Views: 0 Author: Site Editor Publish Time: 2021-09-03 Origin: Site
ASLO® is a high performance spring centralizer used under high loads and large deformations condition.
█ During offshore oil engineering and casing operations especially
in some complex land wells, cementing engineers need a
highly deforming but strong casing centralizer. They need
to have a smooth shape, which can pass through some
complex well sections smoothly in down hole to reach the target
working position. ASLO® provides a strong restoring
force that overcomes the weight of casing. This guarantees
the best centralization of cementing.
Analysis of working process of ordinary One piece spring centralizer
█ We installed an ordinary 13 3/8 " one piece spring centralizer on a 13 3/8" casing, and then pressed into an ID 15.01" casing--this is to simulate a customer's real downhole application. Then take the product out for a standard API restoring force test with ID 17" casing, and we found that restoring force of the product dropped by 30%. After measurement, it was found that OD of the product became smaller after the extreme pressing, which means that the product did not rebound to previous state.
▇ This confirms the previous complaints from cementing engineers about performance of the centralizer in this case. The products after extreme pressing could not meet the performance requirements we designed originally. This means that the actual centering rate of casing does not meet our design requirements.
█ By analyzing products with the help of computer-aided design technology, we found out when ordinary products are extremely pressed, there are some very concentrated stress points in some parts. We know that these products are made of spring steel through a series of heat treatment processes. The basic condition to maintain elasticity is that the steel undergoes a complex heat treatment procedures to form uniform special metal grains. These concentrated stress points formed during extreme pressing caused permanent damage to these grains, although the pressing lasted only 20 minutes.
How to solve this problem by ASLO®
▇ ASLO® uses one piece structure.
▇ Using stronger blade .
▇ Designing some narrow slots in high stress areas
of these blades.
ASLO®'s computer-aided stress analysis shows
this design eliminates some excessively concentrated
stress points of the blades, and the stress distribution
is more uniform.
These clever stress slots serve two purposes：
▇ Deformation or even closure under pressing，
which provides us with an additional lateral
deformation elasticity. This means that ASLO®'s
blades deform in vertical and horizontal directions
simultaneously, while ordinary products only have
one in vertical direction.
▇ Avoid damage to spring metal grains at high
Actual Application Performance of ASLO®
Test Verification of ASLO®
13 3/8“ X OD 18 1/2”ASLO® Centralizer
Install to 13 3/8" casing and press in OD 15.01" casing, leave for 24 hours.
After taking out, testing with OD 17 "casing according to API 10D standard.
Restoring force = 2081lbf, equal to 1.7 times API standard requirement.
▇ Compared with the ordinary one piece spring centralizer, even under the extreme pressing for more than 24 hours, the ASLO® centralizer performs perfectly and fully meets our design requirements.
█ Smooth shape
█ Firm and strong structure
█ Low running force
█ High restoring force
█ Perfect elastic recovery after extreme pressing.