Slide 10 of 31
Standard porosity measurements can often be inconclusive for defining permeability and producibility. For example, these rock samples have equivalent porosity but different permeability and producibility characteristics. The thin sections on these cores show different pore size distributions and silt content. The information provided by these thin sections is important, but it is expensive and impractical to analyze all the zones of interest this way. This is where the CMR Combinable Magnetic Resonance tool can be of value.
The CMR tool can take a measurement of pore size distribution every 6 in. in the well.
This measurement enables us to determine permeability and, hence, producibility over the zone of interest.
The CMR transverse relaxation time, or T2 measurement, which is the area under the red curve, is directly proportional to porosity, and the decay rate relates to pore size. Short times indicate small pores and low permeability, while longer times indicate larger pores with generally higher permeabilities. These two samples have about the same T2 amplitude, indicating similar porosity characteristics, but the considerably different relaxation times clearly identify the sample with higher permeability.