelectric conversion efficiency of geothermal fluid, which restricts the large-scale commercial development of geothermal resources. To resolve these major bottleneck problems, systematically reviews and analysis of the research progress and development trend of EGS are conducted in this paper. Particular attentions are devoted to four key technologies involved in the development of HDR geothermal resource by EGS: (1) the hydraulic fracturing technology for HDR reservoirs, including reservoir reconstruction methods, hydraulic fracturing network forming mechanisms and fracture propagation prediction models is illustrated in detail; (2) the fracture characterization methods, mathematical models and solution methods are described from three aspects including pore-scale multi-field coupled models, reservoir-scale multi-field coupled models and upscaling methods; (3) the efficient extraction technology of wellbore thermal fluid, involving the mechanism of flashing flows in geothermal wells and the experimental and numerical methods for investigating the characteristics offlashing flows are discussed; (4) the HDR geothermal power generation technologies, considering the principles of geothermal power generation, the types of power generation systems and the main application markets are introduced. In conclusion, EGS is a technology-intensive system, however, due to the complex working conditions of the underground reservoirs and the instability of the ground equipment, theoretical research tends to be separated from the practice. For the purpose of promoting the applicability of EGS, intimate combination and mutual guidance with the pilot tests are necessary to develop a production-research combined mode, and to raise the awareness and break through the key points in a constant back-and-forth.</p></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46290392","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":"Key issues and explorations in shale gas fracturing","authors":"Jianchun Guo,&nbsp;Qianli Lu,&nbsp;Youwei He","doi":"10.1016/j.ngib.2023.02.002","DOIUrl":"10.1016/j.ngib.2023.02.002","url":null,"abstract":"<div><p>During volume fracturing of shale gas reservoirs, hydraulic fractures may readily communicate with natural fractures to propagate forward and induce the formations to slip along the fracture surfaces. The resulted inter-well frac-hit and casing deformation affect the safe and efficient operation of shale gas fracturing. In addition, unpropped fractures caused by small natural fracture width lead to deteriorating fracture conductivity, which in turn impacts the stimulation effect of shale gas reservoirs. This paper discusses the three key issues, i.e. inter-well frac-hit, casing deformation and unpropped microfractures, that impact the economic exploration and exploitation of shale gas, and proposes engineering prevention and control measures through literature review and research on mechanism by integrating theoretical and experimental analysis, which have been applied on site. Firstly, after clarifying the mechanism and main controlling factors of inter-well frac-hit, an evaluation model and prediction method of frac-hit based on machine learning were established. The measures for preventing and controlling inter-well frac-hit, including temporary plugging at fracture tip and shut-in of old wells, were determined after evaluation with the well-cluster fracture model. Secondly, an analysis model of casing deformation caused by fracture shear and slippage was established after stress analysis. According to the analysis of stress on casing intersected with fractures during fracturing, it is ascertained that increase of fluid pressure within natural fractures is the main factor that causes casing deformation. The methods for preventing casing deformation were proposed in terms of fracturing operation and well construction. Thirdly, the mechanism of micro-proppant migration was analyzed by integrating the model of particle migration and the transport experiment in large-scale plate, and the experiment confirms that micro-proppant can effectively improve the fracture conductivity. It is concluded after field application that the prevention and control measures proposed for inter-well frac-hit and casing deformation can mitigate frac-hit and casing deformation significantly, and micro-proppants are conducive to improving post-frac shale gas production. The measures provide a support for large-scale and economic development of deep shale gas.</p></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44385352","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":"Models of helium enrichment in helium-rich gas reservoirs of petroliferous basins in China","authors":"Shengfei Qin ,&nbsp;Jiyuan Li ,&nbsp;Jiamei Wang ,&nbsp;Gang Tao ,&nbsp;Xiaofeng Wang","doi":"10.1016/j.ngib.2023.01.006","DOIUrl":"10.1016/j.ngib.2023.01.006","url":null,"abstract":"<div><p>Owing to the characteristics of chemical inertness, low molecular weight, low boiling point, strong permeability and high heat conductivity, helium is extensively used in the fields of aerospace, low-temperature superconductivity, medicine and high tech, and it is a kind of irreplaceable strategic rare resource. So far, however, less research has been conducted on the enrichment of helium in natural gas reservoirs. To solve this problem, this paper discusses the classification standard of helium-rich gas reservoirs. Based on this, the origin, source and enrichment process of helium in typical helium-rich gas reservoirs are studied, highlighting the contribution of main helium sources to helium-rich gas reservoirs. In addition, helium enrichment models of helium-rich gas reservoir in petroliferous basins are established. And the following research results are obtained. First, 6 helium enrichment models of two categories (crust-source helium enrichment and crust-mantle mixing helium enrichment) are established for different petroliferous basins in China. Second, helium-rich gas reservoirs are characterized by using the multiple helium supply and diverse helium enrichment model. And no matter what enrichment model it is, the contribution of the main helium source to gas reservoirs is indispensable. Third, the helium in the gas reservoirs of central and western basins is mainly crust-source helium, and its enrichment models include ancient formation water moving upward along the fault to dilute helium, helium enrichment in the process of natural gas migration along ancient reservoirs, and helium enrichment of shale gas. Fourth, the helium in the helium-rich gas reservoirs of eastern basins is of crust-mantle mixing origin and its enrichment models are mainly hydrocarbon gas based, carbon dioxide based and nitrogen based. In conclusion, the establishment of the helium enrichment models of helium-rich gas reservoirs in petroliferous basins provides reference and guidance for studying helium enrichment laws and main controlling factors and is of great significance to the evaluation of favorable helium exploration areas.</p></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48061251","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":"Typical misinterpretations and scientific concepts in well-logging geologic studies","authors":"Jin Lai ,&nbsp;Xiaojiao Pang ,&nbsp;Xin Zhao ,&nbsp;Yidi Zhao ,&nbsp;Guiwen Wang ,&nbsp;Yuyue Huang ,&nbsp;Hongbin Li ,&nbsp;Yuhang Li","doi":"10.1016/j.ngib.2023.02.003","DOIUrl":"10.1016/j.ngib.2023.02.003","url":null,"abstract":"<div><p>The method and theoretical system of well logging geology have been widely used in the fields of basic geology, petroleum geology and engineering geology, but the different response sensitivity of different well logging series to geological information and the mismatching between geophysical properties of multiple well logs and geological genesis of rocks frequently result in misunderstandings in the research process of well logging geology. Therefore, it is in an urgent need to analyze the typical misunderstanding cases in the research of well logging geology and explore the corresponding scientific ideas and countermeasures. After analyzing the typical misunderstandings in the research of well logging geology, this paper investigates vertical resolution scale of various logging series and its contradiction with detection depth and illustrates the importance of the integration of different scales of data. In addition, the factor inducing “fake logging data” and its influence on interpretation evaluation are clarified and a set of ideas for well logging evaluation of geological interpretation is put forward. And the following research results are obtained. First, the typical misunderstandings in the research of well logging geology can be classified into two categories, namely geological body interpretation misunderstanding and reservoir property parameter calculation misunderstanding. Second, special geological phenomena, such as high-density and high-resistivity mudstone can lead to logging data ambiguity, so attention shall be paid to petrophysical response mechanisms during geological logging interpretation. Third, to carry out well logging evaluation of unconventional oil and gas, it is necessary to integrate new technologies of electric imaging logging, dipole acoustic logging and nuclear magnetic resonance logging, and the calibration of core data and the integration of geological ideas can improve the interpretation accuracy. Fourth, In the process of borehole structural logging analysis, sedimentary response, geostress evaluation and fracture identification, geological ideas shall be integrated to avoid the logging interpretation misunderstanding caused by the same response of different geological phenomena in well logs. In conclusion, the dialectical and systematic thinking from geology to logging and then to geology, from practice to recognition and then to practice and from “a narrow view” to “a broad view” can provide a scientific ideas for the comprehensive research of well logging geology.</p></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48257814","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 numerical well test method of multi-scale discrete fractured tight sandstone gas reservoirs and its application in the Kelasu Gas Field of the Tarim Basin","authors":"Hedong Sun ,&nbsp;Weiping Ouyang ,&nbsp;Songbai Zhu ,&nbsp;Yizhao Wan ,&nbsp;Yongliang Tang ,&nbsp;Wen Cao","doi":"10.1016/j.ngib.2023.01.003","DOIUrl":"10.1016/j.ngib.2023.01.003","url":null,"abstract":"<div><p>The cretaceous gas reservoir in Kelasu Gas Field of the Tarim Basin is a rare ultra-deep and ultra-high pressure fractured tight sandstone gas reservoir where multi-scale discrete fractures of matrix, fracture and fault are developed, so its development cannot be conducted just based on static and dynamic reservoir description. In order to solve this problem, this paper establishes a numerical well test model of vertical wells based on matrix, fractures and faults (large fractures and small faults) by combining the random generation of natural fracture networks with the unstructured discrete fracture modeling method to break through the traditional continuous medium well test model. In addition, the model is solved by using the finite element method with mixed element, and the typical well test type curves under different random fracture networks are obtained. And the following research results are obtained. First, based on the observed data, the fracture network distribution modes of fractured tight sandstone gas reservoirs are classified into three categories. The influence of random generation of fracture networks on typical well test type curves is discussed. The results of discrete fracture well test model are compared with those of the traditional continuous medium well test model, and the applicable conditions of the traditional continuous medium well test model is determined. Second, there are great differences between the results of discrete fracture model and those of dual porosity medium model. 1 The dual porosity medium model is a special case of the discrete fracture model, in which the fractures are evenly distributed within infinitely small spacing. Third, the characteristics of well test type curves under three fracture network distribution modes are discussed. The well test type curves that cannot be interpreted by the conventional dual/triple porosity continuous medium model are successfully interpreted by using the established well test interpretation model of random discrete fracture. The curve matching effect is ideal and the interpreted parameters are reasonable. In conclusion, the new model and the new method reveal the development mechanism of step-by-step production and coordinated gas supply between media of different scales, explain the development characteristics of large inter-well productivity difference and abnormal rapid inter-well pressure response, and provide a reference for the development of similar gas reservoirs.</p></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":null,"pages":null},"PeriodicalIF":3.3,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42638329","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}