Overburden Stress From Linear Bulk Density Function

overburden-stress-bulk-density

Bulk Density vs Depth

Overburden Stress (Sv) vs Depth

Ref. Bulk Density 1 (kg/m³)

TVD Depth for Ref. Bulk Density 1 (m)

Ref. Bulk Density 2 (kg/m³)

TVD Depth for Ref. Bulk Density 2 (m)

Bulk Density=m*TVD+b

Bulk Density depth function, m constant

Bulk Density depth function, b constant

True Vertical Depth of Reservoir (m)

Sv at reservoir TVD (MPa)

Sv gradient at reservoir TVD (kPa/m)

Instructions

This crossplot is used to estimate overburden stress. A linear bulk denisty function is used (Bulk Density=m*TVD+b), along with an integration table.

Inputs are highlighted in yellow and outputs are in green. Start by entering two average bulk density values, at two different depths (from intervals on logs which do not suffer from bad hole conditions). Next, fit the bulk density function to the reference points by changing the slope (m) and intercept (b) values. Finally, enter the true vertical depth of the reservoir. Outputs include overburden stress and overburden stress gradient.

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