Non Destructive Testing

Tank Floor MFL scanning is a non-destructive examination method which uses a magnetic field to detect corrosion and pitting in carbon steel. A powerful magnet is scanned close to the surface to saturate the steel with the magnetic field.

The magnetic field leaks from the steel where there is corrosion and this is detected by the scanner. Between the scanner bridge magnetic poles, a near-saturation magnetic flux is induced in the material examined. The scanner sensor detects flux leakage changes when the plate thickness changes. This may indicate the presence of discontinuities, such as pitting and corrosion, on the process and/or soil side. The scanner is moved over the entire tank bottom surface to provide the required inspection coverage. Technicians interpret the scanner display to identify damaged areas and in some cases, estimate the amount of metal loss. Thickness losses detected by ultrasound are reported and mapped in a CAD rendering of the floor.

Intelligent pigging is a technique of inspection of pipelines using digital technology to understand their condition. It is widely used to gather important data, such as the presence and location of corrosion or other irregularities on the inner walls of the pipe.

Surface-breaking flaws such as cracks, laps, porosity, etc. To be detected, the flaw must reach the surface to be tested.

GW LRUT-Guided Wave Long Range Ultrasonic testing is a rapid screening test method for integrity assessment of pipelines, non-piggable buried, encased piping, vertical or inaccessible piping (e.g. overhead pipe racks) or epoxy coated pipelines to locate areas of potential degradation or engineering concerns and gross discontinuities for targeted assessment and inspection.

This method is used for the detection of surface and near-surface flaws in ferromagnetic materials and is primarily used for crack detection. The specimen is magnetised either locally or overall, and if the material is sound the magnetic flux is predominantly inside the material. If, however, there is a surface-breaking flaw, the magnetic field is distorted, causing local magnetic flux leakage around the flaw. This leakage flux is displayed by covering the surface with very fine iron particles applied either dry or suspended in a liquid. The particles accumulate at the regions of flux leakage, producing a build-up which can be seen visually even when the crack opening is very narrow. Thus, a crack is indicated as a line of iron powder particles on the surface.

A borescope (occasionally called a boroscope, though this spelling is nonstandard) is an optical instrument designed to assist visual inspection of narrow, difficult-to-reach cavities, consisting of a rigid or flexible tube with an eyepiece or display on one end, an objective lens or camera on the other end.

Drilling is an integral part of the Oil exploration activities and as such cannot be overemphasized. Our services cover a wide range of OCTG Integrity checks designed to identify possible defects on your Drill Stem which are the main causes of down-hole failures.

EECL OCTG Inspection division is a universal service provider for inspection, testing and certification services in an oil field industry supported by wide experienced inspection engineers and technicians, we offers cost effective and timely services to our clients for smooth, safe and profitable operations of their facilities.

We do visual/dimensional inspection of Drill pipes/Casing/Tubing/BHA tools/HWDPS/Rig parts and Handling equipment in order to confirm the acceptability as per required standards Eg:-API RP7G/TH Hill DS-1/NS-2 etc.

We have full length EMI inspection pipe surface inspection units, which are capable of detecting transverse and 3 dimensional flaws such as pits, seams linear & rounded. We are providing the inspection services to Drilling contractors/IOC’S/Rental services/manufactures etc.

Pulsed Eddy Current is a unique corrosion survey method that allows ferrous objects to be surveyed without the need to make contact with the surface (in contrast with ultrasonics). This means that measurements can be performed on objects covered with insulation, asbestos, fireproofing, concrete or coating. The high costs for removal of insulation can therefore be avoided. Scaffolding can be reduced by using rope access or by mounting the measuring sensor on an extension pole.

Principle

An eddy current sensor is placed on top of the thermal insulation. By means of a low frequency (pulsed) magnetic field, eddy currents are generated in the material. By measuring the duration of the eddy currents, a thickness calculation is made. This thickness calculation gives the average thickness of the material, within the enclosed magnetic field (footprint). The diameter of the footprint varies between 25 and 150mm dependent on wall thickness and thickness of the insulation.

Performance

• Maximum wall thickness 65mm
• Maximum stand-off 200mm in favourable circumstances
• Diameter 3” up to flat plates
• Duration of one measurement: 10 seconds
• Accuracy: +/- 5%

Typical applications

• Insulated vessels and columns
• Insulated storage tanks / spheres
• Insulated pipelines

On (large) insulated objects where high costs are incurred in crane rental or scaffolding erection, PEC can reduce costs up to 80% compared to the conventional approach.

The position of PEC measurement is not restricted to the location of an inspection aperture in the insulation (i.e. ultrasonics). Readings can be taken anywhere on surface of the object.

Up to 1000 measurements can be taken in a 10 hour shift. This production rate mostly depends on accessibility.

Radiography uses X-rays or gamma-rays to produce an image of an object on film. The image is usually natural-size. X-rays and gamma-rays are very short wavelength electromagnetic radiation which can pass through solid material, being partly absorbed during transmission. Thus, if an X-ray source is placed on one side of a specimen and a photographic film on the other side, an image is obtained on the film of the thickness variations in the specimen, whether these are surface or internal. This is a well-established technique which gives a permanent record and is widely used to detect internal flaws in weldments and castings and to check for mis-constructions in assemblies.

Ultrasonic testing can be performed using two basic methods - pulse-echo and through-transmission. With pulse echo testing, the same transducer emits and receives the sound wave energy. This method uses echo signals at an interface, such as the back of the object or an imperfection, to reflect the waves back to the probe. Results are shown as a line plot, with an amplitude on the y-axis representing the reflections intensity and distance or time on the x-axis, showing the depth of the signal through the material.