skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Semi-quantitative gas hydrate assessment from petroleum industry well logs in the northern Gulf of Mexico

Authors:
; ORCiD logo; ; ; ; ;
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1396510
Grant/Contract Number:
FE0009949
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Marine and Petroleum Geology
Additional Journal Information:
Journal Volume: 85; Journal Issue: C; Related Information: CHORUS Timestamp: 2017-10-04 09:14:41; Journal ID: ISSN 0264-8172
Publisher:
Elsevier
Country of Publication:
United Kingdom
Language:
English

Citation Formats

Majumdar, Urmi, Cook, Ann E., Scharenberg, Mackenzie, Burchwell, Andrew, Ismail, Samrya, Frye, Matthew, and Shedd, William. Semi-quantitative gas hydrate assessment from petroleum industry well logs in the northern Gulf of Mexico. United Kingdom: N. p., 2017. Web. doi:10.1016/j.marpetgeo.2017.05.009.
Majumdar, Urmi, Cook, Ann E., Scharenberg, Mackenzie, Burchwell, Andrew, Ismail, Samrya, Frye, Matthew, & Shedd, William. Semi-quantitative gas hydrate assessment from petroleum industry well logs in the northern Gulf of Mexico. United Kingdom. doi:10.1016/j.marpetgeo.2017.05.009.
Majumdar, Urmi, Cook, Ann E., Scharenberg, Mackenzie, Burchwell, Andrew, Ismail, Samrya, Frye, Matthew, and Shedd, William. 2017. "Semi-quantitative gas hydrate assessment from petroleum industry well logs in the northern Gulf of Mexico". United Kingdom. doi:10.1016/j.marpetgeo.2017.05.009.
@article{osti_1396510,
title = {Semi-quantitative gas hydrate assessment from petroleum industry well logs in the northern Gulf of Mexico},
author = {Majumdar, Urmi and Cook, Ann E. and Scharenberg, Mackenzie and Burchwell, Andrew and Ismail, Samrya and Frye, Matthew and Shedd, William},
abstractNote = {},
doi = {10.1016/j.marpetgeo.2017.05.009},
journal = {Marine and Petroleum Geology},
number = C,
volume = 85,
place = {United Kingdom},
year = 2017,
month = 8
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on May 12, 2018
Publisher's Accepted Manuscript

Save / Share:
  • The northern Gulf of Mexico has been the target for the petroleum industry for exploration of conventional energy resource for decades. We have used the rich existing petroleum industry well logs to find the occurrences of natural gas hydrate in the northern Gulf of Mexico. We have identified 798 wells with well log data within the gas hydrate stability zone. Out of those 798 wells, we have found evidence of gas hydrate in well logs in 124 wells (15% of wells). We have built a dataset of gas hydrate providing information such as location, interval of hydrate occurrence (if any)more » and the overall quality of probable gas hydrate. Our dataset provides a wide, new perspective on the overall distribution of gas hydrate in the northern Gulf of Mexico and will be the key to future gas hydrate research and prospecting in the area.« less
  • In 2009, the Gulf of Mexico (GOM) Gas Hydrates Joint-Industry-Project (JIP) Leg II drilling program confirmed that gas hydrate occurs at high saturations within reservoir-quality sands in the GOM. A comprehensive logging-while-drilling dataset was collected from seven wells at three sites, including two wells at the Walker Ridge 313 site. By constraining the saturations and thicknesses of hydrate-bearing sands using logging-while-drilling data, two-dimensional (2D), cylindrical, r-z and three-dimensional (3D) reservoir models were simulated. The gas hydrate occurrences inferred from seismic analysis are used to delineate the areal extent of the 3D reservoir models. Numerical simulations of gas production from themore » Walker Ridge reservoirs were conducted using the depressurization method at a constant bottomhole pressure. Results of these simulations indicate that these hydrate deposits are readily produced, owing to high intrinsic reservoir-quality and their proximity to the base of hydrate stability. The elevated in situ reservoir temperatures contribute to high (5–40 MMscf/day) predicted production rates. The production rates obtained from the 2D and 3D models are in close agreement. To evaluate the effect of spatial dimensions, the 2D reservoir domains were simulated at two outer radii. The results showed increased potential for formation of secondary hydrate and appearance of lag time for production rates as reservoir size increases. Similar phenomena were observed in the 3D reservoir models. The results also suggest that interbedded gas hydrate accumulations might be preferable targets for gas production in comparison with massive deposits. Hydrate in such accumulations can be readily dissociated due to heat supply from surrounding hydrate-free zones. Special cases were considered to evaluate the effect of overburden and underburden permeability on production. The obtained data show that production can be significantly degraded in comparison with a case using impermeable boundaries. The main reason for the reduced productivity is water influx from the surrounding strata; a secondary cause is gas escape into the overburden. The results dictate that in order to reliably estimate production potential, permeability of the surroundings has to be included in a model.« less
  • A unique set of high-quality downhole shallow subsurface well log data combined with industry standard 3D seismic data from the Alaminos Canyon area has enabled the first detailed description of a concentrated gas hydrate accumulation within sand in the Gulf of Mexico. The gas hydrate occurs within very fine grained, immature volcaniclastic sands of the Oligocene Frio sand. Analysis of well data acquired from the Alaminos Canyon Block 818 No.1 ('Tigershark') well shows a total gas hydrate occurrence 13 m thick, with inferred gas hydrate saturation as high as 80% of sediment pore space. Average porosity in the reservoir ismore » estimated from log data at approximately 42%. Permeability in the absence of gas hydrates, as revealed from the analysis of core samples retrieved from the well, ranges from 600 to 1500 millidarcies. The 3-D seismic data reveals a strong reflector consistent with significant increase in acoustic velocities that correlates with the top of the gas-hydrate-bearing sand. This reflector extends across an area of approximately 0.8 km{sup 2} and delineates the minimal probable extent of the gas hydrate accumulation. The base of the inferred gas-hydrate zone also correlates well with a very strong seismic reflector that indicates transition into units of significantly reduced acoustic velocity. Seismic inversion analyses indicate uniformly high gas-hydrate saturations throughout the region where the Frio sand exists within the gas hydrate stability zone. Numerical modeling of the potential production of natural gas from the interpreted accumulation indicates serious challenges for depressurization-based production in settings with strong potential pressure support from extensive underlying aquifers.« less
  • Hydrate-bearing sands are being actively explored because they contain the highest concentrations of hydrate and are the most economically recoverable hydrate resource. However, relatively little is known about the mechanisms or timescales of hydrate formation, which are related to methane supply, fluid flux, and host sediment properties such as permeability. We used logging-while-drilling data from locations in the northern Gulf of Mexico to develop an effective medium theory-based model for predicting permeability based on clay-sized sediment fraction. The model considers permeability varying between sand and clay endpoint permeabilities that are defined from laboratory data. We verified the model using permeabilitymore » measurements on core samples from three boreholes, and then used the model to predict permeability in two wells drilled in Walker Ridge Block 313 during the Gulf of Mexico Gas Hydrate Joint Industry Project Leg II expedition in 2009. We found that the cleanest sands (clay-sized fraction <0.05) had intrinsic (hydrate-free) permeability contrasts of 5-6 orders of magnitude with the surrounding clays, which is sufficient to provide focused hydrate formation due to advection of methane from a deep source or diffusion of microbial methane from nearby clay layers. In sands where the clay-sized fraction exceeds 0.05, the permeability reduces significantly and focused flow is less pronounced. In these cases, diffusion of dissolved microbial methane is most likely the preferred mode of methane supply for hydrate formation. In conclusion, our results provide important constraints on methane supply mechanisms in the Walker Ridge area and have global implications for evaluating rates of methane migration and hydrate formation in hydrate-bearing sands.« less