1 / 29

Engineering Geology for Gas Pipelines in the Green River Area

Engineering Geology for Gas Pipelines in the Green River Area. Prepared By: John Blair Sean Donahue Celeste Hoffman Kimberly Klinkers Megan Slater. Green River Basin Location. Green River Basin Stratigraphic Correlation Chart showing Study Map Units.

khanh
Download Presentation

Engineering Geology for Gas Pipelines in the Green River Area

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Engineering Geology for Gas Pipelines in the Green River Area Prepared By: John Blair Sean Donahue Celeste Hoffman Kimberly Klinkers Megan Slater

  2. Green River Basin Location

  3. Green River Basin Stratigraphic Correlation Chart showing Study Map Units

  4. Sample of Existing Pipelines and Proposed Pipelines

  5. Gas Fields in the Green River Basin

  6. Pipeline Installation Process • Clearing and grading • Stringing pipes along right of way • Excavating/trenching • Pipe bending, welding, and coating • Lower Pipe into trench • Back fill • Restoration

  7. Geologic Hazards • Geologic Hazards are natural physical conditions that exist and if they were to become active could damage structures as well as injure people. These hazards include. • Fault Crossings • Subsidence • Slope stability • Hydrogeology • Environmental Constraints

  8. What is the importance? • Safety of the general public. • Pipelines stay safe and operational. • Pipeline failure is a serious environmental concern.

  9. Region • The area is composed of several faults. • Most of the Mountain Ranges were formed in the Eocene Era • Green River Basin is surrounded on all sides by mountains. • Wind River Mountains-North • Front Range, Park Range and Sawatch Range of Rockies -East • San Juan Volcanic Field-South • Wasatch Mountains-West

  10. Pipelines and Fault Crossings • Due to the numerous active faults and numerous pipelines, several of these intersect. • This provides potential breaking of pipelines due to movement of faults

  11. Construction of Pipelines • To protect from this, all pipelines are built of steel and treated with a protective coating. • The pipeline is carefully inspected to make sure it meets all safety requirements. • In fault zones pipes are padded with fill material to dampen vibrations and minimize damage.

  12. Safety Considerations • If there is a break in the line, a high-tech computer monitoring system can detect a loss in pressure due to a leak and shut off all access to the length of pipe where a leak is detected. This system is monitored 24 hours a day 7 days a week • Inspections occur in the pipelines through camera inspections

  13. Subsidence • Subsidence is the downward motion of the earths surface relative to a datum. Causes of subsidence: • Mining induced from “caving” in of excavated material • Dissolution of Limestone • Extraction of Natural Gas • Groundwater changes

  14. Subsidence Damage • Subsidence causes a loss of support for the pipeline. • Damage may inhibit the functionality of the pipeline as a result of Structural damage.

  15. Slope Stability Issues-Landslides • Landslides according the USGS are the upward and downward movement of earth materials on a slope. • Causes of Landslide include: • Steep Slopes • Wildfires • Earthquakes • Hydrological Events • Human causes • End Result • Loss of Foundation Support

  16. Landslides-Steep Slopes • Steep slopes constrain where a pipeline line can be placed cost effectively. • Slopes greater than 30 degrees are highly susceptible to failure. • Erosion becomes a significant issue

  17. Landslides • Wildfires • Prevalent in the Green River Basin • De-vegetates the slope, which in turn reduces stability • Earthquakes • Soil liquefaction due to shaking of ground • Cohesion less soils are prone to liquefaction as well as soils the are unconsolidated.

  18. Landslides • Hydrologic Events • Heavy precipitation • Flooding • Human caused • Clearing and grading before pipeline installation • Blasting when bedrock is present

  19. Wyoming Climate • 5th driest state • 2nd highest state • Mountains • Provide majority of surface water • Snow and runoff • Deserts and plains • House groundwater • Aquifers recharged from surface water

  20. Groundwater Resources • Unconsolidated deposits • Alluvial deposits • Eolian sand/silt deposits • Glacial deposits • Lacustrine deposits • Bedrock formations • Sandstone • Limestone • Results in aquifer development “Water-saturated portion of an unconsolidated deposit or geologic bedrock formation which may yield usable quantities and qualities of groundwater through springs and/or wells”

  21. Groundwater Resources • Water wells withdraw groundwater from aquifers to • Monitor water levels and water quality • Discharge through alluvial deposits and bedrock formations • Springs naturally withdraw groundwater from saturated aquifers

  22. Environmental Constraints Weather: • Heavy rainfall and snowmelt paired with limited drainage of the valley can cause flash flood conditions • Snowstorms are frequent from November through May • Wind frequently follows snowfall • Wind can cause extreme cases of drift • High winds and the low temperature of the valley can cause blizzard or near blizzard conditions • Destructive hailstorms occasionally pass over the valley

  23. Environmental Constraints Temperature Concerns: • Winters are Long and Cold • Low overnight temperatures due to cold air collection in the valley can cause freezing issues • Valley temperatures can be considerably lower than surrounding mountainsides • Often valley temperatures are well below zero in the winter months

  24. Environmental Constraints Impacts of the Environment: • Snow, rain and hail all have an effect on slope stability in the valley region • High wind storms and hail storms can damage above ground piping • Low temperatures can cause freezing of the groundwater causing additional stresses on buried pipes

  25. Environmental Constraints Impacts ON the Environment: • Pipe ruptures leak gas • If ruptures flare (left) they can cause a great deal of damage to the surroundings • This also produces a lot of air pollution from the smoke • This can be very dangerous to both humans and animals alike • The excavation required for drilling and laying pipelines is very disruptive to the environment • Animal habitats can be damaged • Construction pollutes area • Soil and slope conditions are changed

  26. References • http://www.dom.com/about/gas-transmission/covepoint/expansion/construction.jsp • http://www.wsgs.uwyo.edu/surficial/ • http://3dparks.wr.usgs.gov/landslide/types.htm • http://www.esa.int/esaCP/SEMX4QVLWFE_index_1.html • http://www.fieldmuseum.org/expeditions/lance/map.html • http://skytruth.mediatools.org/gallery/270 • http://www.wrds.uwyo.edu/sco/climate/wyoclimate.html • http://www.wsgs.uwyo.edu/hydrology/ • http://www.canadiandiscovery.com/PDF/Green-River-Basin.pdf • http://waterplan.state.wy.us/plan/green/techmemos/gwdeterm.html • http://en.wikipedia.org/wiki/Green_River_Formation • http://www.geology.wisc.edu/~unstable/Sedimentary/Green_River_Basin.jpg

More Related