Method of improving absorption of salt water by water-swellable clay by redrying

In a method of drilling a borehole into an earthen formation that contains salt-contaminated water, by circulating an aqueous water-swellable clay-based drilling fluid in an area between a drill pipe and the borehole, said aqueous clay-based drilling fluid composition including water and a water-swellable clay in an amount of about 2 to about 20 pounds of water-swellable clay per barrel of drilling fluid, the improvement comprising,

• the water-swellable clay in the drilling fluid having improved rheological properties wherein contact with salt-contaminated water by treating the clay, after recovery and drying to a moisture content of about 12% by weight or less, based on the dry weight of the clay, by rewetting the clay to a moisture content of more than 12% by weight, based on the dry weight of the clay, and redrying the clay to a moisture content of 12% by weight or less, based on the dry weight of the clay, wherein the treated clay absorbs said salt-contaminated water from said borehole.

In a method of drilling a well employing a cutting bit and an aqueous water-swellable clay-based drilling fluid, said drilling fluid being circulated in said well during drilling,

• the improvement comprising said drilling fluid including a water-swellable clay having improved rheological properties upon contact with salt-contaminated water by treating the clay after recovery and drying to a moisture content of 12% by weight or less, based on the dry weight of the clay, by rewetting the clay to a moisture content of more than 12% by weight, based on the dry weight of the clay, and redrying the clay to a moisture content of about 12% by weight or less, based on the dry weight of the clay.

In a composition including a solid, particulate material suspended in an solubilized salt-containing aqueous carrier with a water swellable clay suspending agent in an amount sufficient to achieve a stable suspension,

• the improvement comprising the water-swellable clay having improved suspending properties in the salt-containing water by treating the clay, after recovery and drying to a moisture content of 12% by weight or less, based on the dry weight of the clay, by rewetting the clay to a moisture content of more than 12% by weight, based on the dry wight of the clay, and redrying the clay to a moisture content of 12% by weight or less, based on the dry weight of the clay.

In a method of suspending a solid, particulate material in a dissolved salt-containing aqueous carrier with a water-swellable clay suspending agent,

• the improvement comprising the water-swellable clay having improved suspending properties wherein contact with the salt-containing water by treating the clay, after recovery and drying to a moisture content of 12% by weight or less, based on the dry weight of the clay, by rewetting the clay to a moisture content of more than 12% by weight, based on the dry weight of the clay, and redrying the clay to a moisture content of 12% by weight or less, based on the dry weight of the clay.