NOVELTY - The method involves positioning a first flow rate regulator (50) in a first interval of a wellbore, where the first flow rate regulator is part of a first sand control assembly. A second flow rate regulator is positioned in a second interval of the wellbore, where the second flow rate regulator is part of a second sand control assembly. Reservoir fluid is caused or allowed to simultaneously flow through the first and second flow rate regulators into a tubing string, where the reservoir fluid is commingled into a single fluid stream within the tubing string.    USE - Method for simultaneously producing reservoir fluid e.g. liquid or gas and water, from zones of a subterranean formation in a well e.g. oil, gas or water production well, injection well and geothermal well, in oil and gas industry.    ADVANTAGE - The method enables utilizing a diffuser to be designed, so that desired decrease in velocity and desired fluid angle occurs so as to eliminate erosion to sleeve assembly components and flow rate regulators. The method enables moving a plate closer to an inlet, thus maintaining flow rate of fluid exiting the flow rate regulator within optimal flow rate range. The method enables avoiding need to require external intervention to operate the flow rate regulator during production. The method enables regulating flow rate of produced reservoir fluids from a multi-zone formation that is inexpensive and does not add complications or length to a completion system.    DETAILED DESCRIPTION - The first and second flow rate regulators are a nozzle and a friction tube. The wellbore is an open-hole wellbore and a cased-hole wellbore. The tubing string is a production tubing string. An INDEPENDENT CLAIM is also included for a sand control completion system.    DESCRIPTION OF DRAWING(S) - The drawing shows a cross-sectional view of a sand control completion system with a closed sleeve.    Sand control screen (38)    Sleeve assemblies (40)    Ports (44)    Shroud (47)    Flow rate regulator (50)