Schlumberger Technology Corporation

Marc J Thiercelin

Sylvaine Le Roy-Delage

Bernard Dargaud

Arkady Segal

Dean Michael Willberg

Ivan Vitalievich Kosarev

Matthew Miller

Brian Oliver Clark

J Ernest Brown

Ian D Bryant

Timothy M Lesko

Claude J Vercaemer

Dominique Guillot

Matthew J Miller

Roberto Suarez-Rivera

Christian Besson

Paul William Way

John Peter Crawshaw

Sylvaine Leroy-Delage

Anton Aleksandrovich Maksimenko

Sonia Marino

Valerie Jochen

Vladimir Mordukhovich Entov

Yury Nikolaevich Gordeev

Evgeny Mikhailovich Chekhonin

Gilbert Lavaure

Dean M Wulberg

Jean-François Baret

A method of fracture fluid clean-up from a fracture by assisting Darcy flow with electro-osmotic effects is provided. Proppants having suitable surface potential, and fracture fluids having suitable electrical conductivity are employed. A suitable electric field is imposed, using electrodes placed on the surface or in adjacent wells. The current creates an electro-osmotic flow that carries fluid to the wellbore.

Fracture clean-up by electro-osmosis

A technique enables improvements in hydraulic fracturing treatments on heterogeneous reservoirs. Based on data obtained for a given reservoir, a fracturing treatment material is used to create complex fractures, which, while interacting with the interfaces and planes of weakness in the reservoir, develop fracture connectors, e.g. step-overs, which often grow for short distances along these planes of weakness. The technique further comprises closing or sealing at least one of the fracture connectors to enable reinitiation of fracturing from the truncated branches, and to subsequently develop additional connectors. As a result, the overall fracturing becomes more complex (more branches and more surface area per unit reservoir volume is created), which leads to an increase in the effective fracture area and improved fluid flow through the reservoir.

Method for increasing fracture area

The invention provides economically effective methods for hydraulic fracturing a subterranean formation that ensure improvement of the hydraulic fracture conductivity because of forming strong proppant clusters uniformly placed in the fracture throughout its length. One of these methods comprises: a first stage comprising injection of fracturing fluid into a borehole, the fluid containing thickeners to create a fracture in the formation; and a second stage comprising introduction of proppant into the injected fracturing fluid to prevent closure of the created fracture, and further, comprising introducing an agent into the fracturing fluid to provide formation of proppant clusters in the created fracture and channels for flowing formation fluids.

Method for hydraulic fracturing of subterranean formation

A numerical model of a polymer-based fracturing fluid displacement from a fracture and a filtrate zone by a formation fluid is provided for calculating a change of a fracturing fluid concentration in a produced fluid and for calculating a change of a polymer concentration in the recovered fracturing fluid. Throughout the entire fracturing fluid recovery the produced fluid samples are periodically taken from a well mouth. The fracturing fluid concentration and the polymer concentration in the samples are measured. The measurement results are compared with the model calculations and the fracture length and width are determined based on a match of the measurement results and the model calculations.

Method for hydraulic fracture dimensions determination

The invention provides economically effective methods for hydraulic fracturing a subterranean formation that ensure improvement of the hydraulic fracturcconductivity because of forming strong proppant clusters uniformly placed in the fracture throughout its length. One of these methods comprises: a first stage that involves injection into a borehole of fracturing fluid containing thickeners to create a fracture in the formation; and a second stage that involves periodic introduction of proppant into the injected fracturing fluid to supply the proppant into a created fracture, to form proppant clusters within the fracture to prevent fracture closure and channels for flowing formation fluids between the clusters, wherein the second stage or its sub-stages involve additional introduction of either a reinforcing or consolidation material or both, thus increasing the strength of the proppant clusters formed into the fracture fluid.

A method for stimulating a reservoir formation while running a casing string into the wellbore includes the steps of: connecting a stimulation assembly to a casing string, the stimulation assembly including a packer actuator in operational connection with a packer and a logging sensor; running the casing string into the wellbore and positioning the logging assembly proximate to a selected reservoir formation; logging the reservoir formation; positioning the stimulation assembly proximate to the reservoir formation; actuating the packer to substantially isolate the reservoir formation from the wellbore; performing the stimulation operation; releasing the packers from sealing engagement with the wellbore; positioning the logging assembly proximate to the reservoir formation; logging the reservoir formation; and disconnecting the stimulation assembly from the casing string.

Method and apparatus of reservoir stimulation while running casing

The invention relates to oil production stimulation methods and can be used for both reservoirs with fractures resulting from the fracturing procedure and reservoirs with naturally occurring fractures, for which the fracturing procedure is not mandatory. A material which expands while hardening or setting, is injected into the near-wellbore region of a cased well, into the space between the casing and the reservoir, and the wellbore is then perforated. A material having an expansion degree sufficient for application of pressure to the wellbore walls and for keeping at least one fracture open is used as the material which expands while hardening or setting. After the perforation has been done, the reservoir is hydraulically fractured. For naturally fractured reservoirs, the fracturing procedure is not mandatory.

Well productivity enhancement methods

The methods of evaluating a geometry of a hydraulic fracture in a rock formation penetrated by a borehole comprises the steps of measuring the values of electric or magnetic fields, or both electric and magnetic fields generated due to the electrokinetic effect by the flow of an electrolyte-based fracturing fluid from the borehole into the fracture and from the fracture into the formation or by the reverse flow of the fluid from the rock formation and from the fracture into the borehole and determining the geometry of the fracture from the measured values. The methods may provide for varying the injection pressure, varying the value of the electrokinetic coupling coefficient of the fracturing fluid or applying at least one pressure pulse of a given magnitude to the fracturing fluid.

Method and an apparatus for evaluating a geometry of a hydraulic fracture in a rock formation

A method for on-line acoustic detection of the quality of foams and aerated fluids whereby at least one emitter/receiver pair is placed in a close vicinity to the foam flow. At least one acoustic pulse is emitted and the time within which the acoustic pulse travels from the emitter to the receiver is recorded. Sound speed in the foam is determined by analyzing an acoustic response of the receiver and a pressure in the foam is also measured.

Method and device for on-line acoustic monitoring of foam and aerated fluid properties

The invention relates to monitoring of fluid-filled domains in various media including, for example, subterranean formations, construction elements, bones. Claimed are a method for determining characteristic sizes of a fluid-filled crack in a medium and a system for implementation thereof. In accordance with this method, oscillations of the fluid-filled crack are registered. Wave characteristics of standing interface waves propagating along the fluid-filled crack surfaces are determined based on the registered oscillations taking medium and fluid properties into account. The fluid-filled crack characteristic sizes are calculated based on the determined wave characteristics of the standing interface waves. Also claimed are methods for detecting creation or existence of a fluid-filled crack in a medium, for hydraulic fracturing in a subterranean formation, for detecting cessation of propagation of a fluid-filled crack in a medium, as well as a method for determining properties of a fluid filling a layer in a medium, of the medium and of the layer. Analysis of oscillations of fluid-filled domains based on interface waves propagating along their surfaces underlies all the methods listed above. The proposed methods, by virtue of the simplicity of data processing inherent thereto, can be implemented in real time.

Method and system for monitoring of fluid-filled domains in a medium based on interface waves propagating along their surfaces

A method for stabilising an unconsolidated zone () of a borehole, by forming a region of the borehole having enlarged diameter () in the unconsolidated zone; positioning a fluid-filled casing () in the borehole the liner having a pipe () extending therethrough into a lower portion; pumping cement from the surface inside the pipe so as to exit the liner at the lower portion and flow upwards to fill the annulus () formed between the outside of the liner and the borehole in the unconsolidated zone; withdrawing the pipe () from the casing while pumping fluid therethrough so as to maintain the liner substantially fluid-filled and to displace cement above the liner in the adjacent region; drilling through the cement and liner in the unconsolidated zone after the cement has set.

Borehole stabilisation

A method and materials for stabilizing a wellbore against excess fluid pressure is described. It comprises forming or placing a flexible and essentially impermeable lining on or in the wellbore wall. The flexibility of the lining ensures that it remains in compression as the pressure in the wellbore is increased above the fluid pressure in the surrounding rock and it therefore does not need high tensile strength. The lining may be a preformed elastomer sleeve or formed in situ by the use of a reactive drilling fluid. Appropriate reactive formulations are described for the situation where the rock contains significant quantities of clay.

Compositions and processes for treating subterranean formations

Cementing compositions for oil wells or the like comprise between 30% and 100% (by weight of cement) of rubber particles, with grain size in the 40-60 mesh range. Adding rubber particles in accordance with the invention produces a low density slurry while keeping the cement permeability low. Compositions of the invention are particularly advantageous for cementing zones subjected to extreme dynamic stresses such as perforation zones and the junctions of branches in a multi-sidetrack well.

Cementing compositions and the use of such compositions for cementing wells

The present invention provides cementing compositions for oil wells or the like comprising an hydraulic binder and reinforcing particles constituted by a flexible material of low compressibility, and with an average grain size of less than 500 microns. The compositions of the invention are of particular advantage when cementing zones which are subjected to extreme dynamic stresses, such as perforation zones and the junctions of a multi-branch lateral well. They are also highly suitable for producing plugs.

Cementing compositions and application of such compositions for cementing oil wells or the like

The present invention provides cementing compositions for an oil well or the like, comprising an hydraulic binder, dense particles with a density higher than the density of the hydraulic binder, and reinforcing particles with a density of less than 1.5 g/cm , preferably less than 1.2 g/cm , constituted by a flexible material or rubber, of low compressibility and with an average grain size of less than 600 &mgr;m. The compositions of the invention are of particular advantage when preventing zones which are subjected to extreme stresses, such as perforation zones and the junctions of a multi-branch lateral well. They are also highly suitable for producing plugs.

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D'Auray, France

Marc J Thiercelin