Agenda Introduction
Horizontal well Intervention
Geological Setting
Tubing Conveyed Openhole Logging
Isolation Candidate Selection
1996 Program Review
Summary
Recommendations
Questions
Figure. Williston Basin Setting (Available in full paper)
Comments Weyburn Unit is located in the northern portion of the Williston Basin
125 km SE of Regina
Figure. Weyburn Unit Sakskatchewan, Canada (Available in full paper)
Comments 22 km long X 18 km wide = 396 square kms
130 horizontal wells with 253 legs
520 vertical producing wells
168 injection wells
1.2 billion barrels of oil in place
Figure. Weyburn Unit - Production History and Forecast (Available in full paper)
Comments field discovered in 1954
waterflood started in 1963
production peaked at about 7500 m/d
vertical infill program in 1980's
horizontal pilots in 1991 and 1992
horizontal infill program started in 1993 and is still ongoing, the majority of which have been drilled under balanced
opportunities identified until the end of 1998
the current production is 3500 m/d
horizontal wells account for 19% ofthe producing well count, however, they contribute 65% ofthe total oil production
recently announced Canada's largest CO2 miscible flood at Weyburn, injection of CO2 by Q3 1999
Figure. Horizontal well Intervention (Available in full paper)
Comments horizontal well technology, especially multi-lateral technology, has outpaced developments in cost effective intervention
intervention can mean anything such as stimulations, isolations (mechanical or chemical), logging
this project is another step in the development ofa horizontal well intervention strategy that will ensure that PanCanadian is aware ofor involved in development of the technology required to optimize recovery using horizontal wells
the downhole environment in Weyburn is severe, H2S ∼5%, high brine and ofcourse will be faced with CO2 in the future
all interventions must be compatible with the above
130 horizontal wells, 70% ofwhich are multi-lateral, with approximately 250 km of openhole section
one small interval in a horizontal well that is in communication with the under lying Vuggy can be the dominant producing feature ofthe well
quad wells have 4000 m ofopenhole section; where do we start looking? - only source ofinformation is fluids and pressure while drilling
objective ofthis project was to isolate these highly conductive zones so that the well could be pumped down with the existing lift equipment
for other projects this type of intervention could be used to reduce operating costs or to reduce voidage requirements when infrastructure constraints become apparent
if intervention is impportant under waterflood it is critical under miscible flood