Delayed blending of additives in well treatment fluids

A method of delivering a well treatment fluid composition, said well treatment fluid being selected from the group consisting of fracturing fluid and acidizing treatment fluid, to a hydrocarbon-bearing formation, comprising the steps of:

• providing a well treatment fluid that comprises a surfactant stabilized emulsion, the emulsion comprising a continuous phase and at least one discontinuous phase, the discontinuous phase comprising at least one chemical or biological agent;
• adding and mixing into the fluid, prior to pumping it into the well, at least one chemical that undergoes a chemical reaction or that dissolves in the well treatment fluid composition;
• wherein the chemical that undergoes a chemical reaction or that dissolves causes a change in at least one characteristic of the well treatment fluid selected from the group consisting of (1) pH, (2) alcohol concentration, (3) stabilizing surfactant concentration, (4) organic ion concentration, (5) salinity, and (6) destabilizing surfactant concentration as the chemical reaction proceeds or as the chemical is dissolved;
• and wherein the change in the at least one characteristic causes sufficient destabilization of the emulsion to cause the chemical or biological agent to be released;
• pumping the well treatment fluid into the well before the reaction of the chemical or dissolution of the chemical goes to completion.

A method of delivering a well treatment fluid composition to a hydrocarbon-bearing formation, comprising the steps of:

• providing a well treatment fluid that comprises a surfactant stabilized microemulsion, the microemulsion comprising a continuous phase and at least one discontinuous phase, the discontinuous phase comprising at least one chemical or biological agent;
• adding and mixing into the fluid, prior to pumping it into the well, at least one chemical that undergoes a chemical reaction or that dissolves in the well- treatment fluid composition;
• wherein the chemical that undergoes a chemical reaction or that dissolves causes a change in at least one characteristic of the well treatment fluid selected from the group consisting of (1) pH, (2) alcohol concentration, (3) stabilizing surfactant concentration, (4) organic ion concentration, (5) salinity, and (6) destabilizing surfactant concentration as the chemical reaction proceeds or as the chemical is dissolved;
• and wherein the change in the at least one characteristic causes sufficient destabilization of the emulsion to cause the chemical or biological agent to be released;
• pumping the well treatment fluid into the well before the reaction of the chemical or dissolution of the chemical goes to completion.