Wettability from electro-kinetic and electro-osmosis measurements

A method for investigating an earth formation, comprising:

• creating a pressure difference in the earth formation proximate to a wellbore;
• measuring a generated electro-kinetic property of the earth formation proximate to the wellbore, the generated electro-kinetic property generated by the pressure difference;
• applying an electric field to the earth formation proximate to the wellbore;
• measuring a generated pressure change in the earth formation proximate to the wellbore, the generated pressure change generated by the electric field;
• determining wettability of the earth formation proximate to the wellbore by the use of at least one of an electro-osmosis coupling constant of the earth formation and an electro-kinetic coupling constant of the earth formation derived from the measurement of the generated electro-kinetic property and the measurement of the generated pressure change.

An apparatus for investigating an earth formation, comprising:

• a pressure differential source adapted to create a pressure difference in the earth formation proximate to a wellbore;
• a sensor adapted to measure a streaming potential of the earth formation proximate to the wellbore, the streaming potential generated by the pressure difference;
• and
• a processor adapted to determine wettability of the earth formation proximate to the wellbore by the use of at least one of an electro-osmosis coupling constant of the earth formation and an electro-kinetic coupling constant of the earth formation derived from the measurement of the streaming potential.

An apparatus for investigating an earth formation, comprising:

• a pressure differential source adapted to create a pressure difference in the earth formation proximate to a wellbore;
• a first sensor adapted to measure a generated electro-kinetic property of the earth formation proximate to the wellbore, the generated electro-kinetic property generated by the pressure difference;
• at least one electrode to apply an electric field to the earth formation proximate to the wellbore;
• a second sensor adapted to measure a generated pressure change in the earth formation proximate to the wellbore, the generated pressure change generated by the electric field;
• and
• a processor adapted to determine wettability of the earth formation proximate to the wellbore by the use of at least one of an electro-osmosis coupling constant of the earth formation and an electro-kinetic coupling constant of the earth formation derived from the measurement of the generated electro-kinetic property and the measurement of the generated pressure change.