--> Abstract: Reservoir Flow Unit Characterization of Complex Channel Sandstone Units in Baolang Oilfield, Yanqi Basin, West China; #90063 (2007)

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Reservoir Flow Unit Characterization of Complex Channel Sandstone Units in Baolang Oilfield, Yanqi Basin, West China

 

Yao, Guangqing1, Fengde Zhou1, Timothy R. Carr2, Jiahao Wang1, Shangru Sun3 (1) China University of Geosciences, Wuhan,Hubei, China (2) Kansas Geological Survey, University of Kansas, Lawrence, KS (3) Henan oilfield company , Sinopec, Nanyang, China

 

Low permeability reservoirs (k≤50 md) are common in the Mesozoic continental units of western and central China. One example, the Baolang oilfield (Jurassic) located in the Yanqi Basin, Xinjiang, West China, has entered a period of rapid decrease in productivity. An incomplete model for this complex reservoir has contributed to the rapid increase in water cut and low estimated ultimate oil recovery. This study applied an integrated approach to undertake a detailed recognition and division of the reservoir flow units at Baolang field. Available data include cores, digital well-logs, petrophysical data, and production histories. The overall framework is a complex of heterogeneous clastic reservoir units deposited as braid-delta and distributary braid-channel sand bodies. Routine core plug data (porosity and permeability) were used to define five types of flow units by generating a flow zone index (FZI). Based on FZI, the petrophysical parameters in un-cored well were calculated by well-log data, and reservoir geological model was constructed across the field. Flow-unit types defined by the FZI have a strong relationship with the pore texture, permeability, and are controlled by lithofacies and diagenesis. Reservoir production and whole core data indicate fracturing present in the reservoirs can enhance permeability. In the defined flow units, predicted reservoir quality has a strong relationship to water injectivity and produced oil and water volumes at Baolang Field. At Baolang Field, the integrated characterization studies of sedimentary facies and transformation to flow-unit analysis have significantly improved the oil recovery ratio, and may be applicable to other complex clastic reservoirs.

 

AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California