US 11,702,924 B2
Determination of stimulated reservoir volume and estimated ultimate recovery of hydrocarbons for unconventional reservoirs
Hui-Hai Liu, Houston, TX (US); Jilin Zhang, Houston, TX (US); Huseyin Onur Balan, Katy, TX (US); and Feng Liang, Houston, TX (US)
Assigned to ARAMCO SERVICES COMPANY, Houston, TX (US)
Filed by ARAMCO SERVICES COMPANY, Houston, TX (US)
Filed on Jan. 8, 2021, as Appl. No. 17/144,677.
Prior Publication US 2022/0220839 A1, Jul. 14, 2022
Int. Cl. E21B 43/26 (2006.01); E21B 47/003 (2012.01)
CPC E21B 47/003 (2020.05) [E21B 43/26 (2013.01); E21B 2200/20 (2020.05)] 2 Claims
OG exemplary drawing
 
1. A method, comprising:
creating a plurality of hydraulic fractures using a horizontal well in an unconventional reservoir, wherein the unconventional reservoir comprises a plurality of stimulated zones;
producing, using a production well comprising the horizontal well, hydrocarbon fluid from the unconventional reservoir;
monitoring, via a monitor disposed at a well head of the production well in the unconventional reservoir, an amount of the hydrocarbon fluid that is produced from the production well, and monitoring a density of the hydrocarbon fluid;
obtaining a cumulative amount of the hydrocarbon fluid that has accumulated over time from a beginning of reservoir production;
obtaining a relationship between the cumulative amount of the hydrocarbon fluid as a function of production time and a square root value of the production time in the function;
determining, by the monitor, a deviation point where the relationship changes from linear to non-linear;
determining, by the monitor, a deviation amount of the hydrocarbon fluid that corresponds to the deviation point;
determining, by the monitor, a first density of the hydrocarbon fluid under a reservoir condition of the hydrocarbon fluid being produced at the production well, a second density of the hydrocarbon fluid at a pore pressure equal to a bottom hole pressure in the production well, a first porosity under reservoir condition at the beginning of reservoir production, and a second porosity of the reservoir for a pore pressure equal to the bottom hole pressure in the production well;
determining, by the monitor, stimulated reservoir volume (SRV) and estimated ultimate recovery (EUR) for the unconventional reservoir based on the deviation amount, the first density, the second density, the first porosity, and the second porosity,
wherein the SRV is calculated as

OG Complex Work Unit Math
where Qc is the deviation amount, mi is a product of the first density and the first porosity, and mw is a product of the second density and the second porosity, and
wherein the EUR is calculated as
EUR=√1.5πQc,
where Qc is the deviation amount; and
managing, at the production well using the monitor, the hydrocarbon fluid based on the SRV and the EUR of the unconventional reservoir.