Systems and methods for controlling flow rate in a focused downhole acquisition tool

A downhole fluid testing system comprising:

• a downhole acquisition tool housing configured to be moved into a wellbore in a geological formation, wherein the wellbore or the geological formation, or both, contains a fluid that comprises a native reservoir fluid of the geological formation and a contaminant;
• a plurality of sensors disposed in the downhole acquisition tool housing that are configured to analyze portions of a first portion of the fluid and a second portion of the fluid and obtain sets of fluid properties of the first and second portions of the fluid;
• a guard probe configured to flow the first portion of the fluid at a guard flow rate;
• a sample probe configured to flow the second portion of the fluid at a sample flow rate;
• and
• a data processing system configured to:
• adjust the guard flow rate over pump time of the fluid, after a contamination level of the first portion of the fluid is at or below a contamination level threshold, based on a total flow rate weighted average fluid property of the first portion of the fluid and the second portion of the fluid and an initial guard flow rate, an initial sample flow rate, or both, wherein the total flow rate weighted average fluid property comprises the fluid property of the first portion of the fluid and the fluid property second portion of the fluid measured over the pump time;
• and
• adjust the sample flow rate based on the adjusted guard flow rate and the total flow rate.

One or more tangible, non-transitory, machine-readable media comprising instructions to:

• receive a plurality of fluid parameters of a first portion and a second portion of a fluid as analyzed by a downhole acquisition tool in a wellbore in a geological formation, wherein the wellbore or the geological formation, or both, contains the fluid, wherein the fluid comprises a mixture of native reservoir fluid of the geological formation and a contaminant;
• determine an initial guard flow rate of the first portion of the fluid flowing through a guard probe of the downhole acquisition tool;
• determine an initial sample flow rate of the second portion of the fluid flowing through a sample probe of the downhole acquisition tool;
• determine a guard flow rate of the first portion of the fluid over pump time based on a cumulative contamination level of the second portion of the fluid and the initial guard flow rate;
• and
• adjust a sample flow rate of the second portion of the fluid based on a relationship between the guard flow rate and a total flow rate of the fluid through the downhole acquisition tool when the contamination level of the first portion of the fluid is at or below a contamination level threshold.