The Al Furat Petroleum Company (AFPC) has achieved a step-change in drilling performance since the introduction of Under-Balanced Drilling (UBD) in September 2002 in the Omar field. To date 7 wells have been drilled using the UBD technique resulting in up to 55% reduction in drilling duration per well, 16% reduction in drilling expenditure and 17% reduction in cost per meter drilled.

This step change has been achieved due to the following advantages that UBD technology offers when compared to traditional methods. Using UBD:

  • A contingency casing, or liner, can be omitted

  • A slim casing design can be used whilst well functionality is maintained

  • Well control events associated with high pressure / low volume kicks, can be quickly, efficiently and safely dealt with

  • The average rate of penetration in the ‘UBD’ section is increased up to 100% due to the lower mud weight used (up to 2.5-5.0ppg reduction in mud weight)

An additional advantage has been the capability to identify and characterise hitherto undetected hydrocarbon zones.

The integrated team approach adopted has proven key to the successful introduction and uptake of UBD technology in AFPC's operations. The success has established UBD as one of the strategic technologies to improve drilling performance and reduce overall well construction costs.

This paper describes the step-change in drilling performance in AFPC's operated Omar field through introduction of UBD technology. Additionally, Project Management aspects and HSE approach used to successfully and safely introduce this technology are included.

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