Determination of well shut-in time for curing resin-coated proppant particles

A laboratory test apparatus for determining the curing time for a curable resin-coated proppant (CRCP) sample under conditions simulating those encountered in the field during the hydraulic fracturing of subterranean reservoir formations to improve the flow of hydrocarbons, the apparatus comprising:

• a. a pressurized vessel for receiving a quantity of the CRCP sample at ambient conditions;
• b. means for increasing the temperature of the CRCP sample in the vessel at a predetermined rate, to thereby effect the gradual curing of the resin on the sample;
• c. means for recording temperature of the CRCP sample in the vessel;
• and
• d. programmable temperature control means associated with a program that replicates the temperature recovery profile of a reservoir during a fracturing treatment.

A laboratory test method for determining the curing time for a curable resin-coated proppant (CRCP) sample under conditions simulating those encountered in the field during the hydraulic fracturing of subterranean reservoir formations to improve the flow of hydrocarbons, the method comprising:

• a. placing a quantity of the CRCP sample in a pressurized vessel at ambient conditions;
• b. placing velocity transducers in contact with opposing sides of the CRCP sample contained in the pressure vessel;
• c. sealing the pressure vessel and applying an external hydrostatic force of predetermined value to the CRCP sample;
• d. increasing the temperature of the CRCP sample in the vessel at a predetermined rate, to thereby effect the gradual curing of the resin on the sample;
• e. providing means for measuring at least one selected physical characteristic of the CRCP that is associated with the state of cure of the CRCP;
• f. activating the measuring means at periodic intervals as the temperature increases;
• g. measuring the at least one physical characteristic of the CRCP;
• h. recording the temperature in the pressure vessel at which the measured at least one physical characteristic indicates that the resin is cured;
• i. recording the temperature in the pressure vessel at which the maximum wave velocity is attained, said temperature corresponding to the temperature at which the resin coating on the proppant is cured;
• and
• j. correlating and recording the value of the temperature as determined in step (h) with the time required to reach said temperature from a temperature recovery shut-in data source.