STANDARD HANDBOOK OF PETROLEUM & NATURAL GAS ...

794 Drilling and Well Completions
Wireline Core Barrel Systems. The wireline system can be used for continuous
drilling or coring operations. The inner barrel or the drill plug center of the
core bit can be dropped from the surface and retrieved without pulling the
entire drill string.
Marine Core Barrels. Marine barrels were developed for offshore coring where
a stronger core barrel is required. They are similar to the conventional core
barrels except that they have heavier outer tube walls.
Rubber Sleeve Core Barrels. Rubber sleeve core barrels are special application
tools designed to recover undisturbed core in soft, unconsolidated formations.
As the core is cut, it is encased in the rubber sleeve that contains and supports
it. Using face discharge ports in the bit, the contamination of the core by
circulating fluid is reduced. The rubber sleeve core barrel has proven to be a
very effective tool, in spite of the fact that the rubber sleeve becomes weak with
a tendency to split as the temperature increases about 175°F.
Core Barrel Specifications. Core barrel sizes, recommended make-up torques,
maximum recommended pulls and recommended fluid capacities are shown in
Tables 4-100 and 4-101 [SO].
Table 4-100
Core Barrels: Recommended MakeuD Values 1501 - -
Core Barrel Size 13.5 x 1.75 14.12 x 2.12 14.50 I 2.12 14.75 a 2.62 15.75 I 3.50 16.25 I 3 16.25 a 4 16.75 a 4 I 6.015.25
Racommended 1.700 3.000 5.000 4.050 7.400 14.900 8.150 9.900 19.OOO
Make uD Toraue lo to to IO to IO
Courtesy Hughes Christensen
Table 4-101
Core Barrels Characteristics [50]
The Maximum Pull is based upon the ultimate
tensile strength in thapin threadarea with a
safety factor of thm.
Courtesy Hughes Christensen