Waitsia Gas Field
In September 2014, Mitsui E&P Australia’s predecessor AWE announced that during drilling of the Senecio-03 well, the underlying Waitsia gas field [ASX announcement] was discovered below the original target formation.
Flow testing of the Senecio-03 well was completed in March 2015. The testing program was designed to determine gas flow rates from zones of two reservoirs in the Waitsia gas discovery and to collect gas samples for analysis. During the second stage of testing, an average flow rate of 12.3mmscf/d, unstimulated, was measured from the Kingia formation over five hours at the end of the 18 hour “clean up” flow period, a technical term for the initial part of the flow test. This result confirms the Kingia is a conventional reservoir and the Waitsia gas field is capable of producing gas at commercial rates.
The Waitsia field is an exciting new opportunity for the Perth Basin, which potentially rivals WA’s largest onshore gas discovery. This could deliver substantial benefits for WA and the Mid West.
- Mitsui E&P Australia (MEPAU) is planning to develop the Waitsia gas field, while working to minimise its development footprint by using existing infrastructure and facilities where possible
- Gas initially produced from the Waitsia field, during an extended production test, is being conveyed via a pipeline to the existing Xyris Production Facility (XPF) and then through the Parmelia Pipeline to businesses and households in WA
Senecio-03 appraisal well
The Senecio-03 appraisal well is located on agricultural land in the Shire of Irwin. The well was originally designed to evaluate the potential for commercial gas production from the Dongara/Wagina formation. The core samples and data from Senecio-03 were used to further assess the viability of conventional and unconventional gas resources in the Mid West.
- Before Senecio-03, the Senecio-01 discovery well was drilled in 2005 and was then side-tracked, which created the Senecio-02 well, in November 2005
- Senecio-02 flowed gas at rates of up to 1 million cubic feet per day, but declined due to the low permeability of the reservoir host rocks (tight)
- Senecio-02 was worked over to install downhole equipment in August 2011 in preparation for a small hydraulic fracture stimulation, which was successfully carried out over a five metre perforation interval
- After the successful stimulation, Senecio-02 achieved a stabilised gas flow rate of 1.35 million standard cubic feet per day (mmscf/d) from the target formation, the Dongara/Wagina formation
Waitsia-01 and 02 appraisal wells
Located approximately 17km east of Dongara, the Waitsia-01 appraisal well completed drilling activities in June 2015. The Waitsia-01 well was drilled to a target depth of 3,507m. The well was designed to further test the gas potential of the Waitsia Field, comprising primary targets in the deep conventional formations in the Kingia and High Cliff Sandstones.
AWE flow tested the Waitsia-01 well during October 2015 [ASX announcement]. The Waitsia-01 appraisal well was not hydraulic fracture stimulated.
The Waitsia-02 appraisal well is located approximately 16km southeast of Dongara. Drilling activities began in June and were completed in July 2015. The Waitsia-02 appraisal well was not hydraulic fracture stimulated.
Waitsia Gas Project – Stage 1A
The decision to commence Stage 1A development of the Waitsia gas field was made in early January 2016 [ASX announcement] following the receipt of upfront government and regulatory approvals.
Stage 1A comprises the installation of new infrastructure and upgrades to existing assets that will connect the recently flow tested Waitsia-01 and Senecio-03 gas wells to XPF for an extended production test (2.5 years). Gas processed at XPF is being delivered via an existing pipeline to the Parmelia Pipeline for domestic consumption in Western Australia.
The new infrastructure included installing two flowlines and a 7km pipeline to XPF, which had been in care and maintenance since 2010.
The initial capacity of XPF was approximately 10 TJ per day, with further expansion possible, and first gas from the extended production test commenced in August 2016.
The project required assessment and approvals from the lead agency, Department of Mines, Industry and Regulation Safety. Other approvals required by several state agencies, as well as the Shire, were also provided.
- Results of appraisal activities providing valuable data are being used to assist the development process for the Waitsia Gas Project Stage 2. This includes results of diagnostic tests at the Waitsia-02 and Irwin-01 wells, as well as the two additional appraisal wells (Waitsia-03 and Waitsia-04).
- MEPAU is continuing to undertake extensive stakeholder engagement throughout the Stage 2 development planning process.