Patent Application
20190345814
The present disclosure relates generally to wellbore drilling and formation evaluation and, more specifically, to a Logging-While-Drilling or Measurement-While-Drilling sensing system for downhole hydrocarbon and gas species detection when forming a wellbore in a subterranean rock formation.
Hydraulic fracturing, commonly known as fracking, is a technique used to release petroleum, natural gas, and other hydrocarbon-based substances for extraction from underground reservoir rock formations, especially for unconventional reservoirs. The technique includes drilling a wellbore into the rock formations, and pumping a treatment fluid into the wellbore, which causes fractures to form in the rock formations and allows for the release of trapped substances produced from these subterranean natural reservoirs. At least some known unconventional subterranean wells are evenly fractured along the length of the wellbore. However, typically less than 50 percent of the fractures formed in the rock formations contribute to hydrocarbon extraction and production for the well. As such, hydrocarbon extraction from the well is limited, and significant cost and effort is expended for completing non-producing fractures in the wellbore.
In one aspect, a sensing sub-assembly for use with a drilling assembly is provided. The sensing sub-assembly includes a cylindrical body including an internal flow channel extending therethrough. The internal flow channel is configured to channel a first fluid therethrough. A recessed cavity is also defined therein. The recessed cavity is coupled in flow communication with an ambient environment exterior of the cylindrical body, and a second fluid flows within the ambient environment. The recessed cavity is configured to receive a continuous stream of the second fluid therethrough. At least one sensor is coupled to the cylindrical body, and the at least one sensor is configured to determine characteristics of the second fluid in the continuous stream that flows through the recessed cavity.
In another aspect, a method of operating a hydraulic fracturing system is provided. The method includes advancing a drilling assembly within a subterranean rock formation. The drilling assembly is configured to discharge a first fluid into the subterranean rock formation, and a second fluid flows past an exterior of the drilling assembly. The method further includes channeling a continuous stream of the second fluid through at least a portion of the drilling assembly, and determining characteristics of the second fluid in the continuous stream channeled through the drilling assembly.
These and other features, aspects, and advantages of the present disclosure will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
Unless otherwise indicated, the drawings provided herein are meant to illustrate features of embodiments of the disclosure. These features are believed to be applicable in a wide variety of systems comprising one or more embodiments of the disclosure. As such, the drawings are not meant to include all conventional features known by those of ordinary skill in the art to be required for the practice of the embodiments disclosed herein.
In the following specification and the claims, reference will be made to a number of terms, which shall be defined to have the following meanings.
The singular forms “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise.
“Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event occurs and instances where it does not.
Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “about”, “approximately”, and “substantially”, are not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Here and throughout the specification and claims, range limitations may be combined and/or interchanged. Such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise.
Furthermore, as used herein, the term “real-time” refers to at least one of the time of occurrence of the associated events, the time of measurement and collection of predetermined data, the time to process the data, and the time of a system response to the events and the environment. In the embodiments described herein, these activities and events occur substantially instantaneously.
Embodiments of the present disclosure relate to a sensing system for downhole hydrocarbon and gas species detection when forming a wellbore in a subterranean rock formation. The sensing system is implemented as a standalone evaluation tool or installed as part of a wellbore drilling assembly. The sensing system determines characteristics of a first fluid discharged from the drilling assembly, and a second fluid that flows past the drilling assembly in the wellbore. More specifically, the sensing system includes a recessed cavity that receives a continuous stream of the second fluid, separate from the main flow of the second fluid. At least one sensor is positioned within the recessed cavity to facilitate protecting the sensor from the caustic and abrasive wellbore environment. The sensor is used to determine characteristics of the fluid, and the characteristics are analyzed to determine the hydrocarbon content of the fluid. As such, the analysis results are used to identify potentially promising fracture initiation zones within the wellbore such that efficient and cost effective completion planning can be implemented.
For example, downhole hydrocarbon and gas species detection while drilling can identify zones of high permeability, such as open natural fractures, clusters of closed but unsealed natural fractures, larger pores and other formation features where hydrocarbons are stored. The analysis results can be used to identify the most promising fracture initiation points or zones, and the information can be used for completion planning, especially for unconventional reservoirs. In addition, the analysis results can be used to identify poor zones (no gas show), which facilitates reducing the time and effort of perforating and stimulating the poor zones. Another potential application is for geosteering assistance, wherein the real time gas show/species information is used to adjust the borehole position (e.g., inclination and azimuth angles) while drilling, such that a well having increased production can be formed. Finally, the sensing can also provide kick detection to facilitate providing real-time alerts of gas flow potential for safety and environmental considerations, thereby reducing the risk of system failure.
Cylindrical body 130 further includes a recessed cavity 138 defined therein. Recessed cavity 138 is either at least partially obstructed from or fully exposed to an ambient environment 140 exterior of cylindrical body 130, as will be explained in more detail below. As shown in
During operation of drilling assembly 100 (shown in
In the exemplary embodiment, sensing sub-assembly 110 includes at least one sensor coupled to cylindrical body 130. As will be described in further detail below, the at least one sensor determines characteristics of first fluid 148 and second fluid 150, and the data obtained from the at least one sensor is analyzed to determine the hydrocarbon content of second fluid 150. Exemplary characteristics determined by the at least one sensor includes, but is not limited to, density, viscosity, electromagnetic characteristics, acoustic impedance, sound speed, sound attenuation, and attenuation coefficient. Exemplary sensors include, but are not limited to, an ultrasound sensor, and an acoustic sensor, such as an acoustic transducer. Alternatively, any sensors for determining characteristics of first fluid 148 and second fluid 150 may be utilized that enables sensing sub-assembly 110 to function as described herein.
In one embodiment, referring to
Alternatively, the at least one sensor includes first pair 152 of sensors and a second pair 158 of sensors, including a third sensor 160 and a fourth sensor 162. Similar to first pair 152 of sensors, third sensor 160 is positioned for determining characteristics of first fluid 148 within internal flow channel 136, and fourth sensor 162 is positioned for determining characteristics of second fluid 150 within recessed cavity 138. In addition, first pair 152 of sensors operate at the same first frequency, and second pair 158 of sensors operate at the same second frequency. In the exemplary embodiment, the operating frequencies of first pair 152 and second pair 158 are defined within a sub-range of the operating frequency of the wide band transducer described above (i.e., sub-ranges spanning a portion of the range defined between and including about 100 kilohertz khz and about 20 megahertz Mhz) that collectively span a wide frequency range. As such, the data obtained from third sensor 160 and fourth sensor 162 are comparable relative to each other for determining the hydrocarbon content in second fluid 150. In addition, operating first pair 152 of sensors and second pair 158 of sensors at more narrowly defined frequency sub-ranges facilitates increasing the frequency resolution of the transmitted and received signals.
In some embodiments, the at least one sensor further includes a third pair 164 of sensors, including a fifth sensor 166 and a sixth sensor 168. Fifth sensor 166 and sixth sensor 168 are positioned for determining characteristics of second fluid 150 within recessed cavity 138. More specifically, one of fifth sensor 166 and sixth sensor 168 is an emitter, and the other sensor is a receiver. In addition, recessed cavity 138 has a length L and a width W shorter than length L. Fifth sensor 166 and sixth sensor 168 are longitudinally spaced from each other within recessed cavity 138 relative to length L. Longitudinally spacing fifth sensor 166 and sixth sensor 168 from each other facilitates increasing the distance therebetween, such that the distance is not limited by the diameter of cylindrical body 130. Moreover, in one embodiment, fifth sensor 166 and sixth sensor 168 are low frequency transducers that operate at a frequency defined within a range between and including about 10 kHz and about 20 kHz. When compared to higher frequency transducers, the sensor readings obtained from third pair 164 of sensors are less likely to be scattered by gas bubbles contained in second fluid 150, for example. As such, operating third pair 164 of sensors at a low frequency range facilitates increasing the amount of useful data obtained for later analysis and evaluation to determine the hydrocarbon content of second fluid 150.
In the exemplary embodiment, circumferential indent 174 defines a first mounting surface 176 and a second mounting surface 178 spaced longitudinally from, and oriented to face each other. In addition, the at least one sensor includes at least one pair 180 of sensors spaced longitudinally from each other, and each sensor in pair 180 is coupled to either first mounting surface 176 or second mounting surface 178. Longitudinally spacing each sensor in pair 180 from each other facilitates increasing the distance therebetween, such that the distance is not limited by the diameter of cylindrical body 130. As described above, the distance between a transmitter and a receiver of a sensor pair is selected based on an operating frequency of the sensor pair.
Referring to
The systems and assemblies described herein facilitate providing at least semi-continuous hydrocarbon and gas species detection feedback when drilling unconventional subterranean wells. More specifically, the drilling assembly facilitates analyzing fluid used in the drilling process in a fast and efficient manner. The data obtained from the analysis of the fluid samples can then be used to determine zones within a wellbore that have either a low likelihood or a high likelihood of having a high hydrocarbon content. As such, the zones having a high hydrocarbon content are identified, and fracture completion planning resulting in improved well production is determined.
An exemplary technical effect of the systems and assemblies described herein includes at least one of: (a) providing real-time and continuous hydrocarbon and gas species detection feedback when forming a well in a subterranean rock formation; (b) identifying potentially promising fracture initiation zones within a wellbore; (c) improving hydrocarbon production for wells; (d) providing geosteering assistance for the drilling assembly; and (e) providing kick detection for real-time gas flow potential safety alerts.
Exemplary embodiments of a drilling assembly and related components are described above in detail. The drilling assembly is not limited to the specific embodiments described herein, but rather, components of systems and/or steps of the methods may be utilized independently and separately from other components and/or steps described herein. For example, the configuration of components described herein may also be used in combination with other processes, and is not limited to practice with only drilling and sensing assemblies and related methods as described herein. Rather, the exemplary embodiment can be implemented and utilized in connection with many applications where analyzing one or more fluids is desired.
Although specific features of various embodiments of the present disclosure may be shown in some drawings and not in others, this is for convenience only. In accordance with the principles of embodiments of the present disclosure, any feature of a drawing may be referenced and/or claimed in combination with any feature of any other drawing.
This written description uses examples to disclose the embodiments of the present disclosure, including the best mode, and also to enable any person skilled in the art to practice embodiments of the present disclosure, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the embodiments described herein is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CN2017/070265 | 1/5/2017 | WO | 00 |
