Well Construction Practices For Appraisal And Development Of Unconventional Resources In The Mereenie Field, Amadeus Basin, Northern Territory
Engineering Honours Degree, 2012
University of Adelaide
Development of unconventional resources worldwide is expanding dramatically, having begun in the massive shale gas plays of North America. Huge advancements in horizontal drilling and hydraulic fracturing have enabled production from vast, new hydrocarbon plays. Increasing price and demand for natural gas has been the main driver towards development of tight and shale gas in Australia.
The Mereenie field covers approximately 200km2 of the Amadeus Basin in the Northern Territory of Australia. The field has been producing conventional oil and gas for 28 years, 19 of which have been operated by Santos. The field contains several unconventional gas targets with 3 TCF of booked contingent resources. Tight gas prospects, which make up 2.5 TCF, exist in the Upper and Lower Stairway formations as well the Pacoota 3 and Pacoota 4 subgroups. The remaining 0.5 TCF is found in shale formations in the Middle Stairway, Horn Valley Siltstone and Pacoota 2 subgroup.
The emerging nature of unconventional gas development in Australia has warranted investigation into the evaluation, appraisal and development of tight gas and shale gas resources in the Mereenie field. Optimal well construction and stimulation techniques have been drawn from an in depth analysis of past and current development in analogous fields.
Tight and shale gas fields from North America and around the world were identified as analogous to the Mereenie field. Selection of these fields was achieved by comparison to specific Mereenie field characteristics. The appraisal and development practices of selected analogue fields were researched and evaluated to identify applicability to the Mereenie field.
Tight gas plays in the Medina group and Berea Sandstones of the Appalachian Basin in North America and the Shanxi Formation of the Ordos Basin in China were identified as analogies to Mereenie tight gas plays. Tight gas development strategies were identified as a mixture of vertical and horizontal wells with large hydraulic stimulation programs. Cased and cemented completions are recommended for fracture control. Nitrogen foam is the optimal fracture fluid for low pressure and low temperature reservoirs.
Barnett, Eagle Ford, Haynesville-Bossier and Horn River shale plays were analysed and compared to Mereenie shale gas targets. Development strategies were unanimously found to be horizontal wells with large laterals and massive multi-stage fracture stimulation programs. Lateral lengths of 2000-3000ft are recommended. Open hole completion and stimulation of wells with slick water and at least 10 fracture stages was found to be optimal.