Liuhua 11-1 Development-Subsea Production System Overview
Authors: Hall Johnce E. , Sheng Wang Zhu , Krenek Michael J. , Douglas Lany D. , Maefarlane Andrew M. 
Published: October 2008

The Liuhua 11-1 Field is being developed using 20 subsea completed wells. The development capitalizes on an innovative 'Modular Building Block' method that does not require a seafloor template structure for the field's diverless subsea production system. The modular assemblies are installed on the seafloor from semi-submersible floating production system while simultaneous in-field drilling and well completion activities are conducted, Electrical pumps downhole drive produced fluids through subsea pipelines to a floating production, storage, and offloading facility.

The Liuhua 11-1 Development subsea system uses new and emerging dlverless technology in several key areas. These include:A modular seafloor commingling production manifold system for multiple wellsWet-mateable electrical power connectionHorizontal spool trees and associated running toolsRemotely operated vehicle (ROV) intervention packagesOn-site-fabricatm rigid flowline and pipeline connectionsROV-deployed, control-umbilical jumpers and instrument packages

Field Development Overview

Amoco Orient Petroleum Company (AOPC), partner China Offshore Oil Nanhai East Corporation (CONHE), and partner Kerr-McGee China Petroleum Ltd. are completing the initial development of the Liuhua 11-1 Field. The field is located approximately 120 miles (200 km) southeast of Hong Kong in the South China S- as noted in OTC paper 8172 (Ref. 1). The water depth at the site is approximately 1,020 ft (310m).

The primary components of the Liuhua 11-1 Field Development are:Q The semi-submersible floating production system (FPS)The subsea production systemQ The floating production, storage, and offload (FPSO) vessel

Three of the primary subprojects of the Liuhua Project were organized to deliver these components.

The FPS is permanently-moored over the wells. The FPS, described in OTC paper 8187 (Ref. 2), is a semi-submersible drilling rig. It was converted to support the subsea equipment installation and operations activities, while maintaining its drilling and work over capability. The FPS has seven moonpools:Derrick moonpoolFonvard and atl ROV moonpoolsStarboard and port catenary riser suspension moonpoolsStarboard and port moonpools for installing flowline jumper

The Liuhua 11-1 Field development plan calls for 20 to 24 subsea wells and a manifold system, serviced by the FPS. The overall field arrangement is depicted in Fig. 1. Due to heavy oil and low reservoir pressure, the wells are produced using downhole electric submersible pumps (ESPS). Power for these pumps is generated, and controlled the FPS. The power is transmitted to the ESPS via in-water power cable (IWPC) risers suspended in the water column, as described in OTC paper 8177 (Ref. 3).

No fluids are produced to the FPS. Produced well fluids are commingled in the subsea manifold system, located below the FPS and pictured with the riser may and well layout in Fig. 2.

From the manifold the well fluids then flow into two production pipelines detailed in OTC paper 8189 (Ref. 4). These pipelines, along with a well test line, lead to the turret of the single-point-moored FPSO.