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For exploring the regional distribution of continental reservoirs characterized by deep burial depth, intense compaction, high diagenesis, and tight reservoir pore space, the seismic sedimentology was analyzed in the Lower Jurassic strata in the hinterland of the Junggar Basin utilizing the sequence stratigraphy and the instantaneous phase, root mean square amplitude and frequency decomposition attributes extracted from flattened seismic data volume. Three sequences are identified, including SQ1, SQ2 and SQ3. From SQ1 to the transgressive systems tract of SQ2, sequences are dominated by fluvial sedimentary, while the highstand systems tract of SQ2 to SQ3 were dominated by deltaic sedimentary. The seismic attribute analysis exhibits consistent results which channels are recognizable and reliable. They are single-channel configurations to oxbow lakes, crevasse splay, and other fluvial microfacies during their migration and evolution. Rivers evolves from low curvature and wide riverbeds to high curvature and narrow riverbeds, before settling into medium-curvature and wide riverbeds. Additionally, there is a gradual shift in flow direction from south-north to northeast-southwest. The results can provide reference and guidance for utilizing seismic data to identify meandering rivers. [ABSTRACT FROM AUTHOR]

The main tool for increasing of oil reserves are exploration works. Improving the scientific and technical support for exploration is a priority task for the oil industry. The article deals with the development of technology for prospecting and exploration of hydrocarbon deposits in the Pre-Jurassic basement rocks of Western Siberian oil and gas province, as well as approaches to improving the reliability of mapping prospective zones using seismic data. Using the example of the Sredne-Nazymskoye field, the seismogeological aspects of the forecast of oil and gas potential of the Pre-Jurassic complex and the main directions for reducing the uncertainties of the geological structure are shown.

Seismic attribute analysis, a method of highlighting important information in seismic data, has been used in various fields. Recently, several studies have used seismic attributes to interpret seismic anomalies associated with subsurface gas. In this study, we applied seismic attribute analysis to seismic data acquired in Yeongil Bay to identify the subsurface gas distribution. Before applying seismic attributes to the Yeongil Bay seismic data, we selected promising seismic attributes and applied them to F3 Block seismic data to analyze the relation between the seismic attributes and seismic anomalies caused by subsurface gas. Since there are previous studies on the subsurface gas in the F3 Block, we could identify the characteristics of the seismic attributes based on the F3 Block seismic data. Then, we applied the selected seismic attributes to the Yeongil Bay seismic data to define the subsurface gas distribution. Through seismic attribute analysis, a three-dimensional gas distribution model of Yeongil Bay was generated, and this model can provide quantitative information on the subsurface geology of Yeongil Bay. [ABSTRACT FROM AUTHOR]

Copyright of Petroleum Geology & Oilfield Development in Daqing is the property of Editorial Department of Petroleum Geology & Oilfield Development in Daqing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Bozhong Sag is the largest petroliferous sag in the Bohai Bay Basin, and the source rocks of Paleogene Dongying and Shahejie Formations were buried deeply. Most of the drillings were located at the structural high, and there were few wells that met good quality source rocks, so it is difficult to evaluate the source rocks in the study area precisely by geochemical analysis only. Based on the Rock-Eval pyrolysis, total organic carbon (TOC) testing, the organic matter (OM) abundance of Paleogene source rocks in the southwestern Bozhong Sag were evaluated, including the lower of second member of Dongying Formation (E3d2L), the third member of Dongying Formation (E3d3), the first and second members of Shahejie Formation (E2s1þ2), the third member of Shahejie Formation (E2s3). The results indicate that the E2s1+2 and E2s3 have better hydrocarbon generative potentials with the highest OM abundance, the E3d3 are of the second good quality, and the E3d2 L have poor to fair hydrocarbon generative potential. Furthermore, the well logs were applied to predict TOC and residual hydrocarbon generation potential (S2) based on the sedimentary facies classification, using ΔlogR, generalized DlogR, logging multiple linear regression and BP neural network methods. The various methods were compared, and the BP neural network method have relatively better prediction accuracy. Based on the pre-stack simultaneous inversion (P-wave impedance, P-wave velocity and density inversion results) and the post-stack seismic attributes, the three-dimensional (3D) seismic prediction of TOC and S2 was carried out. The results show that the seismic near well prediction results of TOC and S2 based on seismic multi-attributes analysis correspond well with the results of well logging methods, and the plane prediction results are identical with the sedimentary facies map in the study area. The TOC and S2 values of E2s1+2 and E2s3 are higher than those in E3d3 and E3d2L, basically consistent with the geochemical analysis results. This method makes up the deficiency of geochemical methods, establishing the connection between geophysical information and geochemical data, and it is helpful to the 3D quantitative prediction and the evaluation of high-quality source rocks in the areas where the drillings are limited. [ABSTRACT FROM AUTHOR]

The reservoirs of ultra-deep and low-permeability sandstones typically exhibit characteristics of lithological tightness and poor physical properties. Fractures control the oil and gas content as well as the productivity of such reservoirs. However, the distribution of fractures is complex, exhibiting strong heterogeneity. Therefore, a systematic study on reservoir fracture modeling can provide geological foundations for the development of such reservoirs. Due to the considerable burial depth of these reservoirs, conventional methods relying solely on seismic information have limited reliability, and the established discrete network models of fractures are often less dependable. In this paper, taking the X gas reservoir in a basin in western China as an example, we discuss a fracture modeling method based on the integration of geological information to enhance the efficiency and accuracy of fracture modeling. The modeling method primarily involves the use of deterministic methods to obtain large-scale fractures, while random simulation is employed for small and medium-scale fractures. The fracture development control factors and seismic attribute information are integrated using permanence of ratios (PR) model to establish a fracture development probability field model. Subsequently, the geometric parameters of fractures and the fracture density model are used as input parameters to generate a discrete network model of small and medium-scale fractures using a object-based modeling method. Finally, based on the fracture equivalent property model and verified through geological understanding, analysis of production dynamics, and numerical simulation of the gas reservoir, it is demonstrated that the fracture model established using the proposed method aligns with geological understanding and exhibits high reliability. [ABSTRACT FROM AUTHOR]

The Triassic in Halahatang Hade area of the Tarim Basin, as one of the favorable horizons for oil and gas enrichment, has only been studied at the basin level. However, the understanding of the regional zone is unclear, the sedimentary evolution within the sequence is unclear, and the exploration guidance for the block is not targeted, so the regionalization research is urgently needed. Based on the high-resolution 3D seismic data, core and logging data covering the whole area, the Seismic attribute structure was analyzed by using seismic Sedimentology research methods, and the sedimentary facies types and Phase plane distribution range of the Karamay Formation in Halahatang Hade area with an area of 18 000 km 2 were identified, so as to more accurately describe the sedimentary facies evolution characteristics. To provide a basis for predicting the distribution of lithological oil and gas reservoirs in combination with regional tectonic background and fault distribution in the future. The analysis shows that the Triassic Karamay Formation in Halahatang Hade area of the Tarim Basin is a lake delta sedimentary system, with obvious differences between the upper and lower members. The sand body in the lower section gradually decreases from northeast to southwest, reflecting a decrease in the influence of river channels. The delta plain subfacies are developed at the slope of the Yaha ancient uplift, and the delta front subfacies and lake facies are successively developed towards southwest. The lake basin in the upper section of the Karamay Formation contracted, and the delta plain subfacies were widely developed, which transited to the delta front subfacies and lake facies from southwest to west. Among them, Incised valleys sedimentary system is developed in delta plain subfacies. [ABSTRACT FROM AUTHOR]

AbstractIn this paper, a method is proposed for the prediction of thermal maturity in the source rock using indirect methods. The applied data are well logs (neutron, density, resistance, and acoustic) in 13 wells and seismic data in six oil and gas fields in the central part of the Persian Gulf. Well-logs and seismic data are much more abundant than geochemical data and cover an extensive area in the oil and gas fields. These properties compensate for the lack of geochemical data that are scattered and limited to a few wells. This study is carried out in two steps. First, the amount of thermal maturity in the Kazhdumi Formation is calculated from well logs and is presented as an index in each well. Data obtained from organic thermal evaluation analyses are used to validate the results of thermal maturity prediction. These data include Rock-Eval pyrolysis in two wells. Then, seismic data are processed and studied in two-dimensional sections at the location of the target fields. In this step, seismic attributes are extracted from the seismic data using the multi-attribute regression analysis method, and thermal maturity is calculated using these attributes. Prediction is performed by probabilistic neural network analysis, and a seismic section is extracted indicating variations in thermal maturity in the Kazhdumi Formation.Keywords: Source rock, Thermal maturity, Well log, Seismic attribute Introduction The Kazhdumi Formation is an important source rock in the Persian Gulf basin, in the south of Iran (Bordenave Burwood, 1990). Thermal maturity of the Kazhdumi Formation is low in the central Persian Gulf compared to the eastern and western sectors (Rabbani 2008; Ghasemi-Nejad et al. 2009; Rezaie Kavanrudi et al. 2015; Rabbani et al. 2014; Baniasad et al. 2019). This formation is over-mature in proximity to the Hormoz Strait. The TOC content of this formation depends on the variety of depositional environments across the basin, increasing to the northwest with a maximum of 6 wt% in the proximity of the Hormoz strait (Rezaie Kavanrudi et al. 2015; Noori et al. 2016). The kerogen type is mainly ⅡS and type Ⅲ in different areas (Ghasemi-Nejad et al. 2009). The stratigraphic equivalents of the Kazhdumi Formation are the Burgan Formation in the west and south of the Persian Gulf (Kuwait), producing hydrocarbons from the second-largest hydrocarbon oilfield in the world, and the Nahr-Umr Formation in Qatar and Iraq. The Burgan and Nahr-Umr formations consist of fluvial sandstone in the south and east of the Persian Gulf compared to the shale-dominated volume in the north and central part (Ghasemi-Nejad et al. 2009; Noori et al. 2016).The source rock potential of this formation is largely unknown and there is a lack of published reports in the central part of the Persian Gulf. the aim of this study is to use log and seismic data for indirect estimation of thermal maturity in this area. Materials & MethodsIn this study, neutron, density and sonic as well as gamma-ray logs are used to predict thermal maturity. The maturity index (MI) by Zhao et al. (2007) was used to describe the level of thermal maturity based on well logs. The response of the neutron and density logs is affected by the fraction of water in a formation. The hydrocarbon density also decreases due to thermal maturation. The maturity index is calculated based on the equation from Zhao et al. (2007)(Eq. 1) N: the number of log readings or the number of samples.Øn9i: neutron porosity of rock samples with 9% density porosity or higher. The 9% is a cut-off for porosity in the calculations. Values lower than 9% are indicative of very dense formations such as anhydrite or dense dolomite known as non-source shales. The cumulative value of the calculated MI is presented as a maturity index in the Kazhdumi Formation in each well. In the second step, seismic data analysis, inversion of seismic data and log prediction are carried out. Inversion analysis starts with seismic data processing using well logs and 2D post-stack seismic data. An acoustic impedance log is created by the combination of density and sonic logs. Check-shot data are used for depth-to-time conversion resulting to the correlation of well and seismic data. Following this, an initial strata or impedance model is constructed. This model is produced using the seismic volume, available well data and defined horizons. Seismic data, the initial strata model as well as available wells are applied as the input data for inversion analysis, and then the inversion method is selected. Discussion of Results & ConclusionsGenerally, thermal maturity status in the Kazhdumi Formation is between immature to mature in the study area in the central part of the Persian Gulf. According to the presented data in this study, this formation is mainly immature in 2, 3, 5 and 7 fields. Field number 4 is early mature and number 1 is mature. Field 6 shows an immature to mature level indicating that the maturity varies in this field.In the next step, seismic attributes are selected by regression analysis for MI prediction. Attributes selection is a process for the extraction of seismic attributes from the raw seismic data for modeling the target log. Multi-attribute analysis is an automatic procedure for the selection of the most relevant seismic attributes to the target log.Finally, extracted attributes are used for the log prediction by Probabilistic Neural Network analysis (PNN). It is trained based on the selected attributes in the previous step and then predicts the target parameters.Acoustic impedance is recognized as the most important seismic attribute reflecting the geological properties (Chopra and Marfurt, 2005). The optimum number of attributes for MI prediction is four which shows the lowest prediction error, although the training error continuously decreases by adding more attributes. The validation plot of the target log is estimated by excluding the data step by step from the calculation. The reliability of the regression model is tested by comparing the prediction with the actual log values.Thereafter, the 2D seismic section is converted to an MI volume. The variation in MI is continuous laterally and vertically, therefore, can be tracked throughout the basin.A comparison of the computed MI with geochemical data indicated that this method is applicable for thermal maturity prediction in the study area. The increase in MI corresponds to an increase in the Tmax values, thus providing a good indicator of thermal maturity variation.The last point to consider is the significance of the selected seismic attributes and their relationship with the target parameter. Results indicated that acoustic impedance is the most important seismic attribute in MI prediction. Acoustic impedance contains information about the velocity and formation density which are both affected by the formation fluids (Broadhead et al. 2016; Atarita et al. 2017). It is inversely related to the organic matter content (Harris et al. 2019). The computed thermal maturity is inversely related to the neutron porosity and water saturation which are both controlling parameters of the acoustic impedance in a formation.Other attributes that have been used in the log prediction are time and amplitude-weighted frequency. These attributes are related to different geological properties of source/reservoir formations (Taner et al. 1994; Chen and Sidney 1997; Chopra and Marfurt 2005). Amplitude envelope (reflection strength) mainly represents acoustic impedance and is useful for identifying porosity, hydrocarbon and gas accumulation, sequence boundaries, and lithological/depositional environment variations (Chen and Sidney 1997; Hart 2002). Average frequency is defined as a signature of events and is useful for correlation, often reflecting oil and gas reservoirs by seismic attenuation (Taner et al. 1994). Amplitude-weighted frequency is a product of the amplitude envelope and the instantaneous frequency, providing a smooth estimation of instantaneous frequency by removing spikes and noises (Chen and Sidney 1997).To sum up, well logs and seismic attributes are successfully applied to predict thermal maturity in the Kazhdumi Formation in the central part of the Persian Gulf.The analysis shows that the Kazhdumi Formation is mainly immature to early mature in the central part of the Persian Gulf.Seismic data are spatially continuous which is an advantage in source rock evaluation, resulting in continuous predictions of thermal maturity in hydrocarbon fields.Using seismic data is also cost-effective and less time-consuming than geochemical testing.

The reservoirs of ultra-deep and low-permeability sandstones typically exhibit characteristics of lithological tightness and poor physical properties. Fractures control the oil and gas content as well as the productivity of such reservoirs. However, the distribution of fractures is complex, exhibiting strong heterogeneity. Therefore, a systematic study on reservoir fracture modeling can provide geological foundations for the development of such reservoirs. Due to the considerable burial depth of these reservoirs, conventional methods relying solely on seismic information have limited reliability, and the established discrete network models of fractures are often less dependable. In this paper, taking the X gas reservoir in a basin in western China as an example, we discuss a fracture modeling method based on the integration of geological information to enhance the efficiency and accuracy of fracture modeling. The modeling method primarily involves the use of deterministic methods to obtain large-scale fractures, while random simulation is employed for small and medium-scale fractures. The fracture development control factors and seismic attribute information are integrated using permanence of ratios (PR) model to establish a fracture development probability field model. Subsequently, the geometric parameters of fractures and the fracture density model are used as input parameters to generate a discrete network model of small and medium-scale fractures using a object-based modeling method. Finally, based on the fracture equivalent property model and verified through geological understanding, analysis of production dynamics, and numerical simulation of the gas reservoir, it is demonstrated that the fracture model established using the proposed method aligns with geological understanding and exhibits high reliability.

Faults are an important factor inducing mine safety accidents, and it poses difficulties on the identification of faults within 5 m of drop.Taking the Liupanshui coalfield of Guizhou province as the study area, this paper investigated the coalfield strata and carried out an on-site survey.It proposed a seismic physical model and used the unique velocity ratio of 1∶1.74 to realize the construction and analysis of small faults with a burial depth of 800 m, 1 000 m and 1 200 m and a drop of 5 m, 3 m and 1 m.This paper extracted a variety of seismic properties by seismic dynamics method to analyze small faults, and obtained the sensitivity of seven seismic properties to the characteristic response of small faults, including amplitude envelope, amplitude first derivative, and amplitude second derivative, and the correlation between seismic properties and drop was established accordingly.The results show that when the small fault drop of the coal seam is less than or equal to 5 m, there is a linear relationship with the traditional amplitude attributes, and a linear relationship with the seismic properties related to phase and frequency.There is high correlation between the amplitude envelope and the amplitude imaginary part, and low correlation between the instantaneous frequency, the amplitude first derivative, the cosine instantaneous phase, the amplitude second derivative and the amplitude envelope.

In order to better manage producing reservoirs and optimally place additional production wells, there is need to carry out a detailed hydrocarbon prospectivity studies in any given field. The aim of this paper was to integrate 3D seismic volume and wire-line logs from five wells with seismic attribute analysis in evaluating hydrocarbon prospects across the "Zech" field in the eastern part of the Coastal Swamp depo-belt of the Niger Delta Basin. Emphasis were on identification and correlation of reservoir intervals, formation evaluation, structural interpretation and mapping of reservoir tops, and amplitude extraction from seismic attribute analysis. Result from this prospect evaluation studies reveals that five reservoir zones (Z1, Z2, Z3, Z4 and Z5) were identified. Correlation of these reservoir zones across wells, shows that there were influence of structures on reservoir package, as variable thicknesses of zones were observed across faults. Petrophyiscal analysis of key reservoir properties shows that the reservoir of interest were characterized by average shale volume of 0.10 (10%), porosity of 0.23 v/v (23%) and permeability 1220 mD. In addition, the water saturations ranged between 0.08 and 0.39 v/v (8-39%), with corresponding hydrocarbon saturations that ranged from 0.60-0.91v/v (60-91%). These values indicate that the reservoirs properties were of good quality. Structural interpretation revealed the presence of growth faults and associated rollover anticline, collapsed crest structures, series of hanging walls and footwalls, which constitutes major hydrocarbon traps in the area. Generated structural top maps revealed that theses faults form structural closures. Extracted amplitude from seismic attribute analysis revealed the presence eight-hydrocarbon prospective zones that were amplitude supported. Generally, this integrated data and analytical approach is key in understanding reservoir evaluation and hydrocarbon prospectivity studies. [ABSTRACT FROM AUTHOR]

Gaussian pyramid (GP) has the property of decomposing the 2-D data into multiple scales. It has been successfully applied in image processing, but rarely used in seismic data processing and interpretation. Specifically, seismic data are not just a 2-D image in one time slice or horizon. Moreover, the pattern of geological body varies rapidly in 3-D spaces. Hence, the classical GP method exists a limitation in processing 3-D seismic data. Especially in fracture detection, the 2-D isotropic Gaussian kernel used in GP tends to blur the fracture details. In this letter, to match the high-dimensional seismic data, we propose a structure-oriented adaptive Gaussian pyramid (SOA-GP) algorithm, which expands the 2-D GP method to the 3-D situation. In this case, to eliminate the influence of transverse change of wave impedance and consider stratigraphic characteristics, the 2-D Gaussian filter is also substituted by the 3-D structure-adaptive anisotropic Gaussian kernel, which is constructed by instantaneous phase-based gradient structure tensor (GST) method. Meanwhile, seismic attributes are applied to the multiresolution seismic data decomposed by the SOA-GP method to realize multiscale fracture detection. Finally, we apply this new 3-D SOA-GP method to field data. It demonstrates that the multiscale decomposition of the new method could produce more details of fracture and less disturbance from noise. [ABSTRACT FROM AUTHOR]

Copyright of Coal Geology & Exploration is the property of Xian Research Institute of China Coal Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Understanding the fracture patterns of hydrocarbon reservoirs is vital in the Zagros area of southwest of Iran as they are strongly affected by the collision of the Arabian and Iranian plates. It is essential to evaluate both primary and secondary (fracture) porosity and permeability to understand the fluid dynamics of the reservoirs. In this study, we adopted an integrated workflow to assess the influence of various fracture sets on the heterogeneous carbonate reservoir rocks of the Cenomanian–Santonian Bangestan group, including Ilam and upper Sarvak Formations. For this purpose, a combination of field data was used including seismic data, core data, open-hole well-logs, petrophysical interpretations, and reservoir dynamic data. FMI interpretation revealed that a substantial amount of secondary porosity exists in the Ilam and Sarvak Formations. The upper interval of Sarvak 1-2 (3491 m to 3510 m), Sarvak 1-3 (3530 m to 3550 m), and the base of Sarvak 2-1 are the most fractured intervals in the formation. The dominant stress regime in the study area is a combination of compressional and strike-slip system featuring reverse faults with a NW–SE orientation. From the depositional setting point of view, mid-ramp and inner-ramp show a higher concentration of fractures compared to open marine environment. Fracture permeability was modeled iteratively to establish a realistic match with production log data. The results indicate that secondary permeability has a significant influence on the productivity of wells in the study area.

Abstract In the Niger Delta, the Jay Field offshore structural model and seismic attribute analysis were carried out to enhance prospect evaluation and mitigate risk in field development operations, especially in regions with few wells and poor seismic data. Integration of a 3D seismic cube and one well with composite logs was used to carry out this analysis. Horizon and fault mapping was enhanced with Seismic attribute analysis, and an optimum frequency for spectral decomposition was identified using spectral analysis. The 3D structural framework revealed collapsed crest structures and rollover anticlines which act as hydrocarbon traping systems on the field. Detailed spectral analysis was carried out before using the spectral decomposition attribute to identify the most suitable (spectral) frequency at which the possible reservoir zones become more pronounced. The spectral frequency of 25Hz has been analysed to give high amplitude in the hydrocarbon accumulated region (indicated around the well position). This was used to evaluate prospective regions. The spectral decomposition attribute analysis predicts regions of possible quality reservoirs. This paper reveals that seismic attributes such as spectral decomposition, energy, and similarity can improve reflection patterns in poor to good quality seismic data. In this paper, the energy and spectral decomposition are veritable attributes that have improved reflection patterns and had allowed to identify anomalous amplitude associated with hydrocarbon accumulation in this paper.

Understanding the fracture patterns of hydrocarbon reservoirs is vital in the Zagros area of southwest of Iran as they are strongly affected by the collision of the Arabian and Iranian plates. It is essential to evaluate both primary and secondary (fracture) porosity and permeability to understand the fluid dynamics of the reservoirs. In this study, we adopted an integrated workflow to assess the influence of various fracture sets on the heterogeneous carbonate reservoir rocks of the Cenomanian–Santonian Bangestan group, including Ilam and upper Sarvak Formations. For this purpose, a combination of field data was used including seismic data, core data, open-hole well-logs, petrophysical interpretations, and reservoir dynamic data. FMI interpretation revealed that a substantial amount of secondary porosity exists in the Ilam and Sarvak Formations. The upper interval of Sarvak 1-2 (3491 m to 3510 m), Sarvak 1-3 (3530 m to 3550 m), and the base of Sarvak 2-1 are the most fractured intervals in the formation. The dominant stress regime in the study area is a combination of compressional and strike-slip system featuring reverse faults with a NW–SE orientation. From the depositional setting point of view, mid-ramp and inner-ramp show a higher concentration of fractures compared to open marine environment. Fracture permeability was modeled iteratively to establish a realistic match with production log data. The results indicate that secondary permeability has a significant influence on the productivity of wells in the study area. [ABSTRACT FROM AUTHOR]

Spectral decomposition is a robust attribute in the characterisation of post-stack seismic data. Reflected wavelets from specific geological lithologies show distinct patterns in the frequency spectrum, which is related to the wavelet frequency content and the interference pattern of a structure within a layer. Generally, the frequency spectrum of a wavelet has a smooth pattern through the entire bandwidth. However, the structure of a layer, such as its thickness and lateral distribution, will appear as a periodic function in the frequency domain. This research investigates the distinct patterns of reflective layers with different thicknesses using instantaneous amplitude and fast sparse S-transform (ST). To verify the efficiency of both methods, we have examined these approaches on channel-shaped and wedge-shaped synthetic models. The results showed that the fast sparse ST could predict features of both synthetic models better than the instantaneous amplitude. Next, the fast sparse ST is performed on experimental field data selected from a time interval containing a hydrocarbon channel reservoir. We used a sparse deconvolution algorithm to suppress the wavelet effect and balance all the frequencies. The results of this research showed the efficiency of the fast sparse ST in predicting a hydrocarbon channel reservoir's thickness. [ABSTRACT FROM AUTHOR]

The Shunbei No. 5 strike-slip fault and its associated fractures in Tarim Basin control the formation of reservoirs and impact the migration and accumulation of oil and gas. Selecting appropriate seismic attributes to characterize and describe the spatial distribution of fractured reservoirs plays an important role in fractured reservoir prediction. Due to the seismic resolution of faults and fractures at different scales, it is necessary to use different methods and their combinations to identify fractures at different scales. To further characterize the fractures that associated with strike-slip faults in the Shunbei area in Tarim Basin, this paper compares the capability characterizing faults and fractures of individual seismic attributes and their combined attributes.The seismic attribute comparison shows that the high-precision coherent volume that constrained by dip angle and plane feature attribute can characterize the large-scale faults with fault distances over 40 m.The multi-coherent merge and strain-energy attributes can represent mesoscale fractures with a fault distance of 40-15 m. In addition, fracture-gave gain and thin likelihood enhancer can characterize small-scale fractures with a fault distance less than 15 m.The results of correlation fitting of typical seismic attributes to actual fracture data and fracture density curves that interpreted from EMI imaging logging were ranked.Finally, four seismic attributes including chaos, planes, third component of structural tensor, and frequency division coherence fusion are optimized for fracture density calculation.The calculated results show that the potential reservoirs that associated with the high-density fracture zone is mainly located within 1.5 km of the transpression section of the fault in the upper section of the lower to middle Ordovician Yingshan Formation.

Reflected wave seismology has the following defects: the acquisition design is based on the assumption of layered media, the signal processing suppresses weak signals such as diffracted wave and scattered wave, and the seismic wave band after the image processing is narrow. They limit the full utilization of broadband raw data. The concept of full wave seismic exploration is redefined based on the idea of balanced utilization of reflected wave, diffracted wave and scattered wave information, its characteristics and adaptive conditions are clarified. A set of key technologies suitable for full wave seismic exploration are put forward. During seismic acquisition period, it is necessary to adopt multi geometry, i.e. embed small bin, small offset and small channel interval data in conventional geometry. By discretizing of common midpoint (CMP) gathers, small offset with high coverage, the weak signals such as diffracted wave and scattered wave in the raw seismic data can be enhanced. During seismic processing, the signal and noise in the original seismic data need to be redefined at first. The effective signals of seismic data are enhanced through merging of multi-geometry data. By means of differential application of data with different bin sizes and different arrangement modes, different regimes of seismic waves can be effectively decomposed and imaged separately. During seismic interpretation stage, making the most of the full wave seismic data, and adopting well-seismic calibration on multi-scale and multi-dimension, the seismic attributes in multi-regimes and multi-domains are interpreted to reveal interior information of complex lithology bodies and improve the lateral resolution of non-layered reservoirs.

Deep‐water clastic settings frame major stratigraphic plays the world over. The advanced seismic interpretation tools provide prediction of accurate physical characteristics of undiscovered reservoirs, including their lithology, thickness, and porosity. The designed amplitude spectrum (DAS)‐based processing tool on Full spectrum seismic may yield a remarkable stratigraphy. This study deals with the prediction of thick and porous (possibly gas‐rich) litho‐facies using the DAS tool on high‐resolution seismal profiles within the offshore Indus Basin (OIB), SW Pakistan. The seismic and trace envelope magnitudes bound the demarcation of stratigraphic traps. The DAS processing tool on relative acoustic impedance inversion (RAI) magnitude demarcates the aggradational porous sandstone‐filled reservoirs, which are encased within a transgressive non‐porous shale‐filled channel‐levee system. The thickness predicted by band‐limited seismic acoustic impedance (AI) simulation for channels, point bars, and levees is 28, 27, and 24 m, respectively. The DAS‐based RAI processing on AI reservoir simulation accurately resolves the lenses of channel sandstone, point bars and levees, and confirms the channelized basin floor fans (BFFs) with an average 11, 34, 24, and 52 m thickness and a lateral extent between 10 and 25 km. The western zones have implications for basin development, which have accumulated the porous and thickest reservoir facies inside the aggradational parasequences of BFFs of Miocene sedimentary sequences. Hence, the presented scheme of exploration serves as a comparable example for exploring the hydrocarbon‐bearing plays inside OIB and global deep‐water depositional systems. [ABSTRACT FROM AUTHOR]

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Copyright of Petroleum Geology & Recovery Efficiency is the property of Petroleum Geology & Recovery Efficiency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Deep reservoirs associated with gravity-flows are garnering considerable attention. Predicting reservoirs deposited by nearshore subaqueous fans is challenging and often underreported in seismic sedimentology analysis. Utilizing post-stack seismic attributes is a quick and straightforward method for quantitatively characterizing these reservoirs. However, reservoir prediction deteriorates when dealing with complex sedimentary volumes and intricate tectonic development. Spectral decomposition (SD) offers an alternative approach to optimize the seismic data. The frequency-dependent S-transform (ST) holds great potential in seismic interpretation. SD based on the ST was employed in the seismic sedimentary characterization of steep slope complex fan reservoirs. Three fourth-order sequence stratigraphic boundaries and three complex fans were ideally shown on seismic frequency decomposition profiles. A 20 Hz seismic sedimentology analysis frequency was determined by comparing three spectral decomposition results following the well-seismic reflection analysis. The internal architectures of fan deltas and the individual outlines of nearshore subaqueous fans were more distinguishable in 20-Hz frequency decomposition data than in full-frequency data. The progradation direction of steep slope fans can be better recognized in frequency decomposition profiles compared to full-frequency seismic data. Three factors influence the seismic sedimentary characterization and prediction of steep slope fans when employing SD. The ability of the ST to preserve phase is crucial for improving the imaging quality of the amplitude attribute. Sedimentary mechanisms control the sedimentary features of steep slope fans, impacting the imaging of seismic attributes. While channelized fan deltas can be better identified, unchannelized nearshore subaqueous fan deposits, which exhibit more heterogeneous sedimentary characteristics, present limitations. The unique volcanic evolution is another factor that impacts the image of the root-mean-square (RMS) attribute. Despite demonstrating excellent local adaptability in signal analysis, the S-transform cannot fully compensate for the combined effects of faults and sedimentary heterogeneity in nearshore subaqueous fans. • S transform was used to improve seismic attribute image of steep slope fans. • Spectral decomposition presents steep slope fans along the complicated faults. • The local adaptability of S-transform is the point to improve the quality. • S transform is different from WT even same wavelet function contains. [ABSTRACT FROM AUTHOR]

Although the Triassic Xujiahe Formation in Yuanba area of northern Sichuan has a large amount of resources, the proportion of proved reserves to the amount of resources is low. Production of most of the pilot production wells is high at the initial stage, but it declines rapidly, mainly due to tight rock properties and strong heterogeneity of Xujiahe Formation. Thus, it is important to investigate the distribution of high-quality reservoirs. The Member 3 of Xujiahe Formation develops sandstone interbedded with mudstone, and its lateral thickness of different sandstone groups varies greatly, so it is a challenge to identify appropriate time windows for seismic attribute analysis, thus, so the prediction effect of the glutenite in the Member 3 of Xujiahe Formation. In this study, through analysis of core data and logging facies, single-well sedimentary microfacies subdivision is carried out. Single-well lithological interpretation is also studied with application of lithological identification technique. Then, lithological associations and its seismic responses at the top and bottom interfaces of each sandstone group in the Member 3 of Xujiahe Formation are well investigated, The lithological association with the glutenite above and the mudstone below the stratigraphic interface respectively, corresponds to a trough in seismic profiles; in this case, when extracting the seismic attributes of sandstone groups above the stratigraphic interface, only the difference of between drilling horizons and seismic horizons needs to be considered. The lithological association with the mudstone above and glutenite below the stratigraphic interface respectively, corresponds to a peak in seismic profiles; in this case, when extracting the seismic attributes of sandstone groups above the stratigraphic interface, influence of which should be eliminated; thus, a method of time window determination for seismic attribute extraction is established. Among amplitude, frequency, and phase attributes, the total peak energy has the good correlation with thickness of the glutenite at well sites and it also can reflect the distribution of distributary channels well. The results show that belt-like glutenite in each sandstone group in the Member 3 of Xujiahe Formation extends in a NW-SE direction and thins out toward the southeast, and the distribution of glutenite has certain inheritance in the longitudinal direction, the glutenite in the third sandstone group in the Member 3 of Xujiahe Formation (TX33) and the first sandstone group in the Member 3 of Xujiahe Formation (TX31) are both developed.

The precise prediction of coal seam thickness in operating mines is crucial for the construction of transparent mines. Geological borehole data or a small amount of seismic information is frequently used in traditional coal seam thickness prediction methods; however, these methods have poor precision. In this study, we introduced a model for predicting coal seam thickness based on the comprehensive preference for seismic attribute combination (CPSAC) and the least squares support vector machine (LS-SVM) optimized by the whale optimization algorithm (WOA). We used the CPSAC to modify the mass disturbed data in the seismic attribute data to predict the coal seam thickness. To achieve this the sample size was reduced by optimizing the seismic attribute combinations, and the modified attribute data was entered into the LS-SVM., Furthermore, to create an accurate prediction model for coal thickness, we employed the WOA to determine the optimal penalty coefficient and kernel coefficient of the LS-SVM. An empirical case study was conducted in the northeast mining area of the ZJ mine in the Huainan coalfield. The coal thickness of two mining faces in this research area were estimated and compared, demonstrating the proposed method's high prediction accuracy. The proposed method has guiding implications for developing an accurate mining geological model and facilitating the accurate use of coal resources. [ABSTRACT FROM AUTHOR]

Single seismic attribute is often difficult to achieve ideal results in the study on 4-level and 5-level reservoir architectures due to its strong multi-resolution and less hidden geological information. Frequency division RGB fusion technology can effectively improve the accuracy of reservoir architecture in sparse well pattern oilfield by extracting seismic data of effective frequency band and highlighting the boundary of geological body through RGB fusion images. Frequency division RGB fusion technology was used to analyze the architecture of major reservoir in the fifth member of Wenchang Formation, LFY oilfield, Pearl River Mouth Basin. The results show that the frequency division RGB fusion with 20, 35 and 60 Hz can better identify the distributary bar and distributary channel boundary of braided river delta in LFY oilfield, and clearly describe the plane distribution characteristics of different architecture units. Under the guidance of braided river delta sedimentary model, the 5-level and 4-level architecture characteristics of the fifth member of Wenchang Formation in LFY oilfield were analyzed. 4-level architecture unit has three vertical superposed styles of distributary bar-distributary bar, distributary channel-distributary bar and distributary channel-distributary channel, and has three lateral splicing styles of distributary bar-distributary channel stacking, distributary bar-distributary bar stacking and distributary channel-inter-distributary bay stacking. The width and thickness of 5-level single architecture unit in the fifth member of Wenchang Formation, LFY oilfield are 5-7 km and 40-60 m; the thickness of 4-level single architecture unit is 2-10 m; the length and width of 4-level single architecture unit are 3-6 km and 2-3 km in the plane. [ABSTRACT FROM AUTHOR]

Copyright of Natural Gas Geoscience is the property of Natural Gas Geoscience and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the Bohai Bay rift basin in eastern China, lacustrine turbidite sandstone is an important target for oil and gas production and development. However, this sandstone has complex sedimentary patterns and a limited reservoir distribution, leading to challenges in understanding and predicting targets. With seismic sedimentology, including the analysis of seismic attributes, stratigraphic slices and seismic facies, this paper establishes a prediction process suitable for thin sand bodies and subtle traps in the Chezhen Sag. Combined with 3D seismic data and wireline logging data, the planar distribution of sand bodies of the Shahejie Formation (P2S) in the Chezhen Sag is predicted. The evolution and distribution of P2S sand bodies in the Chezhen Sag are revealed by stratigraphic slice mapping on multiple sedimentary planes, and subtle traps in the lower submember of Member III of the Shahejie Formation (P2S3x) are characterized. The P2S3x results indicate three favorable trap areas, namely the Che 20 fan delta sand body, the Che 66 nearshore underwater fan sand body and the Che 241 shallow water delta sand body. These three lithologic subtle traps have great exploration potential, and new exploration wells should be deployed to target them. [ABSTRACT FROM AUTHOR]

The ‘TMB’ Field was evaluated to detect hydrocarbon prospects for the purpose of increasing production volume using seismic attribute analyses. A total of eight sand tops were correlated across the Wells and faults orientation with significant displacement were picked across the field. Three horizons (Res. E, Res. H and Res. J) were used to generate the time maps which were converted to depths by a polynomial function from Time-Depth relationship. Two of the faults are major syn-tectonic growth faults that divides the field into three Fault Blocks (FB1, FB2 and FB3). Seismic attributes (Average Energy, Root Mean Square (RMS), Sweetness and Relative Acoustic Impedance (RAI)) amplitudes were examined to identify hydrocarbon prospect in the reservoirs. An area of interest (prospect) in one of the Fault Blocks (FB3) revealed attribute amplitude responses that suggest the presence of hydrocarbon was identified. The extracted attribute from Average energy, RMS and Sweetness attributes showed high amplitudes similar to attributes obtained from areas around Well log locations (proven area). Normal curves from attribute’s histogram distributions support hydrocarbon presence in FB3. The observed prospects are vertically stacked with fault-dependent anticlinal closures that serves as trap within the FB3 fault block.

The Laoshan Uplift (LSU) in the South Yellow Sea Basin of the Lower Yangtze Plate is a potential site for hydrocarbon exploration; thus, determining the strata attributes and distribution is imperative. Tracking a wide range of seismic reflection horizons for lateral comparisons is challenging because the first well (CSDP-2) encountered in the Paleozoic strata of the LSU is located in a structurally complex deformation zone and has yielded poor seismic data quality. In this study, we present a novel approach to seismic horizon tracking in areas with few or no wells and adopt a cross-regional analogy and inverse analysis method to track the seismic horizon. Seismic attribute characteristics of the marine strata of the LSU were compared with the seismic horizons calibrated in the Wx1 well in the stable Qingdao Depression (QDD), and horizontal tracking was performed. An inverse analysis was then performed on the CSDP-2 well area to predict the distribution of marine strata in the LSU. The results revealed that the Permian and Triassic strata of the LSU and QDD have similar seismic attributes. Finally, the seismic horizon of the LSU was tracked horizontally based on a comparison of the seismic attributes of the LSU and QDD. Previous studies showed that seismic reflection horizons are difficult to calibrate, and the marine strata attributes in the LSU remain controversial. This study adopted a cross-regional comparison and inversion analysis method to perform a seismic multi-attribute comparison based on the calibrated results of the QDD for the Wx1 well. The remaining Permian and Triassic strata lie almost entirely within the LSU. Moreover, the maximum reported thicknesses of the Upper Permian and Lower-Middle Triassic strata in the LSU were approximately 500 and 2750 m, respectively. Our findings will aid in the exploration and evaluation of early hydrocarbon resources in the LSU. • Predicting Permian and Triassic strata distribution in the Laoshan Uplift. • Cross regional analogy and inverse analysis method with seismic multi-attribute. • Implications marine hydrocarbon exploration potential in the Southern Yellow Sea. [ABSTRACT FROM AUTHOR]

The interpretation of subsurface fluid flow features in seismic reflection data is a key part of identifying the presence of hydrocarbon and active petroleum systems. Currently, this kind of study is mainly conducted utilizing offshore seismic reflection data with very limited cases utilizing onshore seismic reflection data. In addition, the Alamein basin is an area of prolific study in onshore Egypt, with most related studies concentrating on basin analysis and reservoir characterization. Therefore, in our study we aimed to make practical and effective use of onshore seismic reflection data with seismic attribute analysis to describe seismic facies, delineating and interpreting subsurface fluid flow features. The relatively vertical V-shaped and pipe or concave-up-shaped features with distorted reflections inside them are revealed through the analysis of variance, sweetness, chaos, instantaneous frequency and the RMS amplitude of seismic attributes. These subsurface fluid flow features are a product of mature source rock that migrates hydrocarbon vertically through faults (especially deep-seated faults) and fracture systems (fault and fracture-related subsurface fluid flow features). The classification scheme presented in our study could be implemented in the onshore case worldwide. [ABSTRACT FROM AUTHOR]

The 'TMB' Field was evaluated to detect hydrocarbon prospects for the purpose of increasing production volume using seismic attribute analyses. A total of eight sand tops were correlated across the Wells and faults orientation with significant displacement were picked across the field. Three horizons (Res. E, Res. H and Res. J) were used to generate the time maps which were converted to depths by a polynomial function from Time-Depth relationship. Two of the faults are major syn-tectonic growth faults that divides the field into three Fault Blocks (FB1, FB2 and FB3). Seismic attributes (Average Energy, Root Mean Square (RMS), Sweetness and Relative Acoustic Impedance (RAI)) amplitudes were examined to identify hydrocarbon prospect in the reservoirs. An area of interest (prospect) in one of the Fault Blocks (FB3) revealed attribute amplitude responses that suggest the presence of hydrocarbon was identified. The extracted attribute from Average energy, RMS and Sweetness attributes showed high amplitudes similar to attributes obtained from areas around Well log locations (proven area). Normal curves from attribute's histogram distributions support hydrocarbon presence in FB3. The observed prospects are vertically stacked with fault-dependent anticlinal closures that serves as trap within the FB3 fault block. [ABSTRACT FROM AUTHOR]

The eastern Sichuan Basin has undergone multiple stages of tectonic evolution and shows complex structural characteristics. It is found that there are a series of NW-SE base-trending strike-slip faults in this area besides NE-SW strike-blocking structures. There are almost no previous studies on strike-slip faults in the eastern Sichuan Basin. This paper fills in the blank of geometry and kinematics research on the strike-slip fault zone in this area. Based on highly precise 3D seismic section, coherent attribute slice and time slice, the geometric and kinematic characteristics of the fault are analyzed. The dynamic characteristics are analysed based on the structural style of the superimposed development model and the nature and activity intensity of strike-slip faults in different periods. and it was found that No. 15 strike-slip fault was a large basement strike-slip fault. The research results show that the profile of the No. 15 strike-slip fault mainly shows a subvertical fracture, positive flower structure and negative flower structure and a composite flower structure with positive and negative flower structures superimposed on each other in the upper and lower planar sections with linearly outspread and zonal distribution characteristics; spatially, there is a “ribbon” effect and a “dolphin” effect. the left strike-slip distance of the TS interface is 0.462 km, and the right strike-slip distance of the TP2 interface is 0.782 km. The strike-slip fault experienced at least three active stages of superimposed deformation during its formation and reconstruction, among which episode II in the middle Caledonian movement was the main active stage of the No. 15 strike-slip fault zone. This study of the structural style and genetic mechanism of a strike-slip fault zone is of guiding significance to the exploration and development of strike-slip fault-controlled reservoirs in the study area.

Copyright of Petroleum Geology & Recovery Efficiency is the property of Petroleum Geology & Recovery Efficiency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The seismic data interpretation reveals properties of the subsurface structures, appropriate for further geological or exploration investigations. The buried channels are desired exploratory targets for petroleum reservoir exploration, drilling concerns or geological investigations. Therefore, it is required to precisely identify the geometry of the buried channels through the signal image analysis and the geological interpretation of the seismic data. The continuous wavelet transform (CWT) is a spectral discrete transform method for non-stationary signal analysis, useful to enhance the resolution of the seismic data both in time and frequency domains. In the presented study, we propose a strategy for a precise identification of buried channels, using a vast number of time–frequency seismic attributes on 3D seismic data. The spectral decomposition by the CWT method has been performed on 20, 25, 30, 35, and 40 Hz frequency sections. The seismic attributes have been extracted, including the energy, the instantaneous amplitude, the average root mean square, the Prewitt and Grubbs filters, the similarity, the semblance, and the grey-level covariance matrix. The most favorable results have been selected to be integrated, so providing new attributes through RGB composition. This integration has been performed both for single frequency and multi-frequency seismic sections. As a result of applying the proposed strategy on the selected synthetic and field dataset, the boundaries of the buried channel as well as its inner structure, have been individuated. The final model of the seismic attributes has revealed that the proposed strategy represents an alternative to the conventional procedure of identification the buried channel. [ABSTRACT FROM AUTHOR]