Case study Cflex 1

Challenge

Extreme losses were anticipated when drilling a 12 ¼ inch assembly into a weak section of the formation. Use of a drill-down liner was planned to reach the zone but the anticipated losses meant no cement could be pumped through the shoe. Problems were expected in effectively cementing the liner and curing the loss.

Solution

A 9 5/8 inch Cflex RL stage cementing tool was installed on the drill-down liner string approximately 240 ft (73m) above the shoe (RL designates a rotational locked configuration in which the inner sleeve will not rotate).

The drill-down liner was run with 100% losses until it stalled. At that point, the liner hanger and packer were set. Cement was squeezed through the Cflex tool down to the shoe, thus isolating and stopping losses around the shoe.

This provided a cement seal in the annulus between and around the 9 5/8 inch drill-down liner shoe and the open hole. As a result, the entire overburden section was isolated and cased off prior to drilling out the shoe

Results

The liner was successfully cemented with 50 bbl (8m3) squeezed through the Cflex tool. The liner hanger and packer were set, and the Cflex tool was tested and operated as planned.

Problem time and costs were avoided, because the Cflex tool enabled drilling of the reservoir sections at sufficient hole diameter to complete the reservoir with the optimal casing size.

Potential remedial cementing was not required.

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)