A method of plugging a fracture in a subterranean formation which includes placing into the fracture a composition comprising microspheres or microbeads, wherein the microspheres are created by surface crosslinking of droplets in a water-in-water emulsion. Such microspheres may form a filter cake in the formation. The microspheres may include a chemical agent to be released when the microspheres dissolve.

Polymeric Microspheres As Degradable Fluid Loss Additives In Oilfield Applications

This invention relates to compositions and methods for treating subterranean formations, in particular, oilfield stimulation compositions and methods using water-in-water polymer emulsions to uniformly dissolve a rheologically active polymer, such as a thickener or friction reducer, in the treatment fluid. The emulsions have a low viscosity and are easily pumped for mixing into a treatment fluid, where upon dilution with an aqueous medium, the polymer is easily hydrated without forming fish-eyes. The partitioning agent in the water-in-water emulsion does not generally affect the rheology of the treatment fluid. The invention also relates to further processing of the emulsion by wet grinding, high shear mixing and/or heating to enhance the hydration rate in the preparation of the well treatment fluid.

Polymer delivery in well treatment applications

A thickened aqueous composition is delivered to a subterranean location accessible via a wellbore by steps of i. providing a biphasic aqueous mixture comprising two aqueous solutions which, at surface temperature and pressure, are able to co-exist as separate aqueous phases in contact with each other, ii. pumping said biphasic aqueous system down the wellbore to the subterranean location, and iii. converting the biphasic mixture below ground so that its phases combine into a single aqueous phase which is more viscous than the biphasic mixture. The two phases of the aqueous biphasic mixture contain dissolved solutes which segregate between the two phases such that at least one first solute is present at a greater concentration in the first aqueous phase than in the second aqueous phase while at least one second solute is present at a greater concentration in the second aqueous phase than in the first aqueous phase. The solute in the first phase may be a thickening polymer or other thickening material such as viscoelastic surfactant. The solute in the second phase may be a different polymer, surfactant or salt. Conversion to a single phase may be carried out in various ways including dilution, change in pH, change in salinity, increase in temperature and adsorption of one solute onto formation rock.

Provision of viscous compositions below ground

This invention relates to compositions and methods of treating a subterranean formation penetrated by a well bore including providing a treatment composition comprising a rheological polymer, a partitioning agent, a charged polyelectrolyte, and a first liquid medium, forming a stabilized heterogeneous mixture comprising a dispersed rheological polymer-rich phase and a partitioning agent-rich phase, and injecting the treatment fluid into the well bore. The invention relates to methods and compositions for preparing a well treatment fluid, including mixing polyethylene glycol partitioning agent, a charged polyelectrolyte, a first aqueous medium, and one or more rheological polymers selected from the group consisting of guar, modified guar, cellulose, modified cellulose, heteropolysaccharide, heteropolysaccharide derivative, or polyacrylamide, to hydrate the one or more polymers and form a water-in-water emulsion, and mixing the water-in-water emulsion with a second aqueous medium to form a well treatment fluid.

Stabilizing biphasic concentrates through the addition of small amounts of high molecular weight polyelectrolytes

The invention relates to a water-based drilling fluid composition comprising a carboxymethyl cellulose (CMC), wherein the CMC is characterized by forming a gel at 25°C after high-shear dissolution in a 0.3 wt% aqueous sodium chloride solution, the final content of the CMC in the aqueous sodium chloride solution being I wt% for a CMC having a degree of polymerization (DP) of >4,000, 1.5. wt% for a CMC having a DP of >3,000-4,000, 2 wt% for a CMC having a DD of 1,500-3,000, and 4 wt% for a CMC having a DP of <1,500, the gel being a fluid having a storage modulus (G') which exceeds the loss modulus (G') over the entire frequency region of 0.01-10 Hz when measured on an oscillatory rheometer operating at a strain of 0.2.

Use of cmc in drilling fluids

A process for supporting facings and the associated groundwater in advance working systems, especially with shields operated by earth pressure for the construction of tunnels and for micro-tunnelling, in which the worked soil in the earth pressure chamber is mixed with a fluidising medium (I) and a pressure opposing the groundwater pressure is created by taking off the mixture. Medium (I) is a gel which reduces the permeability of the soil, and the soli/gel mixture is obtained by mixing and agitating in the working space or the feed screw.

Process for preparation and use of gels as additives for mechanical shield driving

Die vorliegende Erfindung betrifft eine Zubereitung aus einem nicht-ionischen Hydrokolloid, insbesondere Polysaccharidethern, vorzugsweise Celluloseethern, und mindestens einem ionischen Hydrokolloid, insbesondere Polysaccharidether, vorzugsweise Celluloseether, und mindestens einer oberflachenaktiven Substanz.

Zubereitungen aus nicht-ionischen und ionischen Hydrokolloiden und deren Verwendung als Hilfsmittel für den Tunnelbau

of EP0761747Prepn. comprises a non-ionic hydrocolloid, esp. polysaccharide ether, pref. cellulose ether, and at least an ionic hydrocolloid, esp. polysaccharide ether, pref. cellulose ether, and at least one surface active material. Also claimed is a prepn. comprising the above materials and an unrefined natural polysaccharide. Pref. the non-ionic hydrocolloid is a polysaccharide ether, pref. alkyl cellulose, alkyl hydroxyalkyl cellulose, hydroxyl alkyl cellulose or (hydroxy) alkylated ether starch. The ionic hydrocolloid is a carboxyalkyl or carboxylalkylhydroxyalkyl cellulose ether or carboxy(alkylhydroxy)alkylated ether starch. The surface active component is an anionic, cationic non-ionic or ampho-tenside. The unrefined natural polysaccharide is made of xanthan, starch, guar, natural rubber, ground locust bean, traganth, tamarind, alginate, protein, esp. cellulose material such as pine wood-sulphate, surface and cellulosic wood material.

Compositions of non-ionic and ionic hydrocolloids and their use as auxiliary agent in tunnel construction

Verfahren zum Stutzen der Ortsbrust und des anstehenden Grundwassers bei Vortriebssystemen, insbesondere mit Erddruckschilden betriebenen Schildsystemen fur den Tunnelbau im begehbaren und nichtbegehbaren Bereich sowie Microtunnelling bei dem der abgebaute Boden in der Erddruckkammer mit einem fluidisierenden Medium vermischt und durch gezieltes Abfuhren des Gemisches in der Erddruckkammer ein dem Erddruck und dem Grundwasserdruck entgegenwirkender Druck erzeugt wird, wobei, das das dem abgebauten Boden zugefuhrte fluidisierende Medium ein die Durchlassigkeit des Bodens verringerndes Gel ist und das durch Mischen und Verruhren im Abbauraum oder der Forderschnecke ein Gemisch aus Boden und Gel hergestellt wird.

Jörn-Bernd Dr. Pannek

Papers

Process for preparation and use of gels as additives for mechanical shield driving

Zubereitungen aus nicht-ionischen und ionischen Hydrokolloiden und deren Verwendung als Hilfsmittel für den Tunnelbau

Compositions of non-ionic and ionic hydrocolloids and their use as auxiliary agent in tunnel construction

Verfahren zur Herstellung sowie Verwendung von Gelen als Additive für einen mechanischen Schildvortrieb