Norwest Energy (ASX:NWE) advises that the Halliburton hydraulic fracture stimulation equipment has commenced arriving at the Arrowsmith-2 location. The frac spread comprising a large number of vehicles, trailers, pumps, blenders and ancillary equipment has been undergoing routine servicing in Moomba, South Australia in advance of the Arrowsmith-2 campaign. Currently, rain in South Australia has slowed down vehicle movements due to road closures, however the first stage of the hydraulic fracture stimulation program is still expected to commence before the end of July.

The Arrowsmith-2 frac campaign is a major undertaking, and as in any project planning and preparation is essential. Apart from preparing the site for the frac and testing activities, a suite of routine diagnostics has recently been carried out on the well, which included running a cement bond log (CBL) to confirm wellbore integrity, and a diagnostic fracture injection test (DFIT) to assist in the determination of various reservoir and frac properties. The CBL involved running a logging tool to test cement integrity behind the 5 ½' casing. The DFIT involved perforating the lowermost zone (High Cliff Sandstone) then slowly pumping a small volume of fluid into the well, thereby gradually increasing the pressure until a small fracture was initiated in the perforated interval. Rates and pressures were continuously monitored and recorded throughout the testing phase, providing valuable information to assist in optimising the stimulation program for the well.

The results of both these tests were encouraging, with the DFIT providing data on the frac initiation pressure required to break down the formation, and the associated pressure response indicating favourable conditions for fraccing. Other important reservoir and frac properties were also determined. The CBL indicated that the cement bond integrity is consistent throughout, providing evidence of an effective barrier between the steel casing and the surrounding formations.

With these encouraging results in hand, Norwest is now fully prepared to carry out the hydraulically fracture stimulation program to assess the potential of the four horizons intersected by the well:

  • Kockatea Shale (shale gas) (thickness - 450m)
  • Carynginia Formation (shale gas) (thickness - 250m)
  • Irwin River Coal Measures (shale gas) (thickness - 330m)
  • High Cliff Sandstone (tight gas) (thickness - 22m)

The Arrowsmith-2 campaign will be conducted over six to eight weeks in conjunction with AWE Limited to maximise cost saving benefits by sharing the usage and associated costs for equipment and services. Once the well has been stimulated, results from the well testing program will enable Norwest to establish the viability of the various target zones for future shale gas production throughout the field.