Liuhua 11-1 Field Development: An Innovative Application of Technology
Authors: Baillie A.R. , Chen Jing Hui 
Published: October 2008

Amoco Orient Petroleum Company (Amoco) and Nanhai East Oil Corporation (NHEOC) are currently evaluating the development of the Liuhua 11–1 Field, situated in the South China Sea. The development poses a number of challenges including deep water, harsh environment and a complex reservoir containing a heavy, viscous crude overlying an active aquifer. An imaginative solution to these problems has been identified through the application of existing and new technologies, involving a floating production system, subsea trees with Electric Submersible Pumps (ESPS), wet-mateable electrical power connectors and horizontal well completions. This paper provides an overview of this technology and demonstrates how an innovative design developed to address the unique set of Liuhua 11–1 Field Development.

INTRODUCTION

The Liuhua 11–1 Field is located in the South China Sea approximately 120 miles (193 km) southeast of Hong Kong. Water depth over the field site averages 1000 feet (305 m). A location map is shown in Figure 1.

Following the discovery of the Liuhua 11–1 Field in 1987, Amoco and NHEOC undertook an extensive delineation and appraisal drilling program which concluded in 1989. After further review of the appraisal results, pre-development operations engineering studies commenced in 1991 with the objective of identifying and evaluating the most economic and technically feasible methods of developing the field. It became clear that the Liuhua 11–1 Development posed a particularly complex series of problems that would require the adaptation of existing technology and the application of technology new to the industry.

Reservoir evaluations showed that artificial lift in the form of ESPS would be required to lift the heavy (20-22aAPI) crude and that all wells should be horizontal to minimize formation water ingress and optimize recovery rates. Environmental data showed the development site to be in a region of severe typhoon and monsoon activity and, more unexpectedly, subject to internal waves or "solitons" in the1000 feet (305 m) water column, giving rise to subsea currents up to 6 knots down to the seabed.

Amoco and NHEOC are currently nearing completion of the pre-development operations engineering studies with the objective of preparing for the submission of an Overall Development Program (ODP) in mid-1992. The prime focus of work has been technology resolution, component feasibility testing and development of cost estimates in order determine field commerciality.

The success of the Liuhua 11–1 Field Development is dependent upon the use and application of technology new to the industry. In particular, the development would be the first industry application of ESPS with subsea trees. This has led to the development of a novel tree design to facilitate ESP workover operations and the design and development of an underwater mate able electric power connector for use at the subsea tubing hanger/tree cap interface. This paper gives a brief overview of the background, current status and assessment of the key technological components involved in the development.