The Effects of Perforation Erosion on Practical Hydraulic-Fracturing Applications

TLDR

Predicting perforation erosion and its impact on fracture dimensions, fluid distribution, and pressure drop is essential for designing hydraulic‑fracturing treatments, particularly massive horizontal wells using limited‑entry techniques, because perforation diameter and discharge coefficient increase dynamically as proppant‑laden slurries are pumped. This study develops a perforation‑erosion model based on experimentally verified abrasion mechanisms to calculate the time‑dependent changes in perforation diameter and discharge coefficient and assess their influence on fracture dimensions, fluid distribution, and downhole pressure during a treatment. The model incorporates perforation number, perforation‑cluster spacing, in‑situ stress difference, and fracturing‑fluid viscosity to quantify erosion effects. Results show that the model accurately predicts perforation‑erosion effects in practical hydraulic‑fracturing scenarios, enabling more appropriate treatment designs, especially for limited‑entry techniques, by separately tracking the simultaneous increases of diameter and discharge coefficient.

Abstract

Summary Predicting perforation erosion and its effects on fracture dimensions, fluid distribution, and pressure drop can be an essential part of successful design of hydraulic-fracturing treatments, especially for massive treatments along the horizontal wells when limited-entry techniques are implemented. Both the perforation diameter D and discharge coefficient Cd increase dynamically as proppant-laden slurries are pumped through perforations, making it necessary to consider the changes of these two variables in terms of time to predict the perforation-erosion effects. In this paper, we conduct a study of the perforation-erosion effects by implementing our new perforation-erosion model derived from experimentally verified abrasion mechanisms to calculate the rate changes of these two variables and the consequent influence on the fracture dimensions, fluid distribution, and downhole pressure during a treatment. The selected parameters affecting the erosion effects in the study include perforation number, perforation-cluster spacing, in-situ stress difference, and fracturing-fluid viscosity. The results demonstrate that our model can predict the perforation-erosion effects on practical hydraulic-fracturing applications in a physically clear and mathematically concise manner under different circumstances by inspecting the simultaneous increases of D and Cd separately, leading to more-appropriate treatment designs, especially with the limited-entry techniques.