Hydraulic fracturing (frac) — method of oil and gas wells stimulation by means of fluids and proppant pumped into the formation at high pressure. While pumping the frac fluid, highly conductive channels (hydraulic fractures) are being formed. The fractures connect the wellbore and the formation. They are fixed by proppant. Oil is much easier to flow from the reservoir into the well through these channels.
Multi-stage hydraulic fracturing — a method of stimulating oil production with several frac operations in one horizontal wellbore. Thus, it provides a multiple increase in the coverage area of the formation by one well.
In fields with low permeability reservoirs, multi-stage hydraulic fracturing is performed with various activation methods for frac ports:
• Abrasive perforation using CT/Tubing
• Cumulative perforation with CT/cable
• Ball-activated shifted ports
• CT-activated shifted sleeves
• Burst-port system assembled with packer
High flow rate hydraulic fracturing presents stimulating oil and gas wells with high pumping rate (up to 18m3) using special frac equipment. It is mainly used at hard-to-recover formations. It makes possible to form an intense network of fractures along the entire length of the horizontal section, thereby increasing the volume of recovered hydrocarbons.
Hybrid Fracturing — frac method that involves combinations of frac fluids of various properties to ensure the most efficient pumping. At the initial stage Slick Water with a friction reducer is usually used, then viscous gelling systems are applied to fix fractures most effectively. Stages are isolated with drill-out plugs using Plug & Perf technology (with CT or cable).
Hydraulic fracturing with low viscosity fluid (Slick Water) — type of hydraulic fracturing using a low-viscosity displacement fluid pumped with a high rate using a special additive that helps reducing friction losses of proppant going along walls of the well.