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This paper gives a contrastive analysis of the main progress made in petroliferous basins sedimentary geology domestically and internationally, and discusses the main problems and their solutions in the development of petroliferous basins sedimentology in China, New developments include coarse-grained depositional sysytem, shallow-water deltic depositional system, beach bar depositional system, deep-water gravity flows, fine-grained depositional system, carbonate reefs, mixosedimentite, microbialite, seismic sedimentology and sedimentary physical simulation. It also reveals the developing gap of Chinese sedimentology in the areas of microbialite and sedimentary simulation, etc. and analyzes the sedimentary features and paleogeography pattern of prototype basins, multi-scale paleogeographic recovery during major tectonic movements, the different explanation of new sedimentology theories in the deep-buried sandbodies development. The paper details the difficulties when it comes to the typical depositional systems combination and the setup of sedimentary models in China. Therefore, the developing tendency is described of sedimentology theories like source to sink, sedimentary dynamics as well as regional sedimentology in China, seismic sedimentology, and studying methods and technologies in sedimentary simulation. Key words: development, shallow-water delta, gravity flow, beach-bar, mixosedimentite, microbialite, seismic sedimentology, sedimentology, China

Based on cores and logging data, and gravity flow theory, the sedimentary characteristics and facies model of gravity flow deposits in the Longdong area in southwestern Ordos Basin were analyzed. Five types of gravity flow deposits are recognized: slides, slumps, sandy debris flows, muddy debris flows and turbidity currents. Affected by multiple provenances, paleogeomorphology and triggering mechanisms jointly, the gravity flows resulted in sublacustrine fans and slump olistoliths in the basin center. Containing channels, the sublacustrine fans can be divided into three subfacies, inner fan, middle fan and outer fan and subdivided into six microfacies, main channel, main channel lateral margin, distributary channel, distributary channel lateral margin, inter-channel and sheeted turbidite sand. It is inferred that they are caused by seasonal floods. The slump olistoliths, with no channels, consist four parts: slide rock, slump rock, debris flow lobe and sheeted turbidite sand, and are inferred to be the product of collapse of break belts triggered by events like earthquakes. Combining facies models with types of gravity flow deposits can reveal the sedimentary characteristics and genetic models of gravity flow deposits in deep water more directly and provide theoretical basis for deep water oil and gas exploration. Key words: gravity flow deposit, genetic type, sedimentary system, sedimentary model, Yanchang Formation, Ordos Basin

The seismic sedimentology characteristics of sub-clinoformal shallow-water meandering river delta can be comprehensively analyzed by core, well logging and 3-D seismic data. This paper summarizes the sedimentary pattern of sub-clinoformal shallow-water meandering river delta of Suning area in Raoyang sag, Jizhong depression of Bohai Bay Basin. In Suning area, there are eight fourth-order sequences recognized from the upper part of Sha 1 Member (Es1s) to Dong 3 Member (Ed3), reflecting periodical change of lake level. From the central lake to the shore, and from the transgressive to highstand systems tracts, the color of mudstones varies from grey to red, showing a drop of lake-level. The seismic reflection pattern indicates the drop of lake level: the shingled reflections in Es1s (SQ?3) indicate water depth of 40−60 m in the lake center, followed by sub-parallel (SQ?4-SQ?6) with lower continuity reflections, and disappearance of shingled reflections, showing water depth no more than 30 m. Analysis of core, well logging, and seismic amplitude strata slices reveal that the sequences SQ?4-SQ?6 of Es1s are sub-clinoformal shallow-water meandering river delta, different from the shingled reflection shallow-water meandering river delta in SQV3 of Es1s. The main seismic sedimentology characteristics are channel forms and lobate landforms advancing to the central lake by multiple zones, indicating numerous distributary channel and deltaic lobes depositions. Key words: shallow-water meandering river delta, sub-clinoformal seismic reflection, seismic sedimentology, Raoyang sag, Bohai Bay Basin

According to the study of petrology, log-phase, seismic facies, and sandstone distribution, the distribution of the Cretaceous rift sedimentary system in Fula sag of the Muglad Basin have been predicted, and the sedimentary models in two rift periods have been established. There developed eight 3rd-order sequences in the two rift periods in the Cretaceous of Fula sag, which have 5 types of sedimentary facies, namely, braided river delta, meandering river delta, fan delta, lacustrine, and turbidite fan. There mainly developed fan delta-meandering river delta facies in the west steep slope, braided river delta-meandering river delta in the east step-fault, and lacustrine and turbidite fan facies in the center of the sag respectively in the Fula sag. It is found from comparison of the depositional models in the two rift periods that, in the depositional stage of Abu Gabra Formation in early Cretaceous, the rifting activity was strong, the distribution of sedimentary system was mainly affected by syn-sedimentary faults, and there were preferential channels and areas of sediments transportation and accumulation; in the depositional stage of Darfur Group in late Cretaceous, the rifting activity weakened, the distribution of sedimentary system was less affected by syn-sedimentary faults, and the sediments were in wide distribution. Key words: rift lake basin, sedimentary facies, depositional model, Sudan, Fula sag, Muglad Basin

The exploration of beach and bar sandstone reservoirs is a tricky issue. In this study, under the guidance of seismic sedimentary theory, the 90° phase shift technique, stratal slicing, and quantitative seismic sedimentology were used to identify and characterize the distribution of beach and bar sandbodies and reflect the evolutionary history in the Chepaizi area, Junggar Basin. Four third-order sequences in the Lower-Cretaceous and relevant systems tracts in the study area were studied using seismic sedimentology, and with the assistance of the comprehensive analysis of core, lithology and well-logging data, stratal slices were interpreted and calibrated, and the distribution and evolution of beach bar sandbodies were predicted. Based on the detailed and extensive analyses on sedimentary characteristics and seismic sedimentary quantitative results, this study established two typical beach and bar sedimentary models in the Chepaizi area, namely normal bedrock-beach bar and fan delta-beach bar. In early sedimentary period of SQ I, beach and bar sandbodies were reformed by coastal, wave and onshore currents, and developed around the lateral margin of the fan delta front. During sedimentary periods of SQ II to SQ IV, the northern provenance stopped supplying sediments, and the wave and coastal currents eroded the bedrock of the western Chepaizi uplift and transported sediments to the study area, forming beach and bar sandbodies parallel to or obliquely intersecting with coastal line. Key words: seismic sedimentology, phase shift, stratal slice, beach and bar, Chepaizi area, Junggar Basin

Seismic diagenetic facies is an important control on reservoir quality. This study investigated the feasibility of predicting sandstone diagenetic facies using conventional 3D seismic data by seismic sedimentology and calibrated by laboratory core-analysis data in the Qijia area of the Songliao Basin. Three core issues are related to seismic characterization of diagenetic facies, including how to correlate stratigraphic and diagenetic units from seismic data, how to evaluate the relationship between core-based diagenetic facies and seismic attributes, and how to find an effective way of mapping seismic diagenetic facies. Well- and seismic-based, high-resolution sequence analysis and seismic stratal slicing provide reservoir-scale (20 m) seismic representations of diagenetic units. Core-based analyses of sandstone diagenetic processes and diagenetic sequences reveal the kind of diagenesis that most influences reservoir quality. An investigation of reservoir parameters and acoustic rock properties further reveals the link between diagenetic facies and impedance, leading to a recognition of calcite cementation as the process that can be detected by seismic data. A seismic-based lithology cube (e.g., 90°-phased seismic volume) provides the amplitude (impedance) signal for detection of diagenetic facies. Stratal slices made from the seismic-based lithology cube are then used to interpret depositional facies and systems. Eventually a seismic diagenetic-facies map is generated through analysis of the relationships between depositional facies, impedance, and diagenetic facies. A case study of clay- and calcite-cemented sandstone in the Qijia area shows that although still in its infancy, seismic detection of sandstone diagenetic facies using conventional seismic data is definitely feasible. Key words: seismic diagenetic facies, seismic detection of diagenetic facies, seismic sedimentology, diagenesis, sandstone

This study summarizes the research experiences of non-marine seismic sedimentology in recent years in China and uses Qijia area, Songliao Basin, as a template to establish general guidelines for seismic sedimentology. Basic data sets include stacked 3D seismic volumes, 2D regional seismic lines, data for regional geologic settings, and well data. The workflow emphasizes the integration of seismic and geologic interpretations and balanced use of seismic sedimentology, sequence stratigraphy and seismic stratigraphy. Basic steps include well-to-seismic tie for the establishment of sequence framework, wavelet-phase adjustment, picking of geologic-time parallel seismic events, seismic resolution analysis, petrophysical analysis, selection of seismic attributes, stratal slicing, seismic depositional facies analysis, and applications to exploration and development. Expected maps range from key interpreted well-seismic sections, flattened relative geologic-time sections, stratal slices, and depositional facies maps, etc. The workflow is applied in the study of the Cretaceous Qingshankou Formation in the Qijia area, Songliao Basin, which can be used as a reference for seismic sedimentologic study in non-marine basins, especially in postrift depression-type basins in China. Key words: non-marine postrift basin, seismic sedimentology, guidance, workflow, thin bed, shallow-water delta

On the basis of a large number of core and thin-section observations, the petrologic and pore evolution characteristics of welded tuffs in the Fengcheng Formation in the Wu-Xia area, Junggar Basin, are evaluated, and the genesis of vesicular welded tuffs and the formation mechanism of vesicles are analyzed. Volcanic activity in the Fengcheng Formation is characterized by welded pyroclastic rocks. There are predominant plastic shards with rounded edges and obvious devitrification in the rocks. Plastic debris (fiamme) is commonly deformed and wrinkled, and crystal fragments are usually corroded. A lot of lithophysae occur in the welded tuffs, and the welded texture is obscured due to the occurrence of these lithophysae features. Vesicles are the cavities of lithophysae, which are formed by solidification contraction. They have little or no late filling cement because the volatile constituent and water vapour in the bubbles have escaped with the help of devitrification. Lithophysae distribution within a cooling unit are characterized by vertical zonation: increasing upwards but decreasing gradually later. The cavities of lithophysae have greatly improved the reservoir quality of welded tuffs. Influenced by the intensive welding process, lithophysae are not subject to collapse or damage. In the study area, deeply buried vesicular welded tuffs are important hydrocarbon reservoir rocks, and the vesicular welded tuff has good petroliferous properties. Key words: welded tuffs, vesicle, lithophysa, pyroclastic flow, Fengcheng Formation, Wu-Xia area, Junggar Basin