Abstract

Properties of shale in an acid environment are important when acid or CO2 is injected into geologic formations as a working fluid for enhanced oil and gas recovery, hydraulic fracturing and reduced fracture initiation pressure. It has previously been shown that acid fluids can enhance the formation conductivity and decrease the hardness of shale. However, less is known about the effect of dilute acid on the adhesion properties of shale. In the study, shale samples are characterized in detail with advanced analysis. Adhesion properties of shale via dilute acid treatment were revealed by atomic force microscopy (AFM) for the first time. Results indicate that acid treatment can greatly enhance adhesion forces of the shale surface. After acid treatment, the average adhesion forces show a platform-like growth with an increase in loading force. Through analysis of results from AFM, scanning electron microscopy, and X-ray diffraction, we affirm that the enhanced adhesion forces are mainly from increased specific surface area and reduced elastic modulus. The results presented in this work help understand the adhesion properties of shale oil/gas present in an acidic environment, which have great significance in unconventional resources development.

Details

Title
Effect of dilute acid treatment on adhesion properties of Longmaxi black shale
Author
Pan-Pan, Zhang 1 ; Tian, Shou-Ceng 1 ; Mao Sheng 1 ; Tian-Yu, Wang 1 ; Waleed Ali Khan 1 ; Xu, Quan 2 ; Li-Zhi, Xiao 1 

 State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum (Beijing), Beijing, China; Harvard SEAS-CUPB Joint Laboratory on Petroleum Science, Cambridge, MA, USA 
 State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum (Beijing), Beijing, China 
Pages
1320-1331
Publication year
2019
Publication date
Dec 2019
Publisher
KeAi Publishing Communications Ltd
ISSN
16725107
e-ISSN
19958226
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2320917287
Copyright
Petroleum Science is a copyright of Springer, (2019). All Rights Reserved., © 2019. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.