Marine shale gas resources have great potential in the south of the Sichuan Basin in China. At present, the high-quality shale gas resources at depth of 2000–3500 m are under effective development, and strategic breakthroughs have been made in deeper shale gas resources at depth of 3500–4500 m. To promote the effective production of shale gas in this area, this study examines key factors controlling

Compared with marine facies shale strata, lacustrine shale strata are more complicated in geological conditions, and thus more difficult to explore and develop. To realize economic exploration and development of lacustrine shale oil, the geological regularities of accumulation and high yield of retained movable petroleum in shale should be understood first. In this work, taking the shale strata of

A set of shale-dominated source rocks series were deposited during the heyday of lake basin development in the Member 7 of Triassic Yanchang Formation, Ordos Basin, and the thickness is about 110 m. Aimed at whether this layer can form large-scale oil enrichment of industrial value, comprehensive geological research and exploration practice have been carried out for years and obtained the following

The paleotectonic pattern, lithofacies paleogeographic features, sedimentary evolution and its controlling effects on hydrocarbon accumulation assemblages during the depositional period of the Sinian Dengying Formation in middle-upper Yangtze region were investigated based on outcrops, drilling, log and seismic data. The study shows that, (1) Affected by the breakup of the Rodinia supercontinent, the

The diagenesis and diagenetic facies of shale reservoirs in Lucaogou Formation of Jimusar Sag were studied by means of microscopic observation and identification of ordinary thin sections and cast thin sections, X-ray diffraction, scanning electron microscope and electron probe tests. The results show that alkaline and acidic diagenetic processes occurred alternately during the deposition of Permian

High-yielding oil wells were recently found in the first member of Paleogene Shahejie Formation, the Binhai area of Qikou Sag, providing an example of medium- and deep-buried high-quality reservoirs in the central part of a faulted lacustrine basin. By using data of cores, cast thin sections, scanning electron microscope and physical property tests, the sedimentary facies, physical properties and main

Through lithofacies analysis and architecture anatomy of the Carboniferous Ross Sandstone turbidites outcropped at western Ireland, the depositional model of deepwater turbidite lobes is established. Seven types of lithofacies are recognized including goniatites-rich shale, laminated shale, laminated siltstone, massive sandstone, fine-medium sandstone with mud-clast, basal gravel, and chaotic mudstone

Ancient marine carbonates experienced complex modifications, making it difficult to identify reservoir genesis and effective porosity before hydrocarbon migration. To solve these issues, we used element mapping and carbonate mineral laser U-Pb radiometric dating techniques to study the diagenetic environments based on geochemistry and diagenesis-porosity evolution based on geochronology of the dolomite

The concept and characteristics of fluvial fan are elucidated through literature review and case analysis. Firstly, the concept and terminology of fluvial fan are introduced. Secondly, the progress and controversy on the formation mechanism, analysis methods and sedimentary models of fluvial fan are elaborated, and fluvial fan is compared with alluvial fan, river and lacustrine delta. Finally, ten

Carboniferous carbonate reservoirs at the eastern edge of the Pre-Caspian Basin have undergone complex sedimentation, diagenesis and tectonism processes, and developed various reservoir space types of pores, cavities and fractures with complicated combination patterns which create intricate pore-throats structure. The complex pore-throat structure leads to the complex porosity-permeability relationship

Low maturity coal samples were taken from the Ordos Basin to conduct gold tube thermal simulation experiment in a closed system, and the characteristics of the products were analyzed to find out the fractionation mechanism of carbon isotopes and the causes of abnormal carbon isotopic compositions of natural gas. At the heating rates of 2 °C/h (slow) and 20 °C/h (rapid), the low maturity coal samples

Based on well test interpretation, production performance analysis, overburden permeability and porosity test, gas-water core flooding test and high-pressure mercury injection, a quantitative correlation has been built of in-situ effective permeability with routine permeability and water saturation, and the ranges of Main Flow Channel Index (MFCI) are determined for different permeability levels in

Based on the characteristics of injection-production units in fractured-vuggy carbonate reservoirs, nine groups of experiments were designed and performed to analyze the interference characteristics and their influencing factors during water flooding. Based on percolation theory, an inversion model for simulating waterflooding interferences was proposed to study the influence laws of different factors

Based on long-term dynamic tracing of dissolved inorganic carbon (DIC) and stable carbon isotope (δ13CDIC) in produced water from 20 coalbed methane (CBM) wells in western Guizhou, the spatial-temporal dynamic variations of δ13CDIC of the GP well group produced in multi-layer commingled manner were analyzed, and the relationship between the value of δ13CDIC and CBM productivity was examined. The produced

A deep learning method for predicting oil field production at ultra-high water cut stage from the existing oil field production data was presented, and the experimental verification and application effect analysis were carried out. Since the traditional Fully Connected Neural Network (FCNN) is incapable of preserving the correlation of time series data, the Long Short-Term Memory (LSTM) network, which

A large data bank of more than 700 gas-condensate samples collected from literature and experiments was established. On this basis, empirical correlations and equations of state commonly used to calculate dew-point pressure (DPP) were evaluated. A new model for estimating DPP was proposed. All the empirical correlations and the Peng-Robinson state equation were compared, and sensitivity of parameters

This article outlines the development of separated zone oil production in foreign countries, and details its development in China. According to the development process, production needs, technical characteristics and adaptability of oilfields in China, the development of separate zone oil production technology is divided into four stages: flowing well zonal oil production, mechanical recovery and water

The main area of the Jiaoshiba anticline of the Fuling shale gas field was taken as the research object, laboratory rock mechanical experiments and direct shear experiments were conducted to clarify the mechanical anisotropy characteristics and parameters of rock samples with rich beddings. Based on the experimental results, a 3D fracture propagation model of the target reservoir taking mechanical

AM-AMPS-TAC polymers with different charge distribution are synthesized using acrylamide (AM), 2-acrylamido-2-methylpropanesulfonate (AMPS) and 3-acrylamidopropyl trimethylammonium (TAC) at different feed ratios by polymerization in solution. The salt-responsive behavior, reasons leading to salt-responsiveness, and effects of polymers molecular structure on salt-responsiveness are studied by laboratory

Based on detailed core description and systematic joint test data, enrichment laws of continental shale oil have been examined deeply. Key technologies such as the identification and quantitative evaluation method for sweet spot, precise design and tracking of horizontal well trajectory, and the low-cost horizontal well volume fracturing technology of the whole process “slick water + quartz sand” for

Pure shales in the first member of Qingshankou Formation (simplified as Qing 1 Member) in the southern Songliao Basin, i.e., the semi-deep and deep lacustrine shales, are characterized by a high content of clay minerals and poor hydrocarbon mobility, making the development of shale oil difficult. According to the drilling and testing results, the shale of Qing 1 Member can be classified into 3 lithofacies

Based on the latest geological, seismic, drilling and outcrop data, we studied the geological structure, tectonic evolution history and deformation process of the southwestern Sichuan fold-thrust belt to find out the potential hydrocarbon exploration areas in deep layers. During key tectonic periods, the southwestern Sichuan fold-thrust belt developed some characteristic strata and structural deformation

Large-scale gas accumulation areas in large oil-gas basins in central and Western China have multiple special accumulation mechanisms and different accumulation effects. Based on the geological theory and method of natural gas reservoir formation, this study examined the regional geological and structural background, formation burial evolution, basic characteristics of gas reservoirs, and fluid geology

The origin of overpressure and its effect on petroleum accumulation in the large Permian/Triassic conglomerate oil province in the Mahu Sag, Junggar Basin have been investigated based on comprehensive analysis of log curve combinations, loading-unloading curves, sonic velocity-density cross-plot, and porosity comparison data. The study results show that there are two kinds of normal compaction models

Based on analysis of NMR T2 spectral characteristics, a new method for identifying fluid properties by decomposing T2 spectrum through signal analysis has been proposed. Because T2 spectrum satisfies lognormal distribution on transverse relaxation time axis, the T2 spectrum can be decomposed into 2 to 5 independent component spectra by fitting the T2 spectrum with Gauss functions. By analyzing the

Through field geologic survey, fine interpretation of seismic reflection data and analysis of well drilling data, the differential deformation, tectonic transfer and controlling factors of the differential deformation of the Gumubiezi Fault (GF) from east to west have been studied systematically. The study shows that GF started to move southward as a compressive decollement along the Miocene gypsum-bearing

Based on comprehensive analysis of core, cast thin section, logging and seismic data, the sedimentary and reservoir architectures of the MB1-2 sub-member of Mishrif Formation in Halfaya Oilfield, Iraq, are studied. The MB1-2 sub-member of Mishrif Formation has three types of microfacies, lagoon, bioclastic shoal, and tidal channel, and facies architecture controlled by sequence stratigraphy. In the

The influence of water on gas generation from humic type organic matter at highly to over mature stage was investigated with thermal simulation experiments at high temperature and pressure. The result of the experiments indicates that the effect of water on gas generation was controlled by the thermal maturity of organic matter. Water could enhance gas generation and increase hydrocarbon gas yields

Layering detection is an important step in petroleum engineering. Time series of post-stack seismic data and wire-line log data belong to subsurface layering. They exhibit multifractal properties with complex patterns because of the heterogeneity and different genetic properties in the earth layers. In a multifractal configuration, any piece of a series has a distinct Hurst exponent that reflects its

The Duvernay project in Canada was taken as an example to summarize the advanced technology and engineering management model of shale oil and gas development in North America. Preliminary suggestions were put forward to accelerate the commercial development of domestic continental shale oil and gas. The advanced technologies, valuable knowledge and rich experience were introduced, including the evaluation

By using salt dissolution experiment, imbibition experiment and high temperature and high pressure nuclear magnetic resonance (NMR) on-line test, the evaluation methods for salt dissolution of inter salt shale oil-bearing cores were established, and the effects of salt dissolution on spontaneous imbibition and permeability were analyzed. The intensity of salt dissolution is quantitatively evaluated

Tight oil reservoir development is faced with the key technical problem that “water cannot be injected and oil cannot be produced” yet. With the diphenyl ethers water-soluble (gemini) surfactants as water phase shell and C10–C14 straight-chain hydrocarbon compounds as oil phase kernel, a nanofluids permeation flooding system was prepared by microemulsion technology, and its characteristics and EOR

In view of high oil viscosity at high temperatures, slow steam chamber expansion rate, low oil rate, and low oil/steam ratio of domestic super heavy oil blocks developed with dual-horizontal well steam assisted gravity drainage (SAGD), the solvent-aided oil viscosity reduction tests were carried out, based on which the analytical equations and similarity laws of solvent-expanded SAGD (ES-SAGD) were

It is difficult to build an effective water flooding displacement pressure system in the middle section of a horizontal well in an ultra-low permeability sandstone reservoir. To solve this problem, this study proposes to use packers, sealing cannula and other tools in the same horizontal well to inject water in some fractures and produce oil from other fractures. This new energy supplement method forms

The effects of gravity, capillary force, and viscous force on the migration characteristics of oil and gas interface in oxygen-reduced air-assisted gravity drainage (OAGD) were studied through a two-dimensional visualization model. The effects of bond number, capillary number and low-temperature oxidation on OAGD recovery were studied by long core displacement experiments. On this basis, the low-temperature

The feasibility of gas kick early detection outside the riser was analyzed based on gas-liquid multiphase flow theory. Then an experimental platform for gas kick early detection based on Doppler ultrasonic wave was established and the propagation experiments in two-phase flow of gas-water (sucrose solutions) were conducted. The time and frequency domains of the Doppler ultrasonic wave signals during

Most multiphase flow separation detection methods used commonly in oilfields are low in efficiency and accuracy, and have data delay. An online multiphase flow detection method is proposed based on magnetic resonance technology, and its supporting device has been made and tested in lab and field. The detection technology works in two parts: measure phase holdup in static state and measure flow rate

Considering the complicated interactions between temperature, pressure and hydration reaction of cement, a coupled model of temperature and pressure based on hydration kinetics during deep-water well cementing was established. The differential method was used to do the coupled numerical calculation, and the calculation results were compared with experimental and field data to verify the accuracy of

Continental shale oil is a general term for liquid hydrocarbons and many kinds of organic matter in continental organic-rich shale series with vitrinite reflectance of more than 0.5% at buried depth of more than 300 m, and is an important type of source-rock oil and gas. Based on the evolution model of oil generation and expulsion in organic-rich shale series controlled by maturity, continental shale

Based on thin-section, argon-ion polished large-area imaging and nano-CT scanning data, the reservoir characteristics and genetic mechanisms of the Lower Silurian Longmaxi shale layers with different laminae and laminae combinations in the Sichuan Basin were examined. It is found that the shale has two kinds of laminae, clayey lamina and silty lamina, which are different in single lamina thickness

Abstract The shales in the 2nd Member of Shanxi Formation in the east margin of the Ordos Basin were deposited in a marine-nonmarine transitional environment during the Permian. Based on the recent breakthroughs in the shale gas exploration and theoretical understandings on the shale gas of the study area, with a comparison to marine shale gas in the Sichuan Basin and marine-nonmarine transitional

Abstract The Huizhou Movement refers to the Middle Eocene tectonic transition from the early to the late Wenchang Rifting stage (about 43 Ma ago) in the Pearl River Mouth Basin. Based on seismic reflection, drilling, logging and geological data, fault characteristic analysis, denudation thickness recovery, magmatism statistics, regional tectonic dynamics comparison and other methods are used to reveal

Abstract By using thin section identification, cathodoluminescence, major and trace elements and fluid inclusion tests and authigenic illite dating, based on observation of core cracks, combined with the microscopic characteristics and imaging logging characteristics of fractures, the stages of the fractures in the Huagang Formation of the central reversal tectonic belt of the Xihu Sag in the East

Abstract Taking the Cambrian Yuertus Formation outcrop profiles in the Aksu-Keping-Wushi areas of northwestern Tarim Basin as examples, the depositional environments of organic rich fine sediment were analyzed by examining the outcrop profiles macroscopically and microscopically. The study reveals that: (1) The lower part of the Yuertus Formation consists of organic-rich fine sediment or thin rhythmic

Abstract The pore structure characteristic parameters of vuggy carbonate reservoirs were extracted, and matrix resistivity of vuggy reservoir was calculated by the percolation network simulation. A segmented cross-scale resistivity calculation method was established, in which the finite element method was used to simulate the resistivity of vuggy reservoirs. The mathematical models of vug porosity

Abstract Take the Cambrian Xiaoerblak Formation in the Keping (Kalpin) outcrop area as an example, a 28 km reservoir scale geological model was built based on description of 7 profiles, observation of more than 1000 thin sections, petrophysical analysis of 556 samples and many geochemical tests. The Xiaoerblak Formation, 158–178 m thick, is divided into three members and 5 submembers, and is composed

Abstract Well Zhongqiu 1 obtained highly productive oil-gas stream in the footwall of Zhongqiu structure, marking the strategic breakthrough of Qiulitag structural belt in the Tarim Basin. However, the oil and gas sources in Zhongqiu structural belt and the reservoir formation process in Zhongqiu 1 trap remain unclear, so study on these issues may provide important basis for the next step of oil and

Abstract Taking the inter-salt organic-rich shales in the third member of Paleogene Shahejie Formation (Es3) of Dongpu sag in Bohai Bay Basin as an example, the origin of overpressure, development characteristics, formation and evolution mechanism, formation stages and geological significance on shale oil and gas of overpressure fractures in the inter-salt shale reservoir were investigated by means

Abstract Take the lacustrine delta in the second member of Paleogene Shahejie Formation in block Wang43, Dongying depression, Bohai Bay Basin as an example, the deposition architectural characteristics of lacustrine deltaic sand bodies controlled by syn-depositional faults in complex fault blocks of rift basin are examined from the aspect of the tectonic-deposition response, using cores, well logs

Abstract The origins and logging responses of flushed zones in some blocks of Orinoco heavy oil belt, Venezuela are still unclear. To solve this issue, we examined the conventional logging, nuclear magnetic resonance logging, fluid viscosity, core analysis and oil field production data comprehensively to find out the logging responses and origins of the flushed zones. The results show that the main

Abstract Weiyuan shale gas play is characterized by thin high-quality reservoir thickness, big horizontal stress difference, and big productivity differences between wells. Based on integrated evaluation of shale gas reservoir geology and well logging interpretation of more than 20 appraisal wells, a correlation was built between the single well test production rate and the high-quality reservoir length

Abstract The real pores in digital cores were simplified into three abstractive types, including prolate ellipsoids, oblate ellipsoids and spheroids. The three-dimensional spheroidal-pore model of digital core was established based on mesoscopic mechanical theory. The constitutive relationship of different types of pore microstructure deformation was studied with Eshelby equivalent medium theory, and

Abstract To accurately measure and evaluate the oil-water production profile of horizontal wells, a dynamic measurement experiment of oil-water two-phase flow in horizontal wells and numerical simulation were combined to establish a method for measuring the partial phase flow rate of oil-water two-phase stratified flow in horizontal wells. An experimental work was performed in horizontal oil-water

Abstract An automatic well test interpretation method for radial composite reservoirs based on convolutional neural network (CNN) is proposed, and its effectiveness and accuracy are verified by actual field data. In this paper, based on the data transformed by logarithm function and the loss function of mean square error (MSE), the optimal CNN is obtained by reducing the loss function to optimize the

Abstract To deal with the stress interference caused by simultaneous propagation of multiple fractures and the wettability reversal and physical property changes of the reservoir caused by fracturing fluid getting in during large-volume fracturing of tight oil reservoirs through a horizontal well, a non-planar 3D fracture growth model was built, wettability reversal characterizing parameters and change

Abstract As the classical transient flow model cannot simulate the water hammer effect of gas well, a transient flow mathematical model of multiphase flow gas well is established based on the mechanism of water hammer effect and the theory of multiphase flow. With this model, the transient flow of gas well can be simulated by segmenting the curved part of tubing and calculating numerical solution with

Abstract As the ultra-heavy oil reservoirs developed by steam assisted gravity drainage (SAGD) in the Fengcheng oilfield, Xinjiang have problems such as huge steam usage, long preheating period, low production, and inaccessible reserve in local parts. Based on the rock mechanics and porosity/permeability characteristics of heavy oil reservoir and interlayer, a series of true triaxial experiments and

Abstract Based on the exploration and development practice of marine shale gas in Fuling, Weiyuan, Changning, Luzhou and Southeast Chongqing in southern China, combined with experiments and analysis, six factors controlling differential enrichment of marine shale gas are summarized as follows: (1) The more appropriate thermal evolution and the higher the abundance of organic matter, the higher the

Abstract Based on the traditional numerical simulation and optimization algorithms, in combination with the layered injection and production “hard data” monitored at real time by automatic control technology, a systematic approach for detailed water injection design using data-driven algorithms is proposed. First the data assimilation technology is used to match geological model parameters under the

Based on three-dimensional seismic interpretation, structural and sedimentary feature analysis, and examination of fluid properties and production dynamics, the regularity and main controlling factors of hydrocarbon accumulation in the Tazhong uplift, Tarim Basin are investigated. The results show that the oil and gas in the Tazhong uplift has the characteristics of complex accumulation mainly controlled