TECHNICAL FIELD
The present disclosure relates to systems and methods for running marine drilling riser. More specifically, the present disclosure relates to a marine riser tool configured to automatically provide load compensation and/or alignment between two riser joints when being joined.
BACKGROUND
This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
A drilling riser includes a relatively large-diameter pipe that connects a subsea blowout preventer (BOP) stack to a surface rig. The large-diameter pipe is configured to take mud returns to the surface. In addition to the large-diameter main tube, many drilling risers include a plurality of high-pressure external auxiliary lines. These auxiliary lines can include high pressure choke and kill lines for circulating fluids to the BOP, and usually power and control lines for the BOP.
As the drilling riser is being installed, a riser running tool is often used to grip the next section or joint of riser at its upper end while the previous joint of riser is held in place by a spider system at the drill floor. Prior to connecting the two riser joints, a manual rotational alignment processes is carried out. After stabbing and connecting pins and boxes of the two riser joints together, the riser running tool lowers the joint or riser through drill floor and into the sea water. It has been found that most of the damage to riser joints occurs while stabbing and connecting riser joint pins and boxes.
SUMMARY
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 determining or limiting the scope of the claimed subject matter as set forth in the claims.
According to some embodiments, a drilling riser running system is described that is adapted to connect and run riser joints for use in a drilling process. The system includes: a riser running tool configured to securely hold a first riser joint at a top end and with a top drive system above the riser running tool, to lower a bottom end of the first riser joint towards a top end of a second riser joint being held by its top end near a drill floor; and an automated alignment system configured to automatically bring the bottom end of the first riser joint and the top end of the second riser joint into proper rotational alignment with each other prior to making contact between the first and second riser joints.
According to some embodiments, the automated alignment system comprises a processing system configured to determine whether or not the bottom end of the first riser joint and the top end of the second riser joint are in proper rotational alignment. The processing system can be further configured to: determine an appropriate corrective actuation amount that will bring the bottom end of the first riser joint and the top end of the second riser joint into proper rotational alignment; and instruct the top drive system and/or the riser running tool to rotate according to the determined corrective actuation amount.
According to some embodiments, the automated alignment system can include a sensor system configured to detect the rotational position information of at least the bottom end of the first riser joint. The sensor system can include one or more optical sensors that can detect a known landmark on the bottom end of the first riser joint. The sensor system can use other types of sensor technology, including: RFID, LiDAR, laser, ultrasonic, inductive, and/or magnetic.
According to some embodiments a drilling riser running system is described that includes: a riser running tool configured to securely hold a first riser joint at a top end and with a top drive system above the riser running tool, to lower a bottom end of the first riser joint towards a top end of a second riser joint being held by its top end near a drill floor; and a load compensation system configured to automatically reduce effective weight at the bottom end of the first riser joint in cases when contact between the bottom end of the first riser joint and the top end of a second riser joint may cause damage. The load compensation system can include one or more hydraulic piston assemblies that are configured to sense load on the system and to adjust the load.
According to some embodiments, a method of running a riser system is described that includes: lowering a bottom end of a first riser joint towards a top end of a stationary second riser joint using a riser running tool suspended from a top drive system; automatically detecting whether or not the bottom end of the first riser joint and the top end of the second riser joint are in proper rotational alignment; and automatically bringing the bottom end of the first riser joint and the top end of the second riser joint into proper rotational alignment with each other prior to making contact between the first and second riser joints.
BRIEF DESCRIPTION OF THE DRAWINGS
The subject disclosure is further described in the following detailed description, and the accompanying drawings and schematics of non-limiting embodiments of the subject disclosure. The features depicted in the figures are not necessarily shown to scale. Certain features of the embodiments may be shown exaggerated in scale or in somewhat schematic form, and some details of elements may not be shown in the interest of clarity and conciseness.
FIG. 1 shows a drilling system with an improved riser running tool is deployed at a marine wellsite, according to some embodiments;
FIG. 2 shows further detail of a drilling system with an improved riser running tool being deployed at a marine wellsite, according to some embodiments;
FIG. 3 shows further detail of an improved riser running tool, according to some embodiments;
FIG. 4 is a partial cross section illustrating further detail of an improved riser running tool, according to some embodiments;
FIGS. 5A and 5B illustrate further details of an improved riser running tool with self-alignment and weight compensation capabilities in the vicinity of the drill floor, according to some embodiments; and
FIG. 6 is a block diagram illustrating further details relating to operating a riser running tool, according to some embodiments.
DETAILED DESCRIPTION
One or more specific embodiments of the present disclosure will be described below. These described embodiments are only exemplary of the present disclosure. Additionally, in an effort to provide a concise description of these exemplary embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure. Like reference numerals are used herein to represent identical or similar parts or elements throughout several diagrams and views of the drawings.
According to some embodiments, an enhanced riser running tool is described that includes riser connection self-alignment as well as a riser connection counter weight mechanism. For the riser self-alignment functionality, the riser running tool can be configured with embedded sensors (e.g. RFID's. LiDAR, Laser, Optical, etc.), that work in conjunction with the automated riser stab system to detect the correct riser alignment. The riser running tool can also be equipped with either hydraulic or electric servo motors that are capable of rotating the riser joint to the perfectly aligned connection angle.
According to some embodiments, a riser connection counter weight mechanism includes an air/oil cylinder. The air/oil cylinder will be rated for the riser joint weight, with a safety factor included. This riser connection counter weight mechanism significantly reduces the risk of collision damage to the auxiliary line pins in cases where the riser joints come into contact before the pins and boxes are perfectly aligned.
FIG. 1 shows a drilling system with an improved riser running tool deployed at a marine wellsite, according to some embodiments. The drilling system 100 is being deployed on a vessel, such as a drillship, or on a floating platform positioned above subsea wellhead 108 on sea floor 106. According to some other embodiments, the drilling system 100 is being deployed from a fixed platform above wellhead 108. Drilling system 100 is shown lowering BOP stack 140 down through sea water 104 for connection to wellhead 108. The BOP stack 140 can include various components such as a wellhead connector, blowout preventors, annular diverters, subsea flexjoint(s) and riser adapter(s). Above BOP stack 140 are a number of riser joints below seawater surface 102 of which riser joint 132 is shown. Shown below drill floor 130 and passing through moon pool door 128 are further riser joints 134, 136 and 126. Riser joints 134 and 136 are shown with buoyancy modules. Mux cable line 124 is also shown being deployed below drill floor 130. Diverter 122 is also visible below rotatory table and drill floor 130. Above the drill floor 130 is “dog house” 112 and spider 118 which is shown currently holding the uppermost flange of riser joint 126. The riser running tool 110 is shown holding the next riser joint 116 above the spider 118. The riser running tool 110 is being deployed by top drive system 120. Also shown on the right side is a new riser joint 114 in the horizontal position that can be deployed by the riser running tool following the attachment of riser joint 116 to riser joint 126 and the lowering or running of riser joint 116.
FIG. 2 shows further detail of a drilling system with an improved riser running tool being deployed at a marine wellsite, according to some embodiments. In FIG. 2, the rotary table 242 and the gimbal 240 are visible. Also visible is the upper most portion 226 of lower riser joint 126 that is being held by spider 118. An alignment module 230 is also shown mounted on spider 118 which can be configured to facilitate automatic rotational alignment between the lower riser joint 126 and upper riser joint 116, and reduce risk of damage as is described in further detail herein. A processing system 232 is shown in dog house 112, although it could be located in part or wholly in another location at the drill site. According to some embodiments, processing system 232 includes a general purpose data processor and other computer components such as storage and input/output modules, and is configured to carry out processing tasks including automatic rotational alignment and/or automated counter balancing/load compensation functionality.
At the upper end of riser joint 116, tool head module 210 of riser running tool 110 is shown engaging and holding riser joint 116 at its upper end 216. A hydraulic and test fluid supply line 222 is run from the top drive 120 to the riser running tool 110, and is configured to supply hydraulic power and control as well as to supply filling and pressure testing fluid to the riser auxiliary lines. Further detail of liquid filling while tripping and automated pressure testing capabilities is described in cop. Also visible in FIG. 2 are bale arms (including bale arm 220) and weight compensation pistons (including piston assembly 260) which can be used to facilitate weight/load compensation to reduce the risk of damage, as is described in further detail in the co-pending patent application entitled “Riser Running Tool With Liquid Fill And Test,” filed on even date herewith, hereinafter referred to as the “co-pending patent application,” and which is incorporated herein by reference.
FIG. 3 shows further detail of an improved riser running tool, according to some embodiments. Tool head module is shown engaged with upper end 216 of riser joint 116. Riser joint 116 includes a large central tube 310 configured to carry fluid such as drilling mud from the wellhead to the surface. Riser joint 116 also includes a number of auxiliary lines 312, 314 and 316, which can include high pressure choke and kill lines for circulating fluids to the BOP, as well as power and control lines for BOP operation. According to some embodiments, tool head 210 grips onto the riser joint 116 by inserting a portion into the box section of the main tube 310 and expanding a split ring that engages grooves on the inner portion of the main tube 310. According to some embodiments, the riser running tool 110 is configured to provide weight or load compensation which can greatly reduce the risk of damage in the event of an unanticipated impact, such as due to mis-alignment between the riser joint 116 being lowered and the riser joint being held in the spider (e.g. riser joint 126 shown in FIGS. 1 and 2). According to some embodiments, two hydraulic cylinders 260 and 360 are used to provide load compensation as indicated by the dashed arrows 342. As will be described in further detail herein, hydraulic cylinders 260 and 360 can be used to detect an unanticipated impact as well as compensate for such impact by reducing the effective load. According to some other embodiments, weight/load compensation capability can be provided by the top drive 120 as indicated by dashed arrows 344. In such cases, the connections between bale arms 220 and 320 and riser running tool 110 can be made without excess “play” in the vertical direction. According to some embodiments, known top drive-based load compensation system can be used. For further details on such systems, see, e.g.: Cameron's TD-250-AC-1M, TD-500-AC-2M, TD-750-AC-1M-C, and TD-1000-AC-2M top drive systems that can include self-calibrating thread compensation.
FIG. 4 is a partial cross section illustrating further detail of an improved riser running tool, according to some embodiments. The lower portion of tool 210 includes riser bore pin assembly 414 that is shaped to fit into the box section of each riser joint's main central tube. The assembly 414 includes a split ring 420 that can be expanded under hydraulic power (e.g. from line 222, although the hydraulic connection is not shown). When split ring 420 is expanded, protrusions on the split ring outer surface securely engage grooves on the inner portion of the riser's main bore such that the riser can be safely and securely lifted and positioned for deployment (or storage). Also shown is a main bore vent line 450 that is configured to provide testing of the main riser tubing. According to some embodiments, the riser running tool can be configured to perform pressure testing on the main riser bore (e.g. tube 310 shown in FIG. 3). In cases where the main riser bore is being tested, sealing can be provided between assembly 414 and the inner surface of central tube 310 (shown in FIG. 3).
Auxiliary line testing subassembly 416 includes a box 412 to automatically engage the upper pin of an auxiliary line (e.g. line 316 shown in FIG. 3). The box 412 is configured to form a seal with the auxiliary line when the central pin assembly 414 is engaged with the central tube (e.g. tube 310 shown in FIG. 3). Testing subassembly 416 includes a fluid port 410 that attached to line 222 as shown. While only a single testing subassembly 416 is shown for clarity in FIG. 4, according to some embodiments, riser running tool head 210 includes a plurality of testing subassemblies that matches the number of auxiliary lines being used with the particular riser being run. By automatically forming sealed fluid communication with each auxiliary line in the riser joint, filling and testing of the auxiliary lines can commence as soon as the riser joint is “latched” or fixed (e.g. with bolts) to the riser being held in the spider. For further details of filling and testing of the auxiliary lines, see the co-pending patent application.
The central body of the riser running tool is separated into two sections: lower section 402 and upper section 404. Relative movement between the two sections 402 and 404 (dashed arrow 440) is controlled by piston assemblies 250 and 350, as well as the external forces from the top drive and the attached riser joint(s). A hydraulic control system 430 is included that is configured to measure and control the hydraulic pressure in the piston assemblies 250 and 350 for facilitating weight/load compensation. By monitoring the hydraulic pressure in assemblies 250 and 350 a critical event, such as contact between the two riser joints sections earlier than expected, can be detected. The assemblies 250 and 350 can be configured under control of system 430 to automatically reduce load and/or “pull up”, as indicated by dashed arrow 442 to reduce the force of the unwanted impact. The riser connection counter-weight/load compensation mechanism has been found to significantly reduce the risk of collision damage, especially to the auxiliary line pins, in cases where the riser joints come into contact before the pins and boxes are perfectly aligned. The counter-weight, or weight compensation system provides load compensation in the vertical direction, as indicated by the dashed arrow 440. According to some embodiments, the assemblies 250 and 350 include air/oil cylinders. The air/oil cylinders can be rated for the riser joint weight, with a safety factor included. Using air/oil cylinders, for example, the connection counter-weight/load compensation functionality can be provided passively (i.e. without active monitoring and actively “pulling up”).
FIGS. 5A and 5B illustrate further details of an improved riser running tool with self-alignment and weight compensation capabilities in the vicinity of the drill floor, according to some embodiments. The riser running tool (tool 110 shown in FIGS. 1-4) is lowering the upper riser joint 116 towards the lower riser joint 126. According to some embodiments, the riser running system includes self-alignment functionality. The riser running tool system can include an alignment module 230 mounted on spider 118, such that it has a clear view of the upper and lower riser joints 116 and 126 as the upper joint 116 is being lowered. The module 230 can include two optical cameras 564 and 566 that are mounted and have fields of view configured to view the lower end 218 of riser joint 116 and the upper end 226 of lower riser joint 126 as the upper joint 116 is being lowered. According to some embodiments, images from the cameras 564 and 566 can be automatically analyzed to determine whether or not the correct rotational alignment has been achieved between the upper and lower riser joints. If the alignment is not correct, the module 230 and cameras 564 and 566 are used to calculate how much rotation (shown by dashed arrow 550) needs to be provided by the top drive system to provide correct alignment. Data from the alignment module can be used for feedback control purposes as rotation is imparted to ensure correct alignment prior to making contact between the riser joints. In some cases, existing visual markers such as lifting lug 560 can be used for determining alignment. In other cases, other existing visual markers can be used. According to some embodiments, visual markers can be added to the upper and/or lower portions of the riser such as painted or embedded optically reflecting stripes 562 and 568. In some cases, the upper camera 564 is aimed slightly downwards and the lower camera 566 is aimed slightly upwards to enhance the cameras' fields of view. In other cases, a single camera with sufficiently wide field of view may be used. In some cases, the lower tool joint rotational position does not need to be detected and a memorized rotational position from the previous alignment operation is used, or the rotational position of all riser joints are aligned to a predetermined rotational position or fixed alignment mark on the drill floor. According to some embodiments, other types of known sensor technology is used besides or in addition to optical cameras. Examples of other types of sensor technology that can be used include RFID, LiDAR, Laser, Ultrasonic, Inductive, and Magnetic. In the case of RFID, tags 570 and 572 are shown embedded in the upper and lower riser joints, respectively, and alignment module 230 is equipped with an RFID reader 574. According to some embodiments, the riser running tool (tool 110 shown in FIGS. 1-4) can also be equipped with either hydraulic or electric servo motors that are capable of rotating the riser joint to the perfectly aligned rotational position. According to some embodiments, a riser connection counter-weight mechanism is provided that significantly reduces the risk of collision damage, especially to the auxiliary line pins, in cases where the riser joints come into contact before the pins and boxes are perfectly aligned. The counter-weight, or weight compensation system provides load compensation in the vertical direction, as indicated by the dashed arrow 540.
FIG. 6 is a block diagram illustrating further details relating to operating a riser running tool, according to some embodiments. In block 610, the riser running tool stabs and engages the upper end of the next riser joint to be installed. In some cases, the next riser joint will be in a horizontal position (such as joint 114 shown in FIGS. 1 and 2) and other cases it might be in a vertical position. In some cases, the engagement takes place by radially expanding of a split ring such as split ring 420 shown in FIG. 4 where the raised portions of the split ring engage and lock on to matching grooves formed on the inner portion of the main tubing of the riser joint. Also performed along with the engagement of the central riser bore, fluid connections are made with each of the auxiliary lines of the riser joint. This can be made, for example, by engagement of each testing subassembly (such as testing sub 416 shown in FIG. 4) which each auxiliary line. In block 612, the riser running tool and the top drive system, raises and positions the riser joint such that lower end of the riser joint is above the upper end of riser joint being held by the spider. In cases where it is in a horizontal position, this step includes bringing the riser joint into vertical alignment. In block 614, the top drive lowers the riser running tool and riser joint being held to mate with the lower riser joint being held in the spider.
In decision block 616 the rotational alignment system, shown in FIGS. 5A and 5B and described in further detail supra, is used to determine whether or not rotational correction is needed due to mis-alignment. If correction is needed, in block 618 the upper riser joint is rotated by an appropriate amount by the top drive and/or the riser running tool. Following rotating (or at the same time), lowering of the upper riser is continued (block 614). In decision block 620, the counter-weight/load compensation system (shown, e.g. in FIG. 4) and described in further detail supra, is used to detect an “unwanted” or “unexpected” contact between the riser joints. In this case “unwanted” or “unexpected” means that contact is made between the riser joints while the joints are not properly aligned. This can be detected as contact (as sensed by the weight compensation system and/or observed by the alignment sensor system) prior, or at location above where, contact would be expected with proper alignment. The vertical position of the upper riser joint can be determined by the top drive system, and either early contact or contact while the riser joint is in a position higher than it should be assuming proper alignment, indicates a dangerous, unwanted or unexpected contact. In such cases, in block 622, the load compensation system is used to “pull up” or reduce the load on the riser joint, and in some cases the top drive can be instructed also to “pull up”. The result is greatly reducing the risk of damage due to the unwanted or unexpected contact. Following block 622 the rotational alignment can be checked and corrected (blocks 616 and 618) and the riser can continue to be lowered.
According to some embodiments, the alignment sensor system described can work closely with the load compensation system to give an “early warning” of likely impact prior to any contact occurring. In this case the sensor system might detect an “imminent unwanted impact” when it detects the joints being out of rotational alignment and the riser surfaces becoming so close to each other that impact will occur if no immediate corrective action is taken. In such cases, the alignment sensor system can send a message to the weight compensation system and/or the top drive to “stop” and “pull up” so as to avoid contact or greatly lessen risk of damage in case contact were to occur.
Assuming proper alignment and contact between the two risers is made as expected, in block 624 the two riser joints are fixed or “latched” together such as with bolts. Once the two joints are latched, the filling and testing of the auxiliary line can commence as described in further detail in the co-pending patent application. In block 626 the top of the joint is held by the spider and the riser running tool is disengaged.
Although most of the foregoing has been described with respect to marine drilling risers, according to some embodiments the techniques described herein are applied to other types or risers such as tie-back drilling riser and production riser that have auxiliary tubes or lines.
While the disclosure may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and have been described in detail herein. However, it should be understood that the disclosure is not intended to be limited to the particular forms disclosed. Rather, the disclosure is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure as defined by the following appended claims.
The techniques presented and claimed herein are referenced and applied to material objects and concrete examples of a practical nature that demonstrably improve the present technical field and, as such, are not abstract, intangible or purely theoretical. Further, if any claims appended to the end of this specification contain one or more elements designated as “means for” or “step for” performing a function, it is intended that such elements are to be interpreted under 35 U.S.C. 112(f). However, for any claims containing elements designated in any other manner, it is intended that such elements are not to be interpreted under 35 U.S.C. 112(f). While the subject disclosure is described through the above embodiments, it will be understood by those of ordinary skill in the art, that modification to and variation of the illustrated embodiments may be made without departing from the concepts herein disclosed.
Patent Application
20210108469
