New Acid Fracturing Model on Reservoir-Centric Platform for Carbonate Formations

Abstract

Acid fracturing is a widely accepted method for stimulation of carbonate reservoirs. A new high-resolution fracture hydrodynamics and in-situ kinetics model integrated on a reservoir-centric exploration and production platform improves acid fracturing simulation accuracy and performance for completion, stimulation, and reservoir engineering groups. This paper describes key features of the new acid fracturing model and the workflows that have been enabled on the E&P platform. We demonstrate that the new acid fracturing model can simulate the key effects of acid fracturing at a new level of fidelity and quality. For example, it reproduces viscous fingering effects that occur naturally when alternating fluid systems of different viscosities are pumped into the fracture. The model simulates diverting agents that reduce leakoff in the fracture area and their effects on fracture geometry. Combining the 3D earth model in the E&P platform and high-resolution simulator allows the modeling of small-scale heterogeneities that affect fracture conductivity with a high level of accuracy. The model is also capable of simulating hybrid acid-proppant treatments. Finally, a fluid and materials database is incorporated to capture the impact of modern acid systems and diversion agents. The new model was validated against the results of laboratory experiments and published data. The first results of the platform stimulation-to-production workflow implementation are presented for a formation with high calcite content. The new approach enables engineers to evaluate completion and stimulation designs directly by quantifying the impact on hydrocarbon production and seamlessly integrates carbonates completion design and reservoir engineering disciplines. The novel high-fidelity approach to acid leakoff, diversion systems, and rheology of different fluid mixtures significantly extends the design and evaluation tools for acid fracturing treatments in carbonate formations. Integrating the acid fracture model and E&P platform enables simulation of multiple acid treatments all the way to production evaluation and opens the path towards optimal design of single- and multiple-well treatments.