The laboratory conducts complex strength downhole screen testing. The testing is carried out in the set of benches used for various mechanical stress testing arising during equipment usage.
The mechanical bench is used for downhole sand screens testing based on API 19SS (2016), ISO 17824:2009, GOST 32504–2013– “Petroleum and natural gas industries-Downhole equipment-Sand screens”, except pre-pack screens. To test the working capacities with applied loads, the testing simulates sand screen components with operational loads.
MPF-100 bench specification:
The MBM-1 (Mechanical Breaking Machine) with a force capability up to 1 ton is used for the wire separation testing. Special equipment is used for the testing. The speed of punch movement from 0.01 mm/min to 500 mm/min and the wire separation moment are set with the mechanical press.
MTM-80 (Mechanical Torque Machine) hydraulic wrench with a torque capability of 80 kN m is used for torsion testing. The bench allows screen testing basic sizes up to 250 mm in diameter.
Description of the main types of mechanical testing are below:
1. Pull Test, Push off Test, End Ring Push off Test, Supporting screen elements push
Testing performed at MPF-100 multifunctional testing bench The main task is to determine the downhole screen’s mechanical strength to axial loads according to the declared specifications. The bench consists of a support frame, a hydraulic cylinder of two-way axial loads, adapters for mechanical fasteners of the screen, and the bench control system. Screen testing sample fixed on the load frame is used for testing.
The testing involves the applied axial loads to the testing screen sample. This requires the sample to be fixed reliably to the load frame and the fixation between the sample and the hydraulic cylinder rod. Testing is performed by following programs:
Testing work scheme:
The MPF-100 mechanical testing bench is certified and calibrated by independent certification authorities.
Wire wrap separation testing is performed on the MBM-1 bench. The task of the testing is to determine the mechanical strength of the wire wrap screen weld. The testing is performed with the rectangular wire wrap coupons cut from the screen. MBM-1 mechanical press punch movement produces the separation force to the wire wrap from the guide rods. The value of this force is the strength of the wire screen weld.
The wire separation testing bench is designed to test loads up to 10 kN. For manufacturers, the validity criterion of the direct screen wrap is that at a tensile load of at least 1.23 kN (125 kgf) no splitting occurs of the welded wire connection and stiffeners.
The wire wrap separation test bench is regularly checked for accuracy and calibration of the generated forces. Wire wrap separation testing is a part of comprehensive mechanical strength screen testing.
It tests the mechanical strength of the screen for torsional loads. The liner rotates with the screen, and the screen shall withstand specific torsional loads. Testing performed at MTM-80 bench.The testing is performed at the hydraulic wrench bench, the main purpose of which is to install couplings on the nipple part of the base pipe. The hydraulic wrench bench is used to control the applied force torque to the support foot of the screen basepipe end holder, rotating around the sample axis. The screen in the second wheelbarrow is fixed to the cemented part of the screen element. The practical validity criterion in practice is to withstand a nominal torsional torque of 25 kN m by the screen.
The testing verifies the screen’s mechanical strength against bending load. A downhole liner consists of a connection of different equipment and must be flexible. It stems from the fact that the drilled trajectory of the well has a spatial curvature, and the running liner must include screen bending. To assess the effect of bending loads on the screen, special tests are performed.The screen supports, weighting agent, laser level, and leveling rod are used for the bend testing. The screen sample bending shape in a circle is taken into account. The minimum requirement of the screen bend sustain is 45ª by 30.3 m (100 ft) in length.
The bend testing should be repeated at least 10 times. The screen must retain its characteristics after testing. The change in the slot clearances must be less than 5%, and the quality of the welds must be retained.
© Sand Control Drilling Equipment Trading Ltd
Abu Dhabi, United Arab Emirates