Improving seismic calibration and geomechanical models through characterization of anisotropy using single and multi well data: Case Study in Forties Field, UK

Donald, Adam; Paxton, Andrea; Keir, Donald

doi:10.1190/1.3255818

Cited by 9 publications

(1 citation statement)

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“…A full sensitivity analysis of the Draupne shales was performed to assess the stability of the shales at varying drilling angles while the rock strength of the shales was also examined as studies have shown the strength of anisotropic shales can greatly reduce by up to 85% when being drilled close to 45 degrees. 12 The sensitivity analysis looked to assess the potential of the Draupne shales reducing the strength due the angle of the hole and the subsequent influence on the well bore stability through this section. The planned mud weight of 1.39sg was used to drill out the shoe and the section.…”

Section: ½" Hole Sectionmentioning

confidence: 99%

Multidisciplinary Approach and Engineered Solution Sets New North Sea Performance Benchmarks

et al. 2012

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To efficiently develop reserves in the Norwegian North Sea, the operator must drill a challenging 12¼" directional borehole through a Chalk formation with high stick-slip potential. In Gaupe North, a negative vertical section was required in the initial kickoff to properly line up the well path before entering the reservoir target. The reservoir is comprised of channel/sheet sandstones interbedded with shale sequences with different pressure regimes and nearby reservoir depletion issues. The 8½" wellbore must penetrate an unstable organic shale just above the reservoir, infamous for causing hole stability problems and stuck pipe events. The regulatory agency requires this shale to be drilled in an 8½" section, requiring long exposure time, which increases risk for hole problems when running the production liner. The objective was to efficiently drill these trouble-zones and deliver two horizontal producers in a cost effective manner using an integrated engineering solution.To achieve the objective, a sophisticated multidisciplinary approach was employed including: bit/BHA offset analysis to reduce stick-slip in the chalk; BHA/RSS and drilling fluids modeling/planning; and drilling parameter plots to identify optimum RPM/WOB. Also, a real-time parameter analysis system was deployed to optimize ROP without compromising hole cleaning or well integrity.The synergy provided by a fully integrated service provider increased drilling performance and was a major contributor to the success of the Gaupe wells performance. Well 6/3-A-1H broke the previous Rushmore index for subsea development wells in the region and set a Norwegian record for wells in this class. Both wells (15/12-E-1H & 6/3-A-1H) achieved positive P10 curves and saved a total of 18 days vs AFE. Compared to an analogous UK North Sea field, significant increases in ROP were achieved resulting in the wells being drilled 20+ days faster than benchmark. The average increases in ROP for the two Gaupe wells were approximately 146%, 47% and 148% in the 17½", 12¼" and 8½" sections respectively.

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Section: ½" Hole Sectionmentioning

confidence: 99%