Client: Confidential Location: Middle East Well Type: Long Lateral
THE OFF-BOTTOM LINER SYSTEM, WHICH EFFECTIVELY ADDRESSED THESE OPERATIONAL RISKS AND DECREASED RIG TIME
Overview: The National Oil Company (NOC) in the Middle East has an ongoing program to re-complete existing vertical producing wells into horizontal producing wells. For this application, the Operator sidetracks from existing 7” casing and drills a 4,000 – 6,000 ft. 6-1/8” lateral of which approximately 2,000 – 3,000 ft. intersects the reservoir section. The NOC typically completes the reservoir section with an ICD (Inflow Control Device) completion, then isolates the curve section between the reservoir and the 7” casing with an Off-Bottom Liner Hanger System.
This system enables the Operator to utilize an existing wellbore to access a new reservoir section. Although this system approach was the best available option at the time, it was a relatively challenging operation with several critical operational risk factors.
Team Oil Tools worked with a customer in the Middle East to develop and successfully deploy a new system, the Off-Bottom Liner System, which effectively addressed these operational risks and decreased rig time. That Operator has now deployed over 20 of these systems with substantially improved results.
The Challenge: Off-Bottom Liner Hanger Systems Traditionally, when re-completing a vertical well into a horizontal well, the Operator takes a two-step approach. First, the Operator mills a window in the 7” casing, then drills out the first new hole size from the window to the top of the target reservoir. Once on depth, the Operator runs the 4-1/2” casing with a liner hanger to isolate this section of the well. In the second stage of the workover, the Operator drills the reservoir section in a 3-7/8” hole size. In this particular application, the 3-7/8” hole size is not sufficiently large enough to enable the optimum open hole completion design to be installed.
Resultantly, the NOC has completed hundreds of wells utilizing an Off-Bottom Liner System. In this system,the Operator mills the window in the casing string, then drills a 6-1/8” hole from the window all the way to the
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REAL WORLD RESULTS: MIDDLE EAST LINER HANGER OFF-BOTTOM CEMENT SYSTEM
final total depth through the reservoir section. This typically is a 4,000 – 6,000 ft. lateral with approximately 2,000 – 3,000 ft.of reservoir contact. After drilling the lateral, the Operator deploys an ICD completion into the reservoir section. On a second trip, the Operator deploys an Off-Bottom Liner System that will seal into the top of the ICD completion. From top down, the Off-Bottom Liner System consists of a liner hanger packer, liner hanger, cementing stage tool, open hole packers and a ball seat mechanism. After running the Off-Bottom Liner System, cement is pumped through the cementing stage tool to isolate the curve section of the well, but does not enter the completion in the reservoir.
The Solution: Off-Bottom Cement System Although the NOC has successfully deployed hundreds of these systems, the system itself is complex and has numerous high risk failure modes. The NOC was experiencing an unacceptable level of failures and each failure could result in days of nonproductive time to effectively remediate. Team Oil Tools worked in partnership with the NOC to develop an enhanced system that addresses many of these challenges. The table below identifies the key components of the system, the primary failure mode and the solution applied to mitigate the failure mode:
Team Oil Tools has now installed over 20 liner systems for this customer in the Middle East. The Off-Bottom Liner System has proven to be very robust and reliable, and is now the preferred system in this particular field. Utilizing this system has saved the customer a substantial amount of rig time because of the enhanced reliability.
For more information, go to TeamOilTools.com or call 281.602.7815