The invention relates to equipment for drilling and well-operations, and in particular to attachment of ram-actuator assemblies to BOP ram bodies.

Drilling BOP's are provided with hydraulically, or electrically activated pipe rams, to close tightly around the drill string in the vertical centre bore of the BOP, and shear rams, which may be used to seal off the well if well control cannot be maintained through other non-destructive actions. The rams are fitted into cavities in the forged and machined steel blocks/bodies, which are assembled into a complete BOP stack. Two radially opposing ram-actuator bonnet fixtures are provided for sealing engagement with the corresponding end faces of the body, where the ram elements are inserted into their respective cavities.

The shearing devices or sealing pipe rams need to be examined, refurbished and/or replaced periodically. The ram-actuator bonnet fixtures are known in the industry as “ram doors”. A door has traditionally been secured to the body by a plurality of large bolts, circumferentially spaced about the ram axis. To allow access to the serviceable components, the bolts are removed, and the door is structurally disconnected from the ram body, thereby exposing seals and ram elements for repair or replacement.

BOP doors may be mounted on the BOP body by a hinge, as disclosed in U.S. Pat. No. 4,253,638 and 5,255,890, so that the BOP body supports the opened door during the service operation. Alternatively, the disconnected doors may each be moved along support members coupled to the ram body, as disclosed in US 2008/0142746 A1 .

The laborious and time-consuming operation of disengaging bolted bonnets from ram bodies, and sub-sequent re-assembly, may contribute to so-called “flat-time” between wells, during service of a BOP stack. Operational inefficiency and other disadvantages of bolted doors can be overcome by boltless door solutions. Background technology from the patent literature can be seen in US 5,897,094, US 2013/0264502 A1 , and US2016/0377194 A1. Moreover, US 2020/0072013 describes a ram block inner seal assembly for use with a BOP comprising a core member and a peripheral member comprised of a material suitable for providing the ram block inner seal assembly.

The invention has for its object to remedy or reduce at least one of the drawbacks of the prior art or at least provide a useful alternative to the prior art.

The object is achieved through the features that are specified in the description below and in the claims that follow.

According to a first aspect, the invention relates to an apparatus for connecting a BOP ram body to a ram-actuator, the apparatus comprising a BOP ram body end portion with locking recesses, and a ram-actuator end portion with protruding connection elements arranged to fit into the locking recesses, and wherein the locking recesses are provided with first grooves and the protruding connection elements are provided with second grooves, wherein the first and second grooves form pairs, each pair being arranged to form an opening for insertion of a locking wedge when the protruding connection elements are in engagement with the locking recesses in the ram body.

The arrangement may further comprise at least one locking wedge provided with an inclined surface adapted to abut against a slanted surface in the grooves on the protruding connection elements of the ram-actuator. The openings for insertion of at least one locking wedge are advantageous in that the ram-actuators may be connected to the BOP ram body by insertion of locking wedges in the openings. Connecting and disconnecting the ram-actuator to and from the BOP ram body can hence be carried out by insertion or removal of the locking wedges by e.g., actuation of the locking wedges by means of an actuator. The actuator may be a linear actuator operable to insert and remove the locking wedge from the openings, thereby providing an arrangement for boltless attachment of ram actuators to a BOP ram body.

The locking recesses may be positioned in the corners or close to the corners of the ram body portion.

The locking wedge may comprise at least one internal pressure channel with a lubricant injection port at an outer end for distribution of high-pressure lubricants.

The locking wedge may comprise at least one lubricant outlet at a side surface of the at least one locking wedge.

A benefit of having internal pressure channels with lubricant injection ports and outlets at a side surface of the locking wedges is that before removal of the wedges, a lubricant can be injected in the pressure channels, facilitating easy removal of the wedges.

According to a second aspect, the invention relates to using electro-mechanical ram-actuators (known from WO 2019/078727 A1 ) locked onto and sealed against end faces of a BOP ram body with protruding connection elements of the ramactuators inserted into cavities in the BOP ram body. The ram-actuators are fixed to the bodies with locking wedges that are pushed from the sides of the ram body, into openings that are formed when the ram-actuators are connected to the body, so that grooves in the protruding connection elements of the ram-actuators are aligned with grooves in the locking recesses at the corners of the ram body. In what follows, an example of a preferred embodiment is described, which is illustrated in the accompanying drawings, in which:

Figure 1 shows, in perspective, an “exploded view” of a ram body, with an electro-mechanical ram-actuator at each end, and four locking wedge actuators on each side of the ram body;

Figure 2A shows a single locking wedge actuator, with two locking wedges;

Figure 2B shows details of a locking wedge;

Figure 2C shows a cross section of a ram-actuator locking interface, where locking wedges are pushed in, to keep the ram-actuator fixed to the ram block.

The apparatus shown in Figure 1 comprises a BOP ram body 1 and two ramactuators 7. The BOP ram body 1 , comprises locking recesses 2 in end portions T of the BOP ram body 1 . In the figure, four locking recesses 2 are shown arranged in each of the end portions T. Each locking recess 2 is positioned close to corners of the end portions T of the BOP ram body 1. At an end face 3 of the ram body end portion T, a cavity 4 is shown, where the ram elements (not shown) are inserted. A vertical centre bore 5 can be seen on top of the body, which forms part of the wellbore of an assembled BOP stack. Top and bottom grooves 6A/6B are included in the locking recesses 2.

The figure further shows the ram-actuators 7 disconnected from the BOP ram body 1 . The ram-actuators 7 can be moved back on a set of support members, (not shown), coupled to the ram body 1. As shown in Figure 1 , ram-actuator portions 7’ are provided with protruding connection elements 8, which fit into the locking recesses 2 at the end portions T of the BOP ram body 1 . First grooves 6A, 6B in the locking recesses 2 correspond with second grooves 9A, 9B in the ramactuator locking interfaces 8, when the ram-actuators 7 are fully connected to the body 1 . Each of the first grooves 6A, 6B forms a pair of opposing grooves with one second groove 9A, 9B, so that the pair forms an opening. The ram-actuators 7 can be fixed to the bodies 1 with locking wedges 10A, 10B inserted into the openings between pairs of opposing grooves 6A, 6B and 9A, 9B by means of locking wedge actuators 1 1 mounted on the sides of the BOP ram body 1. A locking wedge actuator 1 1 , with a top and bottom locking wedge 10A, 10B is shown in figure 2A, where inclined surfaces 12A are also shown.

Reference is now made to figures 2B and 2C.

The locking wedges 10A, 10B have an inclined surface 12A, which will slide along a corresponding, slanted surface inside the grooves 9A, 9B on the protruding connection elements 8 on the ram -actuators, as the wedges are pushed into the openings between the opposing grooves 6A, 6B and 9A, 9B. When they have been fully pushed into the locking position, the wedges 10A, 10/B will force the connection elements 8 into tight contact with the locking recesses 2 in the ram body 1 , providing a pressure tight seal (not shown) between the ram-actuator 7 and the end face 3 of the ram block 1 .

The fully inserted locking wedges 10A, 10B will be stuck in the spaces between the opposing grooves 6A, 6B and 9A, 9B. To release the locking wedges 10A, 10B, to enable full wedge retraction, the wedges are provided with internal lubrica- tion/-pressure channels 12B, which can be pressurized with lubricant through a connection port 12C at the outer end of the locking wedges 10A, 10B. The high- pressure lubricant will exit from openings at the side surfaces of the wedges 10A, 10B and thus aid the release and retraction of the locking wedges 10 A, 10B with the locking wedge actuators 1 1 .