US 12,242,011 B2
Method for estimating water saturation in gas reservoirs using acoustic log P-wave and S-wave velocites
Sheyore John Omovie, Parker, CO (US)
Assigned to GOSHEY ENERGY SERVICES, LLC, Parker, CO (US)
Filed by Goshey Energy Services LLC, Parker, CO (US)
Filed on May 3, 2024, as Appl. No. 18/654,884.
Claims priority of provisional application 63/563,884, filed on Mar. 11, 2024.
Claims priority of provisional application 63/530,494, filed on Aug. 3, 2023.
Prior Publication US 2025/0044474 A1, Feb. 6, 2025
Int. Cl. G01V 1/52 (2006.01); G01N 29/04 (2006.01); G01N 33/24 (2006.01)
CPC G01V 1/52 (2013.01) [G01N 29/043 (2013.01); G01N 33/241 (2013.01); G01N 33/246 (2013.01); G01N 2291/02441 (2013.01); G01N 2291/0422 (2013.01); G01V 2200/16 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A system of estimating hydrocarbon saturation of a hydrocarbon reservoir where at least an oil rig is operated to create a first wellbore into the hydrocarbon reservoir, the system comprising:
an acoustic logging system, comprising:
a motor and a cable, or a drill bit and at least one drilling pipe; and
an acoustic measuring device positioned horizontally adjacent to the hydrocarbon reservoir within the first wellbore;
a processor, wherein the processor is configured to:
measure a compressional wave of a hydrocarbon-bearing interval within a first subsurface reservoir;
measure a shear wave of the hydrocarbon-bearing interval across the first subsurface reservoir;
determine a velocity of the compressional wave of the hydrocarbon-bearing interval;
determine a velocity of the shear wave of the hydrocarbon-bearing interval;
determine a fully brine-saturated trend for the hydrocarbon reservoir;
determine a fully hydrocarbon-saturated trend for the hydrocarbon reservoir;
determine a water saturation of the hydrocarbon reservoir based on a deviation of the velocity of the compressional wave of the hydrocarbon-bearing interval and the velocity of the shear wave of the hydrocarbon-bearing interval from the fully brine-saturated trend and the fully hydrocarbon-saturated trend; and
estimate the hydrocarbon saturation of the hydrocarbon reservoir based on the determined water saturation, wherein the fully brine-saturated trend and the fully hydrocarbon-saturated trend are determined in terms of velocity ratio and shear sonic log or velocity ratio and compressional sonic log,
wherein the determined water saturation is based on:

OG Complex Work Unit Math
wherein a0 is a coefficient of Vp/Vs where Vp is a velocity of a compressional wave and Vs is a shear wave velocity; b0 is a coefficient of shear acoustic log (DTS), c0 is an intercept of the fully hydrocarbon-saturated trend; a100 is a coefficient of Vp/Vs where Vp is a velocity of a compressional wave and Vs is a shear wave velocity, b100 is a coefficient of DTS, c100 is an intercept of the fully brine-saturated trend, and Swt is a water saturation fraction of a total pore space at each lateral depth; or
wherein a0 is a coefficient of a bulk modulus (KB), b0 is a coefficient of a shear modulus G, c0 is the intercept of the fully hydrocarbon-saturated trend, a100 is a coefficient of KB, b100 is a coefficient of G; c100 is the intercept of the fully brine-saturated trend, and Swt is water saturation fraction of a total pore space at each lateral depth; or
wherein a0 is a coefficient of Vp where Vp is a velocity of a compressional wave, b0 is a coefficient of Vs where Vs is a shear wave velocity, c0 is a coefficient of the fully hydrocarbon-saturated trend; a100 is a coefficient of Vp where Vp is a velocity of a compressional wave, b100 is a coefficient of Vs where Vs is a shear wave velocity, c100 is a coefficient of the fully brine-saturated trend, and Swt is water saturation fraction of a total pore space at each lateral depth; or
wherein a0 is a coefficient of Vp/Vs where Vp is a velocity of a compressional wave and Vs is a shear wave velocity, b0 is a coefficient of compressional acoustic log (DTC), c0 is the intercept of the fully hydrocarbon-saturated trend, a100 is a coefficient of Vp/Vs where Vp is a velocity of a compressional wave and Vs is a shear wave velocity, b100 is a coefficient of DTC, c100 is the intercept of the fully brine-saturated trend, and Swt is water saturation fraction of a total pore space at each lateral depth.