Patent Application
20240218780
Displacement of cement is a key factor for good cementation in oil and gas wells. Failure to displace cement slurry accurately when drilling mud or water results either in under displacement or over displacement of the cement slurry. Both of these factors affect the well cost and well construction time. In case of under displacement of the cement slurry, there will be left over cement in the casing that was not displaced to a proper desired depth. This excess cement has to be drilled out. Alternatively, over displacement of cement will result in additional displacement of the cement slurry into an annulus flushing shoe with drilling mud. Hence, wet shoe, the shoe flushed when drilling mud or water, may result in failed shoe integrity which then requires extensive and costly remedial operations impacting well delivery and its construction cost.
One of the major factors for this theoretical cement displacement error is inaccurate pump or displacement efficiency and inherent tubular inner diameter (ID) uncertainty. Inaccurately calculated volume due to inaccurate pump efficiency and use of theoretical tubular ID may result in over-displacement or under-displacement of cement slurry.
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 key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.
In general, in one aspect, embodiments disclosed herein relate to a system displacing cement in an annulus of a well. The system includes a casing string with a casing outer circumferential surface, wherein the casing outer circumferential surface delineates a boundary of the annulus and a wiper plug, having an outer circumferential surface delineated by an inner circumferential surface of the casing string, wherein the wiper plug is placed to follow the displacement of the cement in the annulus. Further, the system includes a float collar, having an outer circumferential surface delineated by the inner circumferential surface of the casing string, configured to allow the cement to pass downward with respect to a surface, and a displacement efficiency calibration collar, having an outer circumferential surface delineated by the inner circumferential surface of the casing string, configured to control volume of the cement displaced in the annulus, wherein the displacement efficiency calibration collar includes a calibration shearing disc.
In general, in one aspect, embodiments disclosed herein relate to a method for displacing cement in an annulus of a well. The method includes providing a casing string having a casing outer circumferential surface that delineates a boundary of the annulus within the casing string and pumping drilling fluid into the casing string until the calibration collar reaches a predetermined distance from the float collar. Further, a predetermined volume of the cement is pumped into the casing string while running the casing string into the well and the wiper plug is placed into the casing string. The wiper plug is displaced, using the drilling fluid, until the wiper plug latches to the displacement efficiency calibration collar. Additionally, a number of strokes of the drilling fluid pumped into the casing string needed to achieve latching the wiper plug to the displacement efficiency calibration collar is measured and the number of strokes of the drilling fluid pumped into the casing string needed push the wiper plug and the displacement efficiency.
In general, in one aspect, embodiments disclosed herein relate to a displacement efficiency calibration collar for displacing cement in an annulus of a well. The displacement efficiency calibration collar includes a housing that extends horizontally over a casing string, the housing comprising a rounded profile component and a calibration shearing disc structured to be compatible with a wiper plug, the wiper plug latching to the inner profile. Additionally, the displacement efficiency calibration collar includes an outer profile structured to be compatible with a float collar, the outer profile latching to the float collar and a plurality of shear pins, coupled to the inner profile and the outer profile, configured to break when a given pressure is exerted on the plurality of shear pins.
Other aspects and advantages of the claimed subject matter will be apparent from the following description and the appended claims.
Specific embodiments disclosed herein will now be described in detail with reference to the accompanying figures. Like elements in the various figures are denoted by like reference numerals for consistency. Like elements may not be labeled in all figures for the sake of simplicity.
In the following detailed description of embodiments disclosed herein, numerous specific details are set forth in order to provide a more thorough understanding disclosed herein. However, it will be apparent to one of ordinary skill in the art that the invention may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid unnecessarily complicating the description.
Throughout the application, ordinal numbers (e.g., first, second, third, etc.) may be used as an adjective for an element (i.e., any noun in the application). The use of ordinal numbers does not imply or create a particular ordering of the elements or limit any element to being only a single element unless expressly disclosed, such as by the use of the terms “before,” “after,” “single,” and other such terminology. Rather, the use of ordinal numbers is to distinguish between the elements. By way of an example, a first element is distinct from a second element, and the first element may encompass more than one element and succeed (or precede) the second element in an ordering of elements.
In the following description of
It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a horizontal beam” includes reference to one or more of such beams.
Terms such as “approximately,” “substantially,” etc., mean that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.
It is to be understood that one or more of the steps shown in the flowcharts may be omitted, repeated, and/or performed in a different order than the order shown. Accordingly, the scope disclosed herein should not be considered limited to the specific arrangement of steps shown in the flowcharts.
Although multiple dependent claims are not introduced, it would be apparent to one of ordinary skill that the subject matter of the dependent claims of one or more embodiments may be combined with other dependent claims.
Embodiments disclosed herein provide a method and system for calibrating the displacement of cement to avoid under-displacement and over-displacement. A Displacement Efficiency Calibration Collar (DECC) is a device that aids determination of accurate displacement efficiency using theoretical and real displacement volumes and aids for the cement slurry volume to be pumped to bump the plug at desired depth. In other words, the DECC calibrates the displacement efficiency during cement job. In one or more embodiments, the DECC minimizes the displacement efficiency uncertainty on cement job quality, minimizes the tubular ID uncertainty, as well as pump displacement efficiency.
Further, as this disclosure reduces chances of under-displacement and over-displacement, it consecutively reduces the time and cost needed to clean out of excess hardened cement in the casing string and removal of cement from desired portion of casing which results in wet shoe scenario, respectively. Since accurate displacement efficiency is determined using the DECC, the volume of remaining drilling fluid is pumped based on new displacement efficiency. As such, the wiper plug is bumped into the float collar using a more accurate amount of cement.
A casing string (106) is made of a plurality of joints of casing connected together. Each joint of casing is a tubular made of a durable material, such as steel. The casing joints may also be made of a lighter material, such as fiberglass. The casing string (106) has a casing outer circumferential surface (108). The casing outer circumferential surface (108) delineates a boundary of an annulus (110). The annulus (110) is the space located between the casing outer circumferential surface (108) and the wellbore (102). Because wells (100) are often supported by a plurality of casing strings, the annulus (110) may also include the space located between the casing outer circumferential surface (108) and a shallower casing string's inner circumferential surface. The casing string (108) is lowered into the wellbore (102) at a predetermined depth of the casing string (126).
The casing string (106) is shown having a float shoe (112). A float shoe (112) is the portion of the casing string (106) located furthest away from the surface location (104), i.e., the deepest component of the casing string (106) in a vertical well (100). The float shoe (112) is a rounded profile component. The rounded profile allows the casing string (106) to guide the casing string (106) towards the center of the wellbore (102) to minimize hitting rock ledges and washouts. The inner components of the float shoe (112) are made of a drillable material, such as cement or thermoplastic.
The casing string (106) of the well (100) is shown as also having a float collar (118). The float collar (118) is also located along a portion of the casing string (106) further away from the surface location (104); however, the float collar (118) is located at a shallower depth than the float shoe (112), i.e., the float collar (118) is closer to the surface location (104) than the float shoe (112). The outer portion of the float collar (118) may be made of a durable material, such as steel, and may match the size of the casing string (106). The inner components of the float collar (118) are made of a drillable material, such as cement or thermoplastic.
The casing string (106) is commonly made with both a float shoe (112) and a float collar (118).
In one or more embodiments, a cement displacement control apparatus includes the wiper plug (114), the float collar (118), and DECC (120). The cement displacement control apparatus determines an accurate displacement efficiency using theoretical and real displacement volumes and extrapolates the data for the remaining cement slurry volume to be pumped to bump the plug at desired depth. A wiper plug (114) follows the cement and is pumped from the surface location (104) into the casing string (106). The wiper plug (114) is used to avoid contamination between cement and drilling fluid (116). The wiper plug (114) is made of a drillable material, such as thermoplastic or rubber and it placed into the casing string using the cement head (124). As shown on
Returning back to
The increase in pressure on the wiper plug (114) will give indication that cement has been displaced to desired point. In one or more embodiments, the pressure on the wiper plug (114) may be measured using shear pins (301), which are designed to operate until a certain pressure is applied on them. However, as described above, in case of wrong displacement efficiency assumption, actual displacement volume will differ from the planned displacement volume. Such mismatch will result into either, under displacement or over displacement of cement inside the casing string (106). In case when the wiper plug fails and does not bump into the float collar (118), the standard practice is to pump additional half shoe track volume. If the planned pump efficiency is wrong and half shoe track volume is pumped, then chances of resulting in the wet shoe are significantly high. However, using DECC (120) together with the wiper plug (114) and the float collar (118), reduces or mitigates the above stated problems.
In one or more embodiment, the casing string (106) is shown having a displacement efficiency calibration collar (DECC) (120). DECC (120) is the portion of the casing string (106) located at the shallower depth than the float collar (118). In one or more embodiments, the DECC (120) may be located above the float collar (118) at a distance of 10% of the casing string (106) depth. The distance of 10% of the casing string (106) depth from the casing string (106) is taken to simplify calculations, as described below. However, in one or more embodiments, the location of DECC (120) with respect to the float collar (118) may be smaller or larger than 10% of the casing string depth.
As shown on
Initially, a casing string (106) having a casing outer circumferential surface (108) that delineates a boundary of the annulus (110) is provided. (S400). The casing string (106) includes the float collar (118) and DECC (120). The casing string is run down the wellbore (102) to the predetermined depth (126). Additionally, the DECC (120) may be located above the float collar (118) at a distance of 10% of the casing string (106) depth. The drilling fluid (116) is used to displace the DECC (120) to the predetermined distance from the float collar (118) (S402). The distance of 10% of the casing string (106) depth from the casing string (106) is taken to simplify calculations, as described below. However, in one or more embodiments, the location of DECC (120) with respect to the float collar (118) may be smaller or larger than 10%. The wiper plug (114) is located at the shallower depth above the DECC (120).
When the DECC (120) reaches the predetermined location, the predetermined volume of cement as per annular volume is pumped between the wellbore (102) and the casing string (106) (S404). Further, after the predetermined volume of cement is pumped, the wiper plug (114) is placed into the casing string (106). The wiper plug is used to separate the cement from the drilling fluid (116). The drilling fluid (116) pumped into the casing string (106) exerts the pressure on the wiper plug (114) pushing it downwards to the DECC (120). When the wiper plug (104) reaches the DECC (120), the wiper plug (104) latches to the calibration shearing disc (121) inside the DECC (S406). In one or more embodiments the float collar (118), DECC (120), and the wiper plug (114) are positioned sequentially in the casing string (106).
The drilling fluid (116) is pumped into the casing string (106) in strokes. In one or more embodiments, the number of strokes pumped into the casing string (106) may be measured manually or using a computer processor. The computer processor may be connected to the pumping apparatus. Initially, the drilling fluid (116) is pumped into the casing string (106) until the wiper plug (114) latches to the DECC (120). The measurement of the number of strokes of the drilling fluid pumped into the casing string needed to achieve latching of the wiper plug (114) to the calibration shearing disc of DECC (121) is performed to calculate the number of strokes of the drilling fluid (116) needed to push the wiper plug (114), latched to the calibration shearing disc of DECC (121), to reach the float collar (118) (S408).
After latching in the calibration shearing disc of DECC (121), under the predetermined pressure, shear pins of the DECC (301) break and calibration shearing disc of DECC (121) are freed from DECC (120). A number of strokes of the drilling fluid (116) needed to push the wiper plug (114) attached to the calibration shearing disc of DECC (121) is based on the number of strokes until the latching is achieved and the position of the DECC (120) relative to the float collar (118). Specifically, the following formula is used to calculate the number of remaining strokes (S408):
Where p signifies the location of DECC (120) represented as a percentage of distance between the DECC (120) and the float collar (118) over the depth of the float collar (118). Further, N signifies the number of strokes pumped into the casing string (106) before the latching of the calibration shearing disc (121) to the float collar (118) is achieved. The number of remaining strokes may be calculated manually or automatically.
In one or more embodiments, the cement is pumped into the casing string (106) based on the calculated number of remaining strokes. Calculating the number of remaining strokes minimizes a potential risk of under displacement or over displacement. However, if a mistake during measuring or calculating occurs, the mistake may be rectified by pumping additional cement of volume equal to the volume between DECC (120) and the float collar (118).
In one or more embodiments the method described in
For exemplary purposes, if in a particular well, the float collar (118) is placed at depth of 5000 feet and the DECC (120) is installed at depth of 4500 feet above the float collar (118). The DECC would be installed at 10% of the float collar (118) depth. If the number of actual strokes to achieve latching is 900 then remaining strokes the calibration shearing disc of DECC (121) reaches to float collar (118) will be 100 based on the Equation 1.
Embodiments may be implemented on any suitable computing device, such as the computer system shown in
The computer (500) can serve in a role as a client, network component, a server, a database or other persistency, or any other component (or a combination of roles) of a computer system for performing the subject matter described in the instant disclosure. The illustrated computer (500) is communicably coupled with a network (510). In some implementations, one or more components of the computer (500) may be configured to operate within environments, including cloud-computing-based, local, global, or other environment (or a combination of environments).
At a high level, the computer (500) is an electronic computing device operable to receive, transmit, process, store, or manage data and information associated with the described subject matter. According to some implementations, the computer (500) may also include or be communicably coupled with an application server, e-mail server, web server, caching server, streaming data server, business intelligence (BI) server, or other server (or a combination of servers).
The computer (500) can receive requests over network (510) from a client application (for example, executing on another computer (500) and responding to the received requests by processing the said requests in an appropriate software application. In addition, requests may also be sent to the computer (500) from internal users (for example, from a command console or by other appropriate access method), external or third-parties, other automated applications, as well as any other appropriate entities, individuals, systems, or computers.
Each of the components of the computer (500) can communicate using a system bus (570). In some implementations, any or all of the components of the computer (500), both hardware or software (or a combination of hardware and software), may interface with each other or the interface (520) (or a combination of both) over the system bus (570) using an application programming interface (API) (550) or a service layer (560) (or a combination of the API (550) and service layer (560). The API (550) may include specifications for routines, data structures, and object classes. The API (550) may be either computer-language independent or dependent and refer to a complete interface, a single function, or even a set of APIs. The service layer (560) provides software services to the computer (500) or other components (whether or not illustrated) that are communicably coupled to the computer (500). The functionality of the computer (500) may be accessible for all service consumers using this service layer. Software services, such as those provided by the service layer (560), provide reusable, defined business functionalities through a defined interface. For example, the interface may be software written in JAVA, C++, or other suitable language providing data in extensible markup language (XML) format or other suitable format. While illustrated as an integrated component of the computer (500), alternative implementations may illustrate the API (550) or the service layer (560) as stand-alone components in relation to other components of the computer (500) or other components (whether or not illustrated) that are communicably coupled to the computer (500). Moreover, any or all parts of the API (550) or the service layer (560) may be implemented as child or sub-modules of another software module, enterprise application, or hardware module without departing from the scope of this disclosure.
The computer (500) includes an interface (520). Although illustrated as a single interface (520) in
The computer (500) includes at least one computer processor (530). Although illustrated as a single computer processor (530) in
The computer (500) also includes a memory (580) that holds data for the computer (500) or other components (or a combination of both) that can be connected to the network (510). For example, memory (580) can be a database storing data consistent with this disclosure. Although illustrated as a single memory (580) in
The application (540) is an algorithmic software engine providing functionality according to particular needs, desires, or particular implementations of the computer (500), particularly with respect to functionality described in this disclosure. For example, application (540) can serve as one or more components, modules, applications, etc. Further, although illustrated as a single application (540), the application (540) may be implemented as multiple applications (540) on the computer (500). In addition, although illustrated as integral to the computer (500), in alternative implementations, the application (540) can be external to the computer (500).
There may be any number of computers (500) associated with, or external to, a computer system containing computer (500), each computer (500) communicating over network (510). Further, the term “client,” “user,” and other appropriate terminology may be used interchangeably as appropriate without departing from the scope of this disclosure. Moreover, this disclosure contemplates that many users may use one computer (500), or that one user may use multiple computers (500).
In some embodiments, the computer (500) is implemented as part of a cloud computing system. For example, a cloud computing system may include one or more remote servers along with various other cloud components, such as cloud storage units and edge servers. In particular, a cloud computing system may perform one or more computing operations without direct active management by a user device or local computer system. As such, a cloud computing system may have different functions distributed over multiple locations from a central server, which may be performed using one or more Internet connections. More specifically, cloud computing system may operate according to one or more service models, such as infrastructure as a service (IaaS), platform as a service (PaaS), software as a service (Saas), mobile “backend” as a service (MBaaS), serverless computing, artificial intelligence (AI) as a service (AIaaS), and/or function as a service (FaaS).
Although only a few example embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the example embodiments without materially departing from this invention. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims.
