Abstract: Apparatuses including a subsea pipeline (18) extending from a first location (14) to a second location (16) and including at least one distributed buoyancy region (102) to traverse a seabed topographic feature (12) are presented. Methods including laying a subsea pipeline (218) including laying a negatively buoyant section of pipeline (218A), a distributed buoyancy section (202) of pipeline (218), and a second negatively buoyant section of pipeline (218B) from a pipelay vessel (220) to traverse an undersea topographic feature (212) are also presented.

Abstract: Disclosed are compliant variable tension risers (106) to connect deep-water subsea wellheads (102) to a single floating platform (104). The variable tension risers (106) allow several subsea wellheads (102), in water depths from 4,000 to 10,000 feet, at lateral offsets from one-tenth to one-half of the depth, to tie back to a single floating dry tree semi-submersible platform (104).

Abstract: Disclosed are methods to counter buoyancy and install variable tension risers using a weighted chain ballast line. An example of an apparatus used in conjunction with the embodiments includes compliant variable tension risers to connect deep-water subsea wellheads to a single floating platform. The variable tension risers allow several subsea wellheads, in water depths from 4,000 to 10,000 feet, at lateral offsets from one-tenth to one-half of the depth, to tie back to a single floating dry tree semi-submersible platform.

Abstract: Apparatuses including a subsea pipeline (18) extending from a first location (14) to a second location (16) and including at least one distributed buoyancy region (102) to traverse a seabed topographic feature (12) are presented. Methods including laying a subsea pipeline (218) including laying a negatively buoyant section of pipeline (218A), a distributed buoyancy section (202) of pipeline (218), and a second negatively buoyant section of pipeline (218B) from a pipelay vessel (220) to traverse an undersea topographic feature (212) are also presented.

Abstract: Various apparatuses and methods to traverse an undersea topographic feature (12) with a subsea pipeline (18) are disclosed. The apparatuses and methods of the present invention accomplish this task through the use of a concentrated buoyancy scheme (10). The invention disclosed can allow more efficient and cost effective traversal of hostile terrain for subsea pipelines at great depths while minimizing the risk of rupturing the pipeline (18) or negatively impacting the surrounding undersea environment.

Abstract: Disclosed are compliant variable tension risers (106) to connect deep-water subsea wellheads (102) to a single floating platform (104). The variable tension risers (106) allow several subsea wellheads (102), in water depths from 4,000 to 10,000 feet, at lateral offsets from one-tenth to one-half of the depth, to tie back to a single floating dry tree semi-submersible platform (104). Also disclosed are methods to counter buoyancy and install variable tension risers using a weighted chain ballast line (228, 230).