HETS Zonal Isolation Barrier Qualified for Major Field in North Sea

The Challenge

To manufacture, test and qualify 5” and 6 5/8” ZIBs (5 ½” on going) to provide zonal isolation during fracture operations with hydraulic fracture pressure peaking at 10,000 psi

Requirements

To verify the design is “fit for purpose” through testing and qualification in accordance with ISO 14310 

Solution

READ designed and manufactured the ZIB qualifying it in accordance with ISO 14310 thus passing, and in some cases exceeding, the test specification set by the client.  This included providing zonal isolation of up to 10,000 psi during injection (and frac job) and 4,000 psi during production.  Ten ZIBs are currently in manufacture and will be installed in the next well in 2008.

In-house Finite Element Analysis (FEA) modelling was used to refine the ZIB design and its seals.  An FEA model was also constructed to simulate the chalk formation strength and verify the interaction of the inflated ZIBs with the chalk.  This modelling was carried out in close co-operation with the client’s rock mechanic engineers. 

For this particular application, the ZIBs will be expanded from pressure applied at surface through the completion.  In the event that the completion leaks prior to sufficient inflation pressure being applied, the HETS tool can be deployed to inflate the ZIBs individually.

Value to  Client 

• Client testing of various zonal isolation barriers confirmed only HETS ZIBs successfully withstood the required frac pressure followed by exposure to hydrocarbons, followed (potentially) by water injection.
• The ZIB solution can be activated through expansion as and when required i.e. immediately or after several years.  In this case, the client requires expansion as soon as the completion is in the ground (no waiting time). This ensures that the well can be given the most suitable stimulation and provide maximum productivity as early as possible.