Running of Liner with Buoyancy Assisted Method and Rotating type Centralizer in Deep-Water ERD Well

Content Introduction Salient Points Offset well Analysis Pre-Job Planning Floatation Execution Summary

Introduction The well is a W/Over and Re-Entry well in eastern coast of India with WD ~ 1200m. Brief SOW for the well De-completion and isolation of existing LC and MB ST from the existing 13-5/8” casing Drill 12 ¼” hole and set 9-5/8” production liner Drill 8 ½” production hole Carry-out LC & UC

Salient Points Well was ST from 13-5/8” casing 12-1/4” section length ~ 2600m from 2500m to 5100m MDRT Build from 14˚ to 89˚in 700m Hold for 1300m at Inc. 89˚ Drop 89˚ to 66˚ in 500m 9-5/8” x 9-7/8” liner length: 2600m MDRT Combination of 9-7/8” & 9-5/8” casing

Well Schematic Riser Seabed ~1200m 13-5/8” Casing 12-1/4” Open Hole ST~ 2500m 12-1/4” TD: 5100m MDRT 9-5/8” Liner

Pre-Job Planning of 9-5/8” Liner

Basis of Design Offset well data Liner length~ 2500m WD and well TD almost same Liner was run with conventional method OH ff of ~ 0.6 was observed after 4000m MDRT So, it was decided to have a design OH friction factor of 0.6 for the planned well.

Conventional Method SIMS showed that liner can't be run till TD Helical buckling lockup after ~4000m for OH ff of 0.6 For a ff of 0.5, liner still not able to go beyond ~4400m MDRT. Thus running of liner by conventional method wasn’t feasible.

Conventional Method & Rotation Liner can be run till TD by Rotation at 20-30 rpm Surface torque required is > casing connection and top drive limits ~ 100 k ft. lbs. for 0.6 ff ~ 90 k ft. lbs. for 0.5 ff Thus running of liner by this method also not feasible.

Floatation Floatation assisted method Liner is run empty with mud in the annulus It is possible to run the liner till TD Concerns of helical buckling after 4000m MDRT for OH ff > 0.6

Floatation and Rotation Liner can be easily run till TD by Rotation at 20-30 RPM. Surface torque is in range of ~ 40 k ft.lbs for OH ff of 0.6.

Design Conclusion Decided to run the liner using floatation method With the capacity to rotate, if required Liner might need to be rotated in the last 1000m beyond 4000m MDRT. Surge analysis: running speed of liner was restricted to 1-3m /min to avoid losses ~20 hours of rotation of 2600m long liner string at 20-30 RPM. Robust design of rotating type centralizer is required

Centralizer Plan Various types of specialized centralizers were evaluated Roller centralizer Centralizer sub Protech Centralizers Halliburton Protech centralizer was finalized Directly installed onto the surface of casing and becomes an integral part of casing itself. Top of cement was planned 1000m above the liner shoe. Thus, 1 centralizer per jt. was planned Up to 1000m from bottom for good cementing. Roller centralizer Centralizer sub Protech

Protech Centralizer

Modifications Casing Connection Liner R/tool Complete system of R/Tool, Liner Hanger and casing was designed for torque of > 65 Klb. Ft Casing Connection Inventory had Vam top connection with torque rating of only 25 klb. Ft VT couplings were cut from the existing casings and made up with Vam 21 couplings, which meets the requirement. Liner R/tool Primary release was hydraulic To avoid accidental release of R/tool during RIH, the required compression was increase from 15 Kips to 50 Kips torque pins rating increased from 6 Klb. Ft to 20 Klb. Ft

Modifications Float Equipment New float eq. With 7500 diff. Pressure rating were purchased Tested under 6000 psi pressure for 36 hrs. To ensure their integrity.

Floatation Execution Initial 120m of liner was filled with 11 ppg mud To have enough weight against heave motion ~ 30 Kips. Rest of 2465m of liner was run empty along with the R/Tool. Shoe Track Reamer shoe with singe float valve Two float collar with double valves Liner was run successfully till TD with minor held-up at 4400m MDRT. Liner was reamed down at 20 RPM. No issues

Floatation Execution Once at TD, the liner was lubricated with 11 ppg mud using SES sub @ 3-4 bpm. Total time taken was ~ 5-6 hrs. Liner hanger was set and cemented as per plan.

Special Technology Used Liner Floatation High Torque Casing Connection Rotating Type Centralizers High Differential Rating Float Eq.

Summary 9-5/8” liner was successfully run till well TD using floatation method. Liner was successfully rotated beyond 4000m MDRT @ 20 RPM. CBL-VDL log post cementation showed good quality of cement behind 9-5/8” liner.

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