Abstract
The construction of wells in deepwater environments is accelerating toward a common goal of reducing the personnel required to construct wells and reducing or eliminating entry and working in hazardous zones which commonly existing around well center. Due to its repetitive nature, tubular installations are often viewed as an attractive focus to mechanize or automate. Within these operations an area often overlooked is the rig up, change out, and/or rig down of tubular installation equipment.
Deepwater well construction requires casing strings to be installed in the well by utilizing a drill pipe landing string. While this is common practice, it is a practice that introduces risk as handling tools are required to be changed out during the switch over from casing to drill pipe which requires multiple personnel operating in the red zone. This risk is also present when casing strings of varying diameters are installed which gives the well architecture additional clearance down hole. Additionally, tripping operations also contain multiple components the BHA and varying diameters of drill pipe requiring multiple slip changes.
While tool changeout is common and varies throughout the well construction process, one specific example that is commonly found in deepwater well designs are production tie-backs. They are often tapered with the top section of the casing string being a larger diameter than the bottom section to allow clearance for critical components contained within the completion string such as subsurface safety valves. Currently, to safely execute the installation of a production tie-back string, two slip system changes are needed as operations moved from the bottom section of casing string to the upper section of casing string and then to the drill pipe landing string. In this case, installation requires more equipment present on the rig, increased rig time due to the multiple slip changes, and increased safety risks as additional red zone entries are required to swap out slip systems. Additional examples include drill strings that contain components within the bottom hole assembly (BHA) that vary in diameter. This operation contains the same safety risks and inefficiencies as the previous example.
A novel slip system has been implemented that reduces the number of slip changeouts improving safety on the rig floor and decreasing rig time.