Cementation Exponent m. Function and Calibration – Petrophysics Consultant & Training

1. Cementation Cementation Exponent Exponent m. m. Function Function and Consultant Consultant & & Training and Calibration Calibration – – Petrophysics Training Petrophysics The purpose of m is not to convert O and a*Rw from the log evaluation into the log evaluation of Ro (water saturated formation resistanceivity), but to make the log analysis report on the reservoir saturation. m refers to an internal log analysis parameter. It is unfit for purpose if it fails to generate RO from log data (not Core data). Because the laboratory scale is smaller than the scale of the Rt log, it is not able to simulate in-situ conditions. Log analysis "equations” assume that inputs came from the same rock piece, but this is not true if the inputs are different in scale. This is evidently the case in SCAL m, and logged Rt in heterolithic facies. We have the ability to access log data for Ro as well as M, which allows us to determine the water zones (Sw100 Zones from side-walls. cuttings. and chromatograph) that span a range O within rocks of the same type (similar O- k crossplots). We ignore Nature's reservoir conditions m laboratory, and instead try to create them in the laboratory. Why? This faith in core data is a mistake. Focus on the actual data used in the evaluation and consider the objectives of each step. Saturation Exponent. n. Function. Calibration The goal of n is conversion of log evaluation's value Ro/Rt into actual reservoir Sw. As heterogeneity grows, the log evaluation's metre-scale estimate of Rt/Ro differs from the lab’s cm-scale measurement of Rt/Ro. The n definition plot is used to determine the value of n. It is commonly found in core analysis reports. The n definition plot shows that n is the slope of Log(Sw vs. log(Rt/Ro). This plot is typically populated with core data, but the Rt/Ro scale for the evaluation will not be measured. Log analysis is prone to erroneous answers. The n definition plot can work more efficiently if you consider the objective and concentrate on the data that will be used for the evaluation. This author uses the following approach to calculate n. He populates the n definition plot using sensible data. This is core data, not cm scale core unless we have the opportunity to deal with homogeneous "blockysand" at a metre scale. Do not be deceived into believing that you know the right answer for m or n because you have done core SCAL analysis. Think. All Integrated Petrophysics consultant & training courses available in whole, part or re-assembled. Delivered via Zoom or similar. Live or canned sessions. These are the best petrophysics courses at the best rates