Schlumberger Technology Corporation

Xiangdong Qiu

Reza Taherian

Mohan Kanaka Raju Panga

Frank F Chang

Dominic Joseph Brady

Christopher Daeffler

Stephen Dyer

Kuo-Chiang Chen

Mustapha Abbad

Weishu Zhao

Stephen John Remane Dyer

Abdul Muqtadir Mohammed

Athar Ali

Steve Dyer

Ziad Al-Jalal

Described herein are methods for treating a subterranean formation penetrated by a wellbore with a retarded acidizing fluid containing an acid and an acid retarding agent, the concentrations of which are adjusted based on measured parameter values of the formation. Also described is a method for treating a subterranean formation by introducing an acid to the formation following the introduction of an acid retarding agent to the formation. Also described is a method for acid fracturing a subterranean formation including reducing the concentration of an acid retarding agent contained in a retarded acidizing fluid over the course of the acid fracturing operation.

Methods for making and using retarded acid compositions for well stimulation

In an embodiment a method is described which includes emplacing a sample within a measurement cell, wherein two or more electrodes are configured in the measurement cell; introducing a reactive fluid into the measurement cell; reacting the sample with the reactive fluid, wherein reacting the sample with the reactive fluid results in a change in an ion concentration in the reactive fluid; and measuring the resistivity of the reactive fluid using the two or more electrodes, wherein the resistivity is proportional to the ion concentration in the reactive fluid.

Using resistivity measurements to monitor the reaction kinetics between acids and carbonate rocks

In one possible implementation, fresh hydrochloric acid or (partially) spent hydrochloric acid can be pressurized by a pressure source. The pressurized acid from the acid source is injected into a wellbore during an acidizing operation. In addition, a carbon dioxide source may be provided. Acid from the acid source is combined with carbon dioxide from the carbon dioxide source, and the combined acid and carbon dioxide, pressurized by the pressure source, are injected into the wellbore during the acidizing operation. A processor located at the earth's surface or downhole may be provided. The processor can monitor the relative proportions of carbon dioxide and acid in the acid/carbon dioxide combination, as well as the pressure of the acid/carbon dioxide combination at an injection site in the wellbore. Acidizing operation management decisions can be made based on the monitored relative proportions and/or the monitored pressure.

Optimizing matrix acidizing operations

A chemical stimulation system and a resistivity tool are disposed in a wellbore. Chemical stimulation operations are performed in the wellbore using the chemical stimulation system. Resistivity measurements are made with the resistivity tool before, during, and/or after the chemical stimulation operations. The resistivity measurements may be used to determine the porosity of a formation penetrated by the wellbore. A wormhole distribution and/or penetration in the formation is determined based on the resistivity measurements. Decisions regarding stimulation operations are made based on the determined wormhole distribution and/or penetration. The resistivity tool may be modular and have various arrays allowing various depths of investigation. The depths of penetration of the wormholes into the formation may be determined using the measurements from the multiple depths of investigation. The volume of the formation that is dissolved by the chemical stimulation operations may also be estimated.

Resistivity of chemically stimulated reservoirs

Systems and methods use enhanced flow control devices that can be selectively closed completely or have its effective flow area reduced to restrict production (or injection) by use of a chemical trigger mechanism. In addition, some of the systems deploy specific targeted chemical tracers, dissolvable in the unwanted production fluid (e.g., water or gas). These chemical tracers once dissolved will enter the production stream and be identified at the surface. An appropriate chemical trigger can be placed, for example, by pumping down through the tubing and utilizing intelligent completion valve to place the chemical, or by spotting with coiled tubing and bullhead to the formation. The chemical trigger will only trigger the active chemical in the appropriate flow control device.

Chemically targeted control of downhole flow control devices

The subject disclosure relates to matrix acidizing. More specifically, systems and methods are described for estimating a diffusion coefficient for an acid fluid used to stimulate a subterranean reservoir wherein a spent acid is formulated that includes one or more by-products of the reaction between the fluid and rock. A rock sample, such as in the form of a rotating disk is exposed to spent acid under elevated pressure and temperature conditions while the fluid is sampled and analyzed. A diffusion coefficient for the spend acid is estimated.

Estimating diffusion coefficient for a reservoir stimulation fluid

In one embodiment, the current application discloses a method comprising: performing a computed tomography (CT) porosity scan on a core sample, the core sample comprising a portion of a formation of interest; in response to the CT porosity scan, interpreting a porosity profile of the core sample; and in response to the porosity profile, modeling a response of a formation of interest to a predetermined treatment to determine a reacted formation configuration, wherein the predetermined treatment comprises an acid fluid treatment schedule, and wherein the modeling further comprises modeling acid fluid flow through the formation of interest having the porosity profile, and wherein the modeling further comprises accounting for acid reaction products during the predetermined treatment and shut-in period.

Growing community of inventors

Al-Khobar, Saudi Arabia

Xiangdong Qiu