Patent Application
20240102378
The present invention relates to reusable, electronically instrumented downhole measurement and recording devices to be deployed during in-fracture treatments to wellbores for oil and/or gas operations, which are not currently possible due to the reliability of the previous packaging techniques.
Hydraulic fracturing or “fracking” is the process of injecting high-pressure fluids down a well bore to create small fissures in the surrounding rock formations to release trapped hydrocarbon deposits and increase production. The fissures are held open by suspended solids in the fracking fluid known as proppants. In horizontal wells, fracking is often done in multiple stages, with each stage being isolated after treatment. Isolation is often achieved with the use of frac plugs set along the well casing at varying intervals. Frac plugs often incorporate a frac ball in a ball-on-seat seal, creating a check valve prohibiting fluids from travelling downhole past the plug but allowing well fluids to travel up to the surface. After treatment, the frac balls can be flowed back to surface with the resulting production flow of the well and are captured in specialized surface equipment.
Operators of these wellbores currently rely on surface data to estimate bottom hole conditions. Improved data might be achieved by relying on sensor measurements from the downhole region being treated.
According to a first aspect of the invention, there is provided a downhole gauge comprising:
According to a second aspect of the invention, there is provided a downhole gauge comprising:
According to a third aspect of the invention, there is provided a downhole gauge comprising:
According to a fourth aspect of the invention, there is provided a downhole gauge comprising:
For a detailed description of the preferred embodiments of the invention, reference will now be made to the accompanying drawings in which:
The following discussion is directed to various exemplary embodiments. However, one skilled in the art will under-stand that the examples disclosed herein have broad application, and that the discussion of any embodiment is meant only to be exemplary of that embodiment, and not intended to suggest that the scope of the disclosure, including the claims, is limited to that embodiment.
Certain terms are used throughout the following description and claims to refer to particular features or components. As one skilled in the art will appreciate, different persons may refer to the same feature or component by different names. This document does not intend to distinguish between components or features that differ in name but not function. The drawing figures are not necessarily to scale. Certain features and components herein may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in interest of clarity and conciseness.
In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to”. Also, the term “couple” or “couples” is intended to mean either an indirect or direct connection. Thus, if a first device couples to a second device, that connection may be through a direct engagement between the two devices, or through an indirect connection that is established via other devices, components, nodes, and connections. In addition, as used herein, the terms “axial” and “axially” generally mean along or parallel to a particular axis (e.g., central axis of a body or a port), while the terms “radial” and “radially” generally mean perpendicular to a particular axis. For instance, an axial distance refers to a distance measured along or parallel to the axis, and a radial distance means a distance measured perpendicular to the axis. Any reference to up or down in the description and the claims is made for purposes of clarity, with “up”, “upper”, “upwardly”, “uphole”, or “upstream” meaning toward the surface of the borehole and with “down”, “lower”, “down-wardly”, “downhole”, or “downstream” meaning toward the terminal end of the borehole, regardless of the borehole orientation. As used herein, the terms “approximately,” “about,” “substantially,” and the like mean within 10% (i.e., plus or minus 10%) of the recited value. Thus, for example, a recited angle of “about 80 degrees” refers to an angle ranging from 72 degrees to 88 degrees.
During a hydraulic fracing operation, a highly pressurized liquid, referred to as the “frac fluid,” is pumped down the wellbore and is utilized to initiate and propagate cracks or fractures in the formation rock extending from perforations in the casing that lines the wellbore. Typically, fracking is performed at a plurality of spaced intervals along the well-bore, each interval defining a frac “stage.” At each stage, the casing is perforated and then the portion of the formation extending from the perforations is fracked. Previously fracked stages are isolated from the particular stage being fraced. The cracks formed in the formation by fracking define flow paths through which hydrocarbons in the formation can flow, thereby enhancing fluid communication between the reservoir in the formation and the wellbore.
The pressure and temperature profiles in at the bottom hole during a perforation job provide insight into the effectiveness of the perforation. For example, the size of the pressure spike at the bottom hole assembly (BHA) during a perforation can provide insight into the size and/or geometry of the resulting perforations. As another example, an increase in the temperature of fluids surrounding the BHA shortly after a perforating the casing may indicate an influx of relatively hot formation fluids into the wellbore, which confirms fluid communication between the wellbore and the surrounding formation (i.e., that the perforations extend through the casing). The pressure profile of the frac fluid within a given stage being fracked (i.e., at the location where the cracks in that stage are initiated) influences the development and behavior of the cracks, and thus, provides insight into the fracking process and formation mechanical properties, which can be used to assess and/or tailor a variety of subsequent activities (e.g., subsequent fracking cycles). In addition, the pressure profile of the fracking fluid during a fracking operation can be used to identify stages that were insufficiently isolated during fracking, which may also influence subsequent operations. For example, if a particular stage was not sufficiently isolated during fracking, it can be fracked again to ensure sufficient initiation and propagation of cracks in the formation surrounding that stage.
When working with downhole pressure and temperature measurements, it is preferable to obtain measurements as close as possible to the perforations, where either fluids are injected during a fracturing stage, or where reservoir fluids (including hydrocarbons) enter the wellbore. Embodiments described herein offer the potential to measure temperatures and pressures proximal the perforations to enable a more clear and accurate understanding of the fluid distribution (injection and/or production), as measurements proximal the perforations will substantially reduce and/or eliminate any fluid friction that is often misunderstood and yields significant uncertainties.
The acquisition of downhole temperature and pressure measurements in accordance with embodiments described herein, in particular the downhole treating pressure during fracturing, which is usually an important input into fracturing simulators, offers the potential to enhance the ability of engineers to use the downhole treating pressure to more accurately estimate number of perforations clusters hydraulically connected to the fracture network, the total amount of additional pressure at the nearwellbore (commonly referred as “nearwellbore” pressure), the type of fracture network or geometry being generated, and optimize the fracturing job treatment by adjusting parameters such as injection rate, sand concentration, fluid viscosity, chemicals added, etc.
The pressure and temperature profiles along a wellbore during production operations can assist with production profiling, as well as aid in the identification and location of loss circulation zones. For example, insight into the pressure and temperature within different stages of the wellbore over time can help the operator identify stages that are producing and stages that are not producing (or are insufficiently producing). In artificial lift production operations, comparison of the pressure profiles in the annulus (between a production string and the casing) and the inside of the production string can be used to determine the efficiency of the lift mechanism, and subsequently, optimize the lift mechanism employed. For at least the foregoing reasons, the pressure and temperature profiles of fluids in a wellbore during various downhole operations such as drilling, completion, and production operations can provide valuable insight. Embodiments of apparatus and methods described herein provide means for measuring downhole temperatures and pressures during a variety of downhole operations
Referring to
The two outer housing sections are releasably coupled and contain the inner housing assembly 109. More specifically, in this embodiment, the outer housing sections are releasably coupled with male threads 110 on the outer body 102, and mating female threads 111 on the outer cap 103. The male threads 110 of the outer body 102 are provided on the outside of a cylindrical neck 156 of the outer body that projects axially from a truncation plane 157 of the outer body's externally spherical contour. The mating female threads 111 on the outer cap 103 are provided in a cylindrical counterbore 158 of the of the outer cap that is recessed thereinto from the truncation plane 157 of the outer cap's externally spherically contour. The conically tapered portion of the outer cap's hollow interior bound by conical surface 108 has a wide end that opens into the counterbore 158, but is of lesser diameter thereof, whereby the floor of the counterbore defines an annular shoulder 159 between the cylindrical counterbore 158 and the conical surface 108. Furthermore, in this embodiment the outer housing sections are additionally secured with the use of a set screw 112 disposed in a female threaded hole 113 in the outer cap 103. As shown in
In this embodiment, the outer body 102 includes three identical pressure ports 104 in the outer surface. Each pressure port 104 is a slot having a central slot axis 116, two parallel sides running in the slot's direction of elongation, and two ends of opposing relation to one another in said direction, of which the end nearest to the reference axis 125 is a radiused end. The bottom surfaces of the pressure ports 104 are coplanar with an endmost inner surface 118 of a hollow interior of the outer body 102, which is circumferentially bound by the aforementioned cylindrical inner surface 105. The endmost inner surface 118 of outer body's hollow interior lies distally opposite an open end of the outer body's externally threaded neck. The central slot axes 116 of the pressure ports 104 lie radially of the reference axis 125 and are angularly spaced therearound at equal intervals of 120°. The pressure ports 104 allow fluid communication between the inner housing assembly 109 and the surrounding environment. Naturally, the number, size or shape of the pressure ports 104 can be altered, for example a single, circular pressure port could be used in place of the radially arrayed pressure ports shown in the illustrated embodiment.
Referring to
The inner cap 120 consists of a roughly cylindrical body with an open end received in the hollow interior of the inner body 119 and a closed end residing outside the inner body 119 in distal relationship to the open end thereof at a location residing at or near the spherical exterior of the outer cap 103. The inner cap 120 has an exterior face that, moving from the open end of the inner cap 120 to the closed end thereof, includes a cylindrical section 134 having a gland designed to accept o-ring 122b, a first conical section 135 flaring outwardly from the cylindrical section 134 and having a gland designed to accept o-ring 122a, and a second conical section 136 tapering inwardly towards the closed end. Conical section 135 has a larger diameter than conical section 136, thus defining annular shoulder 138 therebetween that faces away from the inner body 119 and toward the closed end of the inner cap. The taper angle of conical section 136 on the inner cap 120 matches the taper angle of conical section 133 of inner body 119, whereby these conical sections define angled metal-to-metal sealing surfaces with an extrusion gap 137 therebetween. The taper angle of conical section 136 matches the taper angle of conical inner surface 108 of outer cap 103.
The outer body 102 and outer cap 103 are releasably coupled around the inner housing assembly 109such that the annular shoulder of the outer cap 103 makes abutting contact with the annular face 138 of the inner cap 120, and a similar and oppositely facing annular shoulder on the outer body 102, where the inner surface 105 thereof steps down in diameter toward the endmost surface 118, abuts against the annular face 129 of the inner body 119. All other surfaces of the inner housing assembly 109 do not contact any surfaces of the outer body 102 or the outer cap 103. Coupling the outer cap 103 to the outer body 102 around the inner housing assembly 109 forces the inner cap 120 into the inner housing, thus partially closing the extrusion gap 137. Applying external pressure to the frac ball 100 further forces the inner cap 120 into the inner body 119, thereby further closing the extrusion gap 137.
In the illustrated but non-limiting example shown in the drawings, the narrower end of the conically tapered inner cap 120 is directly exposed to the surrounding environment through an aperture in the outer cap 103, where the narrow end of the inner cap 120 is of convexly spherical contour so as to reside flush with the spherically contoured outer surface of the inner cap 120, whereby external pressure from the surrounding environment exerts an axial force on this narrow end of the inner cap, which tightens the mated fitting and sealed relationship between the inner housing sections where they conically interface with one another. This placement of the inner housing's narrow end at the exterior of the outer housing also minimizes the overall outer diameter of the ball relative to the size of the inner housing assembly. Even if this were not the case (for example in a larger diameter ball, where the narrow end of the inner cap is housed within the outer cap in non-exposed relation to the surrounding environment), the inner housing assembly would still be enveloped by pressurized fluid in a manner increasing the pressure tightness of the inner housing assembly, for example by admission of such pressurized fluid into the interior of the outer housing through the ports 104 therein, as well as through the mated threads of the outer housing sections. In other words, the outer housing is specifically not pressure tight, such that the external pressure can serve as a means to increase the pressure tightness of the inner housing assembly, and thereby better protect the internal components housed therein.
Referring now to
Scaffold 142 is generally cylindrical in shape with one side truncated and includes a central cylindrical bore 151 penetrating a first end thereof that faces the closed end of the inner cap, and a concentric through bore 152 that penetrates an opposing second end of the scaffold and is smaller in diameter, thus defining an annular shoulder therebetween 153 that faces the closed end of the inner cap. Furthermore, the scaffold 142 includes a cylindrical flexible section 154 around the outer perimeter, having a triangular catch protrusion at the end 155 with an outer diameter larger than that of the inner cylindrical face 127 of the inner body 119. The scaffold also includes cutouts to provide clearance for various electrical components (not shown) on the CCA 140.
The sensor 121 is installed in the larger diameter section 130 of the cylindrical through-bore in the inner body 119 and abuts against annular face 132 with the output pins 148 extending inwardly through the smaller diameter section 131 of the through-bore. CCA spacer 141 includes a plurality of through-holes that are aligned with the small friction contact sockets 146 on the CCA 140 and is installed around the small friction contact sockets 146. The CCA 140 is releasably coupled to the sensor 121 by aligning and inserting the sensor output pins 148 in the small friction contact sockets 146 with the CCA spacer 141 disposed there between. The CCA 140 is affixed in a position of perpendicular and concentric relation to the reference axis 125. The scaffold 142 is inserted into the interior of the inner body behind the CCA 140, in an orientation aligning the through bore 152 with the large friction contact socket 147, and forcing the cylindrical flexible section 154 to initially yield radially inward before resiliently popping back outwardly to its default diameter to lock the catch protrusion into the circumferential groove 128, thus fixing the CCA 140 in place. The battery 139 is then installed in the scaffold's central bore 151, simultaneously having the metal grounding case 143 contact the spring terminal 149 and the positive terminal 144 insert into the large friction contact socket 147, thus powering the electronic assembly. The battery 139 seats against the scaffold's annular shoulder 153. The inner cap 120, along with o-rings 122a and 122b, encloses the inner housing assembly, forming a pressure tight seal in addition to fixing the battery 139 in place.
In this embodiment, the sensor 121 is a pressure and/or temperature sensor that measures the pressure and/or temperature within the envelope of the outer housing 101. Since the interior of the outer housing 101 is in direct fluid communication with the environment immediately outside the frac ball 100 via ports 104, the pressures and/or temperatures measured and recorded by the sensor 121 are indicative (i.e., the same or substantially the same) of the pressures and/or temperatures immediately outside the frac ball 100 adjacent the ports 104. The sensor 121 converts the measured pressure and/or temperature to an electrical signal that is communicated to the microprocessor, which records and stores the measured pressure and/or temperature in the memory. The battery 139 provides power to the electrical components within the frac ball 100 such that the frac ball 100 can function autonomously during deployment.
In this embodiment, the pressure and/or temperature data recorded in the memory of the frac ball 100 is downloaded to an external device and analyzed at the surface after the frac ball 100 is retrieved to the surface. As best seen in
For use in relatively harsh downhole conditions, the outer housing 101, inner housing 109, and sensor 121 are preferably designed to allow the CCA 140 and battery 139 to function at pressures of at least 15,000 psi and temperatures of at least 150° C. In this embodiment, the outer housing is a spherical ball. Although frac ball 100 can have any suitable outer diameter depending on the particular downhole application, in embodiments described herein, the frac ball 100 has an outer diameter preferably greater than or equal to 2″ (50.8 mm). In one embodiment, the outer diameter of the frac ball 100 is 2.125″ (54.0 mm). For use in the harsh downhole environment, outer housing 101 and inner housing 109 must be made of rigid, durable materials. In one embodiment, outer housing 101 is made of a carbon-fiber reinforced polyether ether ketone (PEEK), and inner housing 109 is made of a lightweight, chemical resistant alloy, for example titanium G5.
In general, the microprocessor can be configured to measure, record, and store measurement data including: pressures and/or temperatures, vibration, inclination, acceleration, flow, resistivity, and density, continuously or at any suitable frequency.
In embodiments described herein, the microprocessor preferably measures, records, and stores (hereafter referred to as “samples”) measurement data at least once every 5 minutes, and more preferably at least once every 1 second. However, it should be appreciated that the frequency at which the microprocessor samples pressure and/or temperature data is variable and programmable, and thus, is not limited to the preferred ranges described above.
Without being limited by this or any particular theory, the greater the frequency at which pressure and/or temperature measurements are made and recorded, the greater the energy (battery) and memory requirements. Additionally, the microprocessor can be configured to employ a “pressure trigger” by which the microprocessor samples pressure and/or temperature at a slower rate (e.g. once per 5-10 minutes) pending a predetermined threshold pressure or temperature is reached, after which the microprocessor samples at a higher rate as disclosed above. This can decrease energy and memory requirements of the frac ball 100, allowing for higher sampling rates during well treatment.
Frac ball 100 can be used during completion operations to measure and record downhole pressures and/or temperatures during such operations, and then retrieved to the surface for subsequent analysis of the measured and recorded downhole pressures and/or temperatures.
This application claims benefit under 35 U.S.C. 119(e) of U.S. Provisional Application No. 63/410,734, filed Sep. 28, 2022, the entirety of which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 63410734 | Sep 2022 | US |
