Introduction:
It is selectively mined attapulgite clay. It is designed for the use of geological drilling, marine drilling, and drilling in salt containing geological areas. It features good thermal stability and salt resistant property, therefore, the number of rejected wells will be small while using it to protect the well walls, and the drilling efficiency will be improved and the cost will be cut down as well.

Advantages:
1. This product features good thermal colloidal and suspending properties, and is suitable to be used as drilling mud under various geological conditions.
2. Because of good thermal stability, it shows no flocculation and dilution under high temperature, therefore, it is applicable for deep drilling and terrestrial heat drilling.
3. Its salt resistant ability makes it free from being affected by electrolytes, thus it can still be in mud form even in saturated brine. It is appropriate for marine and salty stratum drilling.

Typical Physical Properties:

Item	Grade A	Grade B
Reading ,600 revolution, scale	min 30	min 23
Sieve residue,%	max 8	max 8
Free moisture,%	max 15	max 15

Salt water drilling mud and method:
A salt water drilling mud comprising a mixture salt water, a solid phase such as pre-hydrated bentonite, attapulgite, sepiolite, and extended bentonite, among others and optionally a synthetic oil, which is mixed with at least one of five different modules. A first module contains caustic, a natural wax and a natural thinner. A second module contains components of the first module and an alkali metal aluminate prepared by reacting the first module with aluminum metal. A third module contains the components of the first module and an alkali metal phosphate and/or alkali metal silicate. A fourth module contains the components of the first module, a saturated or unsaturated carboxylic acid source, a surfactant, and a preservative. The fifth module contains a combination of the first, third and fourth modules.

Barium compound-containing thickening agent and drilling fluids made therefrom:
A drilling fluid comprises uncalcined colloidal attapulgite clay and up to about 10% by weight (of the weight of attapulgite clay) of a barium compound additive such as BaO or Ba(OH).sub.2. The admixture of clay and barium compound may be slurried in either fresh or salt water to provide an aqueous drilling fluid of significantly higher yield than that attainable with prior art drilling fluids.