How to drill a technically ambitious horizontal well with a minimum facilities workover rig? By careful planning, good drilling practices and the help of some state of the art technology.

The drilling programme was initiated to further develop the Brimmond Field which overlies the Forties Reservoir. The Eocene reservoir was first produced through an 13ft cased hole gravel pack in a previous Palaeocene (Forties) production well. As a result of this success a development phase was instigated, commencing with an 8550ft MD horizontal appraisal and development well.

Feasibility studies had indicated that a significant rig upgrade would be required to facilitate the drilling of a horizontal well within recognised industry parameters. However, upgrading the drilling package would have delayed the project by several months and potentially made the project uneconomical. The challenge was to accelerate the programme by utilising the available minimum facility workover rig. The main limiting factors within the drilling package were: 1x 800hp mud pump, 1 shale shaker, no bulk barite or cement storage, 425 bbls of working mud pit capacity, a kelly and restricted deck space. To compound these limitations, there is no accommodation available and the drilling personnel shuttle daily from other North Sea Platforms.

A number of critical operations were identified which led to the introduction of ‘new technology’ – premixed cement, leading edge LWD tools and hole clean up techniques. After assessing all the challenges, the team embarked on the most technically ambitious well to date for the Forties Field.

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