The Udang Field is located in the Natuna Sea, approximately 1,000 kilometers North of Jakarta. The discovery well was drilled in 1974. Field commenced production 18 January 1979. It now has 10 wells producing about 25,000 BOPD. A total of thirteen wells have been drilled. producing about 25,000 BOPD. A total of thirteen wells have been drilled. Facilities installed consist of a 4,500-ton drilling and production platform supported on eight piles driven 320 feet into the ocean floor. platform supported on eight piles driven 320 feet into the ocean floor. The platform, the biggest in Indonesia, is connected by a 400-foot bridge to a flare tripod. Production facilities capable of processing 40,000 barrels per day of high pourpoint crude are installed on the platform. Processed crude is pumped through dual insulated pipelines, platform. Processed crude is pumped through dual insulated pipelines, to the Udang Natuna, a 93,000 deadweight-ton tanker which is permanently moored 6,100 feet from the platform by a single point mooring system. Export tankers breast moor alongside the Udang Natuna to receive finished crude.

A total of 24 months elapsed between commitment to the project and completed development.

Introduction

Conoco, as operator for itself, Java Gulf Limited, Getty Oil International (Indonesia) Ltd. and Inpex Natuna Limited is developing Udang, offshore oil field in the Natuna Sea, Indonesia. It is located approximately 650 miles North of Jakarta in 300 feet of water, as shown in Figure 1. Production commenced January 18, 1979 and drilling was completed November 15, 1979. This review summarizes the project.

EXPLORATION AND DISCOVERY

On October 16, 1968, a production sharing contract was signed between Pertamina and Continental Oil Company of Indonesia to explore for and develop hydrocarbons in the Block -B- contract area in the Indonesian South China Sea. The area originally contained almost 40,000 square miles of which 5000 square miles are still retained. Udang discovery was drilled in July 1974 and three confirmation wells subsequently drilled in 1974 and 1975. Well test results; and interpretation of the geophysical data indicated an elongated anticlinal closure trending Northeast/Southwest. The principal axis of the closure is about 12.5 kin- long with a width principal axis of the closure is about 12.5 kin- long with a width of 2.5 km. as shown in Figure 3.

DEVELOPMENT PLAN AND DESIGNS

A reservoir simulation study was made to optimize well density, well locations. production rates, production characteristics and ultimate recoveries. From these studies, facilities were then designed to accommodate the required development wells and their associated oil production.

The philosophy guiding development designs is based on having a system utilizing proven concepts with flexibility for expansion that would operate safely under a wide range of conditions. From these guidelines a development consisting of an eight pile drilling and production platform, a 400 foot flarebridge to a tripod and 75 production platform, a 400 foot flarebridge to a tripod and 75 foot flare boom, production separating and treating facilities, twin 8" insulated seabed pipelines (through a single point marine buoy) to a 93,000 DWT storage tanker, and a personnel staging and transfer base at the nearest landfall in the Anambas Islands, 43 miles South was projected. The configuration of these facilities has been illustrated in projected. The configuration of these facilities has been illustrated in Figure 3.

The design environment of the Udang field area can be classified as being moderately severe, with winter storm occurrence being slightly more frequent than in the Gulf of Mexico. For a 100 year storm, a design wave of 38.4 feet has been used, maximum design surface current was 5 ft/sec. Water depth at Udang is approximately 300 feet.

CONSTRUCTION

The jacket template has eight legs with a pile driven through each leg. Steel plate mud mats have been installed to support the jacket during the pile driving stage of the installation. The 48 inch O.D, pilings are grouted in place at grade. pilings are grouted in place at grade. Platform superstructure contains two deck levels in the well bay Platform superstructure contains two deck levels in the well bay area and a support frame for production equipment on two deck levels outside the well hay area.

The flare tripod is a three leg template type with a 30" OD pile driven through each leg, and grouted. A trussed bridge having a triangular cross section connects the platform to the flare boom. The flare boom is oriented at a 45 degrees angle from the horizontal and away from the platform. Platform and tripod fabrication commenced 1 March 1978 on Batam Island, Indonesia, P.T. Paramuda Jaya, as the platform certifying agency for MIGAS reported zero weld repairs required on 385 "T", and "Y" joint welds of the jacket. The jacket is the largest in Indonesia and weights 2200 tons.

After setting and piling the tripod, the 400 foot flare bridge and attached boom was put into place with a single lift. A schematic of the structures is shown by Figure 4. Production facility for the 100 degrees F pourpoint crude is designed for attended operation with only essential pourpoint crude is designed for attended operation with only essential temperature, pressure, and flowrate functions monitored and controlled from the control room. Warning and shutdown functions are indicated on an annunciator panel. Less critical functions are annunciated when an upset or malfunction occurs, but cannot be remotely controlled.

Fabrication of the three modules containing Udang production facilities commenced 10 May 1978 at Batam Island, Indonesia.

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