CorrosaCem™ cement system successfully placed in three-stage production casing using Fidelis™ stage cementers
Download PDFUnconventionals
Isolate multiple weak formations in a corrosive environment
USA
Cementing casing strings in weak formations requires careful design and execution. Multiple weak formations were anticipated while cementing 7-in. production casing, which required a multistage cementing operation. The potential presence of carbonic acid created additional challenges because certain wellbore sections required cementing with an acid-corrosion-resistant slurry design.
The operator’s goal was to achieve full cement coverage of the 7-in. casing while addressing multiple zones with potential lost circulation. Fluid returns (spacer and/or cement) were desired for all stages. Additionally, sections of the wellbore required corrosion-resistant slurries to address the presence of carbonic acid.
Because lost circulation was expected in different sections of the wellbore, a three-stage cement solution was designed using two Halliburton Fidelis stage cementers that featured two sets of CO2-resistant, high-pressure seals on either side of the cementer circulation ports within the internal closing sleeve.
CorrosaCem® cement system, an improved corrosion-resistance, low-Portland-cement solution, was placed across the sections with potentially corrosive environments. All slurries were designed at relatively low density with a low rheological profile to help minimize equivalent circulating density (ECD). Tuned Defense cement spacer, a system that helps mitigate seepage loss, was tailored with BridgeMaker II LCM to help mitigate losses and achieve a full column of cement to surface.
iCem® service was used to perform sensitivity analysis, ensure cement placement, and help maintain an ECD below the fracture gradient. This service was also used to provide fluid volume recommendations to achieve +80% displacement efficiency at each critical depth of interest by leveraging the 3D modeling capabilities of the software.
A total of 120 bbl of Tuned Defense cement spacer with LCM and 396.8 bbl of a 13-lbm/gal CorrosaCem cement slurry were pumped during the first stage of the operation. A total of 205 bbl of 13.5-lbm/gal CorrosaCem cement slurry was placed during the second stage. Approximately 107 bbl of 12.2-lbm/gal EconoCem cement slurry, a lightweight low-rheology system, was pumped during the third stage. Permanent fiber optics installed in the annulus allowed real-time distributed temperature sensing (DTS) data monitoring for heat of hydration during each stage to indicate when the next stage could begin.
Displacement efficiency at each depth of interest
Fidelis™ stage cementers
Confirmed coverage throughout the entire casing string
Circulation to the surface was achieved during all three stages. Both stage tools operated as designed; the wiper plugs landed, and the casing was pressure tested with no flowback observed during any stage. The technology and execution of the CorrosaCem cement system and EconoCem cement, engineered Tuned Defense cement spacer, and Fidelis stage cementers met all operator objectives. A CBL confirmed excellent coverage throughout the entire casing string.
Tailored to improve chemical resistance to CO2 and enhanced mechanical properties that minimize the impact of cyclic loading on the cement barrier integrity.
Tuned® Defense™ Cement Spacer systems prevent lost circulation while optimizing fluid rheology for effective mud displacement.
Enhances cement spacer designs to prevent lost circulation.
The Fidelis™ Stage Cementer provides multiple stage cementing capabilities with hydraulic fracturing durability.
iCem® Service is the most robust cementing design tool in the industry, dramatically increasing the probability of wellbore integrity.
