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Special Topics & Reviews in Porous Media: An International Journal
ESCI SJR: 0.259 SNIP: 0.466 CiteScore™: 0.83

ISSN Imprimir: 2151-4798
ISSN En Línea: 2151-562X

Special Topics & Reviews in Porous Media: An International Journal

DOI: 10.1615/SpecialTopicsRevPorousMedia.v2.i3.70
pages 237-247

ROLE OF ANIONS ON SHALE STABILITY: THE NEGLECTED PHENOMENON

Talal M. AL-Bazali
College of Engineering & Petroleum, Kuwait University, Saudi Arabia
http://www.faculty.eng.kuniv.edu.kw/staff/albazali.jsp

SINOPSIS

The effect of different anions on the swelling behavior and membrane efficiency of low-permeability shales has been studied using a pressure transmission test. Three different shales obtained from deep formations located in an oil field in the Middle East were used in this study. Three different anions, i.e., chloride, carbonates, and formate anions, were utilized in this study to investigate the impact of anion type, size, and concentration on the swelling behavior and membrane efficiency of low-permeability shales. Experimental results confirm the notion that shales are leaky membranes where they do not completely restrict the flow of ions, and that in turn reduces the osmotic pressure that could be used to induce water out of the shale. The measured membrane efficiencies of shales ranged from 0.62 to 5.23%. In addition, it is shown that different anions impact the swelling behavior and membrane property of shales differently, depending on their relative sizes. Low-permeability shales induce larger osmotic pressure when interacting with larger anions such as carbonates and formate anions. It is also shown that salt solutions with the appropriate ions' (anions and cations) type and concentration could provide an inexpensive product to combat wellbore instability problems in low-permeability shales, given that a large enough chemical potential exists between the shale and the salt solution. This work also shows that a potassium chloride solution can be utilized as an osmotic method for low-permeability shales.