Five Years Experience With The First Deepwater SALM
Authors: Gruy Robert H. , Kiely William L. , Pederson Kris I. , Wolfram W.R. , Swan Richard D. 
Published: October 2008

This paper describes the performance of the Tembungo Single Anchor Leg Mooring (SALM) tanker loading terminal during its first five years of operation. This facility, located in 300 ft (91 m) of water, 50 miles (93 km) offshore Sabah, East Malaysia, was the first SALM designed and constructed under commercial license agreement from Exxon Research and Engineering. The Tembungo SALM is one of the first "early production systems" and has been in continuous service since October 1974. It was designed to permanently moor a 94,000 DWT storage tanker in maximum wave heights of 39 ft (12 m), winds of 65 mph (29 m/s) and 2 kt (1 m/s) currents.1

The Teniliungo SALM has performed very effectively since start-up. Operational efficiency rates of up to 98.6 percent on an annual basis have been achieved. A major factor in the high utilization of this terminal has been the absence o£ maintenance requirements on the SALM components. No maintenance has been required on the fluid swivel, chain swivel, universal joints or the anchor chain leg. Items such as pre-planning the annual inspection and maintenance program with the diving contractor and developing detailed procedures for tanker change-out and for hose and hawser replacement were also important contributors towards maximizing operational efficiency.

The primary and most important lesson vividly illustrated by the experience at Tembungo is that a simple, hawser-type SALM terminal can indeed provide very acceptable operational performance for permanent tanker mooring in offshore environments such as those encountered in East Malaysia.

INTRODUCTION

The decade of the 1970's found wide industry acceptance of the concept of employing a Single Point Mooring (SPM) as an integral part of an offshore production facility. In this application, the SPM, which provides direct offshore tanker loading, may allow a field to be brought on-stream at an earlier date than would be possible with a pipeline and it may allow the development of marginal fields which have insufficient recoverable reserves to justify a pipeline.

Use of an offshore loading terminal in conjunction with a floating or fixed production facility constitutes one version of what is popularly called an "early production system".2,3 The Tembungo SALM, described herein, is a good example of such an early production application.

The SALM is located 7,000 ft (2,134 m) from a fixed platform and is connected to the platform via a single 10 in. (254 mm) pipeline. Oil and gas separation is performed on the platform and oil is loaded directly into the storage tanker. While the SALM was designed to permanently moor a storage tanker, which would be periodically offloaded by shuttle tankers moored alongside, it has only been use for shuttle service to date in an operation which employs two dedicated 50,000 DWT tankers which each load for periods of 30 - 60 days.4 While one tanker is loading, the other tanker departs to discharge its cargo. In this service, with prolonged periods of berth occupancy, the two shuttle tankers effectively become temporary storage facilities.