Minimize drilling cost and risk when drilling wells in unconventional gas and oil plays (shale gas and tight oil)
Wellbores in unconventional gas and oil plays are characteristically drilled and completed with a long horizontal section for maximum exposure through the producing reservoir. Drilling the horizontal reservoir section typically does not present too many problems, since the rock strength is adequate to maintain a stable /gage wellbore.
However, drilling the vertical wellbore to the reservoir and building the wellbore angle from vertical to horizontal can present numerous challenges. In building the wellbore from vertical to horizontal, wellbore stability is often compromised by drilling through formations at less than optimal angles.
The resulting instability is often uncontrollable, with varied drilling fluids and changes in fluid density often requiring additional, unplanned, casing. These unplanned events contribute to non-productive time and less than planned well diameter at TD.
Enventure’s expandable open-hole liners (OHL) are often planned into the base casing design to mitigate drilling risks. Unexpected challenges utilize OHL's as a contingency, with the objective to minimize non-productive time.
Many times, expandable OHL’s are used to cover a problematic zone providing an increased wellbore ID that allows drilling and completing with the next casing size as planned. This casing covers up the installed OHL to maintain required wellbore pressure and collapse ratings.
Maintaining the planned diameter throughout the horizontal leg of an unconventional gas and oil well is critical, as the size of the horizontal completion cannot be compromised or well economics will be unacceptable.
Both the loss of part of an openhole section and wearing a hole in a prior casing could lead to sidetracking a well. This can easily run into millions of dollars. Effective application of Enventure’s expandable openhole liners can minimize the impact of unplanned events during drilling and ensure that project / asset economics are not compromised.
