DFIT 자료 해석을 통한 저류층의 투과도 및 초기압력 추정
Estimation of Permeability and Initial Pressure in Reservoir by DFIT Data Analysis
0
조회
0
다운로드
0
인용
0
참고문헌
키워드
초록
치밀 또는 셰일가스층과 같은 비전통 저류층에서 물성을 구할 때 기존의 전통 가스정 시험법을 적용하면올바른 결과값을 얻을 수 없다. 일반적으로 셰일가스 저류층에서는 지층의 저투과성으로 인해 유동 속도가 느려방사형 유동 구간이 나타나기까지의 시간이 매우 오래 걸리며 수압파쇄 후에는 방사형 유동 구간이 전혀 나타나지 않을 수도 있다. 이로 인해 시험 비용이 많이 들 뿐만 아니라 결과값의 정확도 또한 매우 낮다. 이러한 이유로셰일가스 저류층 물성 분석법으로 DFIT(diagnostic fracture injection test)이 새롭게 주목받고 있다. 수압파쇄 전에수행되는 DFIT은 셰일가스의 중요성이 커져감에 따라 저류층의 물성을 얻기 위한 가장 실용적인 방법 중의하나로 알려져 있다. DFIT 데이터를 분석하는 방법에는 여러 가지가 있으며 한 가지 방법으로는 데이터를 잘못분석할 수 있기 때문에 다양한 방법을 통해서 종합적으로 물성을 분석하는 것이 매우 중요하다. 본 연구에서는이러한 다양한 DFIT 분석법들에 대해 설명하고 이를 통해 3개 저류층의 DFIT 데이터에서 여러 가지 분석법들이어떻게 적용되는지 비교, 분석하여 정확한 저류층 물성을 얻고자 하였다.
Abstract
Well testing in unconventional reservoirs, such as tight or shale gas formations, presents considerable challenges. It is difficult to estimate the reservoir properties in ultra-low permeability formation because of poor inflow prior to stimulation and excessive test duration. Moreover, radial flow may not develop in hydraulically fractured horizontal wells. For these reasons, the cost of test is high and the accuracy is relatively low. Accordingly,industry is turning to an alternate testing method, diagnostic fracture injection test (DFIT), which is conducted prior to the main hydraulic fracture treatments. Nowadays, DFIT are regarded as the most practical way to obtain good estimates of reservoir properties in unconventional reservoirs. Various methods may be used for interpreting DFIT data. This paper gives an explanation of those methods in detail and examines three actual field data. These show how various analysis methods can be applied to consistently interpret fracture closure pressure and time, as well as before and after closure flow regimes and reservoir properties from field data.
참고문헌 (15)
- Barree, R.D., "Determination of Pressure Dependent Leakoff and Its Effect on Fracture Geometry", SPE Annual Technical Conference and Exhibition (1996)
- Barree, R.D., "Applications of Pre-Frac Injection", Falloff Tests in Fissured Reservoirs - Field Examples, Low-Permeability Reservoirs Symposium, pp.1998[DOI]
- Barree, R. D., "Holistic Fracture Diagnostics: Consistent Interpretation of Prefrac Injection Tests Using Multiple Analysis Methods", SPE Production & Operations, 24(3), pp.396~406 (2009)
- Benelkadi, S., "Reservoir Permeability Determination Using After-Closure Period Analysis of Calibration Tests", SPE Reservoir Evaluation & Engineering, 7(3), pp.230~237 (2004)
- Castillo, J.L., "Modified Fracture Pressure Decline Analysis Including Pressure-Dependent Leakoff", Low Permeability Reservoirs Symposium (1987)
- Cooper, H. H., "Response of a Finite-Diameter Well to an Instantaneous Charge of Water", Water Resources Research, 3(1), pp.263~269 (1967)
- Ewens, S., "Executing Minifrac Tests and Interpreting After-Closure Data for Determining Reservoir Characteristics in Unconventional Reservoirs", SPE Canadian Unconventional Resources Conference (2012)
- Gu, H., "Formation Permeability Determination Using Impulse-Fracture Injection", Production Operations Symposium (1993)
- Joong Ho Synn, "Estimation of in-situ stresses and the effect of a pre-existing inclined fracture by hydraulic fracturing", Tunnel & Underground Space, 4(1), pp.55~62 (1994)
- Mukherjee, H., "Extension of Fractured Decline Curve Analysis to Fissured Formations", Low-Permeability Reservoirs Symposium (1991)
- Nolte, K.G., "Determination of Fracture Parameters from Fracturing Pressure Decline", SPE Annual Technical Conference and Exhibition (1979)
- Nolte, K.G., "After- Closure Analysis of Fracture Calibration Tests", SPE Annual Technical Conference and Exhibition (1997)
- Background for After-Closure Analysis of Fracture Calibration Tests, "Nolte, K.G.", ~, pp.Unsolicited companion paper to SPE 38676 (1997)
- Soliman, M. Y., "Analysis of Buildup Tests with Short Producing Time", SPE formation Evaluation, 1(4), pp.363~371 (1986)
- Soliman, M.Y., "After-Closure Analysis to Determine Formation Permeability, Reservoir Pressure, and Residual Fracture Properties", SPE Middle East Oil & Gas Show and Conference (2005)