Swell Particles

Swellable particles (often called swellable diverting agents or swellable proppants) are used in hydraulic fracturing to temporarily isolate fracture zones and enhance stimulation efficiency. Unlike solid swell plugs, these particles are pumped downhole with fracturing fluids and selectively block existing fractures to redirect pressure and fluid to untreated zones.

How Swellable Particles Isolate Fracture Zones :

• Injection with Frac Fluid – Small swellable particles are mixed into the fracturing fluid and pumped into the well.
• Migration to Open Fractures – The particles flow into dominant (high-permeability) fractures that have already taken most of the fluid.
• Swelling & Blockage – Upon contact with well fluids (oil, water, or gas), the particles expand and seal off the existing fractures.
• Pressure Diversion – With the dominant fractures blocked, pressure builds, forcing fluid into new, under-stimulated zones.

Degradation or Flowback – After treatment, the particles either :

• Degrade (if dissolvable)
• Get produced back with flowback fluids
• Types of Swellable Particles:
• Oil-Swellable Particles – Expand in hydrocarbon-rich environments.
• Water-Swellable Particles – React with water or brine.
• Thermally Activated Particles – Swell at specific temperatures.
• Dissolvable Particles – Break down over time to avoid formation damage.

Advantages:

• Improves fracture network complexity by forcing fluid into new zones.
• No mechanical intervention (unlike traditional diverters like ball sealers).
• Works in open-hole and cased-hole wells.
• Reduces "frac hits" (unwanted communication between wells).

Applications:

• Refracturing old wells to stimulate new zones.
• Diverting fractures in multi-cluster stages.
• Preventing overgrowth of dominant fractures in unconventional reservoirs.