海洋油气开发中关于TIE BACK等的解释 [复制链接]

经常看一些资料，总是有提及tieback， tie-in的，这个词频在Offshore里出现频率实在是太高了。
在陆地钻井里，tieback是尾管回接，但是海上勘探开发项目，这个词就不知道了，所以向大家求教，这个词的正解。
这里附上几篇短文，提供前后语境：
短文1：
DEA plans tieback to Heidrun for Dvalin gas: HAMBURG, Germany – DEA has submitted a plan for its first field development offshore Norway.
Dvalin (ex-Zidane) will be developed with a four-well subsea template connected to the Statoil-operated Heidrun platform in the Norwegian Sea. (Courtesy DEA)
There the gas will be part-processed in a new module before being transported in a new export pipeline tying into the Polarled trunkline system, and from there to the Nyhamna gas terminal for further processing and delivery to the European market. DEA and partners Edison, Maersk, and OMV plan to develop around 18.2 bcm of natural gas from two reservoirs at an estimated cost of Eur1.1 billion ($1.23 billion), with a planned start-up in 2020. “Over the last few years we have managed to reduce cost by more than 20%. As a consequence, DEA has got the opportunity to open a new area in the Norwegian Sea for gas production and export.” The Dvalin field is in license PL435, blocks 6507/7/9 and 6507/8, 15 km (9.3 mi) northwest of Heidrun and 290 km (180 mi) from Nyhamna in mid-Norway.
短文2：
Statoil gets clearance for two North Sea tiebacks (Courtesy Statoil)
The Norwegian Energy Ministry has approved Statoil’s plans for development and operation of the Utgard and Byrding fields in the North Sea.
Utgard is a gas and condensate field straddling the Norwegian and UK median line, thought to hold 56 MMboe recoverable. The field, discovered in 1982, is 21 km (13 mi) from Statoil’s Sleipner complex – various previous attempts had been made at a development. Statoil has commissioned two wells in a standard subsea concept, with one drilling target on each side of the median line. However, the offshore installations and infrastructure will be in the Norwegian sector. Utgard’s gas has a high carbon dioxide content, and will therefore undergo carbon cleaning and storage at Sleipner. After processing, the liquids will be exported to Kårstø and the dry gas through the Gassled pipeline system. The estimated cost for the project is around NOK3.5 billion ($414 million). Statoil anticipates start-up in 4Q 2019. Byrding is an oil and gas field north of the Troll field, containing an estimated 11 MMboe recoverable. Capex for this project is around NOK1 billion ($118 million). Development calls for a 7-km (4.35-mi) duo-lateral well to be drilled from the existing Fram H-Nord subsea template through which the oil and gas will flow to the Troll C platform. Start-up should follow this summer.
短文3：
Two contractors study tieback options for Cara in the North Sea
ENGIE E&P Norge has awarded feasibility studies for the Cara project in license PL 636 in the northern Norwegian North Sea to TechnipFMC and Aker Engineering and Technology. The contractors will perform two separate and parallel feasibility studies to identify various subsea solutions for a tie-in of Cara to the Gjøa platform. All work should be completed in June.
The aim is to identify the challenges and opportunities at an early stage of the development, and in particular whether Cara could be tied-in to infrastructure serving the ENGIE-operated Gjøa field via subsea facilities.
“Cara is the second largest oil and gas discovery made on the Norwegian continental shelf in 2016, with an estimated volume from 40-80 MMboe. The well shows good reservoir properties and potential for higher resources.”
Recently the Cara license partners submitted their Final Well Report and Discovery Evaluation Report to the Norwegian authorities, allowing the initial phase of reservoir modeling and development solutions (Gate 1) to proceed.

自己的问题自己回答：
Definition
Tie-back in the offshore oil and gas upstream activities refer to the connection of additional risers to thefloating vessel or platform.
Comments
Originally the offshore oil and gas industry used to focus on large fields that could be explored and produced in drilling strait below the floating vesselor the platform.
But the high costs of the surface structure, a FPSOor FSO or FPO or any kind of platform limits this solution to large offshore fields.
In addition most of these large fields are neighbored by multiple smaller fields, calledmarginal fields or pockets.
These marginal fields may individually contain far too short reserves to justify the capital expenditurein heavy surface infrastructures but their aggregation may be significant enough to develop a sub-sea exploration plan.
After drilling these marginal fields, and installing all the sub-sea equipment on the seabed, risers are installed to connect them to the floating vessel or platform.
This connection of these risers to the vessels or platforms is called tie-back.
Tie-back will also be used for all the equipment such as the risers and sub-sea connectors.
A tie-back risers can be either a single large-diameter high pressure pipe, or a set of concentricpipes extending the casing strings in the well up to a surface BOP
Physically this tie-back operation is made through the turret and the associated mooring systems.
The first tie-backs were performed for marginal fields located at few kilometers distance from the main field, but today the risers reach several tens kilometers distance and in the near future hundreds kilometers distance may be expected.
The North Sea and the Gulf of Mexico are the regions where the tie-back concept is widely expanded.
Most of the giant fields of these offshore regions are maturing and depleting while the large infrastructuresbuilt for these fields are still available for decades of production.
The tie-back system in association with the sub-sea risers technologies fits perfectly in these regions toexplore, develop and put in production thousands of marginal fields which can balance the depleting fields and benefits from the available processing capacities on the floating vessels and platforms.