Application of degradable fibers in invert emulsion fluids for fluid loss control

Abstract

A method of treating a subterranean formation including emplacing in a wellbore a fluid, comprising an oleaginous continuous phase, a non-oleaginous discontinuous phase, an emulsifier, at least one degradable material, and at least one bridging material, and contacting the formation with the fluid. A method and apparatus related to an invert emulsion fluid loss pill including an oleaginous continuous phase, a non-oleaginous discontinuous phase, an emulsifier, at least one degradable material, wherein the degradable material hydrolyzes to release an organic acid, and at least one bridging material.

1 - 28 . (canceled) 
     
     
         29 . An invert emulsion fluid loss pill comprising:
 an oleaginous continuous phase;   a non-oleaginous discontinuous phase;   an emulsifier;   at least one degradable material, wherein the degradable material hydrolyzes to release an organic acid; and   at least one bridging material,   wherein the organic acid reverses the fluid such that the oleaginous fluid is the discontinuous phase and the non-oleaginous fluid is the continuous phase.   
     
     
         30 . The invert emulsion fluid loss pill of  claim 29 , wherein the degradable material comprises at least one of lactide, glycolide, polylactic acid, polyglycolic acid, copolymers of polylactic acid and polyglycolic acid, copolymers of glycolic acid with other hydroxy-, carboxylic acid-, or hydroxycarboxylic acid-containing moieties, copolymers of lactic acid with other hydroxy-, carboxylic acid-, or hydroxycarboxylic acid-containing moieties, or mixtures thereof. 
     
     
         31 . The invert emulsion fluid loss pill of  claim 29 , further comprising lime. 
     
     
         32 . The invert emulsion fluid loss pill of  claim 29 , wherein the bridging material comprises at least one of calcium carbonate, dolomite, barium sulfate, ilmenite, hematite, olivine, siderite, galena, manganese oxide, iron oxides, strontium sulfate, celluloses, micas, proppant materials, or mixtures thereof. 
     
     
         33 . The invert emulsion fluid loss pill of  claim 29 , wherein the oleaginous phase is selected from diesel oil, mineral oil, synthetic oil, ester oils, glycerides of fatty acids, aliphatic esters, aliphatic ethers, aliphatic acetals, or combinations thereof. 
     
     
         34 . The invert emulsion fluid loss pill of  claim 29 , wherein the non-oleaginous phase is selected from fresh water, sea water, brine, aqueous solutions containing water soluble organic salts, water soluble alcohols or water soluble glycols or combinations thereof. 
     
     
         35 . The invert emulsion fluid loss pill of  claim 29 , wherein the emulsifier comprises at least one of fatty acids, soaps of fatty acids, amidoamines, polyamides, polyamines, oleate esters, imidazoline derivatives or alcohol derivatives or combinations or derivatives thereof.