NEW METHOD FOR WATER SENSITIVITY EVALUATION OF SHALE-A STUDY ON SPECIFIC WATER WETTABILITY

Based on the theory and lab analysis of modern surface physicochemistry,specific water wettability study is proposed for the first time and described as a new scientific method for water sensitivity evaluation of shale. It is suitable particularly for analysis of borehole wall stability hard and brittle shale in challenge of deep well drilling currently instead of the traditional bulk water wettability evaluation which exhibits some restriction. This paper presents the study and test in determination of specific water wettability. Study and test showed that both EGME and ethylene blue analysis are reliable and accurate for specific surface area determination with good repetition, particularly ethylene blue analysis is an easy and cheap method. Specific surface area and specific water wettability are decisive factors in strength change and hydrate deformation of shale. Data of specific surface area and specific water wettability for 10 shale samples were obtained in the test.