Abstract: A method for obtaining samples of connate fluids from formations traversed by a borehole, wherein a sample test chamber is brought in communication with an isolated portion of the borehole wall, and is opened so as to allow the connate fluids to fill the chamber, and wherein the connate fluids are filtered through porous material including particles of determined sizes. The particles are bound together so as to form a rigid porous member, and have an average diameter which is a multiple of the diameter of the formation particles. Filter includes sieved gravel/sand embedded in a thermosetting resin. Alternatively, the filter includes metal bound together by superficial melting or welding.