Case study Cflex 2

Challenge

Placing cement in a tight annulus between 13 3/8 inch casing and a 9 5/8 inch liner was complicated by 176° F (80° C) downhole temperatures and deviation of 50°. The operator was concerned that the section, located 656 ft (200m) above the 11 3/4 inch liner hanger, would be difficult or impossible to cement conventionally through the float shoe.

Solution

A two-stage cement job was planned using a 9 5/8 inch Cflex R stage cementing tool installed just above the 11 3/4 inch liner hanger. (R designates a rotational configuration.)The design called for the first stage to be pumped conventionally through the float shoe and the second stage to be pumped through the Cflex tool. However, the first stage was unsuccessful, leaving the second stage as the only option to avoid a cement top squeeze.

The challenge then became obtaining a stable circulation rate through the Cflex tool.
There were pack-off tendencies at low circulation rates and both soap and acid were pumped through the cementing tool to open up the annulus between the 9 5/8 inch liner and the 13 3/8 inch casing. A total of 9,435 bbl (1500m3) of fluid was pumped through the Cflex tool prior to the cement job. Cement was then pumped according to planned procedure.

Results

The contingency of cementing through the Cflex tool resulted in the liner being cemented according to customer expectations.

The durable Cflex tool enabled pumping of the fluid volumes required to mitigate the annular pack off problems, ultimately allowing the cement job to be performed as specified.

Key capabilities

• Versatility ensures annulus barrier and zone isolation
• Compatible with swell packers and inflatable packers for precise diversion of cement and other fluids
• No drill-out required when installed in the casing or liner
• Unique seal system for high differential pressure environments
• Large ID/small OD reduces high equivalent circulating density (ECD)