Acidic Gel Fracturing Fluid (For CO2 Foam Fracturing)

1. System Characterizations

This system uses Carboxymethyl Hydroxypropyl guar, Carboxymethyl guar or Carboxymethyl Hydroxyethyl cellulose as thickener, and it crosslinks with organic metal crosslinker under the PH condition of 3.0-6.0 to form the gel. It does not only satisfy the requirement of fracturing treatment in alkali sensitive formations but also can be used for CO2 foam fracturing treatment.

2. Property Indices

Items	Product Indices
Base fluid apparent viscosity, mPa.s	30~80
Crosslinking time, s	60~240
Temperature tolerance，℃	≤160
Gel apparent viscosity, mPa.s	≥50
Matrix permeability damage ratio, %	≤30
Viscosity of broken gel, mPa.s	≤5.0
Surface tension, mN/m	≤28.0
Interface tension, mN/m	≤2.0
Residual content, mg/L	≤600
Emulsion breaking ratio, %	≥95
Friction reduction ratio, %	≥60
Compatibility	No precipitate; no flocculation

3. Application for Treatment

Make the fracturing based fluid according to the fracturing fluid design, and add PH controller after sufficient swelling to control the PH value of the base fluid between 3.0 and 6.0, and then add crosslinker into the base fluid according to design to form the crosslinked fracturing gel, and then mix the fluid system with proppant in the blending unit according to pumping schedule for treatment execution. It can also be used with liquid CO2 by adding foaming agent to carry out CO2 foam fracturing.