Formation evaluation

Workflow

Well X-4

Data Available• GR, Caliper• Resistivity – RT, RXO, Deep,

Medium and Micro (MSFL)• Density, Neutron Porosity,

Sonic

Lithology selection1. Generate Xplot

a) Sonic-Neutronb) Sonic-Densityc) Neutron-density

2. Keep GR as Z axis3. Get regression line for low GR

(clean formations)4. Best match was observed for

Limestone formation

Steps1. Calculating X-plot porosity

from Neutron and Density (Call it PHIND)

2. Calculating X-plot porosity from Neutron and Sonic (Call it PHINS).

3. Compare PHIND and PHINS with core porosity.

4. Select PHIND for calculating effective porosity (PHIE)

Steps1. Calculate Clay Volume VCL

from GR using GR Matrix = 60 and GR shale=105.

2. Calculate PHIE = PHIND – VCL*0.2 (assuming 20% for shale, corresponds to shaly zone at the bottom).

3. Calculate Sw from Archies Equation by using a. PHIND as porosityb. PHIE as porosity

Screenshots

Steps• Calculate NTG = if

((PHIE>=0.1) AND (SWE<=0.5), 1, 0)

X1-Quicklook

X1 – Quick look Analysis

X1- Detailed Log Analysis