Zwitterionic functionalized polymers as deflocculants in water based drilling fluids

摘要

A water soluble polymer which is characterized by the formula: IMAGE wherein x is 50 mole percent or 662/3 mole percent or 75 mole percent and y+z is 50 mole percent, when x is 50 mole percent, y+z is 331/3 mole percent, when x is 662/3 mole percent, and y+z is 25 mole percent, when x is 75 mole percent, wherein the molar ratio of y to z is about 100:1 to 1:100, and M+ is hydrogen or a metal cation selected from the group consisting of lead, aluminum, iron and Groups IA, IIA, IB and IIB of the Periodic Table of Elements and the level of sulfonation based upon the styrene monomer is about 75 to about 100 mole percent.