Journal of the Korean Institute of Gas (한국가스학회지)

The Korean Institute of GAS (한국가스학회)
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A Study on the Production Well Spacing Design Considering Coalbed Depth in Coalbed Methane Reservoirs

석탄층 메탄가스 저류층에서 탄층 심도를 고려한 생산정 간격 설계 연구

  • Chayoung Song (Department of Energy and Resources Engineering, Chonnam National University) ;
  • Dongjin Lee (E&P Overseas Business Department II, Korea National Oil Corporation) ;
  • Jeonghwan Lee (Department of Energy and Resources Engineering, Chonnam National University)
  • 송차영 (전남대학교 에너지자원공학과) ;
  • 이동진 (한국석유공사 해외사업2처) ;
  • 이정환 (전남대학교 에너지자원공학과)
  • Received : 2023.07.06
  • Accepted : 2023.09.13
  • Published : 2023.09.30
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Abstract

This study presents a well spacing design for coalbed methane(CBM) reservoirs using the experimental results of methane gas adsorption measurement of coal samples obtained from North Kalimantan Island, Indonesia. The gas productivity analysis shows that the cumulative gas production increases as the Langmuir volume increases. This indicates that the maximum gas adsorption directly affects the gas production. In addition, the maximum gas production increases with the increase of reservoir permeability, and the dewatering period is shortened. In particular, the cumulative gas production increases as the production influence area increases. However, when comparing productivity per unit well, the maximum cumulative gas production is found between 2,000 ft of depth and 80-160 acres of the influence area. When reservoir depth and production influence area are considered simultaneously, the results of the appropriate well depth and spacing calculations show that gas productivity is highest between 600-2,000 ft. In this case, it is appropriate to design well spacing in the range of 80-160 acres. Therefore, well spacing design considering coalbed depth in undeveloped CBM reservoirs can be accomplished using gas sorption test results from coal samples.

본 연구에서는 인도네시아 북부 칼리만탄 섬 임의의 광구에서 취득한 석탄시료의 메탄가스 흡착량 측정 실험 결과를 활용하여 석탄층 메탄가스 저류층의 적정 생산정 간격 설계 연구를 수행하였다. 가스 생산성 분석결과, 랭뮤어 부피가 증가할수록 누적 가스생산량도 증가하며 이는 최대 가스 흡착량이 가스생산량에 직접적인 영향을 주는 것으로 판단된다. 또한 탄리투과도가 증가할수록 최대 가스생산량이 증가하고 배출수 기간(dewatering period)이 단축되는 것을 확인하였다. 특히 생산 영향영역이 넓어짐에 따라 누적 가스생산량은 증가하지만 단위 가스정 당 생산성 비교 시, 심도 2,000 ft, 영향영역 80-160 acres 사이에서 최대 누적 가스생산량이 산출되었다. 탄층 심도와 생산 영향영역을 동시에 고려하여 적정 생산정 심도 및 간격 산출 결과, 600-2,000 ft 사이에서 가스 생산성이 가장 높게 나타나며, 이때 생산정 간격은 80-160 acres 범위 내로 설계 하는 것이 적정하다. 따라서 탐사 시추 시 회수된 코어 시료 이외의 시추 자료가 없는 미개발 CBM 저류층에서 석탄시료의 가스흡착 실험 결과를 활용함으로써 탄층심도를 고려한 생산정 간격 설계를 수행할 수 있음을 제시하였다.

Keywords

Acknowledgement

본 연구는 한국에너지기술평가원(KETEP)의 지원을 받아 수행한 연구 과제입니다(과제번호 20212010200010). 또한, 본 연구는 국토교통부/국토교통과학기술진흥원의 지원으로 수행되었습니다(과제번호 RS-2022-00143541).

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