오일샌드 저류층 두께와 수직투과도를 고려한 SAGD 유정 간격 및 배열 최적화 = Optimization of Well-Pair Spacing and Well Configuration for the SAGD Process in the Oilsands Reservoirs

국문 초록 (Abstract)

증기중력배유법(steam-assisted gravity drainage, SAGD)의 경제성은 저류층 물성 외에도 유정 간격에 영향을 받는다. 경험적으로 저류층이 두꺼울수록 SAGD 유정 간격을 넓혀 시추하지만, 저류층 물성을 고려한 정량적인 유정 쌍 간 시추 간격 결정 방법이 필요하다. 본 연구에서는 캐나다 아사바스카 지역 오일샌드 저류층의 대표 물성을 활용하여 유정 간격 최적화 방법을 개발하고, 근간격시추법과 추가회수 시추법 간 경제성을 비교한다. 이를 위해 수직투과도 및 저류층 두께에 대한 민감도 분석을 수행하여 경제적인 SAGD 운영이 가능한 저류층 물성 조건을 도출하고 상관관계 분석을 통해 유정 간격을 최적화하였다. 그 결과, 수직투과도가 500 mD일 때 최적의 유정 간격은 저류층 두께를 5배 후 50 m만큼 차감한 거리이며, 수직투과도가 1,500 mD, 2,500 mD일 때는 저류층 두께의 5배임을 밝혔다. 또한, 시추공 배열 방법 별 경제성 비교 시 최적의 유정 간격으로 추가회수 시추법을 적용하는 것이 경제성이 가장 높았다.

다국어 초록 (Multilingual Abstract)

The performance of steam-assisted gravity drainage (SAGD) is influenced not only by reservoir properties, but also by well-pair spacing. Field operators empirically increase the well-pair spacing for thicker reservoirs. However, a quantitative method is needed to determine the well-pair spacing based on reservoir properties. This study accordingly developed an optimization method for well-pair spacing using the properties of representative oil sands reservoir in Athabasca, Canada. In addition, the economic feasibilities of narrow-spacing and infill well-drilling methods were compared. A sensitivity analysis of vertical permeability and reservoir thickness was conducted to identify reservoir conditions under which SAGD operations are economically viable. The results revealed that the optimal well-pair spacing was the reservoir thickness multiplied by five, subtracting 50 m when the vertical permeability was 500 mD, and five times the reservoir thickness for vertical permeabilities of 1,500 mD and 2,500 mD. The infill well-drilling method with the optimized well-pair spacing showed the highest performance among the well configurations considered.

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