Liner running and cementing operations in sidetrack wells
Key words: liner running, sidetrack, liner cementing, casing rotation
Authors: F.F. Akhmadishin (TatNIPIneft, RF, Bugulma), A.R. Iskhakov (TatNIPIneft, RF, Bugulma), I.M. Zaripov (TatNIPIneft, RF, Bugulma), А.V. Kirshin (TatNIPIneft, RF, Bugulma)
Cementing of liners in sidetrack wells is associated with two main constraints: narrow
casing string-borehole annular spaces and high buildup rates. These factors
have adverse effects on the efficiency of wellbore cleanout and hole
conditioning for running a casing string and on liner cementing quality itself.
Large-size drill cuttings, hole wall roughness, presence of filter cake and
drilling mud stagnation zones impede smooth running of the liner to the bottom
of the well. This usually results in stuck liner or failure to reach the target
depth, and forces a drilling team to pull out the liner and perform multiple
conditioning trips, thus increasing sidetrack drilling time up to 7 days.
Practice shows that drill string rotation during hole conditioning facilitates
passing through drill cuttings, i.e. it is sometimes enough to rotate the liner
to push it to the bottom of the well. However, the existing conventional device used to connect the drill
string to well liner does not allow for rotation. Liner deployment and
cementing tool developed in TatNIPIneft enables getting the liner to total
depth by means of liner rotation in setting intervals. Reamer shoe attachment
enables tool running while hole conditioning. Subsequent cementing operations
are conducted with liner rotation. Numerous bench tests proved that casing
rotation significantly increases degree of drill mud replacement by cement
slurry. Rotation provides additional cement flow turbulence and opens space to
flush fluid and cement slurry. This is particularly important in presence of
bottlenecks in sidetrack holes. However, casing rotation during well cementing
jobs remains the least applied technique. This is primarily due to the lack of
specialized wellhead equipment and threaded joints load limitation.
Casing-rotation-while-cementing technology has been widely used in Tatneft
PJSC. A versatile rotating cementing head has been designed and manufactured
for casing rotation during cementing jobs. Acoustic and gamma-gamma cement-bond
logs prove beneficial effect of casing rotation in obtaining a homogeneous
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