The field for the Lingshui 17-2 project is located on the northern part of the Qiong-dong-nan Basin on the western continental shelf of the northern South China Sea, with water depth of 1220m to 1560m. This paper discusses the development and installation of the SCR pull-in systems for this project.
The Riser Pull-in Systems (RPSs) were used for the transferring and pulling of all six SCRs. Based on the riser's locations and installation loads, two RPSs on both sides of the SEMI were installed.
One RPS is located on the north side of the SEMI, with an 800-ton chain jack used as the main lifting equipment. The chain jack and auxiliary facilities are integrated into one temporary module, installed on the north side of topside. This module is used for the 18-in gas export riser pull-in. After the installation, this temporary module will be removed.
For the other five risers, a RPS is built on the south side of the SEMI with a 400-ton main winch used as the main lifting equipment and two 100-ton winches used as the steering winches. The main winch, steering winches, and auxiliary facilities are integrated into one temporary module on the south side of topside and will be removed after the installation. The steering winches in this RPS are also used for the lateral pull-in of the 18-inch SCR by passing wire from the south RPS to the north RPS.
This paper presents detailed descriptions of the installation equipment, aids, tools, and their functions, together with their installation steps.
As shown in Fig.1, Lingshui 17-2 (LS17-2) gas field owned by CNOOC, is approximately 149km away from Sanya, Hainan Province, about 160km southeast from existing Yacheng 13-1 gas field, and about 90 km from gas export pipeline (YC13-1 to Hong Kong).
The development of LS17-2 gas field consists of subsea production system, one SEMI, subsea pipelines and SCRs, as shown in Fig.2. The subsea production system comprises one west manifold and three east manifolds. The subsea well fluid from west production loop will be transported to the LS17-2 SEMI through two 10" SCRs. The well fluid from east production loop will be transported to the LS17-2 SEMI through two 12" SCRs. After processing, the dry gas will be transported to YC13-1 trunk line through 18" gas export SCR. One Mono Ethylene Glycol (MEG) SCR will be used for injection of MEG into well to lower the hydrate formation temperature for the flow assurance.
