May, 2000

Summit Award Winners

THE APEGGA Project Achievement Award

Wabasca Horizontal Well Network Drilling Project

The project was initiated by the Wabasca Resource Development Team of Amoco Canada Petroleum Company Limited in response to challenges presented by development of the Wabasca-Pelican Lake heavy oil play north of Slave Lake.

In 1995, commercial, horizontal drilling for Amoco in Wabasca consisted of a 1,200-metre-long, lined horizontal wellbore. These single wells with slotted liners became known as a single well equivalent (SWE). In order to reduce development costs, the team eliminated the slotted liner and drilled an experimental openhole horizontal well. Success of this unlined wellbore field trial resulted in three more unlined tests, and led to a simplified multilateral technique with wells consisting of up to five legs, only one of which was lined. This process reduced the drill, complete and equip (D, C & E) costs to 60 per cent of a SWE.

As above-average rainfall made road construction on the muskeg increasingly difficult, the team identified the need to get out of the road-building business to make the play a success. This required drilling horizontal wells much longer than conventional techniques allow, since longer wells could develop more land with fewer roads. The team attacked the problem in two ways. The first technique, through innovations in drill string design, using a top drive and special drilling fluid additives allowed one extended reach well to achieve a world record horizontal displacement to true vertical depth ratio of 7.20. The horizontal leg on this well stretched to over 2,700 metres, an increase of over 225 per cent from a standard 1,200-metre well.

The second, patent-pending technique was to drill horizontal wellbores to establish effective fluid communication with a main production well. This technique was attempted on two existing horizontal wells, one of which succeeded. This led to planning and drilling of a large drainage network specifically designed to use this technology. A main conduit drainhole — with production equipment and facilities for the network was drilled from a permanent all-weather surface location. Two wells were drilled to communicate with this conduit well. These communicating wells were drilled from frozen, winter-access-only sites. All three wellbores were then effectively produced from the first permanent conduit location. When fully developed, this network will develop five sections of land from one permanent surface location versus half a section for comparable conventional horizontal methods.

As well as achieving costs of 50-60 per cent of that of conventional wells, a number of operational benefits were realized, including level loading of surface equipment, improved serviceability and more effective use of operations manpower. A major win was also achieved on the environmental side by reducing permanent surface access and flowline requirements. By gathering more production to a single point, the feasibility of waste methane recovery to reduce greenhouse gas loading was enhanced. These efforts helped Amoco to achieve peak production rates in excess of 14,000 barrels of oil per day at Wabasca.

Nearly 80 per cent of major services were provided by Alberta-based companies, including Precision Drilling, Tesco Corp, Bigstone Band Enterprises, McLeay Geological Consultants, Prudential Steel and GL Slotco. Morley Frank, P.Eng., of Bear River Engineering provided drilling engineering and project management.

This model of extended reach wells was quickly adopted by other operators in the area, and is being used successfully in Venezuela.

The technique also may open the door to a new, enhanced oil recovery methods in Alberta’s oil sands.


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