Proppant placement

Abstract

Embodiments of hydraulic fracturing methods disclosed herein use fine mesh proppant. In one embodiment the method is used to fracture a low permeability formation. In one embodiment the method uses flocculation to improve conductivity of a fracture. In one embodiment fluid flow through the fine mesh proppant in the fracture creates a network of connected channels to improve the fracture conductivity.

1 . A method, comprising:
 injecting well treatment fluid comprising fine mesh proppant material into a fracture in a low-permeability subterranean formation thereby forming a proppant pack; and   concurrently or subsequently introducing non-uniformity in the proppant pack to form a conductive flow path for fluid flow through the propped fracture, wherein the non-uniform proppant pack has a higher conductivity relative to the uniform proppant pack at an identical closure stress   whereby the fine mesh proppant material has a particle size less than 105 microns (140 US mesh).   
     
     
         2 . (canceled) 
     
     
         3 . The method of  claim 1  wherein the fine mesh proppant material is selected from the group consisting of: silica, muscovite, biotite, limestone, Portland cement, talc, kaolin, barite, fly ash, pozzolan, bauxite, alumina, zirconia, titanium oxide, iron oxides, zeolites, graphite, carbon black, aluminosilicates, biopolymer solids, synthetic polymer solids and combinations and mixtures thereof. 
     
     
         4 . The method of  claim 1  wherein the non-uniformity is introduced by proppant flowback subsequent to injection. 
     
     
         5 . The method of  claim 1  wherein the non-uniformity is formed by proppant washout. 
     
     
         6 . The method of  claim 1  wherein the non-uniformity is formed by alternating proppant concentration during the well treatment fluid injection. 
     
     
         7 . The method of  claim 1  wherein the treatment fluid comprises different sized proppant materials to facilitate the introduction of the non-uniformity. 
     
     
         8 . The method of  claim 1  wherein the treatment fluid injection comprises a plurality of stages of alternating treatment fluid rheology to introduce the non-uniformity. 
     
     
         9 . The method of  claim 1  further comprising aggregating the fine mesh proppant material to introduce the non-uniformity. 
     
     
         10 . The method of  claim 9  wherein the well treatment fluid comprises flocculating agent. 
     
     
         11 . The method of  claim 9  wherein the well treatment fluid comprises flocculating agent selected from the group consisting of polymers and copolymers of at least one monomer selected from the group consisting of acrylamide, methacrylamide, N-vinylmethylacetamide, N-vinylmethylformamide, vinyl acetate, acrylate esters, methacrylate esters, cyanoacrylate esters, vinyl pyrrolidone and combinations thereof. 
     
     
         12 . The method of  claim 9  wherein the fine mesh proppant material is hydrophobic and the well treatment fluid comprises a hydrophobic binding liquid to agglomerate the proppant. 
     
     
         13 . The method according to  claim 12  wherein the fine mesh proppant material is made hydrophobic by a surface coating. 
     
     
         14 . The method of  claim 1  wherein the fine mesh proppant material is coated with a tackifying agent. 
     
     
         15 . The method of  claim 1  wherein the well treatment fluid further comprises degradable material selected from the group consisting of substituted and unsubstituted 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 and mixtures thereof. 
     
     
         16 . The method of  claim 15  wherein the degradable material comprises fiber. 
     
     
         17 . The method of  claim 1 , wherein proppant in the treatment fluid comprises at least 60 percent by weight, based on the total weight of proppant. 
     
     
         18 . The method of  claim 1  wherein the well treatment fluid comprises at least about 4.8 g/L (0.04 ppg) of the fine mesh proppant material added. 
     
     
         19 . The method of  claim 1  wherein the well treatment fluid comprises slickwater. 
     
     
         20 . The method of  claim 1  wherein the well treatment fluid comprises an effective amount of a friction reducer. 
     
     
         21 . The method of  claim 1  wherein the formation comprises a permeability less than one millidarcy. 
     
     
         22 . The method of  claim 1  wherein the non-uniformity comprises a branched network of open channels. 
     
     
         23 . A method, comprising:
 injecting well treatment fluid comprising fine mesh proppant material and flocculating agent into a fracture in a subterranean formation to form a proppant pack;   aggregating the fine mesh proppant material thereby forming a hydraulically conductive proppant pack in the fracture.   
     
     
         24 . The method of  claim 23  wherein the aggregation occurs before, during, or subsequent to the injection step, or a combination thereof. 
     
     
         25 . The method of  claim 23  wherein the treatment fluid comprises flocculant selected from the group consisting of polymers and copolymers of at least one monomer selected from the group consisting of acrylamide, methacrylamide, N-vinylmethylacetamide, N-vinylmethylformamide, vinyl acetate, acrylate esters, methacrylate esters, cyanoacrylate esters, vinyl pyrrolidone and combinations thereof. 
     
     
         26 . The method of  claim 22  wherein the fine mesh proppant material is hydrophobic and the well treatment fluid comprises a hydrophobic binding liquid to agglomerate the proppant. 
     
     
         27 . The method of  claim 25  wherein the fine mesh proppant material comprises a hydrophobic surface coating. 
     
     
         28 . The method of  claim 23  wherein the flocculation facilitates creation of a branching complex network of channels in the proppant pack. 
     
     
         29 . The method of  claim 23  wherein the flocculation facilitates creation of a branched network of open channels in the proppant pack. 
     
     
         30 . The method of  claim 23  wherein the formation comprises a permeability less than one millidarcy. 
     
     
         31 . A method, comprising:
 injecting well treatment fluid comprising proppant material into a fracture in a low-permeability subterranean formation thereby forming a proppant pack, wherein the proppant is a fine mesh material with a median particle size less than 105 microns (140 US mesh); and   concurrently or subsequently introducing non-uniformity in the proppant pack to form a conductive flow path for fluid flow through the propped fracture, wherein the non-uniform proppant pack has a higher conductivity relative to the uniform proppant pack at an identical closure stress.   
     
     
         32 . The method of  claim 31  wherein at least 60 wt % of the proppant material has a particle size less than 105 microns (140 US mesh). 
     
     
         33 . The method of  claim 31  wherein at least 90 wt % of the proppant material has a particle size less than 105 microns (140 US mesh).