Litter decomposes slowly on shaded steep slope and sunny gentle slope in a typical steppe ecoregion

According to the cores, outcrops, seismic data and wire-line logs, the main influences exerted by slope gradient on sedimentation of lacustrine delta are as follows: 6 kinds of microfacies assemblages are recognized in the elaborate development area and 3 sequences of these assemblages are identified in the well correlation along provenance; the bars-rich delta front is developed in steep slope while the river-rich delta front in gentle slope. The exploration and development experience indicate the reservoirs formed in steep area are favorable for well-connected sandbodies and high sand-bearing ratios.

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Source-to-sink system and its sedimentary records in the continental rift basins: An example from the Paleogene in the Bohai Sea Area, China

Interpretation ◽

10.1190/int-2017-0024.1 ◽

2017 ◽

Vol 5 (4) ◽

pp. ST35-ST51 ◽

Cited By ~ 3

Author(s):

Changgui Xu ◽

Xiaofeng Du ◽

Hongtao Zhu ◽

Donghui Jia ◽

Wei Xu ◽

...

Keyword(s):

Bohai Sea ◽

Steep Slope ◽

Continental Rift ◽

Gentle Slope ◽

The Bohai Sea ◽

Base Level ◽

Source To Sink ◽

Coupling System ◽

Sea Area ◽

Valley Type

The “source-to-sink” concept originated in the study of global change and atmospheric pollution. In recent years, the concept of a source-to-sink system has been widely applied in continental margin sedimentary analysis. In our research, the idea of source-to-sink is applied to the continental rift basin sedimentary system in the Bohai Sea area. The idea emphasizes that the sedimentation dynamics, including erosion, transportation, and accumulation, are considered as a complete source-to-sink system. The sand-rich region often corresponds to a source-to-sink coupling system in a complex continental rift basin, which includes the effective provenance, high-efficiency routing system, and base-level transition. In addition, (1) the effective provenance can be subdivided into explicit and implicit provenance systems in which the implicit provenance system has been shown to be a significant advancement in reservoir prediction for the Bohai Sea area, (2) the sediment-transport pathways and slope-break zone constitute the routing systems, and (3) the base-level transition is one of the allogenic factors that controls the position of the sandstone distribution in a sequence. Based on a large number of previous studies and different characteristics of sequence-stratigraphic models in the Bohai Sea area, we have evaluated three types of source-to-sink systems, including the fault-steep slope, strike-slip fault slope, and gentle slope pattern. In addition, the fault-steep-slope source-to-sink coupling system can be further subdivided into four types, namely, the corner, relay ramps, fault-throw diminishment-type, and valley-type source-to-sink systems. The source-to-sink system of the gentle slope pattern includes the uplift axis valley-type source-to-sink system and the slope-valley-type source-to-sink system. A small-scale, thick layer of fan delta is formed in the fault-steep-slope zone. A continuous braided river delta is formed in the strike-slip fault slope zone. A large-scale, thin layer of braided river delta is formed in the gentle slope zone. The characteristics of source-to-sink systems in continental rift basins are established for the exploration or prediction of favorable zones in the study area, as well as in similar basins.

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Analysis of Sandbody Development Model in Lishui Depression

Earth Science Research ◽

10.5539/esr.v7n2p74 ◽

2018 ◽

Vol 7 (2) ◽

pp. 74

Author(s):

Guowei Hou ◽

Jinshui Liu ◽

Kun Cai ◽

Yonggang Wang

Keyword(s):

Oil And Gas ◽

Control Model ◽

Steep Slope ◽

Development Model ◽

Oil And Gas Exploration ◽

Development Models ◽

Gentle Slope ◽

Body Development ◽

Sand Body ◽

Sand Control

To a certain extent, the development of sand body in lishui depression determines the success of oil and gas exploration, so the development models of sand body become the focus of current research. Based on seismic interpretation and exploration practice, five types of sand body development model were developed in lishui depression, including gentle slope-valley typed sand control model, steep slope-valley typed sand control model, trough fault controlling axial typed sand control model, gentle slope -contemporaneous fault typed sand control model and bulge steep slope-cross section typed sand control model.Different sand body development model determines the development characteristics of sand body and indicates the direction of exploration.

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