Wellheads

As the offshore oil and gas industry has continued to explore in progressively deeper waters, the requirements for well components have changed, as a result of the challenges associated with deep water drilling. Ocean-floor conditions in deep and ultra deep water can be extremely mushy and unconsolidated, which creates well-foundation problems that require development of new well designs to overcome the conditions. Second, underground aquifers in deep water have been observed in far greater frequency than in shallower waters, and it quickly became clear that these zones would have to be isolated with a casing string. Cementing requirements changed, and wellhead equipment designs would also have to change to accommodate the additional requirements.

With CG wellhead systems, conductor and intermediate casing strings can be reconfigured to strengthen and stiffen the upper section of the well (for higher bending capacities), and overcome the challenges of an unconsolidated ocean floor at the well site. Each "water flow” zone encountered while drilling requires isolation with casing and, at the same time, consumes a casing-hanger position in the wellhead. It became obvious that more casing strings and hangers were required to reach the targeted depth than the existing wellhead-system designs would accommodate.

CONDUCTOR WELLHEAD RUNNING TOOL

The conductor wellhead running tool runs the conductor casing, conductor wellhead, and guide base. This tool can be used for jetting in the conductor, or cementing the conductor into a predrilled hole. The tool is a cam-actuated tool that minimizes any high torque that may be encountered during operations.

HIGH-PRESSURE WELLHEAD RUNNING TOOL

The high-pressure wellhead running tool operates just like the conductor wellhead running tool, but it runs the high-pressure wellhead and 20-in. casing. It is a cam-actuated tool that minimizes any high torque that may be encountered during operations.

CASING-HANGER SEAL-ASSEMBLY RUNNING TOOL

The casing-hanger seal-assembly running tool runs the casing, casing hanger, and seal assembly in one trip. It also allows testing of the seal assembly (after installation) and the BOP stack, and it has the additional benefit of bringing back the seal assembly, if debris is in the way and the seal assembly cannot be installed.

MULTIPURPOSE TOOL AND ACCESSORIES

The multipurpose tool runs and retrieves the nominal bore protector and all wear bushings. A jet sub and/or jet sub extension can be attached to the multipurpose tool so that wellhead washout can occur during the retrieval process. The multipurpose tool also retrieves the seal assembly, and becomes a mill-and-flush tool by attaching the mill-and-flush adapter.

BOP ISOLATION TEST TOOL

The BOP isolation test tool allows testing of the BOP stack without allowing pressure to be applied against the casing-hanger seal assembly. The BOP isolation test tool can land on the casing hangers or wear bushings.

SEAL-ASSEMBLY RUNNING TOOL

The seal-assembly running tool is used in the event that a second seal assembly needs to be run. The seal-assembly running tool is a weight-set tool, and, like the casing-hanger seal-assembly running tool, it allows testing of the BOP stack and recovers the seal assembly if it cannot be installed (because of debris in the sealing area of the annulus).

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