Methods of drilling wellbores using variable density fluids comprising coated elastic particles

摘要

The present invention provides variable density fluid compositions and methods for using such compositions in a subterranean formation. One exemplary embodiment of the variable density fluid compositions of the present invention comprises a variable density fluid comprising: a base fluid; and a portion of elastic particles, the elastic particles having an isothermal compressibility factor in the range of from about 1.5x10-3 (1/psi) to about 1.5x10-9 (1/psi).