Schlumberger Technology Corporation

Mark Brady

Mehmet Parlar

Arthur Milne

J Ernest Brown

Wayne W Frenier

Keng Seng Chan

Colin J Price-Smith

Brett Rimmer

Christopher N Fredd

Raymond J Tibbles

Bernhard Lungwitz

Sylvie Daniel

Palathinkara S Vinod

Liz Morris

Pia-Angela Francini

Elizabeth W A Morris

Elizabeth W Morris

Keng Chan

Shrihari Kelkar

Treating compositions containing mutual solvents suitable for forming and maintaining single-phase aqueous fluid treating compositions containing very high concentrations of acids and/or chelating agents are described. Methods of use of these treating compositions for dissolving and removing scale and formation matrix material in oil-field treatments such as stimulation and remediation are given.

Treating composition

A method of treating a subterranean formation with a retarded self-diverting fluid system. The method includes contacting the formation with a mixture of acid, chelating agent, and betaine surfactant in which the betaine surfactant is mixed with an aqueous solution of the chelating agent in which the pH has been adjusted to a pH of below about 3.0, but above the pH at which the free acid of the chelating agent precipitates, and the resulting fluid system is utilized for both acid fracturing and matrix stimulation, as well as workover procedures such as scale and filter cake removal, especially in high temperature formations.

Composition and method for treating a subterranean formation

Propped fractures in formations from which fluids are produced are described that have wormholes extending out into the formations from the faces of the fractures at locations distant from boreholes. Methods are given for creating such propped fractures having wormholes in which either a closed propped fracture is formed and then the wormholes are formed, or the entire fracture and channel system is formed before the closure occurs.

Propped fracture with high effective surface area

A method is given for diverting acids in matrix acidizing and acid fracturing. The acids are diverted with a diverting agent that is an energized or foamed acidic viscoelastic surfactant system that contains a viscoelastic surfactant that gels and increases in viscosity when the acid in the foamed acidic viscoelastic surfactant system is spent. The method provides a synergistic combination of the diverting capabilities of foams and the diverting capabilities of viscoelastic gel systems. The resistance to flow of the gelled foamed viscoelastic surfactant system is greater than expected from a foam or a viscoelastic gel system alone.

Self-diverting foamed system

A method is given for completing an interval of an open-hole injection well penetrating a subterranean formation when the interface between the wellbore and the formation includes a zone invaded by a filter cake that includes bridging materials and other embedded solid materials. The method includes the steps of injecting a clean-up fluid and contacting it with the filtercake for a period of time sufficient to loosen some of the other solids embedded in the filter cake; removing the loosened solids by a high-rate displacement fluid containing suspending additives; and then injecting a dissolving fluid containing a diverter and an effective amount of a salt or acid capable of dissolving the bridging material.

Method for removing filter cake from injection wells

Present invention relates to high brine carrier fluid, said carrier fluid selected from the group consisting of organic acids, organic acid salts, inorganic salts and combination of one or more organic acids or organic acid salts, a co-surfactant and an amount of a zwitterionic surfactant. The invention also relates to methods of treating a subterranean wellbore, including drilling, hydraulic fracturing, gravel placement, scale removing, mud cake removing, using said high brine carrier fluid.

Viscoelastic surfactant fluids stable at high brine concentrations

A method of gravel packing a wellbore which has at least one aperture therein that provides a fluid flow path between the wellbore and an adjacent subterranean formation. At least a part of the formation adjacent to the open hole has a filter cake coated thereon that comprises a water and oil emulsion. The method of gravel packing comprises injecting into the wellbore a gravel pack composition that comprises gravel and a carrier fluid. The carrier fluid comprises an aqueous liquid having a pH that is outside the range at which the filter cake emulsion is stable. The aqueous liquid is present in an amount effective to invert the water in oil emulsion in the filter cake when the carrier fluid comes into contact with the filter cake. As a result, gravel is deposited at or adjacent to the aperture in the wellbore and some of the filter cake is removed. The remainder of the filter cake and the carrier fluid can be broken simultaneously by contact with a breaker fluid that contains at least one of a surfactant and a mutual solvent.

Filter cake cleanup and gravel pack methods for oil based or water based drilling fluids

The Invention relates to novel fluids and techniques to optimize/enhance the production of hydrocarbon from subterranean formations (e.g., &ldquo;completion fluids&rdquo;), in particular, fluids and techniques are disclosed and claimed which remove wellbore damage and near-wellbore damage in the form of coating formed from drilling and production-related operations (&ldquo;filtercake&rdquo;); the techniques can be applied either by themselves or in conjunction with other completion operations, such as gravel packing; preferred embodiments are chelating agent and enzyme systems in a viscoelastic surfactant (VES) matrix.

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Sugar Land, TX, United States of America

Mark Brady