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	JOPC 2025 Vol.27 Number 1
	2025, Vol.27 Num.1
	Online: 2025-02-01

	REVIEW LITHOFACIES PALAEOGEOGRAPHY AND SEDIMENTOLOGY SPECIAL ISSUE ABOUT “DOLOSTONE” PAST AND PRESENT GEOGRAPHY ENVIRONMENT AND HUMAN CIVILIZATION NEW TECHNOLOGY AND NEW METHODS

REVIEW

	1	SHAO Longyi, WANG Langlang, LIAN Haojie, ZHU Hongtao, ZHU Xiaomin

		Current status and progress in nonmarine sequence architecture and sedimentary modelling
		Sequence stratigraphy,as a new method for basin analysis,has received great attention from geologists,especially in the study of continental sequence architecture and numerical modelling,which has become an international hot topic. This article summarizes the current research progress of nonmarine sequence architecture at home and abroad,introduces the concepts of “downstream-controlled area” and “upstream-controlled area” and their respective sequence architecture characteristics in recent years abroad. The sequence architecture of “downstream-controlled area” depends on relative sea (lake)level changes,and the “lowstand normal regression”,“transgressive”,“highstand normal regression” and “falling stage” systems tracts are developed,while the sequence architecture of “upstream-controlled area” does not depend on relative sea (lake)level changes,and the high(channel)amalgamation and the low(channel) amalgamation systems tracts are developed. There are also various views on “sequence architecture” in China,and the most representative one should be the classification of “L-type,T-type,TH-type,H-type(E-H type and L-H type)” sequence architectures. The modelling of nonmarine sequences has evolved from being dominated by the physical flume experiments to the current era of combining flume experiments with numerical simulation. Based on the introduction of the development history and research status of sequence numerical simulation at home and abroad,this article focuses on five numerical simulation methods,including SEDPAK forward modelling,SEDSIM forward modelling,three-dimensional forward modelling based on Delft3D model,DIONISOS three-dimensional forward modeling,and sequence numerical modeling based on the N-S equation. The paper has also summarized the sequence architecture of continetal lacustrine basins and the application of numerical modeling in the field of oil and gas exploration and development,and analyzed the current theoretical challenges,difficulties in numerical modeling technology,and future development directions of numerical modelling.
		2025 Vol. 27 (1): 1-15 [Abstract] ( 6 ) [HTML 1KB] [PDF 826KB] ( 2 )

LITHOFACIES PALAEOGEOGRAPHY AND SEDIMENTOLOGY

	16	WANG Jianpo, WANG Xiaofeng

		Re-understanding of the Ordovician geographical division in China
		The continental crust in China consists of the North China,Yangtze and Tarim cratons,along with several micro-continents and orogenic belts surrounding them. Based on their characteristics, this paper presents development of these geological terranes in China during the Ordovician period based on four types: cratons,micro-continents in oceanic plates,orogenic belts,and uncertain terranes. Additionally,by integrating paleogeographic data,a new perspective on the Ordovician geographical division in China is proposed,encompassing sixteen regions within four mega-regions. During the Ordovician,cratons and micro-continents in China were primarily distributed in the peri-Siberian area,the Paleo-Asian Ocean,the Proto-Tethys Ocean and the northern margin of Gondwana,and the four mega-regions were in alignment with these distributions. The North China and Tarim cratons belong to the Proto-Tethys Ocean Mega-region,despite separating the Paleo-Asian and the Proto-Tethys oceans. The North Xinjiang and Xing'an regions are located within the peri-Siberian Mega-region. The former comprises the Altay,Junggar-Tuha micro-continents,and the East and West Junggar orogenic belts,whereas the latter encompasses the Northeast China micro-continental group of Erguna,Xing'an,Xilinhot,Songliao,and Jiamusi. The Central Tianshan-Beishan Region pertains to the Paleo-Asian Ocean Mega-region,and the Yining micro-continent is a member of this region. Except the North China and Tarim regions,the Proto-Tethys Ocean Mega-region includes the Qaidam-Qilian,Kunlun-Qinling,Yangtze,Cathayasia,Indo-China,and Songpan-Ganzi regions. Among them,the middle-Altun and Quanji micro-continents belong to the Qaidam-Qilian Region,and the Yidun micro-continent belongs to the Songpan-Ganzi Region. The Qangtang,Lhasa,Himalaya,Sibumasu and Hainan regions were separated from the Gondwana Mega-region,with the Baoshan and Lincang micro-continents being part of the Sibumasu Region. The Alexa and Dunhuang terranes are included in the North China Region and the Tarim Region, respectively. There is a great difference between the above understanding of the geographical division of Ordovician period in China and that of the predecessors. The author aims to draw more scholars' attention and explore a more reasonable division scheme.
		2025 Vol. 27 (1): 16-16 [Abstract] ( 6 ) [HTML 1KB] [PDF 4113KB] ( 4 )

	32	SHI Zhensheng, ZHANG Yaxiong, ZENG Fanhui, ZHOU Tianqi, GUO Wei, HUANG Haoyong

		Main sedimentary structure types of marine fine-grained terrigenous clastic rocks and their significance for shale gas
		Sedimentary structures can not only provide insights into the formation environment and hydrodynamics of marine fine-grained terrigenous clastic rocks,but also significantly influence the permeability and fracturability of shale gas reservoirs. Based on comprehensive analysis of relevant materials at home and abroad,the types and origins of marine fine-grained terrigenous clastic rocks were systematically summarized. The rocks exhibit physical,chemical and biological structures. The physical structures mainly include flow structures and soft-sediment deformation structures. Flow structures include cross lamination,horizontal bedding or lamination,massive structure,graded lamination,and composite lamination. Soft-sediment deformation structures include slumps and slides,load structures,flame structures,ball-and-pillow structures,convolute lamination,contorted lamination,disrupted lamination,and dropstones. Chemical structures comprise carbonate concretes and pyrites,with biogenic structures primarily consisting of trace fossils and bioturbation. The three major types of sedimentary structures are mainly the result of fine-grained turbidites,contourites,and pelagites-hemipelagites,with a few arising from sediment deformation. Variations in sedimentary structures directly influence the permeability of shale gas reservoirs and affect the generation and propagation direction of hydraulic fractures.
		2025 Vol. 27 (1): 32-54 [Abstract] ( 8 ) [HTML 1KB] [PDF 30177KB] ( 3 )

	55	LIN Xingyue, ZHU Xiaomin, WANG Xiaolin, ZHANG Meizhou

		Reservoir characteristics and distribution of lacustrine fine-grained sedimentary rocks:a case study from Zhanhua sag,Bohai Bay Basin,China
		In order to deepen the understanding of lacustrine fine-grained sedimentary rock reservoirs,this paper takes the Lower Sub-member of Third Member of Shahejie Formation(Es3L)of Bonan subsag in Zhanhua sag,Jiyang depression,Bohai Bay Basin as the research object,and uses core description,thin section identification,scanning electron microscope observation,physical property analysis and logging curve to reveal the reservoir characteristics,main controlling factors and distribution patterns. Based on mineral composition,sedimentary structure and organic matter content,fine-grained sedimentary rocks in Es3L are divided into six lithofacies: organic-rich laminated gray fine-grained mixed rock(LF1),organic-rich laminated felsic fine-grained carbonate rock(LF2),organic-rich layered gray fine-grained mixed rock(LF3),organic-rich layered/massive felsic fine-grained carbonate rock(LF4),organic-rich layered felsic fine-grained carbonate rock(LF5),organic-rich massive felsic fine-grained carbonate rock(LF6). The main reservoir spaces of the reservoir are intergranular pores,intergranular pores,dissolution pores,and interlayer micro-fractures. The reservoir porosity mainly ranges from 0.67% to 5.56%,with an average of 4.93%. The permeability mainly ranges from 0.02×10^-3 μm² to 4.87×10^-3 μm²(average of 0.59×10^-3 μm²). The dominant control factors for the distribution of the Es3L fine-grained reservoir development include lithofacies,sedimentary environment,diagenesis and thermal evolution of organic matter. In the middle and lower part of the Lower Sub-member of Third Member of Shahejie Formation,the amount of terrestrial input is low,the water salinity is high,and the water stratification is strong. The main lithofacies area LF2 and LF4,which are prone to the development of Class I and Class II high-quality reservoirs. The fine-grained reservoirs in Es3L are in the intermediate diagenetic stage A. The transformation of clay minerals,dissolution,recrystallization and dolomitization,as well as the thermal evolution of organic matter produce secondary pores and fractures,which improve the physical properties of the reservoir.
		2025 Vol. 27 (1): 55-71 [Abstract] ( 6 ) [HTML 1KB] [PDF 8405KB] ( 1 )

	72	SHANG Junxin, FENG Mingyou, XIA Maolong, ZHANG Benjian, WANG Xingzhi, JIA Song, LI Yong, ZENG Yiyang, WEI Mingyang

		Characteristics and origins of soft-sediment deformation structures in the Sinian Dengying Formation,northern Sichuan Basin
		The mechanisms of soft-sediment deformation structures(SSDS)in the Precambrian Dengying Formation in the northern Sichuan Basin remain poorly understood. This study presents a comprehensive analysis of these structures in the Guangyuan area,examining their characteristics,distribution,and origins through field outcrop studies. The results indicate that these deformation structures,which are predominantly located in the middle to lower strata of the third member of the Dengying Formation,are composed of grey-white thin-layered limestone and purplish-red to grey-green thin-layered mudstone. The identified structures include liquefaction veins,convolute folds,breccias,and intrastratal faults,which are primarily observed in sediments from shallow,low-energy,aquatic environments. These deformations are closely linked to a combination of cyclic shear stress and stratigraphic pressure,suggesting recurrent ancient seismic activity as a key contributor. The finding of two distinct seismic liquefaction sequences suggests a minimum of two significant seismic events within the Member 3 of the Dengying Formation. It is further inferred that there was a period of intensive tectonic activity during the deposition of the member 3 of the Dengying Formation in the northern Yangtze Craton,and the seismic activity seemed to be related to the extension of the Late-Tongwan Movement in the rift.
		2025 Vol. 27 (1): 72-84 [Abstract] ( 7 ) [HTML 1KB] [PDF 35615KB] ( 3 )

SPECIAL ISSUE ABOUT “DOLOSTONE”

	85	NING Meng, LUO Jingru, CHEN Jiale, ZHONG Yijiang, WEN Huaguo

		Precambrian marine dolomite cements: review and perspectives
		Marine dolomite cement is widely developed in the Precambrian era,whereas its occurrence in the Phanerozoic is scarce. Precambrian marine dolomite cement has attracted extensive attention in recent years due to its diversity,complex origins,and potential implications for Precambrian seawater chemistry. Research on Precambrian marine dolomite cement mainly focuses on two aspects: one is the formation mechanism through mineralogical analysis,and the other is the investigation into the unique Precambrian‘aragonite-dolomite sea' conditions as reflected by marine dolomite cement. The origin of marine dolomite cement incorporates both primary precipitation and mimetic dolomitization. However,due to a lack of reliable geochemical evidence,there is ongoing controversy in this field. In addition,both the precipitation mechanism of the primary dolomite and the corresponding seawater chemical conditions remain unclear. The identification of precursor minerals for mimetic dolomite is controversial. Based on previous studies,it can be summarized the spatial and temporal distribution,petrological and mineralogical characteristics,and geochemical characteristics. Subsequently,the current research status on the formation mechanism of marine dolomite cements from three aspects,including primary precipitation,secondary replacement,and growth assemblage morphology. Finally,it can be proposed that three aspects should be enhanced: (1)The genesis of diverse types of marine dolomite cements should be investigated based on the principles of mineral nucleation and growth theory,combining with micro area or in-situ geochemical analysis;(2)he specific contribution of microorganisms to the formation of marine dolomite cements requires assessment;(3)To gain a comprehensive understanding of the evolution of Precambrian seawater properties,exploration of the origin of marine dolomite cement is imperative.
		2025 Vol. 27 (1): 85-108 [Abstract] ( 8 ) [HTML 1KB] [PDF 5850KB] ( 7 )

	109	LIU Kaiming, WANG Xingzhi, WEI Mingyang, LI Yang, CHEN Wang, WANG Wenzhi, LI Yong, MA Kui

		Reservoir characteristics and main controlling factors of ultra-deep dolomite in the 4th Member of Sinian Dengying Formation in Penglai area,Sichuan Basin
		The Dengying carbonate reservoirs, as one of the primary producing units of ultra-deep hydrocarbon resources in the Sichuan Basin,is required for further studies on their characteristics and controlling factors. This paper focuses on the ultra-deep dolomite of the fourth member of the Dengying Formation in the recently explored Penglai area of the Sichuan Basin. The study examines the reservoir's petrological characteristics,pore spaces,classification of reservoir types,physical properties,diagenetic evolution,and the main controlling factors of the reservoirs. The analysis is based on field outcrop profiles,drilling cores,microsections,cathodoluminescence(CL)imaging,scanning electron microscopy (SEM) data,and physical property test results. The findings are as follows: (1)The primary lithologies of the fourth member of the Dengying Formation in the Penglai area include dolo-thrombolite,dolo-stromatolite,dolo-spongiomicrobialite,and sand-debris dolomite. The main reservoir spaces consist of primary framework pores and secondary dissolution pores formed by subsequent dissolution processes. (2)Fractured reservoirs, primarily composed of dolo-thrombolite and dolo-stromatolite reservoirs with partial bedding pore development, typically exhibit favorable physical properties. The average porosity can exceed 4%,with the average permeability of the former reaching 2.43×10^-3 μm²,while the average permeability of the latter is only 0.35×10^-3 μm². (3)A comprehensive analysis of diagenetic evolution reveals that the microbial carbonate reservoirs of the fourth member of the Dengying Formation have undergone a sequence of stages: sedimentary-quasi-symbiotic,supergene,shallow-to-medium burial,and deep-to-ultra-deep burial stages. (4)Analysis of reservoir distribution patterns in the study area indicates that the reservoir distribution weakens from the platform interior to the platform edge. Overall,the ultra-deep dolomite in the fourth member of the Dengying Formation in the Penglai area follows a ternary reservoir model characterized by “sedimentary facies-fault-dissolution.” This study provides key insights into the characteristics and controlling factors of the ultra-deep dolomite reservoirs in the Penglai area of the Sichuan Basin,offering significant guidance for future ultra-deep oil and gas exploration in the region.
		2025 Vol. 27 (1): 109-125 [Abstract] ( 6 ) [HTML 1KB] [PDF 13351KB] ( 4 )

	126	LIU Dawei, LI Yingtao, HAN Jun, ZHANG Jibiao, RU Zhixing, YANG Xiaoqun, WANG Shi, HUANG Cheng, XIAO Chongyang

		Ultra-deep dolomite types and their reservoirs potential of the Ordovician Yingshan Formation in Shunbei area,Tarim Basin
		Dolomites of the Ordovician Yingshan Formation,which exhibit significant exploration potential,are found in the Shunbei area of the Tarim Basin. However,there is no systematic explanation on the genesis and physical property variations of the stratified dolomite in this region. Based on detailed petrology observation,carbon and oxygen isotopes,rare earth element analysis,carbonate U-Pb chronology dating,and porosity and permeability testing under different stress states,this study discussed the types and genetic mechanisms of the inner stratified dolomites of the Yingshan Formation. Furthermore,it provides a preliminary evaluation of the differences in physical properties among dolomites of various origin. The findings can be summarized as follows: (1)The relative development of dolomites in the lower part of the Yingshan Formation located in the northern region of Shunbei area primarily consists of two types of stratified dolomites,including the buried pressure-dissolved dolomite(Class I)and the penecontemporaneous seepage reflux dolomite(Class Ⅱ). (2)The Class I dolomites,which are predominantly distributed in low-energy sedimentary facies,have their origin in burial dolomitization. This is attributed to the genetic mechanism of clay mineral transformation,driven by the formation of stylolites during the burial process. These dolomites are relatively more developed in the central part of the Shunbei area. (3)The Class II dolomites are characterized by penecontemporaneous seepage reflux dolomitization in sedimentary facies that display high geomorphology and relatively high energy. These dolomites are primarily distributed and well developed in the western and southern Shunbei area. (4)The measured physical properties of Class Ⅰ dolomites(φ: 0.3%~1.0%;K: 0.003×10^-3~0.074×10^-3 μm²)are lower than those of Class Ⅱ dolomites(φ: 0.4%~2.0%;K: 0.009×10^-3~0.055×10^-3 μm²). However,Class I dolomites can enhance the ratio of dolomite-limestone interbedding,and there are fractures to transform into reservoir potential. This study is of significant reference value for ultra-deep dolomite oil and gas exploration in the Shunbei area of the Tarim Basin.
		2025 Vol. 27 (1): 126-140 [Abstract] ( 6 ) [HTML 1KB] [PDF 10133KB] ( 1 )

	141	ZHANG Kuihua, ZHANG Pengfei, MIAO Zhuowei, ZHANG Qian

		Amplitudes of Earth's orbital parameters and fluctuations of deep-water dolomitization
		Due to the evident correlation between fluctuations in dolomitization intensity in Phanerozoic geological strata and significant geological events throughout Earth's history,it is increasingly important to understand the mechanisms underlying these fluctuations in relation to long-term magnesium and carbon cycles in terrestrial and marine environments,atmospheric processes,and climate change over extended periods. In this study,time series analysis and coupling analysis are analyzed based on high-resolution X-ray diffraction data to reveal the slope amplitude modulation cycle recorded by the deep-water dolomite cycle of the Shahejie Formation in the Bohai Bay Basin. Combining the Quaternary dolomite cycle in Van Lake,Turkey,with the dolomitization events during the Permian-Triassic period,we discussed the coupling relationship between the fluctuations in deep-water dolomitization intensity over the Phanerozoic eon and the amplitude of various Earth orbital parameters across different time scales. Building on the analysis of the salinity evolution characteristics of the Sha 3 submember,it is proposed that the amplitude-modulation effect of Earth's orbital parameters may influence microbial ecological stress and the fluctuations in temperature and pH of fluids through changes in climate and environmental factors. This,in turn,plays a significant role in regulating orbital deep-water dolomitization intensity during the Phanerozoic eon. This study provides a novel perspective for the exploration of the “dolomite problem”.
		2025 Vol. 27 (1): 141-152 [Abstract] ( 4 ) [HTML 1KB] [PDF 1931KB] ( 2 )

PAST AND PRESENT GEOGRAPHY ENVIRONMENT AND HUMAN CIVILIZATION

	153	JIA Ya'na, LI Sanling, ZHAO Wenjie, ZHU Yan, LIU Chonghao, TU Hua, LI Hao, ZHANG Yuzhu

		Environmental evolution and hominin behavior adaptation of Shanghu Paleolithic site,Jiangxi Province
		Understanding the depositional process and paleoenvironment of the archaeological site is crucial for comprehending ancient human technology behavior. The Shanghu site,an open-air Paleolithic site,was newly discovered in southern China. Abundant stone artifacts,characterized by miniaturization,were unearthed from the homogeneous red soil B layer,dated to approximately 26 000 years ago. Integrated field investigation,micromorphology,magnetic susceptibility,grain size,geochemistry and archaeological taphonomy were comprehensively conducted. Our findings reveal that the homogeneous red soil B layer was primarily influenced by low-energy slope water processes,which allowed for the preservation of relatively intact records of ancient human technological behavior. The Shanghu site was frequently occupied by ancient humans during the MIS2 period. This may be related to the fact that ancient humans in North China with small flake tool industry were unable to withstand the extremely cold-dry climate,and were compelled to migrate southward,eventually arriving in the middle and lower reaches of the Yangtze River where the climate was relatively dry and cool. Moreover,ancient humans adopted a logistical mobility strategy to cope with the risks of uneven distribution and reduced predictability of resources caused by the extreme climate.
		2025 Vol. 27 (1): 153-166 [Abstract] ( 5 ) [HTML 1KB] [PDF 12580KB] ( 8 )

	167	MA Yufeng, WU Zhijiang, LI Shuangquan, LIU Hongyan, REN Xiao, GUO Yangshan, WANG Chaodong, GUO Lihua

		Palaeoenvironmental background of Qiaotou Site in Chushandian reservoir area in the upper reaches of Huai River
		The Huai River is a river of great significance to the Chinese civilization. However,compared with researches in the Yellow River and Yangtze River basins,archaeological and palaeoenvironmental research in the Huai River Basin has been relatively lagging behind. Qiaotou Site is an important site of the Shijiahe culture in the upper reaches of Huai River. This paper studied the environmental changes before and after the formation of Qiaotou Site,as well as the relationship between the palaeoflood events and the survival of the site,through stratigraphic investigations and testing and analyses of indoor samples from the Qiaotou site area and its adjacent areas. The results showed that at least 2 km around Qiaotou Site was covered by lakes or marshes during 8.1~4.6 ka BP(9.1~5.4 cal. ka BP)before the formation of Qiaotou Site. After about 4.6 ka BP(5.4 cal. ka BP),the ancestors were attracted to live in this region by its excellent natural environment,such as the warm and humid climate,highland terrain,and water source—Muzi River adjacent to the site's,etc. Unfortunately,this region became unsuitable for human habitation in the millennium after the Shijiahe culture due to the frequent environmental changes such as climatic anomalies(4.0 ka BP),floods caused by climatic fluctuations(3.5 ka BP,i.e. 3.9 cal. ka BP),and the diversion of the Huai River(3.2 ka BP,i.e. 3.6 cal. ka BP). After 3 ka BP(3.3 cal. ka BP),the ancestors settled here again as the temperatures in the Qiaotou site area gradually increased and became warmer. However,the ancestors had to leave this area again after 2.5 ka BP(1.8 cal. ka BP),as the highly fluctuating climate and frequent floods threatened the human survival.
		2025 Vol. 27 (1): 167-183 [Abstract] ( 6 ) [HTML 1KB] [PDF 14524KB] ( 1 )

	184	LUO Wenjing, WU Li, MA Chunmei, ZHU Cheng, LU Shuguang

		Environment evolution since the Holocene revealed by lacustrine sediments of Meiyan borehole in Taihu Lake,eastern China
		In this study,we investigate the Meiyan borehole located on the southeastern shore of Taihu Lake. Based on a reliable chronological sequence established by AMS¹⁴C dating,we use elemental geochemistry,including Rb and Sr concentrations and the Rb/Sr ratio,to reconstruct Holocene climate changes. Additionally,foraminifera analysis is employed to explore whether the Taihu Lake region was affected by transgressions. The results show that from 11.0-9.1 cal. ka BP,the climate of Taihu Lake Basin gradually changed from humid to dry;from 9.1-6.1 cal. ka BP,the general climate was generally humid,with the wettest period occurring during 8.8-7.1 cal. ka BP;from 6.1~2.0 cal. ka BP,the climate was generally dry with the lowest precipitation;from 2.0-0 cal. ka BP,the precipitation gradually increased and the climate was humid. During the whole Holocene period,the eastern area of Taihu Lake was unlikely to have been influenced by transgressions. Regional comparisons show that the Rb/Sr record in Taihu Lake are consistent with environmental proxies record in neighboring regions during the middle and late Holocene,which is characterized by gradually drying climate in the Middle Holocene and wet climate since 2.0 cal. ka BP. To further explore the climate dynamics,we compared the environmental proxy index with the 30° solar radiation in the northern hemisphere,ENSO frequency records and Holocene mean sea level records. We found that the climate of Taihu Lake Basin was controlled by the solar radiation and ENSO changes,with distinct phases of dominance and coupling between the two factors. Solar radiation affected the early and middle Holocene climate of Taihu Lake Basin through direct and indirect effects. Since 2.0 cal. ka BP,the climate has exhibited an El Niño-like state,with an intensified ENSO frequency balancing the effects of weakened solar radiation on precipitation in the monsoon region. As a result,ENSO frequency became the main controlling factor of the climate in the Taihu Lake Basin. The results will provide a reliable basis for understanding the relationship between monsoon and climate change in the lower reaches of the Yangtze River since the Holocene.
		2025 Vol. 27 (1): 184-194 [Abstract] ( 7 ) [HTML 1KB] [PDF 7982KB] ( 2 )

	195	ZHU Guangkun, ZHANG Yurui, QIN Guojin

		Uncertainty in reconstructing palaeogeographic boundary conditions in palaeoclimate modelling
		As climate models are increasingly applied in palaeoclimate studies,the reconstruction of more accurate palaeogeographic boundary conditions has become a key factor in understanding deep-time climate change mechanisms. However,the uncertainty in this reconstruction process has received little attention. This study investigates this uncertainty and its impact on model simulation results,based on reconstruction methods and data selection for palaeo-sea-land distribution,palaeo-sea depth,and palaeo-topography. Our results show that: (1)When reconstructing sea-land distribution,choice of reference plate movement models significantly affects the latitude and longitude of the reconstructed plates,so this demonstrate that model selection should align with research goals. Moreover,accurate correction of sea-land distribution requires multiple palaeoenvironmental proxy indicators,considering their uncertainties. (2)The reconstruction of palaeo-sea depth is more uncertain due to its complex process. Updating the oceanic crust age,choosing a depth-crust age relationship model,selecting a sediment model,and adjusting depth in key areas can all lead to different ocean depth reconstruction results. In particular,special attention should be paid to critical areas like sea channels,the state of this areas directly affect ocean current patterns and temperature-salinity changes in some ocean basins. (3)The uncertainty of palaeo-topography reconstruction is mainly influenced by factors such as the richness and uncertainty of height proxy indicators. (4)Correcting sea-land distribution and reconstructing sea depth leads to differences in basin size and seabed topography. These differences directly impact ocean currents and air-sea exchanges. In summary,uncertainty arises at every step of the palaeogeographic boundary conditions reconstruction process,which will greatly affect the accuracy of model output. To mitigate this,optimizing reconstructions by adding more proxy indicators will be required. Additionally,using multi-model results and geological records for verification is critical when analyzing climate model output,involving palaeogeographic boundary uncertainty.
		2025 Vol. 27 (1): 195-208 [Abstract] ( 7 ) [HTML 1KB] [PDF 4276KB] ( 2 )

NEW TECHNOLOGY AND NEW METHODS

	209	LI Yang

		Extraction of astronomical cycle signals and identification of third-order sequences in the Ordovician of Well XT1, southern margin of Ordos Basin
		In the southern margin of the Ordos Basin,no cyclostratigraphic analysis has yet been conducted on the Paleozoic Ordovician to identify astronomical orbital cycle signals. This analysis is crucial for establishing a high-precision geological timescale and reasonably dividing third-order sequences,which is of significant importance for oil and gas exploration in the area. Combining cyclostratigraphic theory and signal decomposition techniques,a cyclostratigraphic analysis of the Paleozoic Ordovician in the Well XT1 was performed. The results indicate that there are differences in sedimentation rates among different strata. The sedimentation rate during the Yeli and Liangjiashan stages in Well XT1 area ranges from 4.2 to 5.6 cm/ka,while the Majiagou stage varies between 2.2 and 5.5 cm/ka. The sedimentation rate during the Pingliang and Beiguoshan stages increases,ranging from 4.3 to 9.3 cm/ka. Significant Milankovitch cycle signals are present in the Ordovician of Well XT1,recording eccentricity and obliquity astronomical orbital periods. A 405 ka eccentricity cycle was used to establish an age model for astronomical tuning,creating a fluctuating astronomical timescale for the Ordovician in Well XT1,with the sedimentation period for the Yeli to Liangjiashan Formations at approximately 3.25 Ma,and for the Majiagou to Beiguoshan Formations at around 27.4 Ma. Using wavelet transformation,the frequency of the Ordovician third-order sequences was primarily distributed around 0.011 cycles/m,allowing the division of the Ordovician in Well XT1 into approximately 13 third-order sequences. This study provides a new quantitative method and scientific basis for the division of Ordovician sequences and the study of astronomical cycles,contributing to a refined understanding of sedimentary processes and the accuracy of timescales.
		2025 Vol. 27 (1): 209-224 [Abstract] ( 6 ) [HTML 1KB] [PDF 6956KB] ( 3 )

	225	SU Yang, LAI Jin, BIE Kang, LI Dong, ZHAO Fei, CHEN Kangjun, LI Hongbin, WANG Guiwen

		Well logging evaluation and characterization of geological information for deep and ultra-deep drilling wells
		In accordance with the strategic deployment of deep-sea,deep-earth,deep-space and deep-blue initiatives,land drilling is continuously entering towards deep and ultra-deep reservoirs. However, the collection of advanced well log series are limited for the deep and ultra-deep strata, and will result in interpretation ambiguity of well log data. Therefore,it is urgent to use the limited geophysical logging information to fully interpret on the geological information contained in deep and ultra-deep drilling. This paper firstly discusses the focus of logging evaluation in deep and ultra-deep reservoirs based on extensive literature retrieval. Through the analysis of typical research cases,it systematically reviews the application of logging geology in deep and ultra-deep fields,including using logging data to interpret structural geological phenomena,pick up sedimentary information,evaluate and predict reservoir characteristics,and evaluate in-situ stress using logging data. Finally,the development trend of deep and ultra-deep fields is discussed: paying attention to the integration of multi-data source(such as core,experimental data,and seismic data),and developing advanced rock physical models that adapt to the environmental factors of deep and ultra-deep environments based on their differences. At the same time,in the context of the development of big data and artificial intelligence,the advantages of new technology logging are utilized to promote breakthroughs in the field of logging geology in deep and ultra-deep fields,thus breaking through technical bottlenecks.
		2025 Vol. 27 (1): 225-239 [Abstract] ( 5 ) [HTML 1KB] [PDF 8569KB] ( 3 )

	240	REN Yufei, YAN Jianping, WANG Min, SONG Dongjiang, GENG Bin

		Particle size logging inversion method of deep complex clastic rock and its application in fine lithology identification
		The Miocene strata in the L area of the Y Basin in the western part of the South China Sea are characterised by high temperature and ultra-high pressure,which makes drilling difficult and core data rare. In addition, the accuracy of rock chip logging in reflecting lithology is relatively low,making it difficult to meet the requirements of fine identification of lithology. The deep clastic rocks in the second section of Huangliu Formation in the L area of Y basin are used in this study,firstly,using the limited data of core size analysis,rock chip logging and logging,we selected the particle size parameter characterizing lithology: median Md and five logging curves of natural gamma,density,neutron,acoustic time difference and resistivity which are sensitive to changes in the particle size,and constructed the data set of five variables of the median Md and logging,and then we used K-MEANS secondly,using K-MEANS clustering method,the dataset was divided into four classes according to the optimal relationship between “sum of error squares and the number of clusters”(referred to as “granularity classification”),which optimised the correlation between the median Md-granularity and the logging response,and obtained the logging response characteristics of the different classes and the corresponding lithological types. Then,in the actual well data processing process,Fisher's discriminant equation is applied to determine the type of particle size classification to which the unknown depth point belongs,and finally,the intelligent calculation model of median particle size logging based on XGBoost algorithm is established under the particle size classification,and based on the numerical range of median particle size corresponding to different lithologies,it realises the purpose of fine identification of lithology by inverting the median Md curve according to the logging on the wellbore profile. The purpose of fine identification of lithology is achieved by inverting the Md curve on the wellbore profile according to the logging.The results show that the sandstone lithology in the second section of Huangliu Formation in L area is divided into: siltstone,fine sandstone,medium sandstone and coarse sandstone considering the difference of grain size,among which the fine sandstone and medium sandstone are the most dominantly developed lithologies,and the median Md of grain size has the closest relationship with the lithology of different grain sizes,and it is the most reflective of the different grain sizes of lithologies;the intelligent calculation of the median Md of grain size logging model based on XGBoost algorithm is better than that of multiple regression algorithm after the classification of the grain sizes. The prediction effect of the model is better than that of the multiple regression prediction model,and the correlation coefficient between the calculated median particle size and the measured value reaching 0.9397,the average absolute error(MAE) is 0.0195,and the average relative error MRE is 0.1752. The model is an effective method for the fine identification of the lithology of the deep complex clastic rocks,and it also lays a foundation for sedimentary grain sequence analysis and fine interpretation of the reservoir configuration,and the evaluation of the validity on the vertical profile. It also lays the foundation for sedimentary grain sequence analysis,fine interpretation of reservoir configuration and validity evaluation in longitudinal section.
		2025 Vol. 27 (1): 240-255 [Abstract] ( 5 ) [HTML 1KB] [PDF 2632KB] ( 3 )

	256	HUANG Yuyue, WANG Guiwen, KUANG Lichun, QIN Yinglun, WANG Song, DANG Wenle, ZHUO Seqiang, BI Shaochen, LAI Jin

		Shale type division and logging identification in the Member 1 of Luzhai Formation,Lower Carboniferous,Guizhong Depression
		The shale gas of Luzhai Formation in Liucheng North block of Guizhong Depression has made a breakthrough and is expected to become a replacement field for marine shale gas outside Sichuan Basin. However,it is difficult to identify shale type and evaluate reservoir due to the formation heterogeneity and frequent transverse and horizontal phase transformation. In this paper,a shale type division scheme based on “mineral composition+TOC content”is established. Logging identification and prediction of shale composition and TOC content are realized by using elite-mineral conversion optimization equation and BP neural network model,respectively. The shale layers are identified and characterized by two methods: image log dynamic slice and button electrode apparent conductivity image. By elaborating the stratification degree and gas bearing characteristics of different lithofacies types,the favorable shale types and distribution characteristics in the study area are described. The results show that five typical shale types are developed in the Member 1 of Luzhai Formation. Controlled by sedimentary palaeoenvironment,the shale distribution in the study area shows strong vertical heterogeneity. The Member 1 of Luzhai Formation is located in the lower slope sedimentary environment as a whole,and the sedimentary water in the vertical layer(①~⑦)gradually becomes shallower,the content of gray matter decreases while the supply of terrigenous debris increases,and the total organic carbon content also gradually decreases. The shale type gradually changes from organic-rich siliceous mixed shale and organic-rich clayey mixed shale to organic-containing siliceous mixed shale. The shale assemblage types of organic-rich siliceous mixed shale and organic-rich clayey mixed shale in small layer ③ has high organic matter abundance,better laminae combination type and development degree,and higher overall gas content and brittleness,which are favorable shale types in the study area.
		2025 Vol. 27 (1): 256-270 [Abstract] ( 5 ) [HTML 1KB] [PDF 24420KB] ( 3 )

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