An Artificial Lift System That Utilizes Cable Suspended Electrical Submergible Pumps

Introduction Since Dec. 1976, electrical submergible pump assemblies that are installed and retrieved by their reinforced electrical cables have been used to produce oil from the Arimbi Field, offshore the produce oil from the Arimbi Field, offshore the island of Java in Indonesia. This paper describes the equipment and operational aspects of this production system. Seven of the 10 wells completed production system. Seven of the 10 wells completed in the Batu Raja Limestone formation at about 3,400 ft SS are being lifted artificially with this system, and the seven wells produce approximately 10,000 BOPD (1600 m3/d) with 30,000 BWPD (4800 m3/d). Atlantic Richfield Indonesia, Inc., in cooperation with Pertamina, the national oil company of Indonesia, has been developing oil reserves in the Offshore Northwest Java contract area for the past several years. Eight separate geologic structures that produce at a combined rate in excess of 100,000 BOPD (16,000 m3/d) from the Ardjuna Field centered about 60 miles (100 km) east of Jakarta, and two geologic structures that form the Arimbi Field are presently on production. The Arimbi Field is about presently on production. The Arimbi Field is about 120 miles (200 km) east of Jakarta, 20 miles (32 km) offshore, and in about 100 ft (30 m) of water. In Dec. 1972, the Arimbi Field discovery well, X-1 penetrated the Batu Raja Limestone, and drillstem tests established the presence of hydrocarbons. In Jam. 1973, a second well, X-2, was spudded 3 1/2 miles (5 1/2 km) southeast of Well X-1 to test a similar structure. Drillstem tests in the Batu Raja in the second well confirmed a commercial accumulation of oil, and further indicated the development wells would have an initial flowing potential of 6,000 to 8,000 BOPD (950 to 1270 m3/d). However, in both wells the highly undersaturated oil and underlying oil-water contacts indicated that artificial lift would be required very early in the life of the field. The oil tested at Well X-1 is classified as naphthenic-intermediate with an API gravity of 32.5 at 60 degrees F (15-5 degrees C) and a solution gas-oil ratio of 120 scf/B (21.6 m3/m3). Wax content is 20% and the pour point is 95 degrees F (35 degrees C)- Well X-2 crude is point is 95 degrees F (35 degrees C)- Well X-2 crude is also naphthenic-intermediate with an API gravity of 29.5 at 60 degrees F (15.5 degrees C) and solution GOR of 60 scf/B (10.8 m3/m3). Wax content is 22.6% and the pour point is 100 degrees F (37.8 degrees C). point is 100 degrees F (37.8 degrees C).The subsequent development program for the Arimbi Field was implemented from two six-well, four pile platforms, XA and XB (see Fig. 1) near Wells X-1 and X-2, respectively, with a jackup drilling rig. Five directional wells from each platform were completed in the Batu Rajs, with angles of deviation from 23 to 50 degrees. After setting conductor pipe and intermediate casing, 12 1/4-in. (311-mm) hole was drilled to total depth just above the oil-water contact, and 9-5/8-in. (244-mm) casing was set and cemented. A flow station was placed adjacent to each well platform, with the main flow station that accommodates all electric generating equipment being next to the XA platform. Gas/diesel fueled turbines were installed for power requirements for the production facilities and submergible pumps, and an electric subsea cable was placed between the two flow stations to provide power at XB. With well data indicating that the natural flowing life of the wells would be very short, the decision was made to provide for artificial lift at the time of initial completion. Several methods of artificial lift were studied, taking into consideration the following factors: offshore location, equipment required to install and handle artificial lift, sources of lifting power, and economic considerations. In selecting the artificial lift most suitable for the Arimbi Field operations, gas lift, rod pumping system, hydraulic pumps, and submergible electric pumps were studied. pumps, and submergible electric pumps were studied. The small amount of gas available, the production volumes expected, and the limited available platform space indicated that, of the four systems studied, the electric submergible pump system was the best suited for use in the Arimbi wells.