In order to carry out numerical simulation using geologic structural data obtained from Landmark(seismic interpretation system), underground geological structures are abstracted into mechanical models which can reflec...In order to carry out numerical simulation using geologic structural data obtained from Landmark(seismic interpretation system), underground geological structures are abstracted into mechanical models which can reflect actual situations and facilitate their computation and analyses.Given the importance of model building, further processing methods about traditional seismic interpretation results from Landmark should be studied and the processed result can then be directly used in numerical simulation computations.Through this data conversion procedure, Landmark and FLAC(the international general stress software) are seamlessly connected.Thus, the format conversion between the two systems and the pre-and post-processing in simulation computation is realized.A practical application indicates that this method has many advantages such as simple operation, high accuracy of the element subdivision and high speed, which may definitely satisfy the actual needs of floor grid cutting.展开更多
The Pennsylvanian unconformity,which is a detrital surface,separates the beds of the Permian-aged strata from the Lower Paleozoic in the Central Basin Platform.Seismic data interpretation indicates that the unconformi...The Pennsylvanian unconformity,which is a detrital surface,separates the beds of the Permian-aged strata from the Lower Paleozoic in the Central Basin Platform.Seismic data interpretation indicates that the unconformity is an angular unconformity,overlying multiple normal faults,and accompanied with a thrust fault which maximizes the region's structural complexity.Additionally,the Pennsylvanian angular unconformity creates pinch-outs between the beds above and below.We computed the spectral decomposition and reflector convergence attributes and analyzed them to characterize the angular unconformity and faults.The spectral decomposition attribute divides the broadband seismic data into different spectral bands to resolve thin beds and show thickness variations.In contrast,the reflector convergence attribute highlights the location and direction of the pinch-outs as they dip south at angles between 2° and 6°.After reviewing findings from RGB blending of the spectrally decomposed frequencies along the Pennsylvanian unconformity,we observed channel-like features and multiple linear bands in addition to the faults and pinch-outs.It can be inferred that the identified linear bands could be the result of different lithologies associated with the tilting of the beds,and the faults may possibly influence hydrocarbon migration or act as a flow barrier to entrap hydrocarbon accumulation.The identification of this angular unconformity and the associated features in the study area are vital for the following reasons:1)the unconformity surface represents a natural stratigraphic boundary;2)the stratigraphic pinch-outs act as fluid flow connectivity boundaries;3)the areal extent of compartmentalized reservoirs'boundaries created by the angular unconformity are better defined;and 4)fault displacements are better understood when planning well locations as faults can be flow barriers,or permeability conduits,depending on facies heterogeneity and/or seal effectiveness of a fault,which can affect hydrocarbon production.The methodology utilized in this study is a further step in the characterization of reservoirs and can be used to expand our knowledge and obtain more information about the Goldsmith Field.展开更多
Modem oil industry is on the way of complication of the geological structure to use the latest technologies to analyze available geological and geophysical algorithm---continuous wavelet transform in example of synthe...Modem oil industry is on the way of complication of the geological structure to use the latest technologies to analyze available geological and geophysical algorithm---continuous wavelet transform in example of synthetic and real data. of the deposits. This trend requires specialists information. The article describes a new展开更多
3D seismic and petrophysical log data interpretation of reservoir sands in “SIMA” Field, onshore Niger Delta has been undertaken in this study to ascertain the reservoir characteristics in terms of favourable struct...3D seismic and petrophysical log data interpretation of reservoir sands in “SIMA” Field, onshore Niger Delta has been undertaken in this study to ascertain the reservoir characteristics in terms of favourable structural and petrophysical parameters suitable for hydrocarbon accumulation and entrapment in the field. Horizon and fault interpretation were carried out for subsurface structural delineation. In all, seven faults (five normal and two listric faults) were mapped in the seismic section. These faults were major structure building faults corresponding to the growth and antithetic faults in the area within the well control. The antithetic fault trending northwest-southeast and the normal fault trending northeast-southwest on the structural high in the section act as good trapping mechanisms for hydrocarbon accumulations in the reservoir. From the manual and auto-tracking methods applied, several horizons were identified and mapped. The section is characterized by high amplitude with moderate-to-good continuity reflections appearing parallel to sub-parallel, mostly disturbed by some truncations which are more fault related than lithologic heterogeneity. The southwestern part is, however, characterized by low-to-high or variable amplitude reflections with poor-to-low continuity. Normal faults linked to roll-over anticlines were identified. Some fault truncations were observed due to lithologic heterogeneity. The combination of these faults acts as good traps for hydrocarbon accumulations in the reservoir. Reservoir favourable petrophysical qualities, having average NTG, porosity, permeability and water saturation of 5 m, 0.20423, 1128.219 kD and 0.458 respectively.展开更多
In order to detect fault exactly and quickly, cusp catastrophe theory is used to interpret 3D coal seismic data in this paper. By establishing a cusp model, seismic signal is transformed into standard form of cusp cat...In order to detect fault exactly and quickly, cusp catastrophe theory is used to interpret 3D coal seismic data in this paper. By establishing a cusp model, seismic signal is transformed into standard form of cusp catastrophe and catastrophe parameters, including time-domain catastrophe potential, time-domain catastrophe time, frequency-domain catastrophe potential and frequency- domain degree, are calculated. Catastrophe theory is used in 3D seismic structural interpretation in coal mine. The results show that the position of abnormality of the catastrophe parameter profile or curve is related to the location of fault, and the cusp catastrophe theory is effective to automatically pick up geology information and improve the interpretation precision in 3D seismic data.展开更多
With the successful application and breakthrough of deep learning technology in image segmentation,there has been continuous development in the field of seismic facies interpretation using convolutional neural network...With the successful application and breakthrough of deep learning technology in image segmentation,there has been continuous development in the field of seismic facies interpretation using convolutional neural networks.These intelligent and automated methods significantly reduce manual labor,particularly in the laborious task of manually labeling seismic facies.However,the extensive demand for training data imposes limitations on their wider application.To overcome this challenge,we adopt the UNet architecture as the foundational network structure for seismic facies classification,which has demonstrated effective segmentation results even with small-sample training data.Additionally,we integrate spatial pyramid pooling and dilated convolution modules into the network architecture to enhance the perception of spatial information across a broader range.The seismic facies classification test on the public data from the F3 block verifies the superior performance of our proposed improved network structure in delineating seismic facies boundaries.Comparative analysis against the traditional UNet model reveals that our method achieves more accurate predictive classification results,as evidenced by various evaluation metrics for image segmentation.Obviously,the classification accuracy reaches an impressive 96%.Furthermore,the results of seismic facies classification in the seismic slice dimension provide further confirmation of the superior performance of our proposed method,which accurately defines the range of different seismic facies.This approach holds significant potential for analyzing geological patterns and extracting valuable depositional information.展开更多
The detailed structures of the plumbing system of the early Permian Tarim flood basalt were investigated by 3-D seismic imaging.The images show that the Tarim flood basalt mainly erupted from central volcanoes distrib...The detailed structures of the plumbing system of the early Permian Tarim flood basalt were investigated by 3-D seismic imaging.The images show that the Tarim flood basalt mainly erupted from central volcanoes distributed展开更多
A common feature in seismic imageries of the crust and mantle is a layering pattern.Layering structures do exist in multiple scales,such as layered strata and unconformities in local and regional scales,and undulating...A common feature in seismic imageries of the crust and mantle is a layering pattern.Layering structures do exist in multiple scales,such as layered strata and unconformities in local and regional scales,and undulating seismic discontinuities in the crust and mantle.However,layering arti-fact also exists due to limitations in seismic processing and data coverage.There is a tendency for seis-mic stacking methods to over-map reflectors and scatters into along-isochron layers.In contrast,seis-mic tomography methods tend to under-map sub-horizontal layers with along-raypath smears and ar-tifacts of various de-mean processes.To better identify signals and artifacts in seismic imageries,it is necessary to understand the origins of various artifacts and make careful comparison between the solu-tions of different data and methods.展开更多
Spectral decomposition has been widely used in the detection and identifi cation of underground anomalous features(such as faults,river channels,and karst caves).However,the conventional spectral decomposition method ...Spectral decomposition has been widely used in the detection and identifi cation of underground anomalous features(such as faults,river channels,and karst caves).However,the conventional spectral decomposition method is restrained by the window function,and hence,it mostly has low time–frequency focusing and resolution,thereby hampering the fi ne interpretation of seismic targets.To solve this problem,we investigated the sparse inverse spectral decomposition constrained by the lp norm(0<p≤1).Using a numerical model,we demonstrated the higher time–frequency resolution of this method and its capability for improving the seismic interpretation for thin layers.Moreover,given the actual underground geology that can be often complex,we further propose a p-norm constrained inverse spectral attribute interpretation method based on multiresolution time–frequency feature fusion.By comprehensively analyzing the time–frequency spectrum results constrained by the diff erent p-norms,we can obtain more refined interpretation results than those obtained by the traditional strategy,which incorporates a single norm constraint.Finally,the proposed strategy was applied to the processing and interpretation of actual three-dimensional seismic data for a study area covering about 230 km^(2) in western China.The results reveal that the surface water system in this area is characterized by stepwise convergence from a higher position in the north(a buried hill)toward the south and by the development of faults.We thus demonstrated that the proposed method has huge application potential in seismic interpretation.展开更多
The Lower Cambrian Longwangmiao Fm gas reservoir in the GaoshitieMoxi area,the Sichuan Basin,is a super giant monoblock marine carbonate gas reservoir with its single size being the largest in China.The key to the rea...The Lower Cambrian Longwangmiao Fm gas reservoir in the GaoshitieMoxi area,the Sichuan Basin,is a super giant monoblock marine carbonate gas reservoir with its single size being the largest in China.The key to the realization of high and stable production gas wells in this gas reservoir is to identify accurately high-permeability zones where there are dissolved pores or dissolved pores are superimposed with fractures.However,high quality dolomite reservoirs are characterized by large burial depth and strong heterogeneity,so reservoir prediction is of difficult.In this paper,related seismic researches were carried out and supporting technologies were developed as follows.First,a geologic model was built after an analysis of the existing data and forward modeling was carried out to establish a reservoir seismic response model.Second,by virtue of well-oriented amplitude processing technology,spherical diffusion compensation factor was obtained based on VSP well logging data and the true amplitude of seismic data was recovered.Third,the resolution of deep seismic data was improved by using the welloriented high-resolution frequency-expanding technology and prestack time migration data of high quality was acquired.And fourth,multiple shoal facies reservoirs were traced by using the global automatic seismic interpretation technology which is based on stratigraphic model,multiple reservoirs which are laterally continuous and vertically superimposed could be predicted,and the areal distribution of high quality reservoirs could be described accurately and efficiently.By virtue of the supporting technologies,drilling trajectory is positioned accurately,and the deployed development wells all have high yield.These technologies also promote the construction of a modern supergiant gas field of tens of billions of cubic meters.展开更多
Suakin-1 and Suakin-2 wells are in the Sudanese Red Sea segment where the hydrocarbon generation had been proved by previous studies, however, no reasonable reserve was evidenced due to the complexities of the surroun...Suakin-1 and Suakin-2 wells are in the Sudanese Red Sea segment where the hydrocarbon generation had been proved by previous studies, however, no reasonable reserve was evidenced due to the complexities of the surrounding salt structures. Six seismic lines were tied to Suakin-1 and -2 to delineate the controlling salt tectonics. The salt evacuation (Roho) and other salt bodies were recognized and matched with similar salt structures in analogous stratigraphic conditions as the Gulf of Mexico and Angola margin. While a previous inconsistent interpretation in the study area marked the high amplitude horizon of the Lower Zeit formation as the top of the Dungunab formation. Three seismic features indicated the presence of salt dome (autochthonous): velocity pull-up, dragging of the sedimentary layers forming mini basins around the third feature, which is the relative transparency of the seismic signal in two piercing like bodies. This interpretation similarly demarcated that the salt escaped east-wards, thus the mapped welded salt is believed to be formed after the salt evacuation. A 3D seismic with a far offset and wide range of azimuth is recommended for detailed imaging.展开更多
3D seismic prospecting in mining areas of Xieqiao Colliery is a successfulmodel for an advancement from the resource prospecting to mining prospecting stagein coal fields. Its results have proved that faults with a th...3D seismic prospecting in mining areas of Xieqiao Colliery is a successfulmodel for an advancement from the resource prospecting to mining prospecting stagein coal fields. Its results have proved that faults with a throw of 5-10 m can be detected in an area with good seismogeologic conditions by using 3D seismic technique.Detection of underground tunnels for the first time utilizing 3D seismic data indicates that subsided columns, gotten and mine goaf can be detected using 3D seismic technique, so it has a broad applied prospect.展开更多
The Penobscot Field,located within the Scotian Basin offshore Nova Scotia,Canada,represents an underexplored hydrocarbon field with potential for future development.Previous studies have been confined to specific rese...The Penobscot Field,located within the Scotian Basin offshore Nova Scotia,Canada,represents an underexplored hydrocarbon field with potential for future development.Previous studies have been confined to specific reservoir intervals without integrating multiple stratigraphic levels,and a comprehensive static reservoir characterization and volumetric assessment of the Penobscot Field has yet to be undertaken,constraining its full development evaluation.This study presents a comprehensive characte rization of the field by integrating geological,geophysical,and petrophysical datasets,leading to static hydrocarbon reserve estimation.The workflow involves seismic interpretation,structural modeling,petrophysical evaluation,and static volumetric calculations.Seismic analysis revealed a structu rally complex setting dominated by normal and inverted faults,with reservoir intervals primarily within the Missisauga Formation,which is subdivided into upper,middle,and lower units.Petro p hysical evaluation from well logs and core data identified key reservoir properties,including porosity ranging from 12 % to 28 %,permeability spanning from 1 to 1000 mD,and variable water saturations.Stochastic modeling of facies and petro p hysical attributes provided insights into lateral and ve rtical hete rogeneity.The Penobscot Field's original oil-in-place ranges from 41.6×10~6 m3 to 109.7×10~6 m3,with the Middle Missisauga sands presenting the highest reservoir potential.Fault seal analysis indicated predominantly sealing behavior in the shallow sections and semi-permeable conditions at greater depths,suggesting potential lateral migration pathways.The results underscore the field's hydrocarbon potential while emphasizing the significance of structural complexity,facies distribution,and petrophysical variability in reservoir quality,as well as its potential for future development or utilization of similar sand reservoirs for CO_(2) storage utilization.This work provides the first fully integrated static reservoir model of the Penobscot Field,offering critical insights for delineating the hydrocarbon reservoirs potential and future production strategies in the Scotian Basin.展开更多
Constructing underground structures in coastal regions poses significant challenges,particularly due to seawater intrusion,which can cause corrosion and threaten the safety and stability of the caverns and surrounding...Constructing underground structures in coastal regions poses significant challenges,particularly due to seawater intrusion,which can cause corrosion and threaten the safety and stability of the caverns and surrounding facilities.A crucial aspect of preventing seawater intrusion lies in accurate mapping of the geological structure of the reservoir area and its proximity to the coastline.This study uses reflection seismic data,borehole ultrasonic imaging,and core samples to identify geological features that influence subsurface stability.The seismic profile revealed a V-shaped or concave-down structure associated with faults,suggesting a down-dropped block within the subsurface.Seismic facies analysis identified chaotic,high-amplitude reflections within basement rocks,indicating highly fractured and faulted zones,possibly including mylonitic rocks.A novel approach is proposed that combines borehole ultrasonic imaging with fractal theory,integrating core photos,seismic attributes,and geophysical analysis.A functional relationship was established between the joint surface density and the joint information dimension within the borehole.Additionally,a relationship was established between fault information dimension and borehole joint surface density.Results showed that the joint information dimensions within the identified fault zones consisttently exceeded 1.775.By applying a threshold of joint information dimension greater than 1.775,15 small-scale structural prediction zones were identified.Subsequent analysis of core photos from the predicted regions confirmed the presence of relatively long fractured zones,demonstrating the high accuracy of the proposed method in identifying small-scale structures.This study presents a comprehensive method for mapping geological structures in coastal areas,providing an essential reference for the identification and management of small-scale features in underground engineering projects.展开更多
Focusing on the Zengmu-Beikang Basin in the southern South China Sea,we summarized the regional sequence stratigraphic framework and identified mass-transport complex(MTC)that had developed since the Late Miocene(10.5...Focusing on the Zengmu-Beikang Basin in the southern South China Sea,we summarized the regional sequence stratigraphic framework and identified mass-transport complex(MTC)that had developed since the Late Miocene(10.5 Ma),by using high-resolution multibeam bathymetric and 2D seismic datasets.Based on the analysis of high amplitude and continuous seismic reflections within the mass-transport deposits(MTDs),we identified 14 basal shear surfaces(BSS)and divided the MTC into 14 units(MTD1–MTD14 from the youngest to the oldest in numerical order).Two types of seismic facies and five seismic features within the MTDs were recognized,including chaotic and transparent facies(debris flow),chaotic and semi-transparent facies(debris flow),thrust-fold systems,blocks,escarpments,pressure ridges,and normal faults.Analysis of the depositional area,frequency,and vertical extent of the escarpments of the fourteen MTD units revealed their variations in dimensions.Specifically,MTD14–MTD4 exhibited a gradual increase in the size of the deposition unit,with larger-sized MTD7–MTD4;while MTD3–MTD1 showed a gradual decrease in the size.The evolution of the MTDs in the study area is primarily controlled by several factors,including erosion of mass-movement processes(e.g.,slide,slump,and mass flows),sea-level fluctuation and sediment supply,tectonic activity,development of mud diapirs,and topographic influence.It is also plausible that the large-sized MTD7–MTD4 might be formed in the Pliocene due to steep slope gradient and instability caused by the development of mud diapirs,whereas in the Quaternary,the influence of mud diapirs in the shallow strata diminished,and smaller-sized MTD3–MTD1 were formed.展开更多
Coherence analysis is a powerful tool in seismic interpretation for imaging geological discontinuities such as faults and fractures. However, subtle faults or fractures of one stratum are difficult to be distinguished...Coherence analysis is a powerful tool in seismic interpretation for imaging geological discontinuities such as faults and fractures. However, subtle faults or fractures of one stratum are difficult to be distinguished on coherence sections （time slices or profiles） due to interferences from adjacent strata, especially these with strong reflectivity. In this paper, we propose a coherence enhancement method which applies local histogram specification （LHS） techniques to enhance subtle faults or fractures in the coherence cubes. Unlike the traditional histogram specification （HS） algorithm, our method processes 3D coherence data without discretization. This method partitions a coherence cube into many sub-blocks and self-adaptively specifies the target distribution in each block based on the whole distribution of the coherence cube. Furthermore, the neighboring blocks are partially overlapped to reduce the edge effect. Applications to real datasets show that the new method enhances the details of subtle faults and fractures noticeably.展开更多
In January 2010, the Suining Ms5.0 earthquake occurred in central Sichuan Basin, with the epicenter in Moxi-Longnvsi structural belt and a focal depth of 10 km. Based on structural interpretations of seismic profiles ...In January 2010, the Suining Ms5.0 earthquake occurred in central Sichuan Basin, with the epicenter in Moxi-Longnvsi structural belt and a focal depth of 10 km. Based on structural interpretations of seismic profiles in this area, we recognized a regional detachment fault located at a depth of 9-10 km in the Presinian basement of the Suining area, transferring its slipping from NW to SE orientation. This detachment fault slipped from NW to SE, and underwent several shears and bends, which caused the basement to be rolled in and the overlaying strata fold deformation. It formed a fault-bend fold in the Moxi area with an approximate slip of 4 km. Correspondingly, the formation of the Moxi anticline is related to the detachment fault. With the earthquake＇s epicenter on the ramp of the detachment fault, there is a new point of view that the Suining earthquake was caused by re-activation of this basement detachment fault. Since the Late Jurassic period, under the influence of regional tectonic stress, the detachment fault transfered its slip from the Longmen Mountains （LMS） thrust belt to the hinterland of the Sichuan Basin, and finally to the piedmont zone of southwest Huayingshan （HYS）, which indicates that HYS might be the final front area of the LMS thrust belt.展开更多
Turbidity currents represent a major agent for sediment transport in lakes, seas and oceans. In particu-lar, they formulate the most significant clastic accumulations in the deep sea, which become many of the world＇s...Turbidity currents represent a major agent for sediment transport in lakes, seas and oceans. In particu-lar, they formulate the most significant clastic accumulations in the deep sea, which become many of the world＇s most important hydrocarbon reservoirs. Several boreholes in the Qiongdongnan Basin, the north-western South China Sea, have recently revealed turbidity current deposits as significant hydrocarbon res-ervoirs. However, there are some arguments for the potential provenances. To solve this problem, it is es-sential to delineate their sedimentary processes as well as to evaluate their qualities as reservoir. Numerical simulations have been developed rapidly over the last several years, offering insights into turbidity current behaviors, as geologically significant turbidity currents are difficult to directly investigate due to their large scale and often destructive nature. Combined with the interpretation of the turbidity system based on high-resolution 3D seismic data, the paleotophography is acquired via a back-stripping seismic profile integrated with a borehole, i.e., Well A, in the western Qiongdongnan Basin; then a numerical model is built on the basis of this back-stripped profile. After defining the various turbidity current initial boundary conditions, includ-ing grain size, velocity and sediment concentration, the structures and behaviors of turbidity currents are investigated via numerical simulation software ANSYS FLUENT. Finally, the simulated turbidity deposits are compared with the interpreted sedimentary bodies based on 3D seismic data and the potential provenances of the revealed turbidites by Well A are discussed in details. The simulation results indicate that a sedimen-tary body develops far away from its source with an average grain size of 0.1 mm, i.e., sand-size sediment. Taking into account the location and orientation of the simulated seismic line, the consistence between normal forward simulation results and the revealed cores in Well A indicates that the turbidites should have been transported from Vietnam instead of Hainan Island. This interpretation has also been verified by the planar maps of sedimentary systems based on integration of boreholes and seismic data. The identification of the turbidity provenance will benefit the evaluation of extensively distributed submarine fans for hydro-carbon exploration in the deepwater areas.展开更多
Carbonates of Central Luconia, Malaysia, had been serving as hydrocarbon reservoirs for more than 25 years. However, the relationship and impacts of extensive tectonic events to the growth of Miocene carbonates in Cen...Carbonates of Central Luconia, Malaysia, had been serving as hydrocarbon reservoirs for more than 25 years. However, the relationship and impacts of extensive tectonic events to the growth of Miocene carbonates in Central Luconia have not been revealed sufficiently. In this work, two carbonates platforms in the southern part of Central Luconia were used for detailed interpretation and seismic based structural restoration. This work had provided new insight for the interpreta- tion of carbonate growth in Central Luconia and its association with the surrounding tectonic. This work suggested three possible tectonic evolutions from Late Oligocene to Pliocene are responsible for the growth of carbonates in Central Luconia. These stages are equivalent with pre-carbonate stage （Late Oligocene-Early Miocene）, syn-carbonate stage （Middle-Late Miocene） and post-carbonate stage （Pliocene）. Rifting of the South China Sea and subduction of proto-South China Sea are believed to be responsible for the development of faulting during pre-carbonate stage, while movement of the ancient Baram Line is thought to control the parallel striking direction of normal faults during syn- carbonate stage. Finally, subsidence and compaction due to the overburden clastic materials from the prograding deltas is considered as the main reason for the impacts of gravitational tectonics in this area, which corresponding to the post-carbonate stage.展开更多
An important application of spectral decomposition(SD)is to identify subsurface geological anomalies such as channels and karst caves,which may be buried in full-band seismic data.However,the classical SD methods incl...An important application of spectral decomposition(SD)is to identify subsurface geological anomalies such as channels and karst caves,which may be buried in full-band seismic data.However,the classical SD methods including the wavelet transform(WT)are often limited by relatively low time-frequency resolution,which is responsible for false high horizonassociated space resolution probably indicating more geological structures,especially when close geological anomalies exist.To address this issue,we impose a constraint of minimizing an lp(0<p<1)norm of time-frequency spectral coefficients on the misfit derived by using the inverse WT and apply the generalized iterated shrinkage algorithm to invert for the optimal coefficients.Compared with the WT and inverse SD(ISD)using a typical l1-norm constraint,the modified ISD(MISD)using an lp-norm constraint can yield a more compact spectrum contributing to detect the distributions of close geological features.We design a 3 D synthetic dataset involving frequency-close thin geological anomalies and the other3 D non-stationary dataset involving time-close anomalies to demonstrate the effectiveness of MISD.The application of 4 D spectrum on a 3 D real dataset with an area of approximately 230 km2 illustrates its potential for detecting deep channels and the karst slope fracture zone.展开更多
基金Projects 50221402, 50490271 and 50025413 supported by the National Natural Science Foundation of Chinathe National Basic Research Program of China (2009CB219603, 2009 CB724601, 2006CB202209 and 2005CB221500)+1 种基金the Key Project of the Ministry of Education (306002)the Program for Changjiang Scholars and Innovative Research Teams in Universities of MOE (IRT0408)
文摘In order to carry out numerical simulation using geologic structural data obtained from Landmark(seismic interpretation system), underground geological structures are abstracted into mechanical models which can reflect actual situations and facilitate their computation and analyses.Given the importance of model building, further processing methods about traditional seismic interpretation results from Landmark should be studied and the processed result can then be directly used in numerical simulation computations.Through this data conversion procedure, Landmark and FLAC(the international general stress software) are seamlessly connected.Thus, the format conversion between the two systems and the pre-and post-processing in simulation computation is realized.A practical application indicates that this method has many advantages such as simple operation, high accuracy of the element subdivision and high speed, which may definitely satisfy the actual needs of floor grid cutting.
文摘The Pennsylvanian unconformity,which is a detrital surface,separates the beds of the Permian-aged strata from the Lower Paleozoic in the Central Basin Platform.Seismic data interpretation indicates that the unconformity is an angular unconformity,overlying multiple normal faults,and accompanied with a thrust fault which maximizes the region's structural complexity.Additionally,the Pennsylvanian angular unconformity creates pinch-outs between the beds above and below.We computed the spectral decomposition and reflector convergence attributes and analyzed them to characterize the angular unconformity and faults.The spectral decomposition attribute divides the broadband seismic data into different spectral bands to resolve thin beds and show thickness variations.In contrast,the reflector convergence attribute highlights the location and direction of the pinch-outs as they dip south at angles between 2° and 6°.After reviewing findings from RGB blending of the spectrally decomposed frequencies along the Pennsylvanian unconformity,we observed channel-like features and multiple linear bands in addition to the faults and pinch-outs.It can be inferred that the identified linear bands could be the result of different lithologies associated with the tilting of the beds,and the faults may possibly influence hydrocarbon migration or act as a flow barrier to entrap hydrocarbon accumulation.The identification of this angular unconformity and the associated features in the study area are vital for the following reasons:1)the unconformity surface represents a natural stratigraphic boundary;2)the stratigraphic pinch-outs act as fluid flow connectivity boundaries;3)the areal extent of compartmentalized reservoirs'boundaries created by the angular unconformity are better defined;and 4)fault displacements are better understood when planning well locations as faults can be flow barriers,or permeability conduits,depending on facies heterogeneity and/or seal effectiveness of a fault,which can affect hydrocarbon production.The methodology utilized in this study is a further step in the characterization of reservoirs and can be used to expand our knowledge and obtain more information about the Goldsmith Field.
文摘Modem oil industry is on the way of complication of the geological structure to use the latest technologies to analyze available geological and geophysical algorithm---continuous wavelet transform in example of synthetic and real data. of the deposits. This trend requires specialists information. The article describes a new
文摘3D seismic and petrophysical log data interpretation of reservoir sands in “SIMA” Field, onshore Niger Delta has been undertaken in this study to ascertain the reservoir characteristics in terms of favourable structural and petrophysical parameters suitable for hydrocarbon accumulation and entrapment in the field. Horizon and fault interpretation were carried out for subsurface structural delineation. In all, seven faults (five normal and two listric faults) were mapped in the seismic section. These faults were major structure building faults corresponding to the growth and antithetic faults in the area within the well control. The antithetic fault trending northwest-southeast and the normal fault trending northeast-southwest on the structural high in the section act as good trapping mechanisms for hydrocarbon accumulations in the reservoir. From the manual and auto-tracking methods applied, several horizons were identified and mapped. The section is characterized by high amplitude with moderate-to-good continuity reflections appearing parallel to sub-parallel, mostly disturbed by some truncations which are more fault related than lithologic heterogeneity. The southwestern part is, however, characterized by low-to-high or variable amplitude reflections with poor-to-low continuity. Normal faults linked to roll-over anticlines were identified. Some fault truncations were observed due to lithologic heterogeneity. The combination of these faults acts as good traps for hydrocarbon accumulations in the reservoir. Reservoir favourable petrophysical qualities, having average NTG, porosity, permeability and water saturation of 5 m, 0.20423, 1128.219 kD and 0.458 respectively.
文摘In order to detect fault exactly and quickly, cusp catastrophe theory is used to interpret 3D coal seismic data in this paper. By establishing a cusp model, seismic signal is transformed into standard form of cusp catastrophe and catastrophe parameters, including time-domain catastrophe potential, time-domain catastrophe time, frequency-domain catastrophe potential and frequency- domain degree, are calculated. Catastrophe theory is used in 3D seismic structural interpretation in coal mine. The results show that the position of abnormality of the catastrophe parameter profile or curve is related to the location of fault, and the cusp catastrophe theory is effective to automatically pick up geology information and improve the interpretation precision in 3D seismic data.
基金funded by the Fundamental Research Project of CNPC Geophysical Key Lab(2022DQ0604-4)the Strategic Cooperation Technology Projects of China National Petroleum Corporation and China University of Petroleum-Beijing(ZLZX 202003)。
文摘With the successful application and breakthrough of deep learning technology in image segmentation,there has been continuous development in the field of seismic facies interpretation using convolutional neural networks.These intelligent and automated methods significantly reduce manual labor,particularly in the laborious task of manually labeling seismic facies.However,the extensive demand for training data imposes limitations on their wider application.To overcome this challenge,we adopt the UNet architecture as the foundational network structure for seismic facies classification,which has demonstrated effective segmentation results even with small-sample training data.Additionally,we integrate spatial pyramid pooling and dilated convolution modules into the network architecture to enhance the perception of spatial information across a broader range.The seismic facies classification test on the public data from the F3 block verifies the superior performance of our proposed improved network structure in delineating seismic facies boundaries.Comparative analysis against the traditional UNet model reveals that our method achieves more accurate predictive classification results,as evidenced by various evaluation metrics for image segmentation.Obviously,the classification accuracy reaches an impressive 96%.Furthermore,the results of seismic facies classification in the seismic slice dimension provide further confirmation of the superior performance of our proposed method,which accurately defines the range of different seismic facies.This approach holds significant potential for analyzing geological patterns and extracting valuable depositional information.
文摘The detailed structures of the plumbing system of the early Permian Tarim flood basalt were investigated by 3-D seismic imaging.The images show that the Tarim flood basalt mainly erupted from central volcanoes distributed
基金supported by the National Natural Science Foundation of China (No. 40730317)
文摘A common feature in seismic imageries of the crust and mantle is a layering pattern.Layering structures do exist in multiple scales,such as layered strata and unconformities in local and regional scales,and undulating seismic discontinuities in the crust and mantle.However,layering arti-fact also exists due to limitations in seismic processing and data coverage.There is a tendency for seis-mic stacking methods to over-map reflectors and scatters into along-isochron layers.In contrast,seis-mic tomography methods tend to under-map sub-horizontal layers with along-raypath smears and ar-tifacts of various de-mean processes.To better identify signals and artifacts in seismic imageries,it is necessary to understand the origins of various artifacts and make careful comparison between the solu-tions of different data and methods.
基金supported by National Natural Science Foundation of China (Grant No. 41974140)the PetroChina Prospective,Basic,and Strategic Technology Research Project (No. 2021DJ0606)
文摘Spectral decomposition has been widely used in the detection and identifi cation of underground anomalous features(such as faults,river channels,and karst caves).However,the conventional spectral decomposition method is restrained by the window function,and hence,it mostly has low time–frequency focusing and resolution,thereby hampering the fi ne interpretation of seismic targets.To solve this problem,we investigated the sparse inverse spectral decomposition constrained by the lp norm(0<p≤1).Using a numerical model,we demonstrated the higher time–frequency resolution of this method and its capability for improving the seismic interpretation for thin layers.Moreover,given the actual underground geology that can be often complex,we further propose a p-norm constrained inverse spectral attribute interpretation method based on multiresolution time–frequency feature fusion.By comprehensively analyzing the time–frequency spectrum results constrained by the diff erent p-norms,we can obtain more refined interpretation results than those obtained by the traditional strategy,which incorporates a single norm constraint.Finally,the proposed strategy was applied to the processing and interpretation of actual three-dimensional seismic data for a study area covering about 230 km^(2) in western China.The results reveal that the surface water system in this area is characterized by stepwise convergence from a higher position in the north(a buried hill)toward the south and by the development of faults.We thus demonstrated that the proposed method has huge application potential in seismic interpretation.
文摘The Lower Cambrian Longwangmiao Fm gas reservoir in the GaoshitieMoxi area,the Sichuan Basin,is a super giant monoblock marine carbonate gas reservoir with its single size being the largest in China.The key to the realization of high and stable production gas wells in this gas reservoir is to identify accurately high-permeability zones where there are dissolved pores or dissolved pores are superimposed with fractures.However,high quality dolomite reservoirs are characterized by large burial depth and strong heterogeneity,so reservoir prediction is of difficult.In this paper,related seismic researches were carried out and supporting technologies were developed as follows.First,a geologic model was built after an analysis of the existing data and forward modeling was carried out to establish a reservoir seismic response model.Second,by virtue of well-oriented amplitude processing technology,spherical diffusion compensation factor was obtained based on VSP well logging data and the true amplitude of seismic data was recovered.Third,the resolution of deep seismic data was improved by using the welloriented high-resolution frequency-expanding technology and prestack time migration data of high quality was acquired.And fourth,multiple shoal facies reservoirs were traced by using the global automatic seismic interpretation technology which is based on stratigraphic model,multiple reservoirs which are laterally continuous and vertically superimposed could be predicted,and the areal distribution of high quality reservoirs could be described accurately and efficiently.By virtue of the supporting technologies,drilling trajectory is positioned accurately,and the deployed development wells all have high yield.These technologies also promote the construction of a modern supergiant gas field of tens of billions of cubic meters.
文摘Suakin-1 and Suakin-2 wells are in the Sudanese Red Sea segment where the hydrocarbon generation had been proved by previous studies, however, no reasonable reserve was evidenced due to the complexities of the surrounding salt structures. Six seismic lines were tied to Suakin-1 and -2 to delineate the controlling salt tectonics. The salt evacuation (Roho) and other salt bodies were recognized and matched with similar salt structures in analogous stratigraphic conditions as the Gulf of Mexico and Angola margin. While a previous inconsistent interpretation in the study area marked the high amplitude horizon of the Lower Zeit formation as the top of the Dungunab formation. Three seismic features indicated the presence of salt dome (autochthonous): velocity pull-up, dragging of the sedimentary layers forming mini basins around the third feature, which is the relative transparency of the seismic signal in two piercing like bodies. This interpretation similarly demarcated that the salt escaped east-wards, thus the mapped welded salt is believed to be formed after the salt evacuation. A 3D seismic with a far offset and wide range of azimuth is recommended for detailed imaging.
文摘3D seismic prospecting in mining areas of Xieqiao Colliery is a successfulmodel for an advancement from the resource prospecting to mining prospecting stagein coal fields. Its results have proved that faults with a throw of 5-10 m can be detected in an area with good seismogeologic conditions by using 3D seismic technique.Detection of underground tunnels for the first time utilizing 3D seismic data indicates that subsided columns, gotten and mine goaf can be detected using 3D seismic technique, so it has a broad applied prospect.
文摘The Penobscot Field,located within the Scotian Basin offshore Nova Scotia,Canada,represents an underexplored hydrocarbon field with potential for future development.Previous studies have been confined to specific reservoir intervals without integrating multiple stratigraphic levels,and a comprehensive static reservoir characterization and volumetric assessment of the Penobscot Field has yet to be undertaken,constraining its full development evaluation.This study presents a comprehensive characte rization of the field by integrating geological,geophysical,and petrophysical datasets,leading to static hydrocarbon reserve estimation.The workflow involves seismic interpretation,structural modeling,petrophysical evaluation,and static volumetric calculations.Seismic analysis revealed a structu rally complex setting dominated by normal and inverted faults,with reservoir intervals primarily within the Missisauga Formation,which is subdivided into upper,middle,and lower units.Petro p hysical evaluation from well logs and core data identified key reservoir properties,including porosity ranging from 12 % to 28 %,permeability spanning from 1 to 1000 mD,and variable water saturations.Stochastic modeling of facies and petro p hysical attributes provided insights into lateral and ve rtical hete rogeneity.The Penobscot Field's original oil-in-place ranges from 41.6×10~6 m3 to 109.7×10~6 m3,with the Middle Missisauga sands presenting the highest reservoir potential.Fault seal analysis indicated predominantly sealing behavior in the shallow sections and semi-permeable conditions at greater depths,suggesting potential lateral migration pathways.The results underscore the field's hydrocarbon potential while emphasizing the significance of structural complexity,facies distribution,and petrophysical variability in reservoir quality,as well as its potential for future development or utilization of similar sand reservoirs for CO_(2) storage utilization.This work provides the first fully integrated static reservoir model of the Penobscot Field,offering critical insights for delineating the hydrocarbon reservoirs potential and future production strategies in the Scotian Basin.
基金supported by the State Key Research Development Program of China(2022YFC3004603)the National Natural Science Foundation of China(52204197)the Open Subjects of Xinjiang Key Laboratory of Green Mining of Coal Resources,Ministry of Education,China(KLXGY-KB2425).
文摘Constructing underground structures in coastal regions poses significant challenges,particularly due to seawater intrusion,which can cause corrosion and threaten the safety and stability of the caverns and surrounding facilities.A crucial aspect of preventing seawater intrusion lies in accurate mapping of the geological structure of the reservoir area and its proximity to the coastline.This study uses reflection seismic data,borehole ultrasonic imaging,and core samples to identify geological features that influence subsurface stability.The seismic profile revealed a V-shaped or concave-down structure associated with faults,suggesting a down-dropped block within the subsurface.Seismic facies analysis identified chaotic,high-amplitude reflections within basement rocks,indicating highly fractured and faulted zones,possibly including mylonitic rocks.A novel approach is proposed that combines borehole ultrasonic imaging with fractal theory,integrating core photos,seismic attributes,and geophysical analysis.A functional relationship was established between the joint surface density and the joint information dimension within the borehole.Additionally,a relationship was established between fault information dimension and borehole joint surface density.Results showed that the joint information dimensions within the identified fault zones consisttently exceeded 1.775.By applying a threshold of joint information dimension greater than 1.775,15 small-scale structural prediction zones were identified.Subsequent analysis of core photos from the predicted regions confirmed the presence of relatively long fractured zones,demonstrating the high accuracy of the proposed method in identifying small-scale structures.This study presents a comprehensive method for mapping geological structures in coastal areas,providing an essential reference for the identification and management of small-scale features in underground engineering projects.
基金Supported by the Guangzhou Marine Geology Survey,China Geological Survey(No.DD 20160155)。
文摘Focusing on the Zengmu-Beikang Basin in the southern South China Sea,we summarized the regional sequence stratigraphic framework and identified mass-transport complex(MTC)that had developed since the Late Miocene(10.5 Ma),by using high-resolution multibeam bathymetric and 2D seismic datasets.Based on the analysis of high amplitude and continuous seismic reflections within the mass-transport deposits(MTDs),we identified 14 basal shear surfaces(BSS)and divided the MTC into 14 units(MTD1–MTD14 from the youngest to the oldest in numerical order).Two types of seismic facies and five seismic features within the MTDs were recognized,including chaotic and transparent facies(debris flow),chaotic and semi-transparent facies(debris flow),thrust-fold systems,blocks,escarpments,pressure ridges,and normal faults.Analysis of the depositional area,frequency,and vertical extent of the escarpments of the fourteen MTD units revealed their variations in dimensions.Specifically,MTD14–MTD4 exhibited a gradual increase in the size of the deposition unit,with larger-sized MTD7–MTD4;while MTD3–MTD1 showed a gradual decrease in the size.The evolution of the MTDs in the study area is primarily controlled by several factors,including erosion of mass-movement processes(e.g.,slide,slump,and mass flows),sea-level fluctuation and sediment supply,tectonic activity,development of mud diapirs,and topographic influence.It is also plausible that the large-sized MTD7–MTD4 might be formed in the Pliocene due to steep slope gradient and instability caused by the development of mud diapirs,whereas in the Quaternary,the influence of mud diapirs in the shallow strata diminished,and smaller-sized MTD3–MTD1 were formed.
基金sponsored by Important National Science and Technology Specific Projects of China (Grant No.2008ZX05023-005-011 and No. 2008ZX05040-003)the National 973 Program of China (Grant No. 2006CB202208)
文摘Coherence analysis is a powerful tool in seismic interpretation for imaging geological discontinuities such as faults and fractures. However, subtle faults or fractures of one stratum are difficult to be distinguished on coherence sections （time slices or profiles） due to interferences from adjacent strata, especially these with strong reflectivity. In this paper, we propose a coherence enhancement method which applies local histogram specification （LHS） techniques to enhance subtle faults or fractures in the coherence cubes. Unlike the traditional histogram specification （HS） algorithm, our method processes 3D coherence data without discretization. This method partitions a coherence cube into many sub-blocks and self-adaptively specifies the target distribution in each block based on the whole distribution of the coherence cube. Furthermore, the neighboring blocks are partially overlapped to reduce the edge effect. Applications to real datasets show that the new method enhances the details of subtle faults and fractures noticeably.
基金support from the National Basic Research Program(No:2006CB202300)National Natural Science Foundation of China(Grant No:40739906)
文摘In January 2010, the Suining Ms5.0 earthquake occurred in central Sichuan Basin, with the epicenter in Moxi-Longnvsi structural belt and a focal depth of 10 km. Based on structural interpretations of seismic profiles in this area, we recognized a regional detachment fault located at a depth of 9-10 km in the Presinian basement of the Suining area, transferring its slipping from NW to SE orientation. This detachment fault slipped from NW to SE, and underwent several shears and bends, which caused the basement to be rolled in and the overlaying strata fold deformation. It formed a fault-bend fold in the Moxi area with an approximate slip of 4 km. Correspondingly, the formation of the Moxi anticline is related to the detachment fault. With the earthquake＇s epicenter on the ramp of the detachment fault, there is a new point of view that the Suining earthquake was caused by re-activation of this basement detachment fault. Since the Late Jurassic period, under the influence of regional tectonic stress, the detachment fault transfered its slip from the Longmen Mountains （LMS） thrust belt to the hinterland of the Sichuan Basin, and finally to the piedmont zone of southwest Huayingshan （HYS）, which indicates that HYS might be the final front area of the LMS thrust belt.
基金The National Science and Technology Major Project of China under contract No.2011ZX05025-002-02the National Natural Science Foundation of China under contract Nos 41476032,91028009 and 40806019
文摘Turbidity currents represent a major agent for sediment transport in lakes, seas and oceans. In particu-lar, they formulate the most significant clastic accumulations in the deep sea, which become many of the world＇s most important hydrocarbon reservoirs. Several boreholes in the Qiongdongnan Basin, the north-western South China Sea, have recently revealed turbidity current deposits as significant hydrocarbon res-ervoirs. However, there are some arguments for the potential provenances. To solve this problem, it is es-sential to delineate their sedimentary processes as well as to evaluate their qualities as reservoir. Numerical simulations have been developed rapidly over the last several years, offering insights into turbidity current behaviors, as geologically significant turbidity currents are difficult to directly investigate due to their large scale and often destructive nature. Combined with the interpretation of the turbidity system based on high-resolution 3D seismic data, the paleotophography is acquired via a back-stripping seismic profile integrated with a borehole, i.e., Well A, in the western Qiongdongnan Basin; then a numerical model is built on the basis of this back-stripped profile. After defining the various turbidity current initial boundary conditions, includ-ing grain size, velocity and sediment concentration, the structures and behaviors of turbidity currents are investigated via numerical simulation software ANSYS FLUENT. Finally, the simulated turbidity deposits are compared with the interpreted sedimentary bodies based on 3D seismic data and the potential provenances of the revealed turbidites by Well A are discussed in details. The simulation results indicate that a sedimen-tary body develops far away from its source with an average grain size of 0.1 mm, i.e., sand-size sediment. Taking into account the location and orientation of the simulated seismic line, the consistence between normal forward simulation results and the revealed cores in Well A indicates that the turbidites should have been transported from Vietnam instead of Hainan Island. This interpretation has also been verified by the planar maps of sedimentary systems based on integration of boreholes and seismic data. The identification of the turbidity provenance will benefit the evaluation of extensively distributed submarine fans for hydro-carbon exploration in the deepwater areas.
基金Universiti Teknologi PETRONAS, PETRONAS and SHELL for their financial support
文摘Carbonates of Central Luconia, Malaysia, had been serving as hydrocarbon reservoirs for more than 25 years. However, the relationship and impacts of extensive tectonic events to the growth of Miocene carbonates in Central Luconia have not been revealed sufficiently. In this work, two carbonates platforms in the southern part of Central Luconia were used for detailed interpretation and seismic based structural restoration. This work had provided new insight for the interpreta- tion of carbonate growth in Central Luconia and its association with the surrounding tectonic. This work suggested three possible tectonic evolutions from Late Oligocene to Pliocene are responsible for the growth of carbonates in Central Luconia. These stages are equivalent with pre-carbonate stage （Late Oligocene-Early Miocene）, syn-carbonate stage （Middle-Late Miocene） and post-carbonate stage （Pliocene）. Rifting of the South China Sea and subduction of proto-South China Sea are believed to be responsible for the development of faulting during pre-carbonate stage, while movement of the ancient Baram Line is thought to control the parallel striking direction of normal faults during syn- carbonate stage. Finally, subsidence and compaction due to the overburden clastic materials from the prograding deltas is considered as the main reason for the impacts of gravitational tectonics in this area, which corresponding to the post-carbonate stage.
基金financially supported by the National Key R&D Program of China(2018YFA0702504)the Fundamental Research Funds for the Central Universities(2462019QNXZ03)+2 种基金the Scientific Research and Technology Development Project of China National Petroleum Corporation(2017D-3504)the Major Scientific Research Program of Petrochina Science and Technology Management Department"Comprehensive Seismic Prediction Technology and Software Development of Natural Gas"(2019B-0607)the National Science and Technology Major Project(2017ZX05005-004)。
文摘An important application of spectral decomposition(SD)is to identify subsurface geological anomalies such as channels and karst caves,which may be buried in full-band seismic data.However,the classical SD methods including the wavelet transform(WT)are often limited by relatively low time-frequency resolution,which is responsible for false high horizonassociated space resolution probably indicating more geological structures,especially when close geological anomalies exist.To address this issue,we impose a constraint of minimizing an lp(0<p<1)norm of time-frequency spectral coefficients on the misfit derived by using the inverse WT and apply the generalized iterated shrinkage algorithm to invert for the optimal coefficients.Compared with the WT and inverse SD(ISD)using a typical l1-norm constraint,the modified ISD(MISD)using an lp-norm constraint can yield a more compact spectrum contributing to detect the distributions of close geological features.We design a 3 D synthetic dataset involving frequency-close thin geological anomalies and the other3 D non-stationary dataset involving time-close anomalies to demonstrate the effectiveness of MISD.The application of 4 D spectrum on a 3 D real dataset with an area of approximately 230 km2 illustrates its potential for detecting deep channels and the karst slope fracture zone.
