Mitigate drilling risk and minimize non-productive time when drilling wells in deepwater.
It is essential to plan and prepare for unexpected events, since non-productive time is unacceptable due to the high cost of operating in the deepwater environment. The challenges can be unending in this environment. Shallow water flows; salt movement; sutures; rubble zones; tar; narrow pore pressure / frac gradient margins; and the related operational challenges of poor primary cement jobs and no shoe-integrity tests result in multiple squeezes. All of these quickly lead to very high expenditures in deepwater operations.
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. Sizes of expandable OHL's now cover a range from 16 in. (for base casing up to 20 in.) to 5-1/2 in. (for base casing of 7 in.).
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.
Certain OHL sizes are available in High Performance (HP), with a thicker wall to provide higher collapse and yield pressures - often at or exceeding the rating of the base casing. Sizes available are: 7-5/8 x 9-5/8-in., 8-5/8 x 10 3/4 in. and 11 3/4 x 13 3/8 in.
Technically difficult wellbores are now planning in a 16 in. and/or 13-3/8 in. expandable liner to enable larger casing prior to actually drilling through the salt intervals and/or dealing with narrow pore pressure / frac gradient margins.
The SET® Chart provides a table of all the standard sizes available or you can use the SET Designer to configure a system based upon your parameters.
The use of Enventure's SET® expandable OHL technology has enabled the drilling of deepwater offshore wells that have saved operators $50 to $100 million in well re-drilling costs. More importantly it has enabled multi-billion-dollar offshore development programs to proceed as planned, allowing hundreds of millions of BOE to be recovered, as happened with the GOM Perdido project.
