Deepwater Steel Catenary Riser System Design for Lingshui 17-2 Project

2021 ◽  
Author(s):  
Ning He ◽  
Hu Yang ◽  
Fanli Xu ◽  
Yongming Cheng
Keyword(s):  
South China Sea ◽  
System Design ◽  
South China ◽  
Oil And Gas ◽  
Low Cost ◽  
Northern South China Sea ◽  
Steel Catenary Riser ◽  
China Sea ◽  
Scr System ◽  
The Impact

Abstract A riser is a key component for transporting produced oil and gas from the subsea wells to the surface production vessel. Through nearly 30 years of design and implementation, Steel Catenary Risers (SCRs) have been found to have the advantages of relatively low cost and good adaptability to floating platform’s motion. This paper investigates deepwater SCR system design for the Lingshui 17-2 (termed LS17-2) project. This paper first introduces a SCR system for the LS17-2 project. The field for this project is located in the northern South China Sea, with water depth of 1220m to 1560m. LS17-2 consists of a subsea production system, a deep-draft semi-submersible (SEMI), and an export riser/pipeline. The platform was designed to have a large storage capacity with a variable draft during its operation. Based on deepwater SCR engineering experience, the key SCR design challenges are summarized from the engineering executive perspective. The challenges to the SCR system design for the LS17-2 project include harsh environment condition in South China Sea and the impact on fatigue design for the requirement of 30-years’ service life. They call for design optimization and innovative ideas. The engineering design and analysis are discussed together solutions. To demonstrate the deepwater SCR system design for LS17-2 project, examples are provided to illustrate the challenges and solutions. The experience learned from this paper should have significant relevance to future SCR design.

scholarly journals Active and passive fluxes of carbon, nitrogen, and phosphorus in the northern South China Sea

2021 ◽  
Vol 18 (18) ◽  
pp. 5141-5162
Author(s):  
Jia-Jang Hung ◽  
Ching-Han Tung ◽  
Zong-Ying Lin ◽  
Yuh-ling Lee Chen ◽  
Shao-Hung Peng ◽  
...  
Keyword(s):  
South China Sea ◽  
South China ◽  
Nutrient Availability ◽  
Northern South China Sea ◽  
Euphotic Zone ◽  
Organic C ◽  
China Sea ◽  
Vertical Fluxes ◽  
Event Driven ◽  
The Impact

Abstract. This paper presents the measured active and passive fluxes of carbon (C), nitrogen (N), and phosphorus (P) and their response to seasonal and event-driven oceanographic changes in the northern South China Sea (NSCS). The total vertical flux of carbon (TFC) is defined as the sum of active and passive fluxes of biogenic carbon in the surface layer, which may be considered as the central part of marine carbon cycle. These active and passive fluxes of N and P were also considered to understand stoichiometric flux patterns and the roles of nutrients involved in the TFC. The magnitudes of total C, N, and P fluxes were, respectively, estimated to be 71.9–347 (mean ± SD, 163 ± 70) mgCm-2d-1, 13.0–30.5 (21.2.± 4.9) mgNm-2d-1, and 1.02–2.97 (1.94 ± 0.44) mgPm-2d-1, which were higher than most previously reported vertical fluxes in open oceans, likely because a quarter of the fluxes was contributed from active fluxes that were unaccounted for in vertical fluxes previously. Moreover, the passive fluxes dominated the total vertical fluxes and were estimated to be 65.3–255 (125 ± 64.9) mgCm-2d-1 (77 ± 52 % of total C flux), 11.9–23.2 (17.6 ± 4.2) mgNm-2d-1 (83 ± 28 % of total N flux), and 0.89–1.98 (1.44 ± 0.33) mgPm-2d-1 (74 ± 24 % of total P flux). Vertical fluxes of dissolved organic C, N, and P were small (< 5 %) relative to passive fluxes. The contrasting patterns of active and passive fluxes found between summer and winter could mainly be attributed to surface warming and stratification in summer and cooling and wind-induced turbulence for pumping nutrients into the euphotic zone in winter. In addition to seasonal variations, the impact of anticyclonic eddies and internal-wave events on enhancing active and passive fluxes was apparent in the NSCS. Both active and passive fluxes were likely driven by nutrient availability within the euphotic zone, which was ultimately controlled by the changes in internal and external forcings. The nutrient availability also determined the inventory of chlorophyll a and new production, thereby allowing the estimates of active and passive fluxes for unmeasured events. To a first approximation, the South China Sea (SCS) may effectively transfer 0.208 ± 0.089 Gt C yr−1 into the ocean's interior, accounting for approximately 1.89 ± 0.81 % of the global C flux. The internal forcing and climatic conditions are likely critical factors in determining the seasonal and event-driven variability of total vertical fluxes in the NSCS.

scholarly journals Hydrocarbon detection based on Phase decomposition in Chaoshan Depression, northern South China Sea

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Guangjian Zhong ◽  
Renqi Jiang ◽  
Hai Yi ◽  
Jincai Wu ◽  
Changmao Feng ◽  
...  
Keyword(s):  
South China Sea ◽  
South China ◽  
Oil And Gas ◽  
Northern South China Sea ◽  
Forward Modeling ◽  
Hydrocarbon Accumulation ◽  
Phase Decomposition ◽  
Phase Component ◽  
Hydrocarbon Detection ◽  
China Sea

Located in northern South China Sea, Chaoshan Depression is mainly a residual Mesozoic depression, with a construction of Meso-Cenozoic strata over 7000m thick and good hydrocarbon accumulation conditions. Amplitude attribute of -90°phase component derived by phase decomposition is employed to detect Hydrocarbon in the zone of interest (ZOI) in Chaoshan Depression. And it is found that there are evident amplitude anomalies occurring around ZOI. Phase decomposition is applied to forward modeling results of the ZOI, and high amplitudes occur on the -90°phase component more or less when ZOI is charged with hydrocarbon, which shows that the amplitude abnormality in ZOI is probably caused by oil and gas accumulation.

Polarity Variations of Internal Solitary Waves over the Continental Shelf of the Northern South China Sea: Impacts of Seasonal Stratification, Mesoscale Eddies, and Internal Tides

2018 ◽  
Vol 48 (6) ◽  
pp. 1349-1365 ◽  
Author(s):  
Xiaojiang Zhang ◽  
Xiaodong Huang ◽  
Zhiwei Zhang ◽  
Chun Zhou ◽  
Jiwei Tian ◽  
...  
Keyword(s):  
South China Sea ◽  
Continental Shelf ◽  
South China ◽  
Northern South China Sea ◽  
Internal Tides ◽  
Thermocline Depth ◽  
China Sea ◽  
Seasonal Stratification ◽  
Anticyclonic Eddies ◽  
The Impact

AbstractSpatiotemporal variations in internal solitary wave (ISW) polarity over the continental shelf of the northern South China Sea (SCS) were examined based on mooring-array observations from October 2013 to June 2014. Depression ISWs were observed at the easternmost mooring, where the water depth is 323 m. Then, they evolved into elevation ISWs at the westernmost mooring, with a depth of 149 m. At the central mooring, with a depth of 250 m, the ISWs generally appeared as depression waves in autumn and spring but were elevation waves in winter. Seasonal variations in stratification caused this seasonality in polarity. On the intraseasonal time scales, anticyclonic eddies can modulate ISW polarity at the central mooring by deepening the thermocline depth for periods of approximately 8 days. During some days in autumn and spring, depression ISWs and ISWs in the process of changing polarity from depression to elevation appeared at time intervals of 10–12 h because of the thermocline deepening caused by internal tides. Isotherm anomalies associated with eddies and internal tides have a more significant contribution to determining the polarity of ISWs than do the background currents. The observational results reported here highlight the impact of multiscale processes on the evolution of ISWs.

scholarly journals Seasonal changes in gaseous elemental mercury in relation to monsoon cycling over the northern South China Sea

2012 ◽  
Vol 12 (16) ◽  
pp. 7341-7350 ◽  
Author(s):  
C. M. Tseng ◽  
C. S. Liu ◽  
C. Lamborg
Keyword(s):  
South China Sea ◽  
South China ◽  
Northern South China Sea ◽  
Elemental Mercury ◽  
Source Tracking ◽  
Northeast Monsoon ◽  
Air Masses ◽  
Gaseous Elemental Mercury ◽  
China Sea ◽  
The Impact

Abstract. The distribution of gaseous elemental mercury (GEM) was determined in the surface atmosphere of the northern South China Sea (SCS) during 12 SEATS cruises between May 2003 and December 2005. The sampling and analysis of GEM were performed on board ship by using an on-line mercury analyzer (GEMA). Distinct annual patterns were observed for the GEM with a winter maximum of 5.7 ± 0.2 ng m−3 (n = 3) and minimum in summer (2.8 ± 0.2; n = 3), with concentrations elevated 2–3 times global background values. Source tracking through backward air trajectory analysis demonstrated that during the northeast monsoon (winter), air masses came from Eurasia, bringing continental- and industrial-derived GEM to the SCS. In contrast, during summer southwest monsoon and inter-monsoon, air masses were from the Indochina Peninsula and Indian Ocean and west Pacific Ocean. This demonstrates the impact that long-range transport, as controlled by seasonal monsoons, has on the Hg atmospheric distribution and cycling in the SCS.

The Study on the Risk Analysis of Submarine Landslide in the Continental Slope Region of Northern South China Sea

2016 ◽  
Author(s):  
Zhiduo Yan ◽  
Weichen Ding ◽  
Liang Pang
Keyword(s):  
South China Sea ◽  
Slope Stability ◽  
Continental Slope ◽  
South China ◽  
Oil And Gas ◽  
Northern South China Sea ◽  
Submarine Landslide ◽  
China Sea ◽  
Submarine Slope ◽  
Oil And Gas Resources

Abundant oil and gas resources are stored in the continental slope region of northern South China Sea. However, due to the submarine landslide disasters, submarine pipelines and cables and other submarine facilities were damaged, which seriously affected the development of oil and gas resources, leading to a huge economic losses. In order to ensure the safe operation of the submarine gas pipeline, it is necessary to carry out some researches in the submarine slope stability. In this paper, an uncertainty analysis method is applied and a distribution model which is suitable for slope stability influencing factors of this region is put forward. In addition, the risk of submarine slope is analyzed, plotting submarine landslide risk evaluation maps. Different stochastic characteristics of variables such as water depth, angle of slope, shear strength and earthquake acceleration etc can be reflected reasonably, which is helpful for the safety of oil and gas transportation.

scholarly journals Seasonal changes in gaseous elemental mercury in relation to monsoon cycling over the Northern South China Sea

2012 ◽  
Vol 12 (5) ◽  
pp. 12203-12227
Author(s):  
C. M. Tseng ◽  
C. S. Liu ◽  
C. Lamborg
Keyword(s):  
South China Sea ◽  
South China ◽  
Northern South China Sea ◽  
Elemental Mercury ◽  
Source Tracking ◽  
Northeast Monsoon ◽  
Air Masses ◽  
Gaseous Elemental Mercury ◽  
China Sea ◽  
The Impact

Abstract. The distribution of gaseous elemental mercury (GEM) was determined in the surface atmosphere of the Northern South China Sea (SCS) during 12 SEATS cruises between May 2003 and December 2005. The sampling and analysis of GEM were performed on board ship by using an on-line mercury analyzer (GEMA). Distinct annual patterns were observed for the GEM with a winter maximum of 5.7 ± 0.2 ng m−3 (n = 3) and low in summer (2.8 ± 0.2) (n = 3), with concentrations elevated 2 ∼ 3 times global background values. Source tracking through backward trajectory analysis demonstrated air masses during the northeast monsoon in winter came from Eurasia, bringing continental- and industrial-derived GEM to the SCS. In contrast, during summer southwest monsoon and inter-monsoon, air masses were from the Indochina peninsula and Indian Ocean and West Pacific Ocean. This demonstrates the impact that long-range transport, as controlled by seasonal monsoons, has on the Hg atmospheric distribution and cycling in the SCS.

Sign in / Sign up

Export Citation Format

Share Document