Modeling The Effects of Glauconite on Some Openhole Logs from The Lower Senonian In Egypt


J. G. Patchett, R. Wiley, Amoco Production Company,
Mostafa El Bahr, Gulf of Suez Petroleum Company

SPWLA 34th Annual Logging Symposium, June 13-16, 1993



Glauconite is commonly found in the Lower Senonian of the Gulf of Suez (Nezzazat Group Matulla Forma- tion) and the Egyptian Western Desert (Upper Bahariya Formation) in sufficient quantities to have an impact on density, neutron, Pe, and resistivity log response. Glauc- onite is a complex mineral composed mainly of iron, potassium, and magnesium hydrated aluminum sili- cates. Due to its complex mineralogy in particular varia- tions in iron content, it has a wide range of grain densi- ties. Modeling the effects of glauconite on the responses of density, Pe and neutron porosity logs has been used to improve the determination of porosity and lithology from well log data.