The successful development of unconventional hydrocarbons has significantly increased global hydrocarbon resources, promoted the growth of global hydrocarbon production and made a great breakthrough in classical oil and gas geology. The core mechanism of conventional hydrocarbon accumulation is the preservation of hydrocarbons by trap enrichment and buoyancy, while unconventional hydrocarbons are characterized

After the preliminary basic research on the problems encountered during the production period of Gulong shale oil in the Songliao Basin, NE China, and the scientific exploration, the special characteristics of Gulong shale oil in terms of reservoir space, phase distribution, flow pattern, and mineral evolution are proposed. The main results are as follows : (1) The source of organic matter, mechanism

Because of the differences of hydrocarbon accumulation between in-source and out-of-source oil pools, the demand for source kitchen is different. Based on the establishment of source-to-reservoir correlation in the known conventional accumulations, and the characteristics of shale oil source kitchens as well, this paper discusses the differences of source kitchens for the formation of both conventional

A new method for reconstructing the geological history of hydrocarbon accumulation is developed, which are constrained by U-Pb isotope age and clumped isotope (Δ47) temperature of host minerals of hydrocarbon-bearing inclusions. For constraining the time and depth of hydrocarbon accumulation by the laser in-situ U-Pb isotope age and clumped isotope temperature, there are two key steps: (1) Investigating

To evaluate the lateral sealing mechanism of extensional fault based on the pressure difference between fault and reservoir, an integral mathematical-geological model of diagenetic time on diagenetic pressure considering the influence of diagenetic time on the diagenetic pressure and diagenetic degree of fault rock has been established to quantitatively calculate the lateral sealing ability of extensional

In geological history, one major life explosion and five mass extinction events occurred. These major biological and environmental events affected the evolution of the Earth ecosystem and controlled the formation of organic-rich strata. The life explosion occurred in Cambrian and the five mass extinction events happened at the end of Ordovician, Late Devonian, end of Permian, end of Triassic, and end

Through fault structure analysis and chronology study, we discuss the origin and growth mechanisms of strike-slip faults in the Tarim Basin. (1) Multiple stages strike-slip faults with inherited growth were developed in the central Tarim cratonic basin. The faults initiation time is constrained at the end of Middle Ordovician of about 460 Ma according to U-Pb dating of the fault cements and seismic

The lithology, lithofacies, reservoir properties and shale oil enrichment model of the fine-grained sedimentary system in a lake basin with terrigenous clastics of large depression are studied taking the organic-rich shale in the first member of Cretaceous Qingshankou Formation (shortened as Qing 1 Member) in the Changling Sag, southern Songliao Basin as an example. A comprehensive analysis of mineralogy

Based on the data of measured formation pressure, drilling fluid density of key exploration wells and calculated pressure by well logging, combined with the analysis of natural gas geological conditions, the characteristics and formation mechanisms of formation fluid overpressure systems in different foreland basins and the relationship between overpressure systems and large-scale gas accumulation

Based on drilling cores, well logging and seismic data, source rocks and reservoirs are evaluated; and the natural gas genesis is identified through the analysis of natural gas isotopes, components and fluid inclusions, to study the gas accumulation conditions of the gypsum salt rock related strata of the Ordovician lower assemblage in Ordos Basin. (1) The natural gas from Ordovician lower assemblage

Based on outcrop characteristics, combined with regional tectonic background, drilling and geophysical data, the sedimentary characteristics of the Middle Permian Maokou Formation in the northern Sichuan Basin was studied by means of macroscopic and microscopic observation, geochemical element test, total organic carbon content and vitrinite reflectance measurement. There is a set of deep-water sediments

Based on outcrop, drilling, logging, geochemical analysis and seismic data, the karst landform and distribution of Permian volcanic rocks at the end of the sedimentary period of the Maokou Formation in the western Sichuan Basin are examined, and their petroleum geological significance is discussed. Affected by normal faults formed in the early magmatic activities and extension tectonic background in

Based on structural deformation analysis in the oblique Sumatra subduction system, we review uplift mechanisms of the forearc high and formation of the forearc basin. The development of the forearc high has been attributed to the flexural uplift, basin inversion, uplift of older accretion wedge, and backthrust in the landward margin of the accretion wedge. Observation of recently acquired seismic reflection

To improve effectiveness of ASP flooding, it is necessary to establish a reliable parameter design and tracking adjustment method to monitor the process of oil displacement. A differential wide field electromagnetic method was proposed and applied to the ASP displacement monitoring test in a block of the Daqing Oilfield. In the process of ASP flooding, the electromagnetic field was measured many times

Factors affecting CO2 flooding of shale oil reservoir were studied by nuclear magnetic resonance (NMR) experiments, the effects of time, pressure, temperature on the recovery of CO2 flooding in shale oil reservoir were analyzed based on nuclear magnetic resonance T2 spectrum, and the effect of fracture development degree on recovery of CO2 flooding in shale oil reservoir was analyzed based on NMR images

This study extends an integrated field characterization in Eagle Ford by optimizing the numerical reservoir simulation of highly representative complex fractured systems through embedded discrete fracture modeling (EDFM). The bottom-hole flowing pressure was history-matched and the field production was forecasted after screening complex fracture scenarios with more than 100 000 fracture planes based

The mechanism of the hydrophobized poly(ethylene glycol) (PEG)/K+ system inhibiting shale hydration was studied by laboratory experiment. The inhibition performance was evaluated through cuttings hot-rolling dispersion, bentonite inhibition and contact angle tests. The inhibition became stronger as contact angle and PEG concentration increased. A modified cuttings hot-rolling dispersion experiment

By reviewing the mechanisms of drilling fluid lost circulation and its control in fractured formations, the applicability and working mechanisms of different kinds of lost circulation materials in plugging fractured formations have been summarized. Meanwhile, based on the types of lost circulation materials, the advantages, disadvantages, and application effects of corresponding plugging technologies

Carbonate outcrops were taken from Ma 51 sub-member in the Lower Paleozoic in the Yan’an gas field to conduct true tri-axial hydraulic fracturing experiments with water, liquid CO2 and supercritical CO2. CT scan was applied to analyze initiation and propagation laws of hydraulic fractures in carbonate rocks. The experiments show that supercritical CO2 has low viscosity, strong diffusivity and large

Shale samples of Silurian Longmaxi Formation in the Changning area of the Sichuan Basin, SW China, were selected to carry out scanning electron microscopy, CT imaging, high-pressure mercury injection, low-temperature nitrogen adsorption and imbibition experiments to compare the hydration characteristics of montmorillonite and illite, analyze the main factors affecting the water block removal of shale

Based on 991 groups of analysis data of shale samples from the Lower Member of the Cretaceous Eagle Ford Formation of 1317 production wells and 72 systematic coring wells in the U.S. Gulf Basin, the estimated ultimate recovery (EUR) of shale oil and gas of the wells are predicted by using two classical EUR estimation models, and the average values predicted excluding the effect of engineering factors

Taking the Gaoshangpu-Liuzan geothermal field in the Nanpu sag of the Bohai Bay Basin as the research object, this paper discusses the geological conditions and potential of the geothermal resources of the Guantao Formation in the study area, and introduces the development practice of geothermal energy heating in Caofeidian. The average buried depth of the Guantao Formation is 1500–2500 m, the lithology

Based on the theory of structural analysis, the characteristics and structural patterns of subtle faults are studied using 3D seismic data of the Bohai Sea to analyze the development process and origin of the subtle faults. A method of identifying subtle faults is proposed, forming a complete system for analyzing origins of subtle faults in the Bohai Sea. The complex strike-slip fault patterns under

The types, evolution processes, formation mechanisms, and depositional models of deep-water gravity flow deposits in a lacustrine rift basin are studied through core observation and systematic analysis. Massive transport of slide and slump, fluid transport of debris flow and turbidity currents are driven by gravity in deep-water lacustrine environment. The transformation between debris flow and turbidity

To quantitatively determine the effect of different factors such as fracture width, dip angle, extension and filling material on Stoneley wave amplitude decreasing, the shock tube experiment method was changed from fixing the sample and vertically moving the sensor in the borehole to fixing the sensors along the shock tube wall and vertically moving the sample without drilling the borehole in it. The

The pore throat structure characteristics of Paleogene tight sandstone and sandy conglomerate in the Jiyang depression are studied using cast thin section, conventional mercury injection, constant rate mercury injection and micro CT scanning data, and a reservoir classification scheme based on pore throat structure parameters is established. The material composition and structural characteristics of

Based on regional geology, 2D seismic and ocean drilling data, the formation of the Eratosthenes Seamount (ESM) and its surrounding isolated platforms, types of organic reefs and hydrocarbon accumulation conditions in the eastern Mediterranean were analyzed through fine tectonic interpretation and seismic facies study, and the future exploration targets were pointed out. The formation and evolution

Based on drilling data of JT1 and CS1, outcrop profiles and seismic data, the sedimentary pattern, space configuration of source-reservoir-cap combinations and paleouplift evolution characteristics of the Cambrian Lower Canglangpu Member in the central Sichuan paleouplift have been investigated to determine the favorable exploration zones. Controlled by Deyang-Anyue rift, the Lower Canglangpu Member

Based on a large number of geological and geophysical data, the formation, fracture-caves types and hydrocarbon distribution of hoodoo-upland on the Ordovician karst slope in the Tahe area, Tarim Basin, are discussed by analyzing faults and strata thickness. The hoodoo-upland was made of high peaks and narrow valleys in the Ordovician karst slope during the Early Hercynian karst period, which were

Based on outcrop, core, logging, seismic and production data, and the formation of fault-controlled karst reservoirs, the types and characterization of Ordovician fault-controlled karst reservoir architectures in the Tuoputai area of the Tahe oilfield are studied. According to the concept of genetic geologic body, the fault-controlled karst reservoir is divided into architecture elements of four levels

In the process of unconventional natural gas development practice, the “extreme utilization” concept that focuses on “continuously breaking through the limit of development technology” is gradually formed, and supports the scale benefit exploration of unconventional gas in China. On this basis, the development theory of “extreme utilization” is proposed, its theoretical connotation together with development

Based on the differences in production mode and operation process between gas storage and gas reservoir, we established a phase balance test procedure and a theoretical simulation model of phase balance during multi-cycles of injection and production of underground gas storage (UGS) rebuilt from condensate gas reservoir to study the phase characteristics of produced and remaining fluids during multi-cycles

An orthogonal 2D training image is constructed from the geological analysis results of well logs and sedimentary facies; the 2D probabilities in three directions are obtained through linear pooling method and then aggregated by the logarithmic linear pooling to determine the 3D multi-point pattern probabilities at the unknown points, to realize the reconstruction of a 3D model from 2D cross-section

This work was conducted to study the risk of formation damage as the result of mineral scales deposition during smart waterflooding into carbonate core sample, as well as the influence of injected water salinity and ionic composition on mineral scaling and precipitation. The reservoir flowing conditions were simulated by a new laboratory core-flooding procedure, which took into count of the effect

Based on the comprehensive understanding on microfractures and matrix pores in reservoir rocks, numerical algorithms are used to construct fractured porous media and fracture-pore media models. Connectivity coefficient and strike factor are introduced into the models to quantitatively characterize the connectivity and strike of fracture network, respectively. The influences of fracture aperture, fracture

Static experiments and dynamic displacement experiments were conducted to quantitatively determine the amount of precipitate generated by the CO2-formation water reaction at different temperatures, pressures, and scaling ion concentrations during CO2 flooding in the Chang 8 block of Changqing Oilfield, the influence of precipitate on the physical properties of reservoirs was investigated, and the corresponding

Considering the stratum anti-drilling ability, drill bit working conditions, drill bit application effect and drill bit economic benefits, the similarity of stratum anti-drilling ability was evaluated by grey relational analysis theory to screen out candidate drill bits with reference values. A new comprehensive performance evaluation model of drill bit was established by constructing the absolute

To study the casing deformation (CD) in shale gas well fracturing caused by natural fracture slip, a fracture face stress model is built based on stress analysis, and a CD prediction model is established based on complex function to analyze factors affecting wellbore shear stress and CD. (1) The fracture and wellbore approach angles have significant impacts on the wellbore shear stress. In Weiyuan

Triaxial fracturing modeling experiments were carried out on whole diameter shale cores from different layers of Shahejie Formation in the Dongpu sag, Bohai Bay Basin to find out the vertical propagation shapes of hydraulic fractures in different reservoirs. A numerical simulation method of inserting global cohesive elements was adopted to build a pseudo-three-dimension fracture propagation model for

Carbon dioxide is an important medium of the global carbon cycle, and has the dual properties of realizing the conversion of organic matter in the ecosystem and causing the greenhouse effect. The fixed or available carbon dioxide in the atmosphere is defined as “gray carbon”, while the carbon dioxide that cannot be fixed or used and remains in the atmosphere is called “black carbon”. Carbon neutral

Taking the tight oil of the Zhongnan sag in the Ordos Basin, Jimusar sag in the Junggar Basin and Qingxi sag in the Jiuquan Basin as study objects, based on field survey, dissection of tight oil reservoirs, sample test, modeling experiment and comprehensive analysis, this study reveals that the tight oil accumulates at start-up pressure, advances under differential pressure, diffuses at alternating

Aiming at the actual demands of petroleum exploration and development, this paper describes the research progress and application of artificial intelligence (AI) in petroleum exploration and development, and discusses the applications and development directions of AI in the future. Machine learning has been preliminarily applied in lithology identification, logging curve reconstruction, reservoir parameter

By using drilling, high-precision 3D seismic data, data of geochemistry, logging and testing, the reservoir characteristics and accumulation conditions of the KL6-1 lithologic oilfield in the Laibei Low Uplift in the Bohai Sea are examined comprehensively. The study shows that: KL6-1 oilfield is a monolithic, high-quality, large-scale Neogene lithologic oilfield featuring shallow reservoir depth, high

This paper systematically discusses the multiple source characteristics and formation mechanisms of carbonate-rich fine-grained sedimentary rocks through the analysis of material source and rock formation. The hydrocarbon accumulation characteristics of carbonate-rich fine-grained sedimentary rocks are also summarized. The results show that the main reason for the enrichment of fine-grained carbonate

By using the latest geological, seismic, drilling and logging data, this article studies the basic conditions for the formation of the total petroleum system and the orderly coexisting characteristics and accumulation models of conventional & unconventional reservoirs in the Lower Permian Fengcheng Formation in the Junggar Basin. Controlled by thermal evolution, hydrocarbon generation and expulsion

By analyzing the structural background, petroleum geological conditions, and typical regional (paleo) oil and gas reservoirs in marine ultra-deep oil and gas regions in China, this paper reveals the evolution processes of the marine ultra-deep oil and gas reservoirs and the key controlling factors of accumulation. The marine ultra-deep oil and gas resources in China are buried at depth of greater than

Taking the mixed pre-salt carbonate rocks in the upper member of Eocene Xiaganchaigou Formation (E32) of Yingxi area in the Qaidam Basin as an example, the lithofacies and controlling mechanisms of reservoir formation are analyzed based on a large dataset of cores, thin sections and geochemical analysis. The reservoirs in E32 pre-salt layers have five types of lithofacies, of them, mixed granular calcareous

Based on analysis of outcrop, drilling, logging and seismic data, and geotectonic background, the lithofacies paleogeography and paleokarst geomorphology of the Middle Permian Maokou Formation in the northwestern Sichuan Basin were reconstructed, and the petroleum geological significance of the lithofacies paleogeography and paleokarst geomorphology were discussed. The Maokou Formation is divided into

Based on the observation of outcrops and cores, thin section identification, restoration of paleogeomorphology by residual thickness method, fine description of seismic facies, etc., the coupling relationships between the development patterns of various types of Cambrian platform margin mound-shoal complexes and paleogeomorphology in the Gucheng area of Tarim Basin have been examined. The Cambrian

Based on the cores from 47 wells and logging data of 130 wells, the main types of sand bodies in the shallow water delta of the Chang 82 sub-member in the Triassic Yanchang Formation, Longdong Area, Ordos Basin were comprehensively analyzed, the distribution characteristics of sand bodies more than 20 m thick were identified, and the genetic types of the thick sand bodies were sorted out. In this region

With many types of salt structures developed in the Lower Cretaceous Aptian Formation, the passive continental marginal basins in the middle segment of the south Atlantic are hot areas of deep-water petroleum exploration. Based on analysis of differential deformations of salt structures, the influences of the inclination of subsalt slope, subsalt topographic reliefs and basement uplifting on the formation

To understand the evolution of the Miocene gravity flow deposits in the Lower Cong—Congo Fan Basin, this paper documents the Miocene sequence stratigraphic framework, the depositional characteristics and the controlling factors of the gravity flow system. Based on the establishment of high-resolution sequence stratigraphic framework, lithofacies characteristics and sedimentary units of the gravity

Based on the pseudo-analytical equation of electromagnetic log for layered formation, an optimal boundary match method is proposed to adaptively truncate the encountered formation structures. An efficient integral method is put forward to significantly accelerate the convergence of Sommerfeld integral. By asymptotically approximating and subtracting the first reflection/transmission waves from the

Taking reservoir rocks and fluids of the Daqing, Dagang and Changqing oilfields as research objects, the EOR mechanisms and technical approach of polymer flooding were discussed. By comparing the displacement performances of ordinary polymer, glycerol, polymer in “sheet-net” structure and heterogeneous weak gel at the same viscosity and concentration, the relationship between the viscosity of polymer

A new method for selecting dimensionless relaxation time in the lattice Boltzmann model was proposed based on similarity criterion and gas true physical parameters. At the same time, the dimensionless relaxation time was modified by considering the influence of the boundary Knudsen layer. On this basis, the second-order slip boundary condition of the wall was considered, and the key parameters in the

By conducting relative permeability experiments of multi-cycle gas-water displacement and imbibition on natural cores, we discuss relative permeability hysteresis effect in underground gas storage during multi-cycle injection and production. A correction method for relative permeability hysteresis in numerical simulation of water-invaded gas storage has been worked out using the Carlson and Killough

A forecasting method of oil well production based on multivariate time series (MTS) and vector autoregressive (VAR) machine learning model for waterflooding reservoir is proposed, and an example application is carried out. This method first uses MTS analysis to optimize injection and production data on the basis of well pattern analysis. The oil production of different production wells and water injection

To get a deeper understanding on the synergistic enhancement effect of low frequency artificial seismic wave on foam stability, a micro-kinetic model of enhanced foam stability under low frequency artificial seismic wave is established based on a vertical liquid film drainage model and elastic wave theory. The model is solved by non-dimensional transformation of the high order partial differential

By reviewing the development history of stimulation techniques for deep/ultra-deep oil and gas reservoirs, the new progress in this field in China and abroad has been summed up, including deeper understanding on formation mechanisms of fracture network in deep/ultra-deep oil and gas reservoir, performance improvement of fracturing fluid materials, fine stratification of ultra-deep vertical wells, and

A coupled CFD-DEM method is used to simulate the formation process of fracture plugging zone. A photo-elastic system characterizing mesoscale force chain network developed by our own is used to model the pressure evolution in fracture plugging zone to reveal the evolution mechanism of the structure of fracture plugging zone. A theoretical basis is provided for improving the lost circulation control