Hydrocarbon resources are typically located below the earth's surface in subterranean porous rock formations, often called reservoirs. These hydrocarbon bearing reservoirs can be found in depths of tens of thousands of feet below the surface. In order to extract the hydrocarbon fluids, also referred to as oil and/or gas, wells may be drilled to gain access to the reservoirs. Wells may be drilled vertically from surface, deviated from vertical, or vertical to horizontal in order to most effectively and efficiently access the subsurface hydrocarbon reservoirs.
A step in the drilling operations, or well construction, involves casing the wellbore with tubulars and cementing the tubulars in place. This isolates the internal conduit or well from the surrounding formations, which may be prone to collapse or have undesirable hazards present such as shallow gas. Each section of the well is typically drilled with a drill bit that is attached to a length of drill string that extends from the bottom of the wellbore to the drilling rig at surface. Upon the completion of drilling a section of well bore, the drilling string and drill bit are pulled out of the wellbore and a section of casing is deployed into the wellbore, which will be cemented into place creating the desired isolation from the newly drilled formation. However, depending on the depth of the wellbore there is a period time between removing the drilling string/drill bit and rigging up and deploying the casing. During this time period the newly drilled formation is left open and is referred to as an ‘open hole’. The open hole section, depending on the makeup of the formation surrounding it, maybe be prone to stability risks, which can be time consuming and expensive to remedy.
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 one aspect, embodiments disclosed herein relate to interchanging a casing shoe while the casing is deployed downhole in a wellbore. The casing shoe has cylindrical housing shaped body, a first engagement assembly on the circumferential outer diameter of the cylindrical body for engaging the internal surface of the wellbore casing, and a second engagement assembly mounted within the cylindrical body for engaging a running tool. When deployed inside the inner diameter of the wellbore tubular, the running tool engages the first engagement assembly of the casing shoe, and selectively shifts the second engagement assembly from the extended position to the recessed position, releasing the casing shoe from the internal diameter surface of the wellbore tubular.
The casing shoe can be either a guide shoe, a reamer shoe, or equivalent. In addition, either the guide shoe or the reamer shoe can be initially deployed on the first joint of casing. The requirement to change out the casing shoe is typically dictated by the wellbore conditions, which include scenarios where there are restrictions or tight spots present in the wellbore open hole section. These conditions may be created by poor wellbore circulation causing drilling cuttings to build up or wellbore stability issues related to reactive formations resulting in a partial collapse of the wellbore.
In one or more embodiments, the guide shoe may need to be interchanged with a reamer shoe to address a restriction in the wellbore. In this scenario, while the casing remains in the wellbore, a running tool is deployed into the wellbore through the internal diameter of the casing and engages the first engagement assembly of the guide shoe. The running tool selectively shifts the second engagement assembly into the recessed position, releasing the guide shoe from the internal diameter of the casing. The running tool, and attached guide shoe, are pulled out of the wellbore to surface. The guide shoe is changed out and a reamer shoe is installed on the running tool and deployed into the wellbore. The reamer shoe is installed on the last joint of casing in the same location as the removed guide shoe by the running tool selectively shifting the second engagement assembly of the reamer shoe to the extended position anchoring the reamer shoe to the casing. The running tool is disconnected from the reamer shoe and pulled out of the wellbore. With the reamer shoe installed, the top drive and drawworks rotate and apply weight down on the casing and reamer. There are a series of cutting blades mounted on the external surface of the reamer shoe, which cut and ream the formation creating a larger gauge hole in the wellbore open hole section. With the restriction removed the casing is conveyed deeper into the wellbore until the setting depth is reached. At this stage the reamer shoe can be changed out for a guide shoe following the same procedure described above, or the reamer shoe can remain attached to the casing while the casing is cemented in place.
In another aspect, embodiments of the present disclosure relate to a method where the reamer shoe is initially attached to the casing while the casing string is being deployed into the wellbore. In this scenario, the casing and reamer shoe are already in place to address any restriction that may be present in the wellbore permitting the casing to be deployed to the setting depth. As with the previous embodiment, the reamer shoe may be changed out for a guide shoe or the reamer shoe may remain attached to the casing while the casing is cemented in place. If the reamer shoe is to be changed out, a running tool is deployed into the wellbore through the internal diameter of the casing and engages the first engagement assembly of the reamer shoe. The running tool selectively shifts the second engagement assembly into the recessed position, releasing the reamer shoe from the internal diameter of the casing. The running tool, and attached reamer shoe, are pulled out of the wellbore to surface. The reamer shoe is changed out and a guide shoe is installed on the running tool and deployed into the wellbore. The guide shoe is installed on the last joint of casing in the same location as the removed reamer shoe by the running tool selectively shifting the second engagement assembly of the guide shoe to the extended position anchoring the guide shoe to the casing. The running tool is disconnected from the reamer shoe and pulled out of the wellbore. At this point the casing is cemented in place, and the casing running operations are complete.
Other aspects and advantages of the claimed subject matter will be apparent from the following description and the appended claims.
Specific embodiments of the disclosed technology will be described in detail with reference to the accompanying figures. Like elements in the various figures are denoted by like reference numerals for consistency. The sizes and relative positions of elements in the drawings are not necessarily drawn to scale. For example, the shapes of various elements and angles are not necessarily drawn to scale, and some of these elements may be arbitrarily enlarged and positioned to improve drawing legibility. Further, the particular shapes of the elements as drawn are not necessarily intended to convey any information regarding the actual shape of the particular elements and have been solely selected for ease of recognition in the drawing.
In the following detailed description of embodiments of the disclosure, numerous specific details are set forth in order to provide a more thorough understanding of the disclosure. However, it will be apparent to one of ordinary skill in the art that the disclosure 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 is not to imply or create any particular ordering of the elements nor to limit any element to being only a single element unless expressly disclosed, such as using 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.
The drill string (112) may be suspended in wellbore (102) by a derrick structure (101). A crown block (106) may be mounted at the top of the derrick structure (101), and a traveling block (108) may hang down from the crown block (106) by means of a cable or drilling line (103). One end of the drill line (103) may be connected to a drawworks (104), which is a reeling device that can be used to adjust the length of the cable (103) so that the traveling block (108) may move up or down the derrick structure (101). The traveling block (108) may include a hook (109) on which a top drive (110) is supported. The top drive (110) is coupled to the top of the drill string (112) and is operable to rotate the drill string (112). Alternatively, the drill string (112) may be rotated by means of a rotary table (not shown) on the surface (114). Drilling fluid (commonly called mud) (not shown) may pump the mud from the mud system (130) into the drill string (112). The mud may flow into the drill string (112) through appropriate flow paths in the top drive (110) (or a rotary swivel if a rotary table is used instead of a top drive to rotate the drill string (not shown)).
During a drilling operation at the well site (100), the drill string (112) is rotated relative to the wellbore (102), and weight is applied to the drill bit (128) to enable the drill bit (128) to break rock as the drill string (112) is rotated. In some cases, the drill bit (128) may be rotated independently with a drilling motor (not shown). In further embodiments, the drill bit (128) may be rotated using a combination of the drilling motor (not shown) and the top drive (110) (or a rotary swivel if a rotary table is used instead of a top drive to rotate the drill string (112)). While cutting rock with the drill bit (128), mud (not shown) is pumped into the drill string (112). The mud flows down the drill string (112) and exits into the bottom of the wellbore (102) through nozzles in the drill bit (128). The mud in the wellbore (102) then flows back up to the surface in an annular space between the drill string (112) and the wellbore (102) with entrained cuttings (not shown). The mud with the cuttings is returned to the mud system (130) to be circulated back again into the drill string (112). Typically, the cuttings are removed from the mud, and the mud is reconditioned as necessary, before pumping the mud again into the drill string (112).
Post drilling operations, when the drill string (112), the BHA (124), and the drill bit (128) have been removed from the wellbore (102), in some embodiments of wellbore (102) construction, the casing operations may commence. A casing string (116), which is made up of one or more lager diameter tubulars that have a larger outer diameter than the drill string (112) but a smaller outer diameter than the wellbore (102), are lowered into the wellbore (102) on the drill string (112). In some embodiments, the casing string (116) is designed to isolate the internal diameter of the wellbore (102) from the adjacent formation (126). Once the casing string (116) is in position, it is set and cement is pumped down through the internal space of the casing string (116), out of the bottom of the casing shoe (120), and fills the annular space between the wellbore (102) and the outer diameter of the casing string (116). This secures the casing string (116) in place and creates the desired isolation between the wellbore (102) and the formation (126). At this point, drilling of the next section of the wellbore (102) may commence.
Those skilled in the art will appreciate that casing is run as noted above on an equivalent size diameter tubular from bottom to surface which requires additional casing joints similar to all casing running jobs in the art.
In one or more embodiments, to fit or anchor the guide shoe (200) to the casing (202), a set of guide shoe slips (206) may be disposed on the outside profile of the guide shoe (200) and consist of angle ridges (214). In addition, the guide shoe (200) may have a first engagement assembly (208) disposed at the top of the cylindrical housing (204). When a running tool (406) engages the first engagement assembly (208) of the guide shoe (200), the guide shoe slips (204) may be activated to extend gripping the internal diameter surface (211) of the casing (202) anchoring the guide shoe (200) to the casing (202). In the scenario where the guide shoe (200) is fitted to the end of the casing (202) while at depth in the wellbore (102), the guide shoe (200) includes a no-go profile (210) that may be used to accurately locate the lower most end of the casing (202). The non-go profile (210) may be of a tapered design that exists on the outside profile of the guide shoe (200), such that the outside diameter of the guide shoe (200) increases towards the rounded profile end (201) of the guide shoe (200). This creates a physical stopping point for the guide shoe (200) within the casing (202) at which point the guide shoe slips (206) may be deployed.
Conversely, in one or more embodiments, the guide shoe (200) may be released from the casing (202) via deactivation of the guide shoe slips (204) by the engagement of the running tool (406) with the first engagement assembly (208).
In one or more embodiments, the guide shoe (200) may also be replaced with a float guide shoe (not shown). In this case, the casing (202) may be comprised of a float guide shoe. The float guide shoe may have a float valve (not shown) which helps in well control and possible floating of the casing. The float valve is installed to allow forward flow of fluids, but will prevent reverse flow, or u-tubing, from occurring. The float guide shoe may be bull-nosed shaped and help align the liner casing (202) into the center of the wellbore (102) to avoid hitting any ledges or washouts that exist.
In one or more embodiments, to fit or anchor the reamer shoe (300) to the casing (202), a set of reamer shoe slips (306) may be disposed on the outside profile of the reamer shoe (300) and consist of angle ridges (314). In addition, the reamer shoe (300) may have a first engagement assembly (308) disposed at the top of the cylindrical housing (304). When a running tool (406) engages the first engagement assembly (308) of the reamer shoe (300), the reamer shoe slips (304) may be activated to extend gripping the internal diameter surface (211) of the casing (202) anchoring the reamer shoe (300) to the casing (202). In the scenario where the reamer shoe (300) is fitted to the end of the casing (202) while at depth in the wellbore (102), the reamer shoe (300) includes a no-go profile (310) that may be used to accurately locate the lower most end of the casing (202). The non-go profile (310) may be of a tapered design that exists on the outside profile of the reamer shoe (300), such that the outside diameter of the guide shoe (200) increases towards the rounded profile end (301) of the reamer shoe (300). This creates a physical stopping point for the reamer shoe (300) within the casing (202) at which point the reamer shoe slips (306) may be deployed.
Conversely, in one or more embodiments, the reamer shoe (300) may be released from the casing (202) by deactivation of the reamer shoe slips (306) via deactivation of the reamer shoe slips (306) by the engagement of the running tool (406) with the first engagement assembly (308).
In one or more embodiments, the reamer shoe (300) may be replaced with a float reamer shoe (not shown). Therefore, the liner casing (202) may be comprised of a float reamer shoe (not shown). The float reamer shoe (not) may have a float valve (not shown) which helps in well control and possible floating of the casing. The float valve is installed to allow forward flow of fluids, but will prevent reverse flow, or u-tubing, from occurring. The float reamer shoe may also be bull-nosed shaped and help align the casing (202) into the center of the wellbore (102) to avoid hitting any ledges or washouts that exist.
While anchored to the casing (202), the reamer shoe (300) operates as a reamer (not shown) to widen or increase the gauge of the open hole section (402) of the wellbore (102). To perform this function, the top drive (110), which is connected to the casing (202), rotates the casing (202) which in turn rotates the reamer shoe (300). The cutting blades (313) on the outside diameter of the reamer shoe (300) ream or drill away small pieces of the wellbore wall (not shown) or formation (126), thus increasing the diameter of the open hole section (402). This allows for the casing (202) to reach the setting depth without getting stuck or incurring damage. Alternatively, in one or more embodiments, the reamer shoe (300) may be replaced with a turbine/motor reamer shoe (not shown). The turbine/motor reamer shoe (not shown) may comprise a turbine or motor (not shown) that is configured to be deployed downhole and, by using hydraulic power provided supplied by the drilling fluid, drive the rotation of the reamer independent of the top drive (110) and casing (202). This allows the wellbore (102) to be reamed without the need to rotate the casing (202).
Those skilled in the art will appreciate that using lock dogs via an upward force is only one attachment/release mechanism that may be employed by embodiments disclosed herein. Other suitable attachment or release mechanisms such as shear pins, sliding sleeves, etc., which use a downward force or another type of force may also be employed without departing from the scope disclosed herein.
In Step 500, the open hole section (402) of the wellbore (102) is drilled by a drill bit (128) and BHA (124) and is ready for casing operations. The guide shoe (200) is fitted to the casing (202) at surface and is ready to be deployed into the wellbore (102) on the drill string (116).
In Step 502, the guide shoe (200) and the casing (202) are deployed into the wellbore (102) on the drill string (116). The guide shoe (200) exits the casing shoe (120) of the previous casing string (112) and proceeds to be lowered into the open hole section (402).
In Step 504, in accordance with one or more embodiments, a decision is made as to whether the guide shoe (200) has encountered a tight spot (404) in the open hole section (402) of the wellbore (102). Examples of a tight spot (404) may include, but are not limited to, drilling cuttings build up or a partial collapse due to reactive shales/formations, which partially close off the wellbore (102). Such scenarios prevent the guide shoe (200) and casing (202) from being further lowered into the wellbore (102). At this stage, the guide shoe may need to be interchanged with a reamer shoe or another suitable type of shoe to continue traveling downhole, and overcome the tight spot encountered. If a tight spot is not encountered, the process proceeds to Step 520.
In Step 506, the running tool (406) is installed on a slick line system (408) and deployed into the wellbore (102) inside the casing (202). The running tool (406) is lowered via the slick line system (408) to the depth of the guide shoe (200).
In Step 508, the running tool (406) engages the second engagement assembly (212) of the guide shoe (200). In one or more embodiments this may be a sliding sleeve with a set of lock dogs or other method that may be known to one skilled in the art. At this stage the guide shoe slips (206), which are disposed on the cylindrical body (204) of the guide shoe (200), are in the extended position and anchored to the internal diameter surface (211) of the casing (202). The running tool (406) deactivates the slips (206), which are then retracted into the guide shoe (200), releasing the guide shoe (200) from the casing (202).
In Step 510, the guide shoe (200), which is connected to the running tool (406) is pulled out of the wellbore (102) through the inner diameter of the casing (202) by the slick line system (408).
In Step 512, the reamer shoe (300) is installed on the running tool (406), which is attached to the slick line system (408). The running tool (406) engages the second attachment assembly (312) of the reamer shoe (300). The slick line system (408) lowers the running tool (406) and reamer shoe (300) into the wellbore (102) through the inner diameter of the casing (202).
In Step 514, the no-go profile (310) on the outer profile of the reamer shoe (300) engages the internal diameter surface (211) of the casing (202) creating a physical stop and indication feature that the reamer shoe (300) is at the setting depth in the wellbore (102). The running tool (406) activates the reamer shoe slips (304), which extend radially outward providing pressure on the internal surface of the casing (202) anchoring the reamer shoe (300) to the casing (202).
In Step 516, the running tool (406) is disengaged from the second engagement assembly (312). At this stage the running tool (406) is pulled out of the wellbore (102) by the slick line system (408).
In Step 518, the reamer shoe (300) is activated to clear and widen the tight spot (404) in the open hole section (402). With the reamer shoe (300) securely anchored to the end of the casing (202), the top drive (110) and the drawworks (104) apply weight downward and rotate the reamer shoe (300) and casing (202) relative to the wellbore (102). The cutting blades (313) of the reamer guide (300) increases the wellbore diameter by cutting away and reaming the debris and formation that is creating the tight spot (404). The operation may require multiple reaming passes over the tight spot (404) before the casing (202) and reamer shoe (300) can pass and be set at the bottom of the wellbore (102). At this stage, the tight spot (404) has been cleared. The casing (202) and the reamer shoe (300) can now pass without restriction.
In Step 520, a tight spot (404) may have been encountered and cleared or a tight spot (404) may not have been present. In either scenario, the guide shoe (200) and casing (202) are lowered into the open hole section (402) of the wellbore (102) until the guide shoe (200) reaches the bottom of the wellbore (102).
In Step 522, the casing (202) is set in place in the wellbore (102) and the cement operation commences, Specifically, cement is pumped down the internal conduit of the casing (202), out of the bottom of the casing guide shoe (200), and fills the annular space between the casing (202) and the open hole section (402). This secures the casing (202) in place and isolations the wellbore (102) from the surrounding formation (126).
In Step 524, the casing (202) is disengaged and all running tools and equipment are retrieved at the surface (114).
In Step 600, the open hole section (402) of the wellbore (102) has been drilled by the drill bit (128) and BHA (124) and is ready for casing operations. The reamer shoe (300) is fitted to the casing (202) at the surface (114) and is ready to be deployed into the wellbore (102) on the drill string (116).
In Step 602, the reamer shoe (300) and the casing (202) are lowered into the wellbore (102) on the drill string (116). The reamer shoe (300) exits the casing shoe (120) of the previous casing (116) and proceeds to be lowered into the open hole section (402).
In Step 604, in one or more embodiments, the reamer shoe (300) and casing (202) may not be capable of reaching the desired bottom hole depth in the wellbore (102). This may be due to encountering a tight spot (404) in the open hole section (402) of the wellbore (102). Examples of a tight spot (404) may include drilling cuttings build up or a partial collapse due to reactive shales/formations, which partially close off the wellbore (102). Such scenarios prevent the reamer shoe (300) and casing (202) from being further lowered into the wellbore (102). If a tight spot (404) were encountered, the operation sequence would proceed to Step 606. If the reamer shoe and casing (202) were able to reach the desired bottom hole depth in the wellbore (102) without restriction, then the operation sequence proceed directly to Step 610.
Step 606, in one or more embodiments, assumes that a restriction due to a tight spot (404) has been encountered in the wellbore (102). As the casing (202) is fitted with the reamer shoe (300), the reaming operations to widen the wellbore open hole section (402) can commence. With the reamer shoe (300) securely anchored to the end of the casing (202), the top drive (110) and the drawworks (104) apply weight downward and rotate the reamer shoe (300) and casing (202) relative to the wellbore (102). The cutting blades (313) of the reamer shoe (300) increases the wellbore diameter by cutting and reaming the debris and formation that is creating the tight spot (404). The operation may require multiple reaming passes over the tight spot (404) before the casing (202) and reamer shoe (300) can pass and be set at the bottom of the wellbore (102).
Step 608, in one or more embodiments, depicts the reamer shoe (300) and casing (202) as being lowered into the wellbore (102) without obstruction. This may be the result of there being a tight spot (404) that has been cleared by the reamer shoe (300) or it may be that there were no restriction encountered in the open hole section (402) of the wellbore (102). In this step the casing (202) and the reamer shoe (300) have been lowered to the setting location at the bottom of the wellbore (204). In one or more embodiments, the reamer shoe (300) may be cemented in place with the casing (202). Alternatively, the reamer shoe (300) may be recovered at surface (114) for future casing (202) operations.
In Step 610, the casing (202) with the reamer shoe (300) attached may be set and cemented, isolating the surrounding reservoir/formation (126). However, to preserve the reamer shoe (300) and save cost through the potential future use of the reamer shoe (300), before cementing the casing (202) the reamer shoe (300) may be changed out with a guide shoe (200). If the decision is made to retrieve the reamer shoe (300), the process continues to step 612, otherwise the process moves to step 624.
Step 612 depicts the installing a running tool (406) on a slick line system (408) and deploying the running tool (406) into the wellbore (102) inside the casing (202). The running tool (406) is lowered via the slick line system (408) to the depth of the reamer shoe (300).
In Step 614, the running tool (406) engages the reamer shoe (300) by applying a downward force on the second engagement assembly (312) of the reamer shoe (300). The running tool (406) contains a set of lock dogs (not shown) that when engaging the second engagement assembly (406) with a downward force, the lock dogs (not shown) lock into a profile on the second engagement assembly (312).
In Step 616, the reamer shoe (300) is released from the casing (202). Prior to the reamer shoe (300) being release, the reamer shoe slips (306), which are disposed on the cylindrical housing (304) of the reamer shoe (300), are in the extended position and anchored to the internal diameter surface (211) of the casing (202). The running tool (406) deactivates the slips (306), which are then retracted into the reamer shoe (300). The reamer shoe (300) is released from the casing (202) and pulled out of the wellbore (102) through the inner diameter of the casing (202) by the slick line system (408).
In Step 618, the running tool (406), which is connected to the slick line system (408), engages the second engagement assembly (212) of the guide shoe (200). The slick line system (408) lowers the running tool (406) and guide shoe (200) into the wellbore (102) through the inner diameter of the casing (202).
In Step 620, the no-go profile (210) on the outer profile of the guide shoe (200) engages the inner diameter edge of the casing (202) creating a physical stop and indication feature that the guide shoe (200) is at the setting depth in the wellbore (102). The running tool (406) activates the guide shoe slips (204), which extend radial outward providing pressure on the inside of the casing (202) and anchoring the guide shoe (300) to the casing (202).
In Step 622, the running tool (406) is disengaged from the second engagement assembly (212) by applying an upward force with the running tool (406), which releases the lock dogs (not shown). At this stage the running tool (406) is pulled out of the wellbore (102) by the slick system (408).
In Step 624, the casing (202) is set in place in the wellbore (102) and the cement operation commences, wherein cement is pumped down the internal conduit of the casing (102), out of the bottom of the casing guide shoe (200), and fills the annular space between the casing (202) and the open hole section (402). This secures the casing (202) in place and isolations the wellbore (102) from the surrounding formation (126).
In Step 626, the casing (202) is released and all running tools and equipment are retrieved at the surface (114).
Embodiments of the present disclosure may provide at least one of the following advantages. When the casing cannot reach the bottom of the wellbore due to a tight spot in the open hole section, the disclosure provides an option that will save time and costs associated with pulling casing that was run with a guide shoe and replacing with a reamer shoe. The casing guide shoe/reamer shoe are based on existing designs which are modified to allow for retrieval/interchangeability features. Any known running tool may be used to interchange the guide shoe for the reamer shoe or vice versa. Embodiments disclosed herein apply only to running casing and not to drilling or drill bit retrieval. Thus, rather than being applicable to drilling assembly and reamer shoe interchangeability, this disclosure focuses on guide shoe and reamer shoe interchangeability in the context of running casing.
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. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures. It is the express intention of the applicant not to invoke 35 U.S.C. § 112, paragraph 6 for any limitations of any of the claims herein, except for those in which the claim expressly uses the words ‘means for’ together with an associated function.