Abstract

This paper describes the procedures and methods used to successfully drill an extended reach horizontal well in Permian Shale Source Rock Reservoir, in the Cooper Basin, South Australia.

A previous attempt at a similar well design did not reach the objective. An independent review of this well's performance was used as a starting point to design an improved drilling program for the second well.

This included the following:

  • Closer liaison and collaboration was encouraged between the operator and the service providers.

  • Improvements were planned for the second well to eliminate or reduce the severity of hole problems that occurred in the previous well.

  • Written procedures were established to ensure that hole quality was maintained throughout the drilling phase.

  • Technologies that could assist in improving drilling performance were identified, evaluated, and used.

As a result of these initiatives, the second well was considerably more successful than the 1st.

To compare and contrast the results of both wells as an indicator of improvement:

  • The 1st well achieved only 37% of the objective. The 2nd well achieved 170% of the objective.

  • The 1st well exposed 589m of lateral wellbore. The 2nd well exposed 1014m of lateral wellbore

  • The 1st well required 38 days of drilling. The 2nd well was drilled in 11, despite being twice as long

  • The lateral in 1st well required 7 bits. The lateral in the 2nd well was drilled with 1 bit, again despite being twice as long

  • The 1st well observed 485 hours of NPT. The 2nd well was drilled with ZERO NPT.

The technologies and improved procedures used in the second well facilitated its success and these initiatives will be refined for future similar wells. The major contributors to difference between these two wells are:

  • Improved drilling fluid including the use of mud lubricant

  • The use of drillstring torque-reducing subs improved bottomhole assembly (BHA) performance and reduced wear on downhole equipment.

  • A new bit designed to match the rotary steerable system (RSS) tool and formation drilled the entire extended lateral and could have achieved even more.

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