Method and apparatus for determining physical integrity of geological strata

A method and apparatus for determining the physical integrity of geological shales and for simulating the environment experienced by geological strata comprising forming a test specimen of the stratum to be measured; immersing the specimen in a drilling fluid, or a mixture of drilling fluids, for a predetermined length of time; spinning the test specimen while immersed up to a predetermined speed while adjusting the temperature of the fluid; and then physically measuring the specimen for disintegration, liquid absorption, and hardness. The apparatus for simulating the environment experienced by geological strata includes means for immersing the specimen in the drilling fluid which comprises a nail having the specimen attached to the shank adjacent the head to hold the specimen inverted below the surface of the drilling fluid.