Schlumberger Technology Corporation

Dowell, a Division of Schlumberger Technology Corporation

Dowell Schlumberger Incorporated

Schlumberger Technology Corporation - Dowell Division

Roger J Card

J Ernest Brown

Erik B Nelson

Paul R Howard

Jean-Pierre Feraud

Mathew M Samuel

Vernon G Constien

Arthur Gomtsyan

Frank F Chang

Keith Ingram Dismuke

Kevin W England

Kenneth H Nimerick

Dean M Willberg

Palathinkara S Vinod

Thomas O Mitchell

S Bruce McConnell

L Jack Maberry

The improved recovery of hydrocarbons from subterranean formations by hydraulically fracturing a subterranean formation is accomplished. Fracturing fluids using a viscoelastic surfactant fluid containing wormlike micelles are useful to improve recovery of hydrocarbons and limit the loss of fracturing fluid into the formation fracture face. The invention further relates to novel fracturing methods useful for increasing hydrocarbon production, limiting connate water production, resisting fracturing fluid loss into the subterranean formation, and reducing the equipment requirements in mixing and pumping fracturing fluid. The action of micelles of surfactant in aqueous zones of the subterranean formation facilitates the flowback of increased amounts of hydrocarbons once a fractured well is placed back on production.

Methods of fracturing subterranean formations

The improved recovery of hydrocarbons from subterranean formations by fracturing and matrix acidizing a subterranean formation is accomplished. Well treatment fluids having a viscoelastic surfactant fluid containing worm like micelles are useful to improve recovery of hydrocarbons and limit the loss of fracturing fluid into the formation fracture face. The viscolastic surfactant-based fracturing fluids of the present Invention are stable across a wide pH spectrum, allowing them to be used for fracturing treatments at low pH, as well as matrix acidizing treatments. In addition, the stability of these fluids is enhanced in the presence of organic anions. Two-stage fracturing treatments comprised of a viscoelastic surfactant-based fracturing fluid and a polymer-based system, wherein the two fluids are either blended or pumped into the formation sequentially (the polymer last) are also presented.

According to the present invention, a composition and method for hydraulically fracturing a subterranean formation is provided. The composition comprises an aqueous mixture of a hydrated polysaccharide, preferably a galactomannan gum, the hydrated polysaccharide having a plurality of bonding sites; a crosslinking agent for crosslinking the hydrated polysaccharide at the bonding sites at the conditions of the subterranean formation with a polyvalent metal ion to form a polyvalent metal crosslink, thereby increasing the viscosity of the hydrated polysaccharide; and a controlled solubility compound for releasing a chelating agent for controllably breaking the polyvalent metal crosslink and bonding with the polyvalent metal ion released by breaking the crosslink, thereby decreasing the viscosity of the hydrated polysaccharide. The method comprises the steps of injecting the above-described composition into the subterranean formation at fracturing pressures; allowing the controlled solubility compound to begin breaking the polyvalent metal crosslink, thereby reducing the viscosity of the hydrated polysaccharide and yielding a lower viscosity fluid; and removing the lower viscosity fluid from the subterranean formation.

Cleanup additive

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

A method is provided for limiting the inflow of formation water during a well turn around to maximize polymer recovery after a hydraulic fracturing treatment of a formation. The method includes a step for selectively blocking the pore structure in a water-bearing zone and not blocking the pore structure of a hydrocarbon zone at the formation face; performing a hydraulic fracturing treatment using a fluid having a polymer; and turning the well around to recover the polymer. There is also provided a method of acidizing, preferably matrix acidizing, a formation having a hydrocarbon zone and a water-bearing zone. The method includes a step for selectively blocking the pore structure in the water-bearing zone at the formation face to selectively retard migration of acid into the water-bearing zone; and injecting acid into the formation, wherein the acid is diverted from the water-bearing zone to the hydrocarbon zone as a result of the selective blocking step. When the water-bearing zone contains a residual amount of hydrocarbon residues, the method further includes injecting a mutual solvent prior to the step for selectively blocking. In these methods, the step for selectively blocking preferably forms a plug of a viscous fluid in the pore structure of the water-bearing zone at the formation face. The viscous fluid preferably has at least a viscoelastic surfactant capable of forming a worm-like micelle in an aqueous environment, a water-soluble salt to effect formation stability, and an aqueous carrier fluid.

Methods for limiting the inflow of formation water and for stimulating

Methods and compositions for testing subterranean formations

A method is provided for controlling the delay time of aqueous borate-crosslinked polysaccharide-based fluids for hydraulic fracturing and related applications which allows on-the-fly control of the delay time without comprising overall fluid integrity. Without having to modify the total boron content nor pH of the fracturing fluid, the delay time is controlled by adding a polyol to the fracturing fluid at a first rate, determining the resulting delay time and then adjusting the rate of the polyol addition to the fracturing fluid until the desired delay time is achieved.

On-the-fly control of delayed borate-crosslinking of fracturing fluids

A method combining resin consolidation and placement of fibrous material in intimate mixture with particulates provides a means of stabilizing a formation respect to sand production while enhancing well productivity without requiring a gravel pack screen.

Sand control without requiring a gravel pack screen

The addition of fibrous materials in intimate mixture with particulates for fracturing and gravel packing decreases or eliminates the flowback of proppant and/or formation fines while stabilizing the sand pack and lowering the demand for high polymer loadings in the placement fluids. Preferred fibers include glass, aramide, nylon and other natural and synthetic organic and inorganic fibers and metal filaments.

Growing community of inventors

Tulsa, OK, United States of America

Roger J Card