| Question | Why do the water limits apply only to thermal in situ oil sands schemes? |
| Answer | Thermal in situ oil sands operations are targeted by this directive because they are large facilities that can use large quantities of make-up water, have significant energy consumption, and may have large disposal volumes. Setting limits will ensure that operators optimize water use and energy efficiencies, while minimizing water disposal.
The limits and requirements in the directive cannot be applied to mineable oil sands and conventional oil projects because the recovery methods are different.
Water conservation and recycling requirements have been in place for in situ oil sands schemes since 1989 (see ERCB Informational Letter 89-05). This directive builds upon the regulatory initiative that began in the 1980s to address the very large predicted impacts on fresh water resources that may have occurred if no water recycling was conducted.
This directive represents one step towards achieving an overall provincial target of a 30 per cent improvement in water efficiency and productivity by 2015 (from a 2005 baseline), as set out in Water for Life: Alberta’s Strategy for Sustainability. The Water for Life initiative includes the development of water conservation and productivity plans and the establishment of targets for improved efficiency for all water use sectors. |
| Question | Why does this directive use the term “brackish” water rather than “saline” water? |
| Answer | Brackish water is the term used in the Petroleum Registry of Alberta (the “Registry”) for saline groundwater. Since most of the volumetric reporting and corresponding water balance calculations rely on Registry data, this directive uses Registry terminology. |
| Question | Why does the directive introduce three new water use formulas, rather than continuing to use the recycle rate formula provided in Appendix A of ERCB Bulletin 2006-11: Water Recycle, Reporting, and Balancing Information for In Situ Thermal Schemes? |
| Answer | The recycle rate formula that current ERCB scheme approval requirements are based on did not contemplate the use of brackish water for steam injection and assumes zero reservoir retention.
The new water use formulas provide an unambiguous assessment of fresh and brackish make-up water use as a percentage of the total water consumed at a thermal scheme, and they set achievable limits to each based on current technology and historical data. Significant advances in water treatment enabling the use of brackish water supplies to generate steam have been incorporated into the new requirements.
|
|
TOP
|
| Question | Why are the water use limits based on annual use, rather than monthly? |
| Answer | A calendar-year usage limit recognizes the variation in plant operations from month to month and provides operators the flexibility to deal with short-term variations, while still meeting the annual water use limits. Monitoring will be ongoing on a monthly basis to identify problems and follow up with operators to ensure that the annual limits are met.
Annual water diversion volumes are set in the water licences issued under the Water Act by AENV. This will provide consistency between water allocation and water use requirements.
|
| Question | How was the limit of 10 per cent annual fresh water make-up chosen? |
| Answer | The 10 per cent fresh water limit is consistent with the 90 per cent produced water recycle rate currently required in most thermal scheme approvals. This recycle rate was based on historical data from pilot and commercial scheme information and is achievable using current technology. This level of water make-up accommodates water losses, such as moderate levels of reservoir retention and boiler blowdown. |
|
TOP
|
| Question | Why is a 10 per cent fresh water make-up limit required even in areas that have excess surface and groundwater capacity? |
| Answer | Minimizing fresh water use is a cornerstone of AENV’s oilfield injection policy. By imposing a 10 per cent fresh water make-up limit, the directive requires operators of thermal schemes to maximize water recycle, minimize water disposal, and ensure that all plants are operated using good water management practices. |
| Question | Why is there a need for a brackish water make-up limit, and is this consistent with AENV’s Oilfield Injection Policy, which requires operators to use brackish water rather than fresh when it is feasible to do so? |
| Answer | Although the Oilfield Injection Policy encourages operators to use brackish water as an alternative to fresh, the intent is not to use it as an alternative to produced water recycle. Restricting the use of brackish water at a facility will help to ensure that the recycle of produced water is maximized and the disposal of produced water is minimized.
In the absence of a limit, thermal schemes with access to brackish water could reduce the recycle of produced water and make up the difference with brackish water, which in most cases is easier to treat than produced water. This is undesirable for the following reasons:
• Even with heat exchangers, a significant heat loss is associated with disposal of the hot produced water from a thermal scheme. Recycling ensures that the heat from produced water is conserved by staying within the process.
• In the Athabasca and Cold Lake Oil Sands Areas, disposal zones are usually shallow, and finding zones with disposal potential and adequate containment can be challenging. Recycling of produced water decreases the need for disposal.
• As in situ schemes expand and proliferate, the competition for limited brackish water reserves will grow. Brackish water and fresh water must both be conserved and reused to ensure future supplies. It is essential that all uses of water are sustainable and efficient. |
|
TOP
|
| Question | How was the limit of 25 per cent total water (i.e., fresh + brackish) make-up chosen? |
| Answer | This limit allows for brackish water make-up as high as 25 per cent (if no fresh water is being used). Existing steam-assisted gravity drainage (SAGD) operations are expected to fall within this total water make-up limit, based on historical and projected data. Cyclic steam stimulation (CCS) operations have larger reservoir retention due to higher pressure injection, but are also expected to achieve the requirements with proper water management and steaming strategy. The larger brackish water limit allows flexibility in cases where moderate to significant levels of reservoir retention and increased water treatment waste resulting from higher total dissolved solids levels in the brackish water. |
| Question | How does this directive deal with the possible future use of waste water within a thermal scheme? |
| Answer | The 2006 Water Conservation and Allocation Guideline for Oilfield Injection requires operators to investigate the feasibility of using alternatives to fresh water. In this regard, the possible use of waste water from outside sources will continue to be investigated by AENV and the ERCB and may be addressed more fully in subsequent revisions to the directive. |
| Question | Since this is a joint ERCB-AENV directive, who will be responsible for its enforcement? |
| Answer | The ERCB and AENV will share responsibility for enforcement of the directive. Generally, the ERCB will conduct surveillance and enforcement on the measurement, accounting, Registry reporting, and facility water balance requirements of the directive. Surveillance and enforcement of water use limits may be conducted by both the ERCB and AENV, and decisions under Section 8 of the directive for relaxation of enforcement will be made jointly. |
|
TOP
|
| Question | How will this directive affect non-saline groundwater and surface water allocation licences, current and future? |
| Answer | Existing water allocations may be revised by AENV at term renewal of water licences to be consistent with the water balance and directive limits. In addition, the ERCB and AENV will consult on decisions regarding water use at thermal facilities, including water licence applications and thermal scheme applications. |
| Question | Under what circumstances will this directive be subject to future revisions?
|
| Answer | As a joint directive of the ERCB and AENV, revisions will only occur with both organizations agreeing to them. Ongoing revisions will occur in order to keep this directive relevant. |
|
TOP
|
| Question | What approach will be taken with thermal in situ oil sands schemes that have integrated upgraders? |
| Answer | As there are only a few cases currently using or proposing to use integrated upgraders, this situation is not addressed in this edition of the directive. At this time, upgraders are considered separate for the purpose of water transfers and use. The water use limits do not include water volumes consumed at upgraders. |
| Question | Why does the directive allow existing schemes up to one year from the issuance of the directive to meet the water measurement requirements and up to five years to meet the water use limits? |
| Answer | Because these schemes were approved prior to the issuance of the directive, some facilities may need to make changes in order to comply. A one-year time period is considered reasonable for operators to implement metering changes to existing facilities. A five-year time period allows for the more significant changes to existing water treatment and recycle facilities and changes to operational strategies that may be necessary to meet the water use limits. |
|
TOP
|
| Question | What is considered an “existing scheme” by the directive for determining if the water use limits are effective immediately or within five years? |
| Answer | All schemes approved prior to the issuance of the directive will be considered existing schemes, even if not yet constructed. |
| Question | Why is there a need for greater accuracy requirements for measurement of water and steam at thermal in situ schemes than has historically been required for conventional oil operations? |
| Answer | Thermal schemes have complex and costly water management operations involving the tracking and balancing of many water streams; therefore accurate measurement is critical. In addition, effective monitoring and enforcement of the water use limits require accurate measurement and reporting |
| Question | Why do fresh, brackish, and produced water streams entering a thermal facility have to be measured separately? |
| Answer | Allowing these water streams to be mixed prior to measurement would make it impossible to accurately determine the individual water make-up streams and to effectively enforce the directive’s water use limits. |
|
TOP
|
| Question | Why don’t the directive water use limits apply to facilities using less than 500 000 m3/year of make-up water in the absence of produced water recycle? |
| Answer | A water use of less than 500 000 m3/year is typical for a small thermal pilot or experimental scheme. These schemes are of short duration compared to commercial schemes. AENV and the ERCB encourage the use of pilots so that operators can gain valuable site-specific experience prior to going to a full commercial-sized scheme. Experimental schemes are encouraged in order to develop new technologies for improving resource recovery and optimizing scheme efficiencies. Applying the water use limits to these short-lived schemes would require them to construct costly water recycle facilities that may discourage the use of these types of schemes. |
| Question | Why does the directive’s threshold of 500 000 m3 /year include the condition “in the absence of recycle”? |
| Answer | The exemption from the water use limits does not apply to schemes that recycle only enough produced water so that their total make-up water drops below 500 000 m3/year. |
|
TOP
|
| Question | Will pilot schemes and experimental schemes that have decided to recycle their produced water be subject to the water use limits in the directive? |
| Answer | Only if these schemes would use more than 500 000 m3/year of make-up water in the absence of recycle. |
| Question | What information will be published on the ERCB and AENV Web sites? |
| Answer | The exact details of data to be made available to the public have not yet been determined. However, we will report on progress made regarding the directive’s goals. No confidential experimental scheme data will be published. |
|
TOP
|
|
DEFINITIONS
|
| Boiler Blowdown | Typically, a steam generator can only convert about 75 to 80 per cent of its feed water to steam. The water not converted to steam is called blowdown and usually contains all of the impurities contained in the boiler feed water. Depending on the boiler feed water quality, from 60 to 80 per cent of the blowdown can be treated and recycled, with the remainder being disposed. Zero-liquid discharge technology used by some operators has eliminated blowdown. |
| Cold Water Equivalent | All injected water and steam volume measurements corrected to a standard temperature of 15oC and reported in cubic metres (m3). |
Cyclic Steam Stimulation (CSS) | A bitumen recovery process whereby steam is injected into a vertical or horizontal well, typically at the reservoir fracture pressure. During the injection cycle, fracturing the reservoir allows the steam to move rapidly out into the reservoir to deliver heat to the bitumen to reduce its viscosity and allow it to flow easily. During the production cycle, the bitumen is produced to surface using the same well. |
| Produced Water | Water produced from wells in conjunction with hydrocarbons. |
| Registry | The Petroleum Registry of Alberta, an Internet-accessed database of key petroleum-related production and injection information. The Registry also tracks the movement of fluids and gases from wells to facilities and between facilities. |
| Reservoir Retention | The difference between the steam injected into and the water produced from the bitumen reservoir. For a scheme, the reservoir retention as a percentage of the steam injected can be determined from volumetric data reported to the Registry. Positive reservoir retention will result in the need for make-up water for steam injection, even if all of the produced water is recycled. |
| Saline Groundwater | Saline groundwater is defined in Part 1(1)(z) of the Alberta Water (Ministerial) Regulation, May 6, 1999: “saline groundwater means water that has total dissolved solids exceeding 4000 milligrams per litre.” |
| Steam-Assisted Gravity Drainage (SAGD) | A bitumen recovery process whereby steam is injected into a horizontal well to deliver heat to the bitumen in order to reduce its viscosity so it can flow easily. Gravity then causes the bitumen to flow down to a horizontal producer positioned below the injector so it can be produced to surface. |
| Thermal In Situ Oil Sands Schemes | Approved developments that use heat to reduce the viscosity of bitumen so that it will flow and can be produced from wells drilled for that purpose. Most thermal schemes in Alberta inject steam to deliver heat to the bitumen reservoir. |
| Total Water Consumed | Water is consumed at a thermal in situ scheme by either injection as steam into a bitumen reservoir or by disposal into a saline aquifer. In either case, the water is assumed to be lost unless it is subsequently produced, treated, and recycled. |
