A Special Gel for Mud Loss Control

A novel lost circulation material:special gel, was developed for use in controlling severe mud losses. The gel, made by introducing a functional monomer onto the molecular chains of high MW polymers, is a water soluble high MW polymer. When dispersed in water, a reversible supramolecular structure developed in the dispersion, which rendered the dispersion some special characteristics. In This paper the major properties of the gel and the mechanism of controlling mud losses with this gel were introduced. Some case histories in Sichuan and Tuha oil fields were also presented. The special gel, according to field practices, was especially suitable for stopping mud losses which cannot be controlled by conventional mud loss control techniques, foe example, mud losses in fractured, porous and vugular formations with (almost) no mud return, in formations which contain water zones, and in formations where blowout and mud loss coexist.