A Study on Triassic Shale Gas Reservoir Characteristics from Ordos Basin

Unconventional reservoirs are keys to oil and gas exploration and development, especially shale gas reservoirs. Discriminated shale gas reservoir lithofacies are, in particular, a primary problem in shale gas reservoir engineering. The mineral composition will affect both absorbed and free gas contents, therefore their identification is important. The mineral composition is one part of lithofacies. The shale content has always been used in previous lithological identifications: this method is effective in sand reservoirs; however, it is not suitable for use in shale gas reservoirs. This paper takes No.7 section in Yanchang formation in Ordos basin as an example. Through a lithological analysis, it was concluded that overlap method and cross-plot method are not also inappropriate for shale gas reservoirs. The Ordos basin shale gas reservoir is divided into seven lithofacies. We form a mathematical method and apply it to shale gas reservoirs using the shale volume and ΔlgR which are available from conventional well logging and reflect organic matter in the processed dataset. Decision tree is used here. However, there were too many parameters to discriminate all lithofacies precisely. Principal component analysis (PCA) is a technique used to reduce multidimensional data sets to lower dimensions for analysis. This technique can be useful in petro-physics and geology as a preliminary method of combining multiple logs into a single entity or two logs without losing information. Combining PCA and a decision tree algorithm, the lithofacies of a shale gas reservoir were accurately discriminated.

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An Identified Method for Lacustrine Shale Gas Reservoir Lithofacies Using Logs: A Case Study for No. 7 Section in Yanchang Formation in Ordos Basin

The Open Petroleum Engineering Journal ◽

10.2174/1874834120150625e012 ◽

2015 ◽

Vol 8 (1) ◽

Author(s):

Hongyan Yu ◽

Zhenliang Wang ◽

Hao Cheng ◽

Qianqian Yin ◽

Bojiang Fan ◽

...

Keyword(s):

Shale Gas ◽

Ordos Basin ◽

Gas Reservoir ◽

Yanchang Formation ◽

Shale Gas Reservoir ◽

Lacustrine Shale

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Feasibility Study on Technology Named Liquid Explosive Applied in Volume Fracturing Transformation of Shale Gas Reservoir

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.538-541.2281 ◽

2012 ◽

Vol 538-541 ◽

pp. 2281-2284

Author(s):

Jin Jun Wu ◽

Li Cai Liu

Keyword(s):

Feasibility Study ◽

Shale Gas ◽

Optimization Design ◽

Design Method ◽

High Energy ◽

Liquid Explosive ◽

Gas Reservoir ◽

Reservoir Characteristics ◽

Shale Gas Reservoir ◽

Volume Fracturing

According to Chinese shale gas reservoir characteristics and its exploitation situation, based on principle of high energy gas fracturing, combined with theory on volume transformation technology of shale gas reservoir, the feasibility study of liquid explosive technology applied in volume fracturing transformation of shale gas reservoir is precede. Through analyzing action mechanism of liquid explosive technology, studying forming mechanism about multi-crack system produced in shale gas reservoir, and analyzing shale gas reservoir characteristics and drilling and completion technologies, etc., proving the feasibility of technological principle and process design about liquid explosive technology applied in volume transformation of shale gas reservoir, meanwhile, proposing the design adopts the technology combined hydraulic fracturing and liquid explosive together. Also advising to establish theoretical model and optimization design method through series of studying and experiments, and to do field test application, so as to provide a new technology way for its exploration and exploitation.

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