Abstract

After trying several artificial lift systems, TOTAL INDONESIE has prefered to apply and develop gas lift for its Bekapai and Handil fields.

All the wells completed after 1979 were equipped with gas lift mandrels. The old wells completed previously, however, were not equipped with. A heavy work over to fit these old wells with gas lift mandrels and the annular safety devices needed for gas lift is not always economically feasible; it costs 1 to 2 million US.$.

A new technique has been designed to convert these old wells from natural flow to gas lift using macaroni tubing inserted into the existing completion string.

The necessity to fit downhole safety valve (DHSV) for offshore fields has obliged to design gas-lift macaroni down hole safety valve (GL DHSV) which is operated from surface through a hydraulic control line. To obtain a larger production flow passage and better DHSV design, a gas injection through macaroni and production flow through annulus macaroni and tubing is preferable than the reverse.

Its performance in the fields has proven that using the GLM DHSV:

• Gas lift can be performed safety and easily without having to pull out and replace the existing completion string with a string equipped in gas lift mandrel or with a smaller string.

• The gas lift system involves less amount of gas compared to conventional gas lift in where the injected gas occupes the whole casing tubing annulus (above top packer). Moreover the casing will not be in contact with injected gas which is sometime corrosive.

• In dual completion, the design and optimisation of macaroni gas lift can be done more easily than a conventional one since each string is independent from the other.