DRILLING: Field performance: Max-R™ centralizers17 Mar 2021
Thai oil and gas producer
Max-R 7” x 8 ¼” spiral slim blade, “Pioneer”, advanced polymer centralizer
In 2013 Matrix commenced supply of the Max-R Low Friction, Advanced Polymer centralizer to support a Field Development program characterized by challenging well designs and tortuous well paths. The use of Max-R centralizers allowed wells to intersect additional reserves, reduce the number of casing strings and minimize casing running time. The extensive and consistent good quality performance data collected during the course of the drilling programme provided an excellent opportunity to evaluate the Friction Factors achieved with the Max-R centralizers as seen in the field, and compare those to values as tested under controlled conditions. A total of 13 wells were selected by the Operator to be analysed in respect of casing running forces.
Matrix uses industry recognized Torque and Drag software for estimation and evaluation of casing running forces. Each of the wells was modelled using actual survey data, caliper information, casing tally, and fluid data. Hookload measurements from the drilling data log were checked for quality before plotting against a number of simulated Hookload curves generated for different Friction Factors. Where required the Hookload measurements were adjusted for buoyancy effects (due to partial casing fill), swab and surge effects, and circulating pressures. The average Friction Factor at various depths along the open hole section was determined by comparison against the simulated Hookload curves.
For all 13 wells the 7” 23-29# casing was run in SyntheticBased-Mud with a typical SG of 1.3-1.4. Well bore inclinations were up to 64 degrees with azimuthal changes up to 230 degrees, resulting in dogleg severities in excess of 5 degrees/30m. Centralizer placement was designed to not only provide Stand-Off, but also to limit Drag through the Kick-Off and Build sections which are typically relative large contributors to the total Drag experienced. Each string was fitted with Max-R Low Friction centralizers at typical 6 to 8 meter spacing over the entire length of the open hole section (up to 2575 meter in length). All strings were successfully run to planned shoe depth.
With the exception of a single well, the evaluated Friction Factor varied between 0.09 and 0.19 with an average of less than 0.14. These values correlate well with experimental results, and validate the superior performance of Max-R centralizers. Because the Friction Factor determined in this way contains all sources of Drag, the true Coefficient of Friction between centralizer and borehole will be equal or lower than those evaluated values. Field Performance data provide Operators with additional confidence to design future wells that provide an even higher Return on Investment.
The Max-R Low Friction Centralizer is a high quality engineered well construction tool proven to reduce Torque and Drag values allowing Operators to unlock additional reserves, faster and at lower overall cost.