Quantitative Modeling of Acid Wormholing in Carbonates- What Are the Gaps to Bridge

Xiangdong Qiu, Weishu Zhao, Frank Chang, Steve Dyer

Research output: Chapter in Book/Report/Conference proceedingConference contribution

26 Scopus citations


Carbonate matrix acidization extends a well's effective drainage radius by dissolving rock and forming conductive channels (wormholes) from the wellbore. Wormholing is a dynamic process that involves balance between the acid injection rate and reaction rate. Generally, injection rate is well defined where injection profiles can be controlled, whereas the reaction rate can be difficult to obtain due to its complex dependency on interstitial velocity, fluid composition, rock surface properties etc. Conventional wormhole propagation models largely ignore the impact of reaction products. When implemented in a job design, the significant errors can result in treatment fluid schedule, rate, and volume. A more accurate method to simulate carbonate matrix acid treatments would accomodate the effect of reaction products on reaction kinetics. It is the purpose of this work to properly account for these effects. This is an important step in achieving quantitative predictability of wormhole penetration during an acidzing treatment. This paper describes the laboratory procedures taken to obtain the reaction-product impacted kinetics at downhole conditions using a rotating disk apparatus, and how this new set of kinetics data was implemented in a 3D wormholing model to predict wormhole morphology and penetration velocity. The model explains some of the differences in wormhole morphology observed in limestone core flow experiments where injection pressure impacts the mass transfer of hydrogen ions to the rock surface. The model uses a CT scan rendered porosity field to capture the finer details of the rock fabric and then simulates the fluid flow through the rock coupled with reactions. Such a validated model can serve as a base to scale up to near wellbore reservoir and 3D radial flow geometry allowing a more quantitative acid treatment design.
Original languageEnglish (US)
Title of host publicationSPE Middle East Oil and Gas Show and Conference
PublisherSociety of Petroleum Engineers (SPE)
StatePublished - Mar 10 2013
Externally publishedYes

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: The authors would like to thank Jamaliah Abu’Rabie – PhD student of King Abdullah University of Science and Technology (KAUST) for much of the reaction kinetics experimentation used in this study as part of a summer internship program, and Mohammed Abdul Muqtadir of Schlumberger’s Dhahran Research Center for all aspects of the experimentation, core flow and reaction kinetics. Additional aknowledgements go to Sarmad Khan and his supervisor, Dr Abdullah Sultan of King Fahd University of Petroleum and Minerals (KFUPM) for assisting in the experimentation and core CT scanning.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.


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