Non-destructive testing of downhole equipment is a way to determine its characteristics without violating the integrity, serviceability and reliability of the structure of the equipment under study. SCL utilizes the following non-destructive testing:
Optical-laser control of screen slot gaps
Two basic methods are used to check the winding quality of slot screens of sand screens: manual with metric probes and automatic with an optical inspection machine. The manual method is quite time consuming and imprecise. The SCL laboratory uses the Kvantron-150 laser-optical complex to check screen slot gaps. The principle of the inspection machine is to obtain a digital black-and-white image of the screen slot clearances of high accuracy with highlighting of the light and shadow borders that define the boundaries of the screen slot clearances. Automatic inspection with an inspection machine allows the distribution of slot gaps along the entire length of the screen element to be checked with a high accuracy of 10 microns. The distribution of screen slot gaps has a significant impact on the effects of sanding and colmatation, so controlling the slots is important.
There are several criteria different screen manufacturers and customers use to evaluate the slot gaps distribution. The inspection machine software system is set up to evaluate the clearance distribution according to Statoil, Schlumberger, Exxon criteria. All the evaluation criteria are set up along roughly the same principles. At least a certain fraction of the clearances must fall within a given interval around the nominal with a given probability. The choice of the clearance distribution evaluation criterion is determined in accordance with the Customer’s requirements. The Automatic Slotted Gaps Test program involves testing a sample screen along the entire length of the screen element with rotation around the axis.
Technical characteristics of the inspection machine:
The inspection machine is periodically calibrated as a measuring instrument. The measurement accuracy of the inspection machine is confirmed by certification in independent metrology laboratories.
To control the quality of welded joints of downhole equipment, the laboratory uses the method of capillary defectoscopy of welded joints. The method is based on the penetration of liquid substances through the weld seam by capillary forces. When using the capillary flaw detection method, the color contrast of the defective area of the weld is increased compared to the quality weld. Various defects related to the non-welded seam line, pores and sinks can be detected using this method of capillary flaw detection. For this test, a specially colored indicator is used, which is capable of filling open cavities, with the subsequent formation of an indicator pattern. Surface-active substances (surfactants) are added to this indicator in order to improve the penetration of the indicator liquid into the existing cavities of the weld. Using a special developer, the indicator material is fixed to fully reveal defects in welds.
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Abu Dhabi, United Arab Emirates