Unconventional Resources最新文献

Carbonate geothermal reservoirs are widespread in the Beijing-Tianjin-Hebei region, and acidification stands out as the most effective method to enhance the heat recovery potential of these reservoirs. To understand the propagation patterns of acidized wormholes in geothermal reservoirs, a pore-Darcy scale mathematical model of acidizing reactions in geothermal reservoirs has been established. A normal random distribution function is introduced to depict the reservoir's heterogeneity. Using the finite element method, the study simulated the impact of injection rate, acid concentration, diffusion coefficient, and acid-rock reaction rate on wormhole morphology. The findings indicate that the reaction is uniform in the early stage of acidification, becoming non-uniform in the late stage, ultimately forming distinctive wormhole structures. The acidification radius is more extensive along a particular direction post-acidification. Increasing the acid injection rate, acid concentration, and initial specific surface area proves beneficial in enhancing the acidizing effect. The outcomes of this study hold theoretical and technical significance for optimizing the thermal recovery efficiency of geothermal reservoirs.

Tight sandstone gas represents a crucial domain for augmenting reserves and boosting oil and gas production in the Ordos Basin. Currently, the primary focus for development lies in the Upper Paleozoic tight sandstone gas located in the southwestern Ordos basin. The gas reservoirs in this area present distinct characteristics, including significant burial depth exceeding 4000 m, modest-scale sand bodies, an average thin reservoir thickness of 5.8 m, and rapid lateral variations in sand body distribution. These factors contribute to challenges in establishing a clear correlation between reservoir scale and seismic reflection patterns, leading to uncertainties in reservoir prediction. In this study, three types of seismic reflection characteristics of the bottom interface associated with the development of the S₁³ reservoir in Block X have been summarized by using Forward modeling: (1) strong reflection of peaks on seismic sections; (2) weak reflection of troughs on seismic sections; and (3) strong reflection of complex waves with the bottom of the Shanxi Formation. The main factors that cause the above seismic reflection characteristics include the thickness of the lower coal seam, the spatial distribution and thickness of the reservoir. The above analysis breaks the inherent understanding that traditional strong seismic reflections are indicative of reservoir development, and instead, based on the three types of seismic reflection waveforms, waveform clustering is used to realize the differentiation of zones in the study area. Furthermore, combining with the facies-controlled high-resolution inversion, we achieved high-precision identification of tight sandstone reservoirs in Block X. This approach can be applied to similar reservoirs both at China and abroad.

This study presents a detailed investigation into the microfacies, geochemistry, and depositional environments of carbonate rocks from the southern Benue Trough and eastern Dahomey Basin. This analysis involved a combination of techniques, including X-ray diffraction, X-ray fluorescence, scanning electron microscopy with energy-dispersive X-ray spectroscopy and thin-section petrographic examination. Samples from the Igumale Formation of the southern Benue Trough and samples from Ewekoro Formation of the eastern Dahomey Basin were analyzed, offering insights into their mineral compositions, elemental distributions, and depositional environments. In each basin, two carbonate microfacies were identified. The two microfacies found in the Igumale Formation were recognized as micritic bioclastic packstone and sandy bioclastic wackestone. In the Ewekoro Formation, the two microfacies recognized were bioclastic packstone and sparitic peloidal wackestone. The X-ray diffraction analysis of samples from both basins revealed a dominance of calcite. X-ray fluorescence analysis showcased calcium oxide and calcium as the predominant oxide and elements in both basins with varying concentrations. Scanning electron microscopy-energy-dispersive X-ray spectroscopy results unveiled the elemental composition with calcium and silicon emerging as major constituents. The photomicrographs suggest distinct depositional conditions for both samples with those from the Igumale Formation showing evidence of shallow marine and that of the Ewekoro Formation suggesting calm marine environments comprised of fined grained carbonate rocks containing fossils. This study has provided detailed understanding on the nature, microfacies types, mineralogical composition, depositional environment and diagenetic processes of Cretaceous-Paleocene carbonate rocks within the studied basins.

The search for cleaner and renewable energy sources coupled with the need for environmental protection has necessitated the conversion of municipal solid wastes to energy sources. In this study, the pyrolysis of waste tyres in a fixed-bed reactor was carried out in a bid to generate non-condensable gases. The influence of process variables such as sample weight, reaction temperature, and reaction time were modelled and optimized using the central composite design of the response surface methodology. Based on the central composite design of the response surface methodology, the R², adjusted R² and predicted R² values of 0.968, 0.941 and 0.750 respectively, indicated that the model properly fitted the experimental data. This implied the accuracy of the model prediction. The maximum predicted gas yield of 10.212 wt% was estimated under optimal conditions with desirability of 0.697, a dimensionless value indicating the closeness of the combination of input variables to the desired values for the response variables. The gases obtained upon pyrolysis of waste tyres can serve as a source of hydrocarbon gases in the petroleum and petrochemical industry.

Recently, the shale gas exploration of Lower Cambrian Qiongzhusi Formation in Sichuan Basin has made a great breakthrough. However, the pore characteristics and controlling factors of the shale-gas reservoir in the Qiongzhusi Formation are not clear, which hinders further exploration and development of shale gas. This paper focuses on the Qiongzhusi Formation in the Lower Cambrian of the Sichuan Basin. On the basis of mineral composition and the lithofacies types of shale-gas reservoirs in Qiongzhusi Formation were classified by microscopic observation. Additionally, focused ion beam-scanning electron microscope (FIB-SEM), advanced mineral identification and characterization system (AMICS) analysis, large-field stitching scanning electron microscope technology (MAPS) and nitrogen adsorption experiment were employed to comprehensively determine the differential characteristics and controlling factors of pore development. The results indicate that the pore types in Qiongzhusi Formation are mainly composed of interparticle pores and intercrystalline pores. The pore structure of Qiongzhusi Formation is complex. Significant differences in pore structure parameters are observed among different lithofacies. Quartz and feldspar contribute to the preservation of primary pores due to their strong compressive resistance. Clay minerals and carbonate minerals impede pore development by occluding pores. The influence of organic matter on the pore development is relatively small. According to the mineral composition and pore parameters, laminated shale is a relatively favorable reservoir facies among different lithofacies types.

To elucidate the spatial architecture of sand bodies within the Member Chang 6 in the Fuxian area of the Ordos Basin, a comprehensive analysis was conducted leveraging core samples, logging data, mud logging, and other pertinent information. This analysis was guided by both sedimentology theory and the theory of architecture element analysis. Additionally, a detailed investigation of outcrop features was carried out to augment the understanding. The sedimentary characteristics and sand bodies architecture of the Member Chang 6 were meticulously examined at the outcrop locations of Yanhe in Yanchang County, and the Fuxian area. Through this comprehensive examination, a well-defined sand body architecture model was successfully established. The study reveals the presence of nine distinct lithofacies types within the Member Chang 6 of the Fuxian area. Additionally, four primary architecture elements have been identified, namely underwater distributary channels, interdistributary bays, estuary bar, and distant sand bars. The vertical stacking pattern of delta front sand bodies within the meandering river system of the Member Chang 6 can be classified into connected and disconnected types. In terms of lateral arrangement, the superposition pattern is further categorized into butted and cut-stacked types. The sedimentary period of Member Chang 6 in Fuxian area is mainly meandering river delta front. The prevailing water energy is characterized by its subdued nature, resulting in limited sand-carrying capacity. This dynamic leads to the development of a meandering river delta sedimentary model characterized by a gentle near-source slope. The outcomes of this research will serve as a valuable reference for in-depth investigations into the internal architecture of the Chang 6 reservoir and the detailed characterization of oil and gas reservoirs within the Fuxian area.

Effectively utilizing renewable energy sources while avoiding power consumption restrictions is the problem of demand-side energy management. The goal is to develop an intelligent system that can precisely estimate energy availability and plan ahead for the next day in order to overcome this obstacle. The Intelligent Smart Energy Management System (ISEMS) described in this work is designed to control energy usage in a smart grid environment where a significant quantity of renewable energy is being introduced. The proposed system evaluates various predictive models to achieve accurate energy forecasting with hourly and day-ahead planning. When compared to other predictive models, the Support Vector Machine (SVM) regression model based on Particle Swarm Optimization (PSO) seems to have better performance accuracy. Then, using the anticipated requirements, the experimental setup for ISEMS is shown, and its performance is evaluated in various configurations while considering features that are prioritized and associated with user comfort. Furthermore, Internet of Things (IoT) integration is put into practice for monitoring at the user end.

For several decades the UK North Sea has been a prolific oil and gas province, with numerous conventional oil and gas discoveries sourced predominantly by the Upper Jurassic to Lower Cretaceous Kimmeridge Clay Formation (KCF). In this study, we have combined the analysis of total organic carbon/pyrolysis and vitrinite reflectance geochemical data from KCF samples with 1D basin modelling to investigate the potential for shale oil and gas plays in the Outer Moray Firth region. The results of geochemical evaluation show that most of the samples have very good to excellent hydrocarbon generation potential and contain predominantly oil-prone Type-II kerogen. A few samples show a significant oil saturation index above 100 mgHC/gTOC, which indicate a good potential for producible shale oil. The modelling results suggest that vitrinite reflectance values for the KCF vary mainly between 0.51 and 1.15%R_o, with kerogen transformation of up to 86 %. This is indicative of early-oil to late-oil/early-gas maturity window at present day, and within the range reported for proven shale oil plays. The KCF shows good oil saturation in most of the modelled well locations of up to 6.4 mg/g rock, indicating potentially producible shale oil. Predictions from modelling support the interpretations from geochemical data.

The aim of this study is to conduct and examine the results of a Magnetotelluric (MT) survey in Unai, Gujarat, India for geothermal prospect identification. At Unai, the data was acquired, processed, and interpreted in the form of 2D and 3D MT surveys. Data were acquired at 56 stations in uniformly spaced profiles along the ENE-WSE direction (geological strike direction) with a station spacing of 2 km. Qualitative and quantitative data understanding has been done for geothermal prospect identification. Deep and shallow 1D and 2D models of electrical resistivity were made, which suggests the presence of a geothermal aquifer. This is corroborated by polar and skew tipper diagrams. The one-dimensional Occam models and two-dimensional conjugate gradient models confirm the presence of a low resistivity anomaly near the surface ranging from the depth of 100–700 m. This suggests the presence of a shallow geothermal zone. Apart from the shallow geothermal prospect, this study also delineates a deep conductive body which may be attributed to a matured geothermal reservoir. For a better understanding of the prospect geoelectrical cross sections are analysed from a depth of 10 m to 15 km. The MT cross-sections show the presence of geological features such as a series of faults. These faults form horst and graben in nature and may act as a good trap for the shallow reservoirs.

The Carboniferous Kalashayi Formation, situated in the Lungu-Sangtamu area within the Tarim Basin, exhibits protracted sedimentation periods, intricate sand-mud depositional sequences, and scant paleontological and core datasets. Precision in delineating high-resolution sequences using conventional core and logging data poses a considerable challenge. To enhance the stratigraphic accuracy of the Kalashayi Formation in the Tarim Basin and facilitate quantitative analysis, this study employs continuous wavelet transform on the gamma ray (GR) curves obtained from core wells within the study area. Subsequently, various sequence boundaries are discerned by integrating the resulting wavelet coefficient curves with time-frequency energy maps. Discrimination and subdivision of base-level cycle structures of varying orders are achieved through temporal trend analyses of integrated prediction error filter analysis (INPEFA) curves. Integration of drilling, logging, lithofacies, and core data enables the identification and subdivision of high-resolution sequence stratigraphy using wavelet analysis and INPEFA techniques. Ultimately, the Carboniferous Kalashayi Formation in the Lungu-Sangtamu region is classified into 2 long-term, 5 medium-term, and 14 short-term base-level cycles, establishing a meticulously delineated isochronous stratigraphic framework. This framework serves as a fundamental basis for subsequent discussions on reservoir prediction within the study area.