Study on acid etching fracture conductivity of surface cross-linked acid

Acid etching fracture conductivity is an important indicator of affecting acid fracturing effect and evaluating acid fluid performance. According to the API industry standard, fracturing conductivity of surface cross-linked acid and closed acidization laboratory experiments were carried out using etching fracture conductivity device. The results show that the fracture conductivity of surface cross-linked acid was 150 μm2.cm under 40 MPa closing pressure, and still higher than 80 μm2.cm when closing pressure up to 55 MPa; Surface cross-linked acid fracturing after closed acidization, acid etching fracture conductivity was up to 269 μm2.cm under 40 MPa closing pressure which increased 1.7 times compared to before closure acid. The corrosion morphology appears fine after acid-rock reaction and have obvious groove with depth of more than 0.5 ~ 4.5 mm, which could bear high closure pressure and improve long-term conductivity. Meanwhile, the conductivity is better than 5-stage common acid and 5-stage gelled acid, showing much more better liquid properties.