Particle size analysis of some sidewall cores from KU-1 Well, offshore Benin Basin, Nigeria

Abstract

Lithologic description and particle size analyses had been carried out on eight (8) sidewall cores obtained from the reservoir sands of KU-1 Well, offshore Benin  Basin, Nigeria. High resolution core images of the samples under simulated natural and ultraviolet lightning conditions revealed that seven of the samples were  saturated with hydrocarbon in varying degrees. The lithologic description showed that four (4) of the studied samples were medium to fine-grained, poorly to  moderately sorted and moderately consolidated while the remaining four (4) were predominantly fine to very fine-grained, moderately to well sorted and  moderately consolidated. The particle size analysis indicated that the sands were predominantly fine to very fine-grained (70 – 230 US mesh). Some cores  contained significant medium-grained (40 – 60 US Mesh) fractions while a few had coarse-grained (20 – 30 US mesh) fractions. Silt/clay sized fractions were also  substantial, averaging about 30 wt% of the studied core samples. The obtained average grain size for each core provided an invaluable data for gravel packing  operation and screen size selection for oil production within the reservoir from which these cores were obtained.

Keywords: Sidewall Core, Particle Size, Reservoir Sands, Gravel Packing, Screen.