Отправлено: 01.05.10 11:38. Заголовок: RELATIONSHIPS BETWEEN SHALE CONTENT AND GRAIN-SIZE PARAMETERS IN THE SAFANIYA SANDSTONE RESERVOIR, N

RELATIONSHIPS BETWEEN SHALE CONTENT AND GRAIN-SIZE PARAMETERS IN THE SAFANIYA SANDSTONE RESERVOIR, NE SAUDI ARABIA
S. Saner*, M. N. Cagatay** A. M. Al Sanounah*
*The Research Institute, King Fahd University of Petroleum and Minerals, Saudi Arabia

**Institute of Marine Sciences and Management, University of Istanbul, Turkey

Copyright 1996 SCIENTIFIC PRESS LTD
ABSTRACT
The grain-size distribution of a sediment is controlled by the hydrodynamics of the depositional environment. There is a relationship between the petrophysical properties of a reservoir rock, such as porosity and permeability, and the grain-size distribution. Therefore, the grain-size distribution is important in interpreting both the depositional environment and the petrophysical properties of a sedimentary rock. Determination of the grain-size parameters from gamma-ray and/or other shale-indicator well logs may be possible if the necessary correlations are established.

Relationships between the shale content and the grain-size parameters of samples from the Lower Cretaceous Safaniya Sandstone Member in NE Saudi Arabia were investigated by grain-size analyses of 47 samples using sieving and a Microscan II particle-size analyzer. Analysed samples were "clean" and "shaly" fine- to very fine-grained sandstones. Grain-size distribution curves revealed a finer mean, poorer sorting, finer skewness, and a leptokurtic distribution with increasing shale content. The shale content associated with the finer grain sizes promoted a reduction in porosity and permeability, which is a common occurrence in sandstones.

In the studied well, a reasonable correlation between the grain-size parameters and the shaliness log was observed. Vertical variations in the parameters for the sequence indicated two coarsening-upwards and one fining-upwards depositional cycles.


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DIGITAL OBJECT IDENTIFIER (DOI)
10.1111/j.1747-5457.1996.tb00436.x About DOI