In-situ geomechanical testing

A method of testing mechanical properties of an earth formation, the method comprising:

• disposing a test instrument in a wellbore, the test instrument comprising a probe and a plate comprising a material having a predetermined mechanical property, wherein the predetermined mechanical property is determined prior to the test instrument being disposed downhole;
• contacting the material using the probe;
• measuring a load, a displacement, a displacement rate, a strain, or a strain rate of the probe as the probe contacts the material;
• determining a calculated mechanical property of the material based on the measurement taken as the probe contacts the material, wherein the calculated mechanical property is of the same type of mechanical property as the predetermined mechanical property;
• comparing the predetermined mechanical property of the material to the calculated mechanical property of the material to determine an adjustment value;
• contacting the probe against a wall of the wellbore, wherein contacting the probe against the wall of the wellbore occurs at a different time than contacting the material using the probe;
• measuring a load, a displacement, a displacement rate, a strain, or a strain rate of the probe as the probe contacts the wall, the type of measurement taken as the probe contacts the wall being the same as the type of measurement taken as the probe contacts the material;
• and
• determining a mechanical property of the formation based on the adjustment value and the measurement taken as the probe contacts the wall, wherein the mechanical property of the formation is of the same type of mechanical property as the predetermined mechanical property and the calculated mechanical property.