This paper explains the successful execution of Expandable Liner Hanger and primary cementing job for ERD wells in Rajasthan block of North-West India. One of these wells has the longest horizontal 6in. hole section in the Indian Subcontinent. Zonal isolation is especially critical, as these wells are all candidates for multistage fracturing operations in the completion phase.

The successful liner job in these wells face several challenges: placement of 4½ inch liner in 6 inch hole, hole conditioning, cement placement and ECD challenges due to low fracture gradient limit.

An integrated Basis of Design was developed to mitigate the challenges. This includes

  1. The placement of liners with computer aided torque & drag analysis,

  2. Rotation of liner during hole conditioning & cementing at highest possible rpm within acceptable torque limits,

  3. Fine tune fluid properties with computer aided simulator to achieve sufficient cement coverage around the liner (displacement efficiency).

The liner hanger system in this case study has an advanced running tool to facilitate the required rotating capability. The liner hanger also incorporates a contingency tertiary setting mechanism for liner expansion due to the challenging down hole condition. The expandable liner hanger is an integrated hanger packer system. Elastomeric elements are bonded on to the hanger body itself. As the hanger body is expanded, the elastomeric elements are compressed in the annular space, which provides primary annular isolation at liner top.

This case study also examined the impact of liner rotation on displacement efficiency of the cement slurry with computer aided Finite Element Analysis. The results give engineers a better understanding of the relationship between rpm and displacement efficiency of the cement slurry.

The technology and the practices established from this case study have become the standard operating procedures for liner cementing jobs in subsequent ERD wells.

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