In a brown field, the need to have a reliable well re-start and well activation method becomes increasingly important owing to the decline in reservoir pressure and possible heavy hydrostatic column after water breakthrough, leading to re-start and vertical lift difficulties. When this occurs, the well is said to be non-eruptive. The conventional method for solving this challenge is the use of gas-lift activation, which requires a gas source, compressors and scrubbers. Such equipments are currently unavailable on the Ofon field and a different approach to well activation had to be devised.

The Ofon field development plan was in two phases. The second phase, which includes conventional gas-lift activation, was scheduled to commence seven years after the start of the first phase. No provisions were made for conventional gas-lift of wells in the first phase of the project. Unfortunately, the second phase of the project has been delayed for almost 10 years. Consequently, a new approach was devised to restart wells with low eruptivity and artificially lift wells which have lost eruptivity.

The pseudo-gas lift method involves the use of a well with high GOR and high flowing well head pressure (FWHP) to lift another well through a surface pipeline called chicksan. The line is connected to the wellhead of the HGOR well via the swab valve on one end and the other end is connected into the annulus of the well requiring artificial lift. The implementation of this technique is simple and does not require additional equipment. This method has shown to be effective in cases where it is uneconomical to install a conventional gas lift unit, there are space constraints or there is delay in installing a conventional gas lift system as in the case of the Ofon field.

An additional oil production of about 16 MMbbls has so far been obtained from the field with the use of this pseudo gas-lift method. [M = 103].

You can access this article if you purchase or spend a download.