Dwi Flashcards
What are waste disposal options
- Landfills
2. DWI. - deep well injection
How long has DWI bee in used? What for?
1990s for oil and gas
2 main reasons for injecting fluids into subsurface
- to increase p so recovery increases and so do profits
2. Disposal of liquid haz wastes
What are the 5 classes of injection and disposal wells in Alberta based on
The type of fluid injected
Well use and fluid type for class 4 well
Use- direct injection into a reservoir (not for disposal)
Ex: SAGD
Fluid: potable or drinking water
Use and fluid type for class 3 wells
Use-inject HCs, inert gas or other gases
-enhances recover (2-3 degree) and storage of fluids
Fluids: solvents(for enhanced) and sweet gas (storage)
Use and fluid of class 2 wells
Use: injection or disposal of produced waters (bribes)
What are class 4-2 wells
Injection wells
Use and fluid type for 1b
Disposal of: 1. Produced water specific oil field waste streams 3waste streams meeting certain criteria
(Only fluids from oil and gas)
Fluid: on list from regulations or tested against criteria
Use and fluid for 1a
Use: disposal of oilfield and industrial
(Only one that accepts non oil field waste)
Fluid: list in regs but still has to be tested no matter what
What type of well is 1a and 1b
Disposal wells
Chem criteria for dwi
- pH (4.5 to 12.5)
- doesn’t meet surface water discharge criteria
- Has non-halo organic frac less then 10%
- Has one or more halogenated organic compounds total combined [] less then 1000 mg/kg
- PCB [] less then 50mg/kg
Directive 51’s four key areas
- well bore integrity (containment of injected fluids to protect gw and conserve HC)
- Formations suitability for the disposal of fluids (make sure fluids are confined to zone)
3 waste stream suitability
- Reporting and manifest (cradle to grave)
Questions to ask about stream suitability
- Chem of waste stream compatible with disposal zone
2. Any waste management/disposal options more suitable for the disposal of these waste streams
What do packers do?
Isolate the annular fluids from injection fluids
What is a more common name for long string casing?
Production casing
True or false, surface casing should extend below base of all unstable gw zones
True
What is the annulus between
Casing and tubing
How do you get the well bore integrity
By testing and logging
When do you log and test wells
- Prior to any fluids being injected
- if requirements are not met then application is denied - During life of DWI
- to ensure hydraulic isolation
Initial log testing requirements
- Cement top location
- Hydraulic isolation logging
- Casing integrity log
- Initial pressure tests
Cement logging is for:
- Cement is used to hold the casing in place
2. To isolate various zones I.e. disposal zones or HC bearing aquifers
Hi is for
Hydraulic isolation of disposal zone
E.g.temp log, radioactive tracer log, oxygen activation log or cement integrity log
What is casing integrity log
Check for corrosion of casing
