The pad stage in hydraulic fracturing is the initial injection of fluid into the wellbore, designed to open the formation and prepare it for the proppant.
Specifically, a pad stage, consisting of approximately 100,000 gallons of slickwater without proppant material, is a critical first step. This large volume of slickwater serves multiple purposes:
- Filling the Wellbore: The slickwater pad stage fills the wellbore, ensuring the entire section to be fractured is ready for the high-pressure treatment.
- Opening the Formation: The pressure from the injected slickwater begins to open and extend the fractures in the target rock formation.
- Facilitating Proppant Placement: By initiating and widening the fractures, the pad stage helps to facilitate the flow and placement of proppant material, which is injected in subsequent stages.
Think of the pad stage as the "setup" phase. It clears the path and creates the initial openings needed for the main fracturing fluid, which contains proppant (like sand or ceramic beads) to keep the fractures open after the pressure is released.
Key Characteristics of the Pad Stage:
- Composition: Primarily slickwater (water with friction-reducing additives).
- Absence of Proppant: It does not contain proppant material.
- Volume: Often a significant volume, such as the approximately 100,000 gallons mentioned in the reference.
- Purpose: To initiate fracturing, open the formation, and prepare for proppant injection.
This initial proppant-free injection is essential for a successful fracturing operation, ensuring that the proppant-laden fluid can effectively penetrate and prop open the created fractures.
