Method of fracturing subterranean strata

Claim 1

A PROCESS FOR FRACTURING AND PROPPING A SUBTERRANEAN STRATUM PENETRATED BY A WELL WHICH COMPRISES THE STEPS OF: (1) INJECTING A FRACTURING FLUID THRU SAID WELL INTO A SELECTED LEVEL OF SAID STRATUM AT SUFFICIENT PRESSURE TO FRACTURE AND RAISE THE OVERBURDEN; (2) DEPOSITING IN ALTERNATE CIRCUMFERENTIALLY SPACED AREAS OF THE RESULTING FRACTURE A RELATIVELY NONFLUIDIZABLE SOLID PARTICULATE PROPPING AGENT IN A CONCENTRATION SUPPORTING THE OVERBURDEN; (3) SEQUENTIALLY DEPOSITING IN INTERVENING, AREAS A READILY FLUIDIZABLE SOLID PARTICULATE PROPPING AGENT; AND (4) THEREAFTER, FLUIDIZING THE PROPPING AGENT OF STEP (3) AND DESTROYING THE PROPPING NATURE THEREOF SO AS TO LEAVE HIGHLY PERMEABLE FLOW PATHS FORMERLY OCCUPIED BY THE FLUIDIZABLE AGENT ALTERNATELY SPACED AROUND SAID WELL WITH RESPECT TO THE PROPPED AREAS RESULTING FROM STEPS (1) AND (2).