Patent Application
20160349163
The disclosure generally relates to an apparatus and methods for measuring rheology, and more particularly, but not by way of limitation, apparatus and methods for measuring rheology using a helical vane rheology attachment.
The statements in this section merely provide background information related to the disclosure and may not constitute prior art.
Viscous aqueous fluids are found and used in many industries, including the food, personal care product, chemical and petrochemical industries. As an example, in the oil and gas drilling and production industry, viscous aqueous fluids are commonly used in treating subterranean wells, as well as carrier fluids. Such fluids may be used as fracturing fluids, acidizing fluids, and high-density completion fluids. In an operation known as well fracturing, such fluids are used to initiate and propagate underground fractures for increasing petroleum productivity.
During fracturing operations, fluids pumped into the subterranean formation can include solids such as proppant or fibers mixed with a fluid such as an aqueous gel. Such fluids are mixed in a blender including a slinger and a pump impeller, each attached to a drive shaft and enclosed within a casing.
Rheology measurements are frequently required for such fluids in order to provide information for engineering design, quantitative fluid QAQC, product formulation developments, just to name a few. Many rheometers are designed to give data for these purposes. The ones that are most commonly used in the oilfield are of the concentric rotating rheometer type. However, as the fluids become more complex, the routine rheometer design will not be able to function well. For example, when fibers are added to a non-Newtonian fluid, due to the macroscopic nature of fibers in relation to the continuous gel or solution, and the induced macroscopic alignments/entanglements, rheology measurement can be very problematic. Another example is high solid content fracturing fluid, where particle sizes are too big for the gap in the rheometer. While the gap in the rheometer can be increased to some extent to marginally accommodate larger particle sizes, at some point the particle sizes are too big to be accommodated by larger gap size. To add more complexity to the picture, some shear induced gel structure can also cause the fluid to slip along the shearing walls leading to a measurement of only the solvent viscosities. Accordingly, there is a need for procedures and systems to measure rheology for fluids that are normally difficult to measure with existing rheometer geometries, such as high solid content fluids, highly slipping fluids, fluids with fibrous materials, and fluids with large particulates, such need met, at least in part, by the following disclosure.
This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify indispensable features of the claimed subject matter, nor is it intended for use as an aid in limiting the scope of the claimed subject matter.
In an embodiment, a rheometer attachment includes a shaft having a shaft axis and an outer surface and a plurality of helical vanes each extending radially from the outer surface.
In accordance with another embodiment, the plurality of helical vanes each have an inner edge attached to the outer surface of the shaft.
In accordance with another embodiment, at least a portion of each of the plurality of helical vanes is at a variable helix angle, as measured from an axis parallel to the shaft axis, which increases at a rate of at least 1°/mm over the length of the inner edge from top to bottom.
In accordance with another embodiment, at least a portion of each of the plurality of helical vanes is at a fixed helix angle, as measured from an axis parallel to the shaft axis, of from about 5 to about 60 degrees.
In accordance with another embodiment, a rheometer comprises:
In accordance with another embodiment, a method for measuring rheology includes:
Certain embodiments of the disclosure will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements. It should be understood, however, that the accompanying figures illustrate the various implementations described herein and are not meant to limit the scope of various technologies described herein.
In the following description, numerous details are set forth to provide an understanding of some embodiments of the present disclosure. However, it will be understood by those of ordinary skill in the art that the system and/or methodology may be practiced without these details and that numerous variations or modifications from the described embodiments may be possible.
Unless expressly stated to the contrary, “or” refers to an inclusive or and not to an exclusive or. For example, a condition A or B is satisfied by anyone of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).
In addition, use of the “a” or “an” are employed to describe elements and components of the embodiments herein. This is done merely for convenience and to give a general sense of the inventive concept. This description should be read to include one or at least one and the singular also includes the plural unless otherwise stated.
The terminology and phraseology used herein is for descriptive purposes and should not be construed as limiting in scope. Language such as “including,” “comprising,” “having,” “containing,” or “involving,” and variations thereof, is intended to be broad and encompass the subject matter listed thereafter, equivalents, and additional subject matter not recited.
Finally, as used herein any references to “one embodiment” or “an embodiment” means that a particular element, feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily referring to the same embodiment.
Some aspects of the disclosure relate to apparatus for, and methods for, measuring rheology of fluids.
With reference to
With reference to
In some embodiments, the plurality of helical vanes 106 and 206 shown in
With reference to
With reference to
In some embodiments, the plurality of helical vanes 306 and 406 shown in
With reference to
In some embodiments, the rheometer 50 can also comprise a rotor 514 disposed within the cavity 506, a motor 516 connected to the rotor 514 for causing the rotor 514 to rotate relative to the rheometer attachment 508, and a torque measuring device 518 attached to the shaft 510.
Rheometer attachment 508 can be any rheometer attachment described herein, although it is shown in
In some embodiments, the difference between the radius r from the shaft axis 512 of the shaft 510 to an outer edge 520 of rheometer attachment 508 to an inner radius R of the rotor 514 can be from about 0.02 to about 1.5 cm or from about 0.03 to about 0.97 cm or from about 0.1 to about 0.6 cm.
With reference to
In some embodiments, the rheometer 60 can also comprise a motor 614 connected to the shaft 610 of the rheometer attachment 608 for causing the rheometer attachment 608 to rotate relative to the container 600; and a torque measuring device 616 attached to the shaft 610 for measuring torque from the rheometer attachment 608.
In some embodiments, the difference between the radius r from the shaft axis 612 to the outer edge 618 of rheometer attachment 608 to the radius R′ of the container 600 can be from about 0.02 to about 1.5 cm or from about 0.03 to about 0.97 cm or from about 0.1 to about 0.6 cm.
In some embodiments, the rheometer 60 can also comprise a stator 620 disposed within the cavity 606, wherein the rheometer attachment 608 is disposed within the stator 620, and wherein the motor 614 causes the rheometer attachment 608 to rotate relative to the stator 620. In some embodiments, the torque measuring device 616 can be attached to either the stator 620 for measuring the torque from the stator 620 or to the shaft 610 for measuring torque from the rheometer attachment 608. In some embodiments, when the torque measuring device 616 is attached to the shaft 610, the stator 620 can be attached to the container 600 at the top 622 of container 600 or attached to the container 600 at the bottom 624 of container 600.
In some embodiments, and with reference to
In some embodiments, the propeller movement of the plurality of helical vanes described herein (shown as reference numbers 106 in
In some embodiments, the fluid comprises particles which can have a diameter from about 5 μm to about 5 mm or from about 50 μm to about 4 mm or from about 500 μm to about 3 mm. In some embodiments, the fluid can comprise at least about 5 or at least about 7 or at least about 10 percent solids.
In some embodiments, the fluid can comprise particles having a multimodal particle size distribution. In some embodiments, the fluid can be shear thinning or shear thickening. In some embodiments, the fluid can comprise fibers. The fibers can be of a size from about 2 to about 20 mm or from about 3 to about 12 mm or from about 4 to about 10 mm.
A 300 mL quantity of a Fluid A was prepared and the formulation is given in Table 1 below.
Fluid A was a fluid having a multimodal particle size distribution. The Surfactant and Rheology Modifier formed a viscoelastic surfactant aqueous gel to improve particle suspension. Fluid A also had a solid concentration of 23 pounds proppant per gallon added (ppa), a solid volume fraction (SVF) of 51% and a density of 1.85 g/mL.
Fluid A was a shear thinning slurry, where viscosity decreases with increasing shear rate. The continuous phase fluid (Gelling Agent—the viscoelastic surfactant aqueous gel) undergoes shear alignment, where the shear induces semi-parallel configuration of the worm-like micelles. The full solid laden slurry also undergoes shear segregation, where the solid particle concentration changes with respect to shear rate and distance from the shear exerting device such as the rotary cylinder in a Fann 35 viscometer. For these reasons, it was difficult to measure the viscosity of the fluid, especially over time since the shear alignment and shear segregation were exacerbated. Shear segregation worsens as particles of bigger size are added.
Different methods were used to obtain rheological data for Fluid A. First, a Fann 35 rheometer was used with rotor 1 (radius of rotor 1.8415 cm), bob 5 (radius of 1.15987 cm) and spring factor 1 (torsion spring constant of 386 dyne-cm/degree), and at 3 rpm to determine rheometer dial readings. The dial readings are shown at 3 rpm since rheology at low shear rates is indicative of yield stress and also shear slippage and segregation are diminished at lower shear rates. For each measurement, Fluid A was pre-sheared and then left to relax to erase any pre-existing conditions from loading the viscometer, as well as to fill the annulus gap between the sleeve and the bob with Fluid A.
Further testing of Fluid A was performed with a Grace M3600 viscometer to monitor the deviation in viscosity readings when utilizing a bob 5, and rotor 1. In this test, the fluid was tested over time at a constant shear rate in order to see if consistent viscosity readings could be achieved at any point in time. Results of the testing, plotting viscosity (cP) over time, are shown in
Other bob designs were used to determine whether measurement reproducibility could be improved. In order to minimize fluid shear slippage and shear segregation, five helical vane geometry bobs (Vanes 1-5) were designed and produced.
The results from the dial readings at 3 rpm for each geometry (Vanes 1-5 and BOB5) tested for Fluid A are presented in
Fluids B, C and D were prepared and contained water and Gelling Agent (Surfactant and Rheology Modifier). Fluid B contained 25 gallons/thousand gallons (gpt) of Gelling Agent, Fluid C contained 30 gpt of Gelling Agent and Fluid D contained 35 gpt of Gelling Agent. Fluids B-D were tested at 3 rpm using a Fann 35, rotor 1 and spring constant 1, using Vane 5 without pre-shear in duplicate Runs 1-3. Fluids B-D were also tested in the same Fann 35 using BOB5, pre-shearing at 300 rpm for 5-6 seconds, and letting stand for 1 minute. The resulting dial readings are shown in
Fluids E-I were prepared and contained water, guar and varying amounts of fiber. Fluid E contained no added fiber, Fluid F contained 25 pounds per thousand gallons of water (ppt) of fiber, Fluid G contained 50 ppt of fiber, Fluid H contained 75 ppt of fiber, and Fluid I contained 100 ppt of fiber. The viscosity for fluids E-I were each measured in the Fann 35 rheometer using the BOB1, rotor 1, spring factor 1.
Fluids E, F and G were tested in the same Fann 35 rheometer using the Vane 5. Four duplicate measurements were made for each of the F and G fluids. As shown in
The foregoing description of the embodiments has been provided for purposes of illustration and description. Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the disclosure, but are not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.
It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail. Further, it will be readily apparent to those of skill in the art that in the design, manufacture, and operation of apparatus to achieve that described in the disclosure, variations in apparatus design, construction, condition, erosion of components, gaps between components may be present, for example.
Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.
Spatially relative terms, such as “inner,” “outer,”, “center”, “beneath,” “below,” “lower,” “above,” “upper,” “top,” “bottom” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
Although various embodiments have been described with respect to enabling disclosures, it is to be understood the invention is not limited to the disclosed embodiments. Variations and modifications that would occur to one of skill in the art upon reading the specification are also within the scope of the invention, which is defined in the appended claims.
