Sedimentary characteristics and sand body distributions in the Lower Permian He 8 member, Ordos Basin, China

2021 ◽  
pp. 1-50
Author(s):  
Zhiyuan Lu ◽  
Zhiliang He ◽  
Shizhong Ma ◽  
Yu He
Keyword(s):  
Ordos Basin ◽  
Lower Permian ◽  
Braided River ◽  
River Sand ◽  
Meandering River ◽  
Sedimentary Characteristics ◽  
Fluvial Deposits ◽  
Sand Body ◽  
The Ordos Basin ◽  
Sand Bodies

The Lower Permian He 8 Member (P1h8) in the Ordos Basin is a typical producing zone of tight lithologic gas reservoirs. Analyses of sedimentary characteristics, electrofacies, and sand-body distributions of P1h8, conducted on modern fluvial deposits, outcrops, cores, and well logs, revealed that braided rivers that developed in the Lower P1h8 and Upper P1h8 are characterized by meandering river. Within these fluvial deposits, the procedure consists of analyzing high-resolution sequence stratigraphy and sedimentary dynamics defined from calibrated logging curve signatures and depositional studies. According to modern and ancient fluvial deposits, we have developed a process-based sedimentary conceptual model for interpreting and predicting the distribution and geometries of sand bodies in braided and meandering deposits. The main sand body of the braided river system was bars and channel fill deposits. The braided river sand bodies are distributed over multiple vertical superimpositions and overlapping horizontal connections. The meandering river sand bodies are mainly point-bar deposits, which are bead-shaped and exhibit scattered development in the vertical direction. This comparison indicates that there were significant differences between braided and meandering deposystems. The sand bodies in the Lower P1h8 were multidirectionally connected and primarily distributed in a stacked pattern. In contrast, the sand bodies in the Upper P1h8 were distributed in an isolated manner, and fine grains (mud and silt) were deposited between the sand bodies with poor connectivity. We interpreted the fluvial deposits that control the distributions of the sand body of the He8 Member in the eastern Sulige gas field and constructed a corresponding prediction model of a braided-meandering reservoir. This model will promote understanding of the extent of fluvial deposits and sand-body distribution of P1h8, thus elucidating hydrocarbon-bearing sand units of the Ordos Basin for future exploration.

scholarly journals Soft-sediment Deformation Structures and Sand Body Architecture in the Chang 6 Oil Member of the Upper Triassic Yanchang Formation, Southwestern Ordos Basin, China

2019 ◽  
Vol 23 (2) ◽  
pp. 119-126 ◽  
Author(s):  
Qingshao Liang ◽  
Jingchun Tian ◽  
Feng Wang ◽  
Xiang Zhang
Keyword(s):  
Ordos Basin ◽  
Upper Triassic ◽  
Seismic Events ◽  
Soft Sediment ◽  
Delta Front ◽  
Yanchang Formation ◽  
Sand Body ◽  
Sediment Deformation ◽  
The Ordos Basin ◽  
Sand Bodies

Soft-sediment deformation (SSD) structures of the Upper Triassic Yanchang Formation are laterally widespread in the Ordos Basin. In the Huachi-Qingyang (H-Q) area of the Ordos Basin, the Chang6 oil member of the Upper Triassic Yanchang Formation is among the most significant Mesozoic oil-bearing strata. It is characterized by the development of reservoir sand bodies. During the depositional evolution of the Chang6 oil member, SSD structures induced by paleo-seismic events developed in the H-Q area in the middle of the basin. The SSD structures developed in the sand bodies of the Chang6 oil member are mainly ball-and-pillow structures, fold structures, sand dikes, irregular convolute stratifications and synsedimentary faults. The architecture of the sand bodies resulted from paleo-seismic events and gravity slumping and mainly include two types of structures: 1) SSD structures driven by paleo-seismic events with normal sedimentation (delta front sand body) (SN-SSD) and 2) SSD structures driven by paleo-seismic events with turbidites (formed by delta-front slumping and re-distribution due to seismic action) (ST-SSD). As a consequence, genetic models of the sand bodies formed by different sedimentation processes are established.

Study of the Fluvial Facies Reservoir Sedimentary Characteristics of an Oil Field in China

2013 ◽  
Vol 753-755 ◽  
pp. 66-69
Author(s):  
Sheng Yun Yu ◽  
Qing Yun Meng ◽  
Hai Ying Xu
Keyword(s):  
Sedimentary Environment ◽  
Sedimentary Facies ◽  
Flood Plain ◽  
Oil Field ◽  
Distribution Model ◽  
River Sand ◽  
Meandering River ◽  
Sedimentary Characteristics ◽  
Sedimentary Model ◽  
Sand Body

In this paper, 6 kinds of reservoir sedimentary microfacies distribution model-conceptual model have been established by the use of reservoir sedimentology theory and methods, namely, large sandy braided river sand body sedimentary model, large meandering river sand body sedimentary model, low bending-straight distributary channel sedimentary model, crevasse splay (crevasse river) sedimentary model, heart beach sedimentary model, flood plain and distributary plain sheet sand body sedimentary model. On this basis, the sedimentary facies figures of four sedimentary units have been painted, putting forward the evolution law of sedimentary environment in the research zone, thus providing basic data for the facies control modeling.

scholarly journals Seismic sedimentary characteristics and filling structure of the Upper Triassic Yanchang Formation, Ordos Basin, China

2020 ◽  
Vol 8 (2) ◽  
pp. T259-T274
Author(s):  
Congjun Feng ◽  
Mengsi Sun ◽  
Chiyang Liu ◽  
Xili Deng ◽  
Yuze Xue ◽  
...  
Keyword(s):  
Seismic Reflection ◽  
Ordos Basin ◽  
Yanchang Formation ◽  
Sedimentary Characteristics ◽  
Study Results ◽  
History Of ◽  
The Ordos Basin ◽  
Initial Depression ◽  
Depositional Age ◽  
Seismic Sections

Following the analysis of cores, outcrops, well log, and seismic sections, we have studied the seismic reflection configuration and depositional history of the hydrocarbon-rich Yanchang Formation in the Ordos Basin. We divided the seismic reflection configurations into five types: subparallel reflection, parallel reflection, tangential progradational reflection, shingled progradational reflection, and chaotic reflection. Based on our study results, we concluded that the slopes exhibit differences in the different regions of the Ordos Basin during the sedimentary period of the Yanchang Formation: The slope with the largest gradient of approximately 10°–20° occurred in the southwestern basin, followed by the northwestern basin (with a slope of approximately 1.6°–3.3°), but the slope was relatively gentle in the northeastern basin (approximately 0.8°–1.2°). We also found that the paleocurrent direction of the basin mainly includes two directions: The paleocurrent direction of the southwest region is 186°–259°, which indicates the provenance came from the southwestern region, whereas the paleocurrent direction of the northeast region is 10°–79°, which indicates that the provenance came from the northeastern region. In addition, the Ordos Basin was under isostatic subsidence as a whole during this period, and its sedimentary infilling evolution underwent five stages: the initial depression, intense depression, progradational filling, uplifting and denudation, as well as shrinking and extinction stages, just corresponding with the Chang 10-Chang 9, the Chang 8-Chang 7, the Chang 6-Chang 4+5, the Chang 3-Chang 2, and the Chang 1 depositional age, respectively.

Logging Identification Technology of Sedimentary Facies and Gas Layers within Low Pressure, Low Permeability and Low Abundance Gas Reservoirs: Example from SQW Block of the Sulige Gas Field, Ordos Basin, China

2012 ◽  
Vol 616-618 ◽  
pp. 96-99
Author(s):  
Fang Lu ◽  
Xin Jiang Du ◽  
Zhi Jun Mao ◽  
Yan Zhou ◽  
Yue Bin Cui ◽  
...  
Keyword(s):  
Ordos Basin ◽  
Sedimentary Facies ◽  
Low Pressure ◽  
Low Permeability ◽  
Braided River ◽  
Gas Reservoirs ◽  
Gas Field ◽  
Exploration Target ◽  
The Ordos Basin ◽  
Gas Potential

Sulige Gas Field is located in the Suligemiao area, northwest of the Ordos Basin, with a prospecting area of about 4×104km2. Owing to the strong heterogeneity in the SQW Block, one of exploration blocks in the Sulige Gas Field, remains reservoir characteristics of the gas field: lithologic gas reservoirs with characteristics of “three low” (low pressure, low permeability and low abundance). The He8 member of the Shihezi formation, the major exploration target, is deposited in braided river environment. The conventional logging data is very useful to indentify different facies and to estimate gas potential. The technology of discrimination with sedimentary facies and gas layers using logging data is established in this paper. We use the technology combining with AVO and other exploration methods to pick out 4 favorable exploration target areas with the success rate of more than 80%.

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