Expandable Liner Hanger Installation in High Inclination, Extremely Long 3D Complex ERD Reservoir Section to Address Well Integrity and Inter Reservoir Isolation
Authors: Singh Rudra Pratap Narayan , Blanco Miguel , El Mubasher Husham , Dumitrache Bogdan , Khadr Mohamed , Osama Mohamad , Naqbi Abdall , Benygzer Mhammed 
Published: November 2024

Deploying a 7" cemented liner is a complicated process involving reaching desired depth, setting the hanger, releasing the running tool, cementing and pulling out the liner running tool without getting stuck. The most critical aspect of this operation is achieving a good cement bond to isolate the hydrocarbon-bearing reservoir, ensuring inter-reservoir integrity.

Executing a 7" cemented liner in Extended Reach Drilling (ERD) from the Artificial Island (Abu Dhabi offshore) poses significant difficulties due to very long 8.5" hole section, complex 3-D horizontal profile with high dogleg and turning of trajectory up to 180-degree trough interbedded formation to reach landing point. In most cases, 7" liner crosses multiple water, oil & gas bearing formations. Therefore, securing a robust cement bond to isolate the hydrocarbon-bearing reservoirs, ensuring inter-reservoir integrity is paramount.

The challenges multiply significantly when sidetracking an 8.5"-hole section from a shallow depth to the target landing point, extending the hole section to around 10,000 feet. Running this length of a 7" liner in mixed geological formations might need varying degrees of work, from mild to heavy with high circulation rate. Also, to balance high-pressure water zones, a higher mud weight is necessary. This high mud weight, combined with the extremely long 8.5" section with a total depth of approximately +/−18,000 feet, results in increased circulation pressure.

Deploying a conventional liner hanger system has several operational challenges in an extremely long and complex horizontal section as elaborated above. These include lower circulating pressure, limited slack weight to overcome hold-ups, limited rotational capability and the lack of reciprocation during the cementing operation which can jeopardize the cement placement at the near-horizontal 7-inch liner, leading to zonal isolation related issues

When running a standard 7" liner hanger in complex 3D well profiles with interbedded formations and high-density mud, encountering a tight spot requires working the assembly with varying slack-off weights and washing down with high flow rate. However, conventional liner hanger systems have flow rate (2-4 BPM) and pressure limitations to prevent accidental activation, making it challenging to manage tight spots and posing a risk of premature hanger setting. Furthermore, it necessitates significant torque to rotate a liner string that is around 10,000 feet long and installed at approximately 18,000 feet total depth in a horizontal section. Conventional liner hanger system can reach their torque limit during cementing job which may result in the liner not rotated for entire cementing operation. Rotating the liner is crucial to ensure a strong cement bond for isolation between reservoirs, and using a conventional liner hanger system may potentially result in issues related to well integrity.

By using the expandable liner hanger system with higher pressure capability and by allowing a reciprocation of the string during installation, significant amount of torsional friction is converted from torque to drag and reduce the surface torque significantly and enable the rotation of 7" liner string during entire cementing operation in an extremely long and complex 3D trajectory to facilitate a good cement bond. This system has been tested and successfully deployed in two sidetrack wells on an artificial island offshore Abu Dhabi. This was the longest liner, ran approximately 9,800 ft and was deployed at 18,400ft.

This paper describes the application of a ground-breaking expandable liner hanger that allows the deployment and cementing of an extremely long liner in 3D-complex ERD well passing multiple hydrocarbons bearing zones and a bespoke expandable cement design to manage ECD in an extremely long cement column with high mud weight, longer stop time for contingencies during Liner Hanger deployment, resulting in a good cement bond. The proposed Liner hanger system can be implemented any project worldwide where pressure and rotation limits can jeopardize the overall 7" liner hanger deployment operation and possibly lead to well integrity related issues.