Physical properties of sediment from the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope

William Winters; Michael Walker; Robert Hunter; Timothy Collett; Ray Boswell; Kelly Rose; William Waite; Marta Torres; Shirish Patil; Abhijit Dandekar

doi:10.1016/j.marpetgeo.2010.01.008

Physical properties of sediment from the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope

William Winters^*
, Michael Walker
, Robert Hunter
, Timothy Collett
, Ray Boswell
, Kelly Rose
, William Waite
, Marta Torres
, Shirish Patil
, Abhijit Dandekar

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

115 Scopus citations

Abstract

This study characterizes cored and logged sedimentary strata from the February 2007 BP Exploration Alaska, Department of Energy, U.S. Geological Survey (BPXA-DOE-USGS) Mount Elbert Gas Hydrate Stratigraphic Test Well on the Alaska North Slope (ANS). The physical-properties program analyzed core samples recovered from the well, and in conjunction with downhole geophysical logs, produced an extensive dataset including grain size, water content, porosity, grain density, bulk density, permeability, X-ray diffraction (XRD) mineralogy, nuclear magnetic resonance (NMR), and petrography.This study documents the physical property interrelationships in the well and demonstrates their correlation with the occurrence of gas hydrate. Gas hydrate (GH) occurs in three unconsolidated, coarse silt to fine sand intervals within the Paleocene and Eocene beds of the Sagavanirktok Formation: Unit D-GH (614.4. m-627.9. m); unit C-GH1 (649.8. m-660.8. m); and unit C-GH2 (663.2. m-666.3. m). These intervals are overlain by fine to coarse silt intervals with greater clay content. A deeper interval (unit B) is similar lithologically to the gas-hydrate-bearing strata; however, it is water-saturated and contains no hydrate.In this system it appears that high sediment permeability (k) is critical to the formation of concentrated hydrate deposits. Intervals D-GH and C-GH1 have average "plug" intrinsic permeability to nitrogen values of 1700 mD and 675 mD, respectively. These values are in strong contrast with those of the overlying, gas-hydrate-free sediments, which have k values of 5.7. mD and 49 mD, respectively, and thus would have provided effective seals to trap free gas. The relation between permeability and porosity critically influences the occurrence of GH. For example, an average increase of 4% in porosity increases permeability by an order of magnitude, but the presence of a second fluid (e.g., methane from dissociating gas hydrate) in the reservoir reduces permeability by more than an order of magnitude.

Original language	English
Pages (from-to)	361-380
Number of pages	20
Journal	Marine and Petroleum Geology
Volume	28
Issue number	2
DOIs	https://doi.org/10.1016/j.marpetgeo.2010.01.008
State	Published - Feb 2011
Externally published	Yes

Bibliographical note

Funding Information:
Melanie Holland, Peter Schultheiss, and Walter Barnhardt provided helpful reviews of the manuscript. Aditya Deshpande, University of Alaska at Fairbanks, assisted with minipermeameter measurements. BP was the designated operator for fieldwork. The drillers and staff at the well site are thanked for obtaining cores, performing logging runs, and providing logistical support under adverse conditions. This work was supported by the Coastal and Marine Geology, and Energy Programs of the U.S. Geological Survey and funding was provided by the Gas Hydrate Program of the U.S. Department of Energy.

Keywords

Gas hydrate
Grain size
Milne Point
Mineralogy
Permeability
Physical properties
Porosity
Sagavanirktok Formation

ASJC Scopus subject areas

Oceanography
Geophysics
Geology
Economic Geology
Stratigraphy

Access to Document

10.1016/j.marpetgeo.2010.01.008

Cite this

@article{fb430f2ea3c24de487f1a8d1d2f57857,

title = "Physical properties of sediment from the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope",

abstract = "This study characterizes cored and logged sedimentary strata from the February 2007 BP Exploration Alaska, Department of Energy, U.S. Geological Survey (BPXA-DOE-USGS) Mount Elbert Gas Hydrate Stratigraphic Test Well on the Alaska North Slope (ANS). The physical-properties program analyzed core samples recovered from the well, and in conjunction with downhole geophysical logs, produced an extensive dataset including grain size, water content, porosity, grain density, bulk density, permeability, X-ray diffraction (XRD) mineralogy, nuclear magnetic resonance (NMR), and petrography.This study documents the physical property interrelationships in the well and demonstrates their correlation with the occurrence of gas hydrate. Gas hydrate (GH) occurs in three unconsolidated, coarse silt to fine sand intervals within the Paleocene and Eocene beds of the Sagavanirktok Formation: Unit D-GH (614.4. m-627.9. m); unit C-GH1 (649.8. m-660.8. m); and unit C-GH2 (663.2. m-666.3. m). These intervals are overlain by fine to coarse silt intervals with greater clay content. A deeper interval (unit B) is similar lithologically to the gas-hydrate-bearing strata; however, it is water-saturated and contains no hydrate.In this system it appears that high sediment permeability (k) is critical to the formation of concentrated hydrate deposits. Intervals D-GH and C-GH1 have average {"}plug{"} intrinsic permeability to nitrogen values of 1700 mD and 675 mD, respectively. These values are in strong contrast with those of the overlying, gas-hydrate-free sediments, which have k values of 5.7. mD and 49 mD, respectively, and thus would have provided effective seals to trap free gas. The relation between permeability and porosity critically influences the occurrence of GH. For example, an average increase of 4\% in porosity increases permeability by an order of magnitude, but the presence of a second fluid (e.g., methane from dissociating gas hydrate) in the reservoir reduces permeability by more than an order of magnitude.",

keywords = "Gas hydrate, Grain size, Milne Point, Mineralogy, Permeability, Physical properties, Porosity, Sagavanirktok Formation",

author = "William Winters and Michael Walker and Robert Hunter and Timothy Collett and Ray Boswell and Kelly Rose and William Waite and Marta Torres and Shirish Patil and Abhijit Dandekar",

note = "Funding Information: Melanie Holland, Peter Schultheiss, and Walter Barnhardt provided helpful reviews of the manuscript. Aditya Deshpande, University of Alaska at Fairbanks, assisted with minipermeameter measurements. BP was the designated operator for fieldwork. The drillers and staff at the well site are thanked for obtaining cores, performing logging runs, and providing logistical support under adverse conditions. This work was supported by the Coastal and Marine Geology, and Energy Programs of the U.S. Geological Survey and funding was provided by the Gas Hydrate Program of the U.S. Department of Energy. ",

year = "2011",

month = feb,

doi = "10.1016/j.marpetgeo.2010.01.008",

language = "English",

volume = "28",

pages = "361--380",

journal = "Marine and Petroleum Geology",

issn = "0264-8172",

publisher = "Elsevier Ltd.",

number = "2",

}

TY - JOUR

T1 - Physical properties of sediment from the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope

AU - Winters, William

AU - Walker, Michael

AU - Hunter, Robert

AU - Collett, Timothy

AU - Boswell, Ray

AU - Rose, Kelly

AU - Waite, William

AU - Torres, Marta

AU - Patil, Shirish

AU - Dandekar, Abhijit

N1 - Funding Information: Melanie Holland, Peter Schultheiss, and Walter Barnhardt provided helpful reviews of the manuscript. Aditya Deshpande, University of Alaska at Fairbanks, assisted with minipermeameter measurements. BP was the designated operator for fieldwork. The drillers and staff at the well site are thanked for obtaining cores, performing logging runs, and providing logistical support under adverse conditions. This work was supported by the Coastal and Marine Geology, and Energy Programs of the U.S. Geological Survey and funding was provided by the Gas Hydrate Program of the U.S. Department of Energy.

PY - 2011/2

Y1 - 2011/2

N2 - This study characterizes cored and logged sedimentary strata from the February 2007 BP Exploration Alaska, Department of Energy, U.S. Geological Survey (BPXA-DOE-USGS) Mount Elbert Gas Hydrate Stratigraphic Test Well on the Alaska North Slope (ANS). The physical-properties program analyzed core samples recovered from the well, and in conjunction with downhole geophysical logs, produced an extensive dataset including grain size, water content, porosity, grain density, bulk density, permeability, X-ray diffraction (XRD) mineralogy, nuclear magnetic resonance (NMR), and petrography.This study documents the physical property interrelationships in the well and demonstrates their correlation with the occurrence of gas hydrate. Gas hydrate (GH) occurs in three unconsolidated, coarse silt to fine sand intervals within the Paleocene and Eocene beds of the Sagavanirktok Formation: Unit D-GH (614.4. m-627.9. m); unit C-GH1 (649.8. m-660.8. m); and unit C-GH2 (663.2. m-666.3. m). These intervals are overlain by fine to coarse silt intervals with greater clay content. A deeper interval (unit B) is similar lithologically to the gas-hydrate-bearing strata; however, it is water-saturated and contains no hydrate.In this system it appears that high sediment permeability (k) is critical to the formation of concentrated hydrate deposits. Intervals D-GH and C-GH1 have average "plug" intrinsic permeability to nitrogen values of 1700 mD and 675 mD, respectively. These values are in strong contrast with those of the overlying, gas-hydrate-free sediments, which have k values of 5.7. mD and 49 mD, respectively, and thus would have provided effective seals to trap free gas. The relation between permeability and porosity critically influences the occurrence of GH. For example, an average increase of 4% in porosity increases permeability by an order of magnitude, but the presence of a second fluid (e.g., methane from dissociating gas hydrate) in the reservoir reduces permeability by more than an order of magnitude.

AB - This study characterizes cored and logged sedimentary strata from the February 2007 BP Exploration Alaska, Department of Energy, U.S. Geological Survey (BPXA-DOE-USGS) Mount Elbert Gas Hydrate Stratigraphic Test Well on the Alaska North Slope (ANS). The physical-properties program analyzed core samples recovered from the well, and in conjunction with downhole geophysical logs, produced an extensive dataset including grain size, water content, porosity, grain density, bulk density, permeability, X-ray diffraction (XRD) mineralogy, nuclear magnetic resonance (NMR), and petrography.This study documents the physical property interrelationships in the well and demonstrates their correlation with the occurrence of gas hydrate. Gas hydrate (GH) occurs in three unconsolidated, coarse silt to fine sand intervals within the Paleocene and Eocene beds of the Sagavanirktok Formation: Unit D-GH (614.4. m-627.9. m); unit C-GH1 (649.8. m-660.8. m); and unit C-GH2 (663.2. m-666.3. m). These intervals are overlain by fine to coarse silt intervals with greater clay content. A deeper interval (unit B) is similar lithologically to the gas-hydrate-bearing strata; however, it is water-saturated and contains no hydrate.In this system it appears that high sediment permeability (k) is critical to the formation of concentrated hydrate deposits. Intervals D-GH and C-GH1 have average "plug" intrinsic permeability to nitrogen values of 1700 mD and 675 mD, respectively. These values are in strong contrast with those of the overlying, gas-hydrate-free sediments, which have k values of 5.7. mD and 49 mD, respectively, and thus would have provided effective seals to trap free gas. The relation between permeability and porosity critically influences the occurrence of GH. For example, an average increase of 4% in porosity increases permeability by an order of magnitude, but the presence of a second fluid (e.g., methane from dissociating gas hydrate) in the reservoir reduces permeability by more than an order of magnitude.

KW - Gas hydrate

KW - Grain size

KW - Milne Point

KW - Mineralogy

KW - Permeability

KW - Physical properties

KW - Porosity

KW - Sagavanirktok Formation

UR - https://www.scopus.com/pages/publications/78651439549

U2 - 10.1016/j.marpetgeo.2010.01.008

DO - 10.1016/j.marpetgeo.2010.01.008

M3 - Article

AN - SCOPUS:78651439549

SN - 0264-8172

VL - 28

SP - 361

EP - 380

JO - Marine and Petroleum Geology

JF - Marine and Petroleum Geology

IS - 2

ER -

Physical properties of sediment from the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope

Abstract

Bibliographical note

Keywords

ASJC Scopus subject areas

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