US 12,332,157 B2
Methods and systems for determining reservoir and fracture properties
Otto Meza Camargo, Dhahran (SA); Tariq Mahmood, Dhahran (SA); Khalid Hawas, Dhahran (SA); and Antonio Santagati, Dhahran (SA)
Assigned to Saudi Arabian Oil Company, Dhahran (SA)
Filed by Saudi Arabian Oil Company, Dhahran (SA)
Filed on Apr. 22, 2021, as Appl. No. 17/237,284.
Prior Publication US 2022/0341835 A1, Oct. 27, 2022
Int. Cl. G01N 15/08 (2006.01); E21B 47/002 (2012.01); E21B 49/02 (2006.01); G01N 33/24 (2006.01); G01V 20/00 (2024.01)
CPC G01N 15/088 (2013.01) [E21B 49/02 (2013.01); G01N 33/241 (2013.01); G01V 20/00 (2024.01); E21B 47/002 (2020.05); E21B 2200/20 (2020.05)] 12 Claims
OG exemplary drawing
 
1. A method for determining properties of a subsurface formation comprising:
obtaining an intact core plug sample and a fractured core plug sample from the subsurface formation;
conducting a first mechanical laboratory test on the intact core plug sample that comprises performing a conventional core analysis for porosity and permeability of the intact core plug sample, and determining a matrix porosity and a matrix permeability sensitivity to stress for the intact core plug sample at confined pressure conditions;
conducting a second mechanical laboratory test on the core plug sample after it has been fractured, that comprises performing the conventional core analysis for porosity and permeability of the fractured core plug sample, and determining a total porosity and a total permeability sensitivity to stress for the fractured core plug sample at the pressure conditions;
determining a fracture porosity for the fractured core plug sample based on the matrix porosity and the total porosity;
determining a fracture permeability sensitivity to stress for the fractured core plug sample based on the matrix permeability sensitivity to stress and the fracture permeability sensitivity to stress;
obtaining a borehole image log interpreted by using an electrical imaging tool;
determining a plurality of fracture features for the subsurface formation by performing aperture calculations of the subsurface formation using the borehole image log;
determining a geomechanical model and one or more fracture drivers for the fractured core plug sample based on the plurality of fracture features and the fracture porosity;
performing, using the geomechanical model and the one or more fracture drivers, fracture model predictions for a plurality of discrete fracture network realizations to determine a fracture porosity model associated with the subsurface formation;
calculating a fracture pore volume in the subsurface formation based on the fracture porosity model and a rock bulk volume associated with the subsurface formation; and
estimating oil gas reserves in the subsurface formation based on the fracture pore volume.