PORTABLE DUCTILITY TESTER

Testing of Wirelines In Services

Providing that new wirelines are purchased from reputable suppliers they should arrive complete with full certification. This guarantees to the purchaser that the wireline has been manufactured to a specified quality standard and exhibits the properties recorded on the test certificate. Unfortunately, with the ravages of time, the combined effect of operating a wireline under high tensile and bending fatigue stresses, often in corrosive media at elevated temperatures, the wireline ductility gradually becomes impaired.

As a result, the certified "new" wireline properties are no longer applicable and quality assurance relies purely on the experience of the operator and his assessment of the "feel" of the wire.

The availability of the Portable Wireline Ductility Tester provides a wireline operator With the facility to test and hence evaluate the quality of the wireline throughout its working life. In service, failure of Wirelines, due to impairment of the wireline ductility, may in many instances be pre- empted by adopting a full testing programme. torsion testing is particularly useful when operating API9A wirelines in conditions where minute quantities (a few ppm) of H2S may be present, since line failures can occur in as little as 12hours exposure. We strongly recommend that all wirelines be tested prior to commencement of down well operations. This will help prevent one oil company from inheriting a prior oil companies problem.

Test Requirements: Stainless and special alloy wirelines

Unlike carbon steel wirelines, the ductility of stainless and special alloy wires cannot be determined using the torsion test. These materials exhibit a very low number of twists to failure (typically 2 to 4 twists on an 8" gauge length) and Grade 1 type fracture characteristics, independent of the inherent ductility of the wire. Consequently, it's recommended for these types of wirelines, wire ductility is evaluated using a simple wrap test. In this test wire is wrapped in a tight helix around mandrel of equal diameter, which in practice is achieved by wrapping the wire around itself. Care should be taken not to twist the wire at a localised point since under these conditions failures have been experienced within rotation through 180°.

Although this test is not specified in the API9A specification, it is recognised by competent wire manufacturers to provide a good indication of alloy wire ductility. In the test, very high strains generated in the wire surface , which in all but most ductile materials causes immediate
failure.

It is considered that a wire which has survived 10x 36+0° wraps around its own diameter without fracture or signs of surface cracking has passed the test and is suitable for oil well services.

Portable ductility tester

Wire Gauge Length
Pre- set at 8" (203mm) to comply with the API9A torsion test Specification

Wire Size Range
Up to 0125" diameter (3.175mm)

Construction
The machine is of selectional construction manufactured in lightweight, high strength, corrosion resistant materials. The machine jaws have been carefully designed to prevent damage to the wire during testing, thus minimising invalid tests. Powerful torque is applied via 9" (229mm) "bolt-on" handle which is stored within the tester
when not in use. The rotating jaw features a combination of precision thrust and needle roller bearings designed to provide smooth and wear free operation. The fixed jaw mounted on a preset spring- loaded end plate which ensures the change of wire length during torsion testing is not prevented. This feature also eliminates the need for bulky
back tension weights. An internal wire guide accessory is provided to enable the wrap testing of stainless steel wirelines on their own diameter (the recommended ductility test for this material). Each unit is provided with a comprehensive manual. Details are given on operational procedure, fracture classification, wire specification and maintenance requirements.



Limetech wireline Ductility Tester

Independent Laboratory Testing

Fully equipped chemical and metallographic laboratory including scanning electron microscope.

Independent reports based on 50 years combined experience in the wire and rope industry.

Investigation carried out on failed wirelines and strands. Report charges are based on the complexity of the testing to be carried out.

Wide knowledge of wire behaviour in differing conditions and advice on wireline selection.

Complete confidentiality guaranteed on all matters.