Long term zonal isolation is critical for Steam Assisted Gravity Drainage (SAGD) wells. Historically, most of the SAGD wells in Canada have been cemented with On-The-Fly (OTF) mixing procedures. OTF mixing is well suited for the large slurry volumes required for SAGD wells and has been common practice globally. However, there are certain risks associated with OTF mixing that could impact the long-term zonal isolation of a SAGD well. In June of 2018, Magnum had the opportunity to demonstrate our MagBatchTM mixing technology for Suncor in Firebag to cement a SAGD injector well. The total required volume of cement slurry to be batch mixed for this well was 108 m3, with a planned cement and displacement pump rate of 3.0 m3/min.
This job is one of the largest batch mix SAGD cement jobs ever performed in Canada.
Mohr-Coulomb is one of the many criterion evaluated along with other properties such as Young’s Modulus, Poisson’s Ratio, Tensile Strength, etc. for evaluating mechanical properties.
To allow for the planned 108 m3 batch volume and downhole pump rate, two MagBatchTM units, two PCMP-Q cementing units, and 160 T of cement storage capacity were strategically spotted on location to execute the job. The two PCMP-Q units pumped the slurry and displacement downhole at 1.5 m3/min each, for a combined rate of 3.0 m3/min (equating to an annular velocity of 75 m3/min).
Full returns were seen throughout the job, with pump pressures matching the pre-job simulation results. Cement return volumes were also as expected, with zero fall back seen on this well.
A cement bond log (CBL) was ran 12 days later to evaluate results. The CBL was optimal and the customer was very satisfied with the formation isolation. This cement placement technique was subsequently applied to all remaining wells on the pad.
Due to the consistent density with required chemical hydration that the batch mixer is able to achieve, the customer can be confident that the designed mechanical properties have been obtained.
Magnum continues to use MagBatchTM as a solution to our customers to satisfy todays longer, large diameter directional and horizontal well designs.