Installation Method and System
Publication Date: 2015-Jan-27
The IP.com Prior Art Database
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Multilateral System Installation
A new method for installing a multilateral system including a commercial TAML level-5 junction composed of a template, connector, seal assemblies, and associated conveyance tools and associated equipment are discussed herein. .
The following sections contain details of bottomhole assembly ("BHA") configurations to install the system in five trips. Four concept BHA schematics are included within this manuscript for reference. The five trips are described as follows:
Trip 1: Reduce anchor packing setting and window milling
One possible BHA configuration to set the anchor packer and mill the window in a single trip is shown in Figure 1. It consists of an anchor packer set hydraulically to seal on main bore casing, a tieback receptacle (TBR), drilling latch, spacer, whipstock expandable anchor, debris barrier and whipstock-mill assembly.
In addition to resisting axial loads, the anchor packer resists torque to prevent rotation of the BHA and loss of orientation. The volume below the anchor packer is isolated by means of an isolation valve or burst disk sub. The TBR is threaded to the top of the anchor packer and secured with set screws to prevent rotation.
A drilling latch runs latched to the TBR internal threads and seals on the TBR seal bore. The latch mechanism consists of a collet and shear ring. The shear ring secures the collet in the latched condition. The force to shear the shear ring can be adjusted. A straight pull shears the screws on the shear ring allowing the collet to collapse and unlatch from the TBR. Mules (i.e. helical profiles) on the TBR and drilling latch resist rotational loads to maintain the correct orientation. The drilling latch mule can be adjusted in angular increments to achieve a specific orientation of the whipstock with respect to the TBR tip.
A spacer locates the whipstock-mill assembly at the proper distance from the anchor packer. An expandable whipstock anchor secures the whipstock-mill assembly to the main bore casing and resists axial and rotational milling loads. A debris barrier keeps cuttings from falling on the equipment below.
The tri mill assembly (not shown) is initially secured to the whipstock by means of a shear running bolt designed to shear at a specific load allowing the mill assembly to start milling. A gyro or MWD sub (not shown) is installed on the milling string above the tri mill assembly. An internal pressure line between tri mill assembly and whipstock communicates string pressure to set the anchor packer and expandable whipstock anchor.
The BHA described above is run to depth in one trip. After properly orienting the BHA with the gyro or MWD sub, pressure is applied to the string to set the anchor packer and expandable whipstock anchor. Setting pressures of anchor packer and expandable whipstock anchor can be
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adjusted by changing the number of shear screws. At this point, set down weight is applied to break the shear running bolt...