ELEMENT

PERFORMANCE CRITERIA

1. Plan and prepare for the construction of artesian (flowing) aquifer production bores

1.1. Access, interpret and apply compliance documentation relevant to the work activity

1.2. Obtain, confirm and apply work instructions for the allocated task

1.3. Identify, manage and report all potential hazards

1.4. Resolve coordination requirements with others at the site prior to commencing and during work activities

1.5. Discuss scope of work with client and give technical advice, cost structure, workmanship warranty, quantity and quality of materials, construction standards and methods to be used and gain general agreement on drilling plan

1.6. Provide detailed strata logs, pump and development test results conducted during bore development and water and strata samples to the appropriate authorities as required by the relevant State/Territory legislation/licensing agency

1.7. Complete all requirements for bore completion reports, decommissioning or abandonment and send to regulatory authorities within the time specified on bore licence

2. Design production bores for artesian aquifer systems

2.1. Determine most appropriate construction methods from the reading and interpretation of all available documented information

2.2. Design the bore to ensure the exclusion of unsuitable waters and to prevent the inter-mixing of aquifers with different water quality and/or Standing Water Levels

2.3. Determine a drilling fluid program to suit the expected down-hole conditions and anticipated pressures

2.4. Select a bore site that will prevent contamination and minimise interference with other bores and that is safe with respect to potential occupational health and safety hazards

2.5. Select likely water entry mechanism from the formation to the bore such as open hole, slotted casing screens, gravel packs

2.6. Calculate appropriate artificial pack design parameters, and recommended annular thicknesses required

2.7. Undertake calculations to determine appropriate screen/slot design parameters (e.g. diameter, length, aperture size)

2.8. Plot and interpret sieve analysis results onto graphs

2.9. Select appropriate bore/surface casing types, size, strength and wall thicknesses for the anticipated ground/water quality and pressure conditions and any construction requirements

2.10. Ensure all necessary materials anticipated for the job are available and on site prior to commencement of construction phase

3. Construct production bores in artesian aquifer systems

3.1. Use approved procedures to select, slot, assemble and insert casing and screens suitable for the formations in which they are deployed

3.2. Use equipment for assembly and slotting safely and in accordance with approved procedures

3.3. Select, mix and place grout or otherwise seal surface casing from 10 m into competent impermeable strata and back to the surface with a minimum sheath thickness of 20mm above maximum shoe of coupling joint diameter size

3.4. Conduct grouting operations to seal intermediate and/or inner production casing strings with a 15mm minimum thickness grout sheath or to seal selected zones so that the water from the production bore is drawn from one primary formation only, (unless otherwise allowed by the permit)

3.5. Construct bore in accordance with any applicable regulations, minimum construction requirements and the organisation's internal procedures

3.6. Use and maintain drilling fluids and additives within the manufacturer's recommendations and that are non toxic and capable of complete removal from the bore upon completion

3.7. Maintain, test and record fluid properties such as viscosity, mud weight, filtration and sand content so that the potential capacity, efficiency or quality of the bore is not affected

3.8. Maintain plumbness and alignment of the hole within the required limitations and carry out a plumbness test if required

3.9. Prepare for and recognise symptoms of a formation kick and take action to control the bore

3.10. Collect, store, record, label and transport formation samples in accordance with licensing requirements

3.11. Collect, test, store, record, label and transport water samples for chemical analysis in accordance with licensing requirements

3.12. Maintain all records accurately and legibly

3.13. Arrange for geophysical logging tools to be run in bore if required

3.14. Accurately calculate hole, annular fill or pack materials and mud pit volumes in cubic metres or litres

3.15. Determine aquifer formation grain size distribution from sieve analysis and interpret appropriate gravel pack and screen slot aperture dimensions for gravel packed wells

3.16. Select appropriate gravel pack materials

3.17. Place artificial pack material in a manner that will ensure uniform distribution in the annular space without bridging

3.18. Comply with relevant workplace occupational health and safety requirements for both the drilling equipment and construction materials

3.19. Remove drilling fluids from the bore to allow subsequent development

3.20. Maintain tool string inventories

3.21. Construct headworks for the bore including isolation valves to retain/control artesian flow and to permit independent testing of both pressure and flow without interference to reticulation system

3.22. Identify and protect headworks of the bore

3.23. Construct headworks to seal and cap the bore from surface water pollutants, environmental concerns and damage

3.24. Dispose of/neutralise wastewater or hazardous materials from site and complete restoration of the bore site camp facilities

4. Develop bore

4.1. Use development techniques with care to prevent collapsing of casing or screens

4.2. Use development techniques to maintain and improve hydraulic transmissivity around the bore

4.3. Undertake development until a continuous, clean supply of water is obtained, in accordance with acceptable and practical limits set by site, contractual or regulatory requirements

4.4. Measure/calculate and record standing and drawdown water levels

4.5. Perform pump and or development tests to estimate the sand content and sustainable yield of the bore

5. Disinfect/decontaminate bore and drilling equipment

5.1. Disinfect/decontaminate to comply with relevant standards or regulatory requirements

5.2. Handle hazardous chemicals in accordance with manufacturer's recommendations/instructions and any relevant legislative/regulatory requirements

6. Carry out bore maintenance and rehabilitation

6.1. Undertake a process of diagnosis to determine likely cause of bore deterioration

6.2. Devise a program of rehabilitation to ensure that the bore is restored to a reasonable condition

6.3. Wear appropriate/recommended personal protective equipment when handling hazardous cleaning chemicals and follow manufacturer's recommendations

7. Decommission artesian wells with flowing and/or nonflowing elements

7.1. Determine suitable decommissioning procedures and select appropriate materials

7.2. Carry out the decommissioning (abandonment) of artesian aquifer bores, using min 20m long cement plugs sufficient to stem the flow between aquifers both from inside and outside the casing, (slot casing as necessary) or to separate aquifers of differing water quality from each other

7.3. Place cement bridges at the top of the surface casing and at the surface casing shoe

7.4. Verify position/location of hole for future reference

7.5. Dispose of drill and other fluids safely

7.6. Record entire decommissioning procedure and details of bore cementing

7.7. Complete bore completion report and submit to State/Territory Water Authority