Perforation wells

Claim 1

A METHOD FOR COMPLETING A WELL PENETRATING A SUBSURFACE EARTH FORMATION WHILE MAINTAINING SAID WELL UNDER CONTROL WITH A FLUID COLUMN HAVING A HYDROSATIC PRESSURE IN EXCESS OF FORMATION PRESSURE WHICH COMPRISES REPLACING ONLY A PORTION OF THE DRILLING FLUID IN A CASING IN SAID WELL WITH A SOLIDS-FREE HEAT STABLE EMULSION WHICH CONSISTS OF FROM ABOUT 5% TO ABOUT 95% BY VOLUME OF AN AQUEOUS MEDIUM, FROM ABOUT 5% TO ABOUT 95% BY VOLUME OF AN OILY MEDIUM, A WEIGHTING AGENT IN AN AMOUNT WITHIN THE RANGE BETWEEN 1% TO ABOUT SATURATION SOLUBLE AND DISSOLVED IN AT LEAST ONE OF SAID MEDIA, SAID WEIGHTING AGENT HAVING A SPECIFIC GRAVITY GREATER THAN THE SPECIFIC GRAVITY OF THE AQUEOUS MEDIUM, AND AN EMULSIFYING AGENT SELECTED FROM THE GROUP CONSISTING OF SORBITAN MONO OLEATE, SORBITAN SESQUI-OLEATE, POLYOXYLETHYL SORBITAN MON-STEARATE, POLYOXYETHYLENE LAURYL ALCOHOL, SODIUM LIGNOSULFONATE, POLYOXYETHYLENE SORBITOL TETRAOLEATE, POLYOXYETHYLENE SORBITOL MONOLAURATE, UNPRIFIED SORBITAN MONO-OLEATE, SORBITAN MONOLAURATE, AND POLYOXYETHYLENE ESTERS OF MIXED FATTY AND RESIN ACIDS IN AN AMOUNT WITHIN THE RANGE BETWEEN 0.2 AND ABOUT 20 GRAMS PER ML. OF THE EXTERNAL PHASE OF THE EMULSION, INSERTING A PERFORATOR IN THE EMULSION, AND OPERATING THE PERFORATOR IN THE EMULSION TO FORM CLEAN PERFORATIONS IN SAID CASING, SAID EMULSION HAVING A WEIGHT IN THE RANGE FROM ABOUT 7 TO ABOUT 18 POUNDS PER GALLON, BEING HEAT STABLE, AND HAVING A LOW FLUID LOSS AT HIGH WELL TEMPERATURES WHEREBY SAID EARTH FORMATION IS PROTECTED FROM DAMAGE BY CONTACT WITH FLUIDS WHICH MIGHT PLUG OR REDUCE THE PERMEABILITY OR POROSITY OF THE FORMATION.

Claim 2

A METHOD FOR COMPLETING A WELL PENETRATING A SUBSURFACE EARTH FORMATION WHILE MAINTAINING SAID WELL UNDER CONTROL WITH A FLUID COLUMN HAVING A HYDROSATIC PRESSURE IN EXCESS OF FORMATION PRESSURE WHICH COMPRISES REPLACING ONLY A PORTION OF THE DRILLING FLUID IN A CASING IN SAID WELL WITH A SOLIDS-FREE HEAT STABLE EMULSION WHICH CONSISTS OF FROM ABOUT 5% TO ABOUT 95% BY VOLUME OF AN AQUEOUS MEDIUM, FROM ABOUT 5% TO ABOUT 95% BY VOLUME OF AN OILY MEDIUM, A WEIGHTING AGENT IN AN AMOUNT WITHIN THE RANGE BETWEEN 1% TO ABOUT SATURATION SOLUBLE AND DISSOLVED IN AT LEAST ONE OF SAID MEDIA, SAID WEIGHTING AGENT HAVING A SPECIFIC GRAVITY GREATER THAN THE SPECIFIC GRAVITY OF THE AQUEOUS MEDIUM, AND AN EMULSIFYING AGENT SELECTED FROM THE GROUP CONSISTING OF SORBITAN MONO OLEATE, SORBITAN SESQUI-OLEATE, POLYOXYLETHYL SORBITAN MON-STEARATE, POLYOXYETHYLENE LAURYL ALCOHOL, SODIUM LIGNOSULFONATE, POLYOXYETHYLENE SORBITOL TETRAOLEATE, POLYOXYETHYLENE SORBITOL MONOLAURATE, UNPRIFIED SORBITAN MONO-OLEATE, SORBITAN MONOLAURATE, AND POLYOXYETHYLENE ESTERS OF MIXED FATTY AND RESIN ACIDS IN AN AMOUNT WITHIN THE RANGE BETWEEN 0.2 AND ABOUT 20 GRAMS PER ML. OF THE EXTERNAL PHASE OF THE EMULSION, INSERTING A PERFORATOR IN THE EMULSION, AND OPERATING THE PERFORATOR IN THE EMULSION TO FORM CLEAN PERFORATIONS IN SAID CASING, SAID EMULSION HAVING A WEIGHT IN THE RANGE FROM ABOUT 7 TO ABOUT 18 POUNDS PER GALLON, BEING HEAT STABLE, AND HAVING A LOW FLUID LOSS AT HIGH WELL TEMPERATURES WHEREBY SAID EARTH FORMATION IS PROTECTED FROM DAMAGE BY CONTACT WITH FLUIDS WHICH MIGHT PLUG OR REDUCE THE PERMEABILITY OR POROSITY OF THE FORMATION.