Simulation Study on UBGH2-6 Deposit in the Ulleung Basin Considering Hydrate Bearing Sediments and Saturation Distribution Characteristics

Young Min Kim; Won Suk Lee

doi:10.32390/ksmer.2022.59.1.069

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2022 Vol.59, Issue 1 Preview Page Next Page

Research Paper

Simulation Study on UBGH2-6 Deposit in the Ulleung Basin Considering Hydrate Bearing Sediments and Saturation Distribution Characteristics 동해 울릉분지 UBGH2-6 하이드레이트 지층 및 포화율 분포 특성을 고려한 시뮬레이션 연구

28 February 2022. pp. 69-90

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Abstract

Reservoir simulation models with a heterogeneous distribution of hydrate saturation were built based on the complex geology model of the UBGH2-6 deposit in the Ulleung Basin, Korea. Because of the hydrate production by the depressurization method, 74.6% of the cumulative gas production was produced from a thin layer (less than 0.2 m) with low hydrate saturation. A reservoir simulation was performed to evaluate the effect of hydrate saturation and thin-layer structure on gas production. In the case of homogeneous distribution of hydrate saturation, the gas can be produced from all sand layers because of the increasing effective permeability with decreasing hydrate saturation. Production analysis based on various thin layer structures revealed a decrease in the cumulative gas production by 40% after removal of a thin layer with thickness of 0.1 m from the base model. As the radius of the thin layer increases, the hydrate dissociation front can be propagated more by increasing the influence radius of the bottomhole pressure. Considering the proportion of gas production in the thin layers, a detailed investigation of thin layers as the production target is required to establish a strategy for gas hydrate production in the UBGH2-6 deposit.

Keywords

Ulleung basin

Gas hydrate

Depressurization

Hydrate saturation

Thin layer

본 연구에서는 동해 울릉분지 UBGH2-6의 세부지층모델을 기반으로 불균질 하이드레이트 포화율을 갖는 저류층 기본모델을 구축하였다. 감압법 적용 결과, 누적 가스 생산량의 74.6%가 하이드레이트 포화율이 낮은 박층(0.2 m 이하)에 편중되었다. 하이드레이트 포화율과 박층 구조가 가스 생산에 미치는 영향을 분석하기 위해 저류층 시뮬레이션을 수행하였다. 하이드레이트 포화율이 균질한 모델에서는 포화율이 감소함에 따라 유효 투과도가 증가하여 모든 사질에서 가스 생산이 발생하였다. 다양한 박층 분포 시나리오에 따른 분석 결과, 두께가 0.1 m인 박층을 기본모델에서 삭제하면 누적 가스 생산량이 40%까지 감소하였으며, 박층의 분포범위가 길어질수록 공저압 영향반경을 증가시켜 하이드레이트 해리면 전파가 확장되었다. 박층에서의 가스생산량 비중을 고려하였을 때, UBGH2-6 가스하이드레이트 생산 전략 수립에 있어 생산 목표층으로의 박층에 대한 보다 세밀한 규명이 필요함을 알 수 있다.

키워드

울릉분지

가스하이드레이트

감압법

하이드레이트 포화율

박층

References

Huang, L., Zheng, S., Wu, N., and Cheng, J., 2016. Analysis on geologic conditions affecting the performance of gas production from hydrate deposits, Marine and Petroleum Geology, 77, p.19-29. 10.1016/j.marpetgeo.2016.05.034

Huh, D.G. and Lee, J.Y., 2017. Overview of gas hydrate R&D, Journal of the Korean Society of Mineral and Energy Resources Engineers, 54(2), p.201-214. 10.12972/ksmer.2017.54.2.201

Kim, A.R., Kim, J.Y., Cho, G.C., and Lee, J.Y., 2018. Methane production from marine gas hydrate deposits in Korea: thermal-hydraulic-mechanical simulation on production wellbore stability, Journal of Geophysical Research: Solid Earth, 123(11), p.9555-9569. 10.1029/2018JB015875

Korea Institute of Geoscience and Mineral Resources (KIGAM), 2019. Gas hydrate exploration and production study. KIGAM Report 19-1143, Daejeon, Korea, 450p.

Kurihara, M., Sato, A., Ouchi, H., Narita, H., Masuda, Y., Saeki, T., and Fujii, T., 2009. Prediction of gas productivity from eastern Nankai trough methane-hydrate reservoirs, SPE Reservoir Evaluation and Engineering, 12(3), p.477-499. 10.2118/125481-PA

Lee, J., Ryu, B., Yun, T., Lee, J., and Cho, G., 2011. Review on the Gas Hydrate Development and Production as a New Energy Resource, KSCE Journal of Civil Engineering, 15(4), p.689-696. 10.1007/s12205-011-0009-3

Li, G., Li, X.S., Zhang, K., Li, B., and Zhang, Y., 2013. Effects of impermeable boundaries on gas production from hydrate accumulations in the Shenhu area of the South China sea, Energies, 6(8), p.4078-4096. 10.3390/en6084078

Masuda, Y., Naganawa, S., and Ando, S., 1997. Numerical calculation of gas-production performance from reservoirs containing natural gas hydrates, Proc. of the Western Regional Meeting, SPE, Long Beach, California,

Moon, Y.J., Shin, H.J., Lim, J.S., and Jang, W.Y., 2019. Numerical analysis of geomechanical behavior affected by depressurization conditions of gas hydrate production in the Ulleung Basin, East Sea, Korea, Journal of the Korean Society of Mineral and Energy Resources Engineers, 56(1), p.53-61. 10.32390/ksmer.2019.56.1.053

Moridis, G. and Collet, T., 2003. Strategies for gas production from hydrate accumulation under various geologic conditions. LBNL-52568, Proc. of the TOUGH symposium 2003, Berkeley, California, p.1-8.

Moridis, G.J. and Reagan, M.T., 2007. Strategies for Gas Production From Oceanic Class 3 Hydrate Accumulations. Proc. of the 2007 Offshore Technology Conference, Houston, Texas, p.1-29. 10.4043/18865-MS

Moridis, G.J., Kim, J., Reagan, M.T., and Kim, S.J., 2014. System response during short- and long-term gas production from a gas hydrate deposit at the site of a planned field test in the Ulleung Basin of the Korean East Sea. Proc. of the Offshore Technology Conference, SPE, Houston, Texas, p.1-29. 10.4043/25384-MS

Park, K.P., 2008. Gas hydrate exploration: overview and status, Journal of the Korean Society for Geosystem Engineering, 45(5), p.590-600.

Ryu, B., Kim, G., Chun, J., Bahk, J., Lee, J., Kim, J., Yoo, D., Collett, T., Riedel, M., and Torres, M., 2012. The second Ulleung basin gas hydrate drilling expedition 2 (UBGH2).

Ryu, B.J., Collett, T.S., Riedel, M., Kim, G.Y., Chun, J.H., Bahk, J.J., Lee, J.Y., Kim, J.H., and Yoo, D.G., 2013. Scientific results of the Second Gas Hydrate Drilling Expedition in the Ulleung Basin(UBGH2), Marine and Petroleum Geology, 47, p.1-20. 10.1016/j.marpetgeo.2013.07.007

Shin, H.J., Kim, J.S., Lim J.S., and Kim, S.J., 2015. Numerical analysis of dissociation and flow behavior in gas hydrate bearing sediments for the productivity influence factors in the Ulleung Basin, East Sea of Korea, Journal of the Korean Society of Mineral and Energy Resources Engineers, 52(5), p.500-510. 10.12972/ksmer.2015.52.5.500

Stone, H.L., 1970. Probability Model for Estimating Three- Phase Relative Permeability, Transactions of AIME, 249, p.214-218. 10.2118/2116-PA

Tomasini, J. and Stephen, K., 2020. Assessment of the potential for gas production from marine methane hydrate reservoirs by numerical simulation. Proc. of the SPE Latin American and Caribbean Petroleum Engineering Conference, SPE, Bogota, Colombia, p.1-25. 10.2118/199134-MS

van-Genuchten, M.Th., 1980. A Closed-Form Equation for Predicting the Hydraulic Conductivity of Unsaturated Soils, Soil Science Society of America Journal, 44(5), p.892-898. 10.2136/sssaj1980.03615995004400050002x

Zheng, R., Li, S., and Li, X., 2018. Sensitivity analysis of hydrate dissociation front conditioned to depressurization and wellbore heating, Marine and Petroleum Geology, 91, p.631-638. 10.1016/j.marpetgeo.2018.01.010

Information

Publisher :The Korean Society of Mineral and Energy Resources Engineers
Publisher(Ko) :한국자원공학회
Journal Title :Journal of the Korean Society of Mineral and Energy Resources Engineers
Journal Title(Ko) :한국자원공학회지
Volume : 59
No :1
Pages :69-90
Received Date : 2021-10-13
Revised Date : 2022-01-05
Accepted Date : 2022-02-22
DOI :https://doi.org/10.32390/ksmer.2022.59.1.069

Journal of the Korean Society of Mineral and Energy Resources Engineers ISSN:2288-0291(Print) 2288-2790(Online) 한국자원공학회지

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