The Dow Chemical Company

Dowell, a Division of Schlumberger Technology Corporation

Other

Dowell Schlumberger Incorporated

Schlumberger Technology Corporation

Vernon G Constien

Erik B Nelson

Kay E Cawiezel

Paul R Howard

Roger J Card

Jean-Pierre Feraud

Claude T Copeland

Philip F Sullivan

Milton T King

Harold D Brannon

Xiaoping Qiu

Reinaldo C Navarrete

Reinaldo Navarrete

Victor Andrew Joyce

David R Carpenter

Peter E Clark

Coatings for well screens that protect the screens from damage as they are inserted into the wellbore and once in the well, release reactive materials to react with and degrade potentially plugging materials such as drill solids, fluid filtercakes, fluid loss additives, and drilling fluids. The coatings can be specifically designed for individual well conditions and are comprised of a binder that either melts or dissolves within the wellbore and one or more reactive materials such as acids, enzymes, surfactants, chelants, oxidizers or free radical generators and the like which are released into the screen and the near wellbore area and which are effective in degrading or dissolving materials which could potentially plug the screen.

Product for coating wellbore screens

Product and process for coating wellbore screens

The addition of fibrous mixtures in intimate mixtures with particulates for fracturing and gravel packing decreases or eliminates the undesirable flowback of proppant or formation fines while stabilizing the sand pack and lowering the demand for high polymer loadings in the placement fluids. Fibers are useful for forming a porous pack in the subterranean formation. In some cases, channels or fingers of void spaces with reduced concentrations of proppant may be introduced into the proppant pack.

Control of particulate flowback in subterranean wells

Methods and apparatus are disclosed for fracturing subterranean formations using fracturing fluids that are hydrated from dry mix blends. One aspect of the invention comprises a dry blended particulate composition for hydraulic fracturing comprising a particulate hydratable polysaccharide, a particulate crosslinking agent, and a slowly releasing particulate base. The compositions employ controlled release methods of particle dissolution. The invention reveals a dry blended particulate composition capable of significantly improved high temperature stability. Further, methods of fracturing and apparatus for rapidly hydrating and pumping the fracturing fluid into subterranean formations are disclosed.

Apparatus, compositions, and methods of employing particulates as

The invention, in one embodiment, relates to a fluid loss control additive or composition comprising a granular starch composition and fine particulate mica, in specified proportions. The invention further comprises a fracturing fluid containing a starch composition and mica, in a specified ratio. In yet a third embodiment, the invention comprises a method of fracturing a subterranean formation penetrated by a borehole, comprising injecting into the borehole and into contact with the formation, at a rate and pressure sufficient to fracture the formation, a fracturing fluid containing starch and mica, in specified ratios, and in an amount sufficient to provide fluid loss control.

Fluid loss control

The invention, in one embodiment, relates to a fluid loss control additive or composition comprising a granular starch composition and fine particulate mica, in specified proportions. The invention further comprises a fracturing fluid containing a starch composition and mica, in a specified ratio. In yet a third embodiment, the invention comprises a method of fracturing a subterranean formation penetrated by a borehole, comprising injecting into the borehole and into contact with the formation, at a rate and pressure sufficient to fracture the formation, a fracturing fluid containing starch and mica, in specified ratios, and in an amount sufficient to provide fluid loss control. In an additional embodiment, a fluid loss additive is used in a low viscosity preliminary sacrificial conditioning stage solution which will condition high permeability formations to provide a substantially uniform, low permeability fracture face leading to longer fracture lengths and more predictable design and execution of fracturing treatments in high permeability formations.

The crosslinking of galactomannan gum fracturing fluids by borate ion is delayed for high-temperature applications by encapsulating the boron with a polymer coating. The crosslink-delay time is further adjusted by varying the concentration of an organic polyol. The polyol also acts as a stabilizer for the crosslinked fluid at elevated temperatures. Low pumping friction pressures are achieved by the delay in the crosslinking with the boron available at high temperatures to add high-temperature stability to the fracturing fluid at temperatures ranging up to about 350.degree. F.

Delayed borate crosslinked fracturing fluid having increased temperature

The present process permits the use of more efficient, low viscosity fluids to efficiently perforate and fracture a subterranean formation in an overbalanced condition in the wellbore. In accordance with the invention, a method of decreasing the resistance to fluid flow in a subterranean formation around a well having a non-perforated casing fixed therein, the casing extending at least partially through the formation, comprises:

Overbalanced perforating and fracturing process using low-density,

The crosslinking of galactomannan gum fracturing fluids by borate ion is delayed for high-temperature applications by encapsulating the boron with a polymer coating. The crosslink-delay time is further adjusted by varying the concentration of an organic polyol. The polyol also acts as a stabilizer for the crosslinked fluid at elevated temperatures. Low pumping friction pressures are achieved by the delay in the crosslinking with the boron available at high temperatures to add high temperature stability to the fracturing fluid at temperatures ranging up to about 350.degree. F.

An improved method of mixing a fracturing fluid slurry concentrate comprising a hydrophobic solvent base (e.g., diesel No. 2) and a dispersed hydratable polymer (e.g., hydroxypropyl guar) on a real time basis thus continuously producing a fully hydrated fracturing fluid during the actual fracturing of a subterranean earthen formation. Viscosity rise times of less than 5 minutes are achieved in a continuous operation without the use of large volume storage/hydration tanks, employing primarily conventionally necessary pumps.

Method of hydrating oil based fracturing concentrate and continuous

Improved fracturing processes are described which use novel aqueous hydraulic fracturing fluids. The fluids comprise: (a) an aqueous medium, and (b) a thickening amount of a thickener composition comprising (i) a water-soluble or water-dispersible interpolymer having pendant hydrophobic groups chemically bonded thereto, (ii) a nonionic surfactant having a hydrophobic group(s) that is capable of associating with the hydrophobic groups on said organic polymer, and (iii) a water-soluble electrolyte. Additionally, the fluids preferably contain a stabilizing amount of a thiosulfate salt. As an example, an interpolymer of acrylamide and dodecyl acrylate was used in combination with a nonionic surfactant (HLB of about 10 to about 14) to thicken a dilute aqueous solution of KCl and sodium thiosulfate; the aqueous solution had excellent properties for use as a high temperature hydraulic fracturing fluid.

Hydraulic fracturing process and compositions

An aqueous based slurry is described comprising (1) a thickened water-based carrying fluid, (2) a particulate solid, e.g., gravel, and (3) a resin system comprising an epoxy resin and a novel crosslinking agent. The cross-linking agent is a polymethylene polyphenylamine bearing one or more silane groups of the formula

Aqueous based slurry and method of forming a consolidated gravel pack

A compound containing an aromatic or .alpha.-carbonyl enediol functional group is effectively employed as a breaker for the gelled aqueous carrier fluid in aqueous epoxy resin slurries of the type suitable for use in emplacing a permeably consolidated particulate mass in communication with a permeable subterranean formation.

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Sperry, OK, United States of America

Vernon G Constien