A heat-activated, rigid rapid fluid treatment was used to return full circulation and successfully increase the window gradient on the first attempt in a deepwater well in the northern Gulf of Mexico. The use of rapid-setting fluid (RSF) activated by heat to cure loss of circulation is gaining acceptance, said Halliburton’s Javier Urdaneta during a presentation at the 2011 SPE/IADC Drilling Conference in Amsterdam on 3 March. Such a system had been previously used in northern Mexico in onshore applications.
The first application of a RSF in the northern Mexico offshore environment demonstrated the benefits of being able to modify the setting properties of the fluid based on temperature and right set angle without shrinkage. Other RSF advantages exhibited in this application were the capability to tolerate 50% of contamination with water and drilling mud, develop up to 3,500-psi compressive strength in the first two hours and be pumped through the BHA.
For well C-1 in the northern GOM, a temperature simulator was used to model the heat-transfer phenomena caused by early operations in the well. “It was necessary to discern how the RSF system could be modified by water depth, change of geometries and rates, as well as the injection pattern,” Mr Urdaneta said.
The well was stabilized to 1.70 SG, and the BHA was pulled out of hole; the drill pipe was run and placed at 3,465 meters. Rather than pumping through the bit, it was decided to have a cement plug ready to be spotted using the drill pipe. The BOP was closed, and 35 bbl of treatment were bullheaded to the formation. The borehole static temperature was about 53°C before the treatment and 38°C at the end of the displacement. “When 50% of the RSF was placed into the formation, hesitation was applied to minimize the injection rate across the hydrostatic column,” Mr Urdaneta said. “The well was closed for four hours instead of the 12 to 15 hours usually required for cement plugs.”
The RSF treatment enabled drilling ahead for an additional 250 meters and encountered two pay zones. There was no loss of returns or fluid influx in this section. “Cost savings was estimated at about US$3.47 million based on rig time, running in hole and volume of synthetic-based mud lost,” Mr Urdaneta said.
While continuing drilling through two other zones, water influx was encountered. This time an RSF was pumped in two 35-bbl treatments. For the second treatment, the BHA was pulled out of hole and 15 bbl of viscous pill was used, followed by 35 bbl of RSF. After five hours of waiting on cement, the well was opened with full returns. The third treatment was the same as the second one.
The total logged hole depth on the C-1 well was 4,820 meters with no water influx. The RSF has been adopted by the operator in drilling programs in wells in similar environments.
More information on this deepwater application of RSF can be found in SPE/IADC 139929, “First Application of Heat-Activated, Rigid Rapid-Fluid System in Deepwater Environment in Mexico Helps to Cure Severe Loss of Circulation: A Case History,” presented by Jorge Castro, Luis Solis and Javier Urdaneta, Halliburton; and Victor Arreola, Pemex, presented at the 2011 SPE/IADC Drilling Conference, 1-3 March, Amsterdam.