Method and apparatus for remotely orienting a flowline for connection to a subsea structure

An apparatus for aligning a flowline having a lead end with an offshore structure for connection to a riser having a lower end and being associated with the offshore structure, comprising:

• a pipe guide attached to the lead end of the flowline in such a manner that the pipe guide directs the lead end upwardly, the pipe guide directs the lead end;
• a structural guide having a base connected to the offshore structure and a rotary table resting on the base, the rotary table having a front side and being capable of being rotated about a substantially vertical axis so that the front side faces the pipe guide;
• a pull-in device connected to the offshore structure and having a cable for pulling the pipe guide to the structural guide for connection thereto;
• at least one riser guidepost for directing the riser into alignment with the lead end of the flowline for connection thereto once the pipe guide is engaged with the structural guide;
• at least one riser guidepost receptacle attached to the pipe guide in such a manner that the riser guidepost receptacle has substantially the same angular orientation as the lead end of the flowline, the riser guidepost receptacle being adapted to receive the riser guidepost;
• at least one riser guideline for lowering the riser guidepost to the riser guidepost receptacle, the riser guideline having a first end attached to the offshore structure and a second end attached to the riser guidepost;
• and
• a riser connection device attached to the riser and adapted to be lowered along the riser guideline and to mate with the riser guidepost so that the riser may be connected to the lead end of the flowline.

An apparatus for aligning a flowline having a lead end with an offshore structure extending upwardly from the bottom of a body of water for connection to a riser attached to the offshore structure, comprising:

• a pipe guide attached to the lead end of the flowline in such a manner that the pipe guide directs the lead end upwardly, the pipe guide being capable of being pulled along the bottom of the body of water, the pipe guide having a riser guidepost receptacle attached in such a manner that, when the pipe guide is connected to the structural guide, the riser guidepost receptacle has substantially the same angular orientation as the lead end of the flowline;
• a structural guide having a base connected to the offshore structure and a rotary table resting on the base, the rotary table having a front side and being capable of being rotated about a substantially vertical axis so that the front side faces the pipe guide;
• a pull-in device connected to the offshore structure and having a cable for pulling the pipe guide to the structural guide;
• at least one riser guidepost attached to the offshore structure by a riser guideline for directing the riser into alignment with the lead end of the flowline for connection thereto once the pipe guide is connected to the structural guide, the riser guidepost being capable of being received within the riser guidepost receptacle when lowered to the riser guidepost receptacle by the riser guideline;
• and
• a riser connection device for connecting the riser to the lead end of the flowline, the riser connection device being adapted to slide along the riser guideline and mate with the riser guidepost.

A method for aligning a flowline having a lead end and a riser guidepost receptacle attached to the lead end to a riser attached to an offshore structure where the structure includes a structural guide having a front side and the offshore structure extends upwardly from the bottom of a body of water comprising the step of:

• rotating the structural guide about a substantially vertical axis until the front side of the structural guide faces the lead end of the flowline;
• pulling the lead end of the flowline to the structural guide by a cable;
• securing the lead end of the flowline to the structural guide;
• directing a riser guidepost suspended from the offshore structure by a guideline into the riser guidepost receptacle;
• and
• lowering the riser, having a riser connection device attached, along the riser guidepost in such a manner that the riser aligns with the lead end of the flowline.