Laboratory Study on a Novel Self-Diverting Gel Acid System Thickener

Abstract:

Acid stimulation of carbonate formations using hydrochloric (HCl) acid-based systems to improve hydrocarbon production or water injection has been a common practice. The challenge of achieving full zonal coverage with the stimulation fluid still persists. This task is even more difficult in highly slanted layered, naturally fractured reservoirs exhibiting high permeability and porosity contrast. During acid stimulation treatments, the fluid has a natural tendency to take the path of least resistance, penetrating layers with the highest porosity and permeability while little or no acid is injected into lower-quality zones. Excessive fluid loss to these high-quality thief zones results in a nonhomogenous distribution of stimulation fluids across the targeted interval. This leaves neighboring lower-quality zones unstimulated, preventing them from reaching their maximum potential. In this paper, a gel acid system composing hydrophobically modified PAM and viscoelastic surfactant (SA-16) as a novel self-diverting acidizing system was introduced, which can lower acid loss. This novel system was evaluated on temperature stability, viscosity test, gel breaken and acid-rock kinetics test supported by laboratory study. Its favorably high viscosity, ideal gel breaken, upstanding temperature resistance and other prior properties can be applied to acid stimulation.

• Periodical: Advanced Materials Research (Volumes 463-464)
• Pages: 868-876
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.463-464.868
• Online since: February 2012
• Authors: Qi Zhu, Ping Li Liu, Li Qiang Zhao, Ji Mei Chen, Yan Feng Cao
• Keywords: Acidizing Stimulation, Carbonate Formation, Polymer, Self-Diverting Thicker

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