Offshore floating utility platform and tie-back system

Abstract

The present invention relates to a system for producing hydrocarbons from remote subsea wells to a host production facility using a portable floating utility platform and tie-back system. The subject system comprises a floating utility platform positioned near a plurality of subsea wells; a plurality of control umbilicals connecting said platform to a well control system positioned near the wells and a pump and separation control system wherein the produced hydrocarbons flow from the well control system through a HIPPS to the pump and separation control system; and a host production platform equipped to receive the produced hydrocarbons from a reduced pressure export flowline that transports the hydrocarbons the entire tie-back length from the pump and separation control system to the host production platform. Optionally, the system can provide seawater injection capabilities as well as a single-track pigging.

Description

RELATED APPLICATIONS[0001]This application claims priority to U.S. Provisional Application No. 62 / 697,210 filed Jul. 12, 2018. The entire contents of the above application are hereby incorporated by reference as though fully set forth herein.FIELD[0002]The present invention relates to the field of subsea hydrocarbon production. More specifically, the present invention relates to a system for producing hydrocarbons from remote subsea wells to a host production facility using a portable floating utility platform and tie-back system.BACKGROUND[0003]With larger oil and gas discoveries becoming less common, especially in the Gulf of Mexico, attention has turned to previously untapped, less economically viable discoveries. However, with crude oil prices remaining depressed, it is simply not economically feasible for companies to manufacture and deploy new production facilities to these remote, smaller reservoirs, especially in deeper water. For example, the cost alone to develop a deep-wa...

AI Technical Summary

Benefits of technology

The present invention aims to improve tie-back systems by increasing the length of the tie-back and providing a safer, more productive, and cost-efficient method for producing hydrocarbons from remote reservoirs. Additionally, the invention provides a more efficient and affordable method for pigging the export flowline, utilizing a floating utility platform equipped with a pig launching station. The system also enhances hydrocarbon production and power generation capabilities for subsea pumps to export hydrocarbons from depleted reservoirs back to the host facility.

Problems solved by technology

With larger oil and gas discoveries becoming less common, especially in the Gulf of Mexico, attention has turned to previously untapped, less economically viable discoveries.

However, with crude oil prices remaining depressed, it is simply not economically feasible for companies to manufacture and deploy new production facilities to these remote, smaller reservoirs, especially in deeper water.

For example, the cost alone to develop a deep-water strategy, and then manufacture and deploy the necessary infrastructure, can exceed a billion dollars and take up to ten years.

With stagnant oil prices below sixty dollars per barrel, and these remote reservoirs estimated to yield less than 100 MM barrels of equivalent (BOE) of crude oil, the economics do not justify such an investment.

This inherent problem has forced offshore production companies, especially in the Gulf of Mexico, to develop “tie back” systems that utilize long umbilicals and subsea systems to connect these less commercially viable reservoirs to existing production platforms (or “host platforms”).

However, current tie-back systems presently available have their own technical and commercial limitations.

The capital cost and technical requirements for flow assurance in these conventional tie-back systems have limited the tie-back distance to approximately a twenty-five (25+ / −) mile radius from the host facility, leaving several reservoirs out of reach from existing facilities.

In the Gulf of Mexico alone, there exists several additional, commercially viable remote discoveries, that remain untapped because of the limitations associated with current tie-back systems.

Additionally, the Bureau of Safety and Environmental Enforcement (BSEE) has not been willing to allow long distance tie-back systems to utilize a high-integrity pressure protection system (HIPPS) as a safeguard to prevent over pressurization in flowlines.

However, BSEE has yet to approve a HIPPS for a long distance conventional tie-back system due to the fact that the demand signal must travel up to twenty-five (25) miles from the well to the host facility; the time delay between the signal demand and actual shut-off is too long and exposes flowlines to over pressurization for an unacceptable amount of time.

Equipping conventional tie-back systems with piping that meets these standards significantly increases capital development costs, especially when the tie-back system is servicing multiple wells.

Additionally, current tie-back systems are limited in their ability to provide water injection (a.k.a waterflooding) treatments to the reservoir as a means to enhance hydrocarbon production.

As tie-back distances increase, the required control umbilicals, power umbilicals, risers, and equipment to facilitate such treatments render this option less viable from an economics and technical standpoint.

And in similar fashion, when it comes to servicing more remote wells, an umbilical connection between the subsea pumping system and the host facility becomes less viable.

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