APPENDIX G HYDROSTATIC TEST PLAN

Transcription

1 APPENDIX G HYDROSTATIC TEST PLAN

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3 Preliminary Hydrostatic Test Plan for the Proposed North Montney Project Prepared for: NOVA Gas Transmission Ltd. Calgary, Alberta Prepared by: Stantec Consulting Ltd. Calgary, Alberta

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5 1.0 Introduction Pressure testing is required to prove integrity of new pipelines before they are commissioned. Hydrostatic testing is the most common pressure testing method and follows the requirements of Canadian Standards Association (CSA) Z662 - Oil and Gas Pipeline Systems. This national standard stipulates test pressures, test durations and other engineering requirements. This report identifies the preliminary water sources for hydrostatic testing for the two sections of the North Montney Project (the Project). Hydrostatic testing of new pipelines is undertaken following completion of backfilling the trench. Prior to filling the pipeline with water, a cleaning pig is often run through the test section to remove any debris (e.g., welding debris, dirt) from the pipeline. The pipeline test section is then filled with test water. After the pipe is filled, additional water is added to the pipeline with a squeeze pump to reach the desired test pressure. The volume of water needed for a test depends on the length of the test section, diameter of the pipe, and season of testing. Heated water is used for winter testing to avoid freezing of the test medium due to low ground and ambient temperatures. A water-methanol solution may be used in the winter to avoid freezing during above ground testing. If a suitable water source is not crossed by the pipeline, a temporary water fill line is laid on the surface from a nearby water source to the fill point. Trucking water to the test pipeline would be considered. Water sources commonly include rivers, lakes, ponds, dugouts, borrow pits, wells and municipal water supplies. Long sections of new pipelines are divided into smaller test sections that vary in length depending upon the topography traversed and construction season. Pipeline sections that encounter relatively level terrain or tested in the summer are typically longer than test sections with substantial changes in elevation or those tested in the winter. Water is commonly shunted along the pipeline from one test section to another in order to minimize water requirements. Hydrostatic testing starts when the pressure reaches the appropriate test pressure stipulated by federal/provincial requirements and CSA Z662. Test pressure and duration vary, depending upon the type of product to be transported. If the pressure meets testing requirements, the test is deemed successful and the test section can be depressurized. The test water is commonly removed from the new pipeline using a pig that is pushed with compressed air. If the test does not maintain the required test pressures throughout the required period, this indicates there may be a leak. The pipeline is then exposed and an investigation is conducted in order to determine method of repair. G.1

6 2.0 Regulatory Requirements The regulatory requirements for temporary water use in British Columbia are established by the provincial Water Act and Water Regulation. Water withdrawals for hydrostatic testing require less than 24 months and therefore these approvals fall under Section 8 of the Water Act. For NEB regulated pipelines, the Oil and Gas Commission reviews and approves the application. The Oil and Gas Waste Regulations (OGWR) under the Environmental Management Act regulates specific waste discharges associated with pipelines, including water and water/chemical mixes utilized for hydrostatic testing. Section 7(2)(e) of the OGWR authorizes discharge of hydrostatic test water to land without written approval if the requirements outlined below are met. Before Discharge 1. Water must be analyzed to ensure that these parameters are not exceeded. Parameter Chlorides (as Cl) Hydrocarbons Electrical Conductivity Value 500 mg/l No visible sheen 2 ds/m ph 6.5 to 8.5 A Microtox photobacteria bioassay is required if the water used for testing contains methanol, ethylene glycol, or other additives. The Microtox bioassay results must have an EC(50)15 of 75% or greater. 2. Obtain written consent of landowner (if discharging onto private land). During Discharge 1. Volumes of water discharged must be recorded. 2. Minimize erosion or other movement of soil and debris. 3. Discharge at a controlled rate to ensure that water does not pool on the ground. 4. Do not discharge into any watercourse or waterbody, or where discharge can run into any watercourse or waterbody. 5. Discharge onto stable slopes. G.2

7 After Discharge 1. Maintain records of discharge for five years. 2. Allow officer to inspect records if requested (do not submit to BC Ministry of Environment [MOE] unless requested to do so). 3.0 Hydrostatic Test Program Details The following section provides preliminary hydrostatic test details for the proposed pipeline sections. Winter water availability information for each potential water source was estimated using hydrometric data from publically available HYDAT Database (Environment Canada 2014) and measurements from completed field studies (TERA 2014a/b). The winter period is defined here as November 1 st to March 31 st. Where no hydrometric data existed for potential water sources, winter flows were estimated from empirical relationships between drainage area and mean daily discharge, and drainage area and 7Q10 flow. These relationships were used to provide a coarse estimate of potential mean daily and minimum (7Q10) winter flow volumes. The calculated volumes are based on the assumption that the hydrological processes operating at a regional scale are similar in smaller basins. In addition, existing water licence allocations were considered (BC MFLNRO 2014). 3.1 AITKEN CREEK SECTION The Aitken Creek section is anticipated to be tested in 11 sections with water shunted from test section to test section to the extent practical (Figure 1). To determine the nearest and most reliable water source for the Aitken Creek section six waterbodies were reviewed: Pine River Moberly River Peace River Halfway River Cameron River Davies Lake Based on access and water availability, a number of preliminary water sources were identified. Table 1 identifies the sources, their locations and the volumes required for the hydrostatic test program. The hydrostatic test details will be finalized following field verification of water availability, obtaining Section 8 water withdrawal permits and consultation with the pipeline contractor. G.3

8 Table 1 Aitken Creek Hydrostatic Test Details 1 & 2 3 to 5 6 to 8 9 to 11 Location Pine River Peace River Halfway River Halfway River Method Submersible pump screened with cage intake screened with cage intake screened with cage intake screened with cage intake Water Transport Method Overland water pipe or truck Overland water pipe or truck Overland water pipe or truck Overland water pipe or truck Test Medium Water Water Water Water Approximate Volume (m 3 ) 9,500 30,000 23,000 22,000 Date of Activities Q Dewater Dewatering onto stable, well vegetated ground in accordance with BC OGWR Water sources for the Aitken Creek section will be accessed from the right-of-way (ROW). If fill lines are required outside of the ROW, the fill line routes will be assessed as part of the supplemental field program and the findings filed in June KAHTA SECTION The Kahta section is anticipated to be tested in eight sections with water shunted from test section to test section to the extent practical (Figure 1). To determine the nearest and most reliable water source for the Kahta section six waterbodies were reviewed: Beatton River Lily Lake Duhu (Lifeline) Lake Sikanni Chief River Buckinghorse River Mason Lake G.4

9 Based on access and water availability, a number of preliminary water sources were identified. Table 2 identifies the sources, their locations and the volumes required for the hydrostatic test program. The hydrostatic test details will be finalized following field verification of water availability, obtaining Section 8 water withdrawal permits and consultation with the pipeline contractor. Table 2 Kahta Hydrostatic Test Details 1 to 4 TEST SECTION 5 6, 7 & 8 Location Lily Lake and/or Sikanni Chief River Lily Lake and/or Sikanni Chief River Lily Lake and/or Buckinghorse River Method screened with cage intake screened with cage intake screened with cage intake Water Transport Method Overland water pipe or truck Overland water pipe or truck Overland water pipe or truck Test Medium Water Water Water Approximate Volume (m 3 ) 28,000 9,100 17,000 Date of Activities Q and Q Dewater Dewatering onto stable, well vegetated ground in accordance with BC OGWR. Water sources from the Sikanni Chief River and Buckinghorse River will be accessed from the ROW. Overland fill line that is located outside of the ROW will be used to transport water from Lily Lake to the ROW. Fill lines will be removed immediately following completion of testing. The fill line routes will be assessed as part of the supplemental field program and the findings filed in June In addition, a location for a dugout has been identified to support, if required, the pressure testing of Test Sections 5 to 8 on the Kahta section. Lily Lake is proposed as a primary water source to fill the dugout, water would be trucked from Lily Lake to the dugout, stored and later used for the corresponding test sections. G.5

10 4.0 Effects and Mitigation Measures Potential effects associated with hydrostatic testing, as well as specific mitigation measures, have been discussed in Section 8.7 of the EPP, and sections , , and Table 12-5 of the ESA. Overall, all hydrostatic testing activities will be conducted in accordance with the NEB Onshore Pipeline Regulations, DFO guidelines, provincial regulations, the latest version of CSA Z662, as well as the Section 8 Water Act approval and any other applicable permits for water withdrawals. The fill line routes will be assessed as part of the supplemental field program and the findings filed in June G.6

11 5.0 References British Columbia Ministry of Forests, Lands and Natural Resource Operations (BC MFLNRO) Water Licence Web Query. Available at: Environment Canada HYDAT Database. Available at: TERA Environmental Consultants Ltd. (TERA). 2014a. Supplemental Aquatics Summary Report for the Proposed NOVA Gas Transmission Ltd. North Montney Project. March TERA Environmental Consultants Ltd. (TERA). 2014b. Supplemental Winter Aquatic Habitat Investigations for the Proposed NOVA Gas Transmission Ltd. North Montney Project. Draft. April 1, G.7