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복합역산을 이용한 물리검층자료로부터의 셰일성 사암 저류층의 지층 평가
최연진,정우근,하지호,신성렬 한국지구물리.물리탐사학회 2019 지구물리와 물리탐사 Vol.22 No.1
Well logging technologies are used to measure the physical properties of reservoirs through boreholes. These technologies have been utilized to understand reservoir characteristics, such as porosity, fluid saturation, etc., using equations based on rock physics models. The analysis of well logs is performed by selecting a reliable rock physics model adequate for reservoir conditions or characteristics, comparing the results using the Archie’s equation or simandoux method, and determining the most feasible reservoir properties. In this study, we developed a joint inversion algorithm to estimate physical properties in shaly sandstone reservoirs based on the pre-existing algorithm for sandstone reservoirs. For this purpose, we proposed a rock physics model with respect to shale volume, constructed the Jacobian matrix, and performed the sensitivity analysis for understanding the relationship between well-logging data and rock properties. The joint inversion algorithm was implemented by adopting the least-squares method using probabilistic approach. The developed algorithm was applied to the well-logging data obtained from the Colony gas sandstone reservoir. The results were compared with the simandox method and the joint inversion algorithms of sand stone reservoirs. 물리검층은 시추공을 이용하여 저류층의 여러 물성을 측정하는 것으로, 암석물리모델 관계식을 이용하여 공극률, 유체포화도 등의 저류층 특성을 파악하는데 활용되어 왔다. 물리검층자료의 분석은 저류층의 조건과 특성에 맞는 적당한암석물리모델을 선정하고, Archie식이나 시만독스법 등을 활용하여 얻은 결과를 비교함으로써 가장 신뢰성 있는 저류층물성을 결정하게 된다. 이 연구에서는 기존에 제시된 사암 저류층에서의 물리검층자료 복합역산 알고리즘을 바탕으로, 셰일성 사암 저류층의 물성을 평가하기 위한 복합역산 알고리즘을 개발하였다. 셰일의 양을 변수로 하는 암석물리모델 관계식을 제안하였으며, 야코비 행렬을 구성하고 민감도 분석을 수행하여 물리검층자료와 모델변수의 관계를 파악하였다. 확률론적 방법을 이용한 최소제곱법을 적용하여 복합역산을 수행하였다. 개발한 알고리즘은 Colony 가스사암 지역에서얻은 물리검층자료에 적용하였으며, 그 결과를 기존에 활용되는 시만독스법과 사암 저류층에서의 복합역산 결과와 비교해 보았다.
최연진,김은정,김영수,신용철 한국키틴키토산학회 1997 한국키틴키토산학회지 Vol.2 No.3
For the enzymatic production of chitooligosaccharides from chitosan, an endo-chitosanase producing bacterium, Bacillus sp. GM44 was isolated from a soil. The bacterium produced 50U/ml of extracellular chitosanase constitutively. Chitosanase was purified from culture supernatant of strain GM44 by CM-Toyopearl column chromatography and Superose 12HR column chromatography. Molecular mass of the enzyme was estimated as 45,000 by SDS-PAGE. Its optimum pH and temperature were 5.0 and 70t, respectively. It was stable in the pH range of 3.0 to 10.0 and up to 40℃. Its N-terminal amino acid sequence had 90% similarity with an endo-cellulase of Bacillus sp. KSM-330. The enzyme showed high substrate specificity toward chitosan but could hydrolyze swollen chitin and CM-cellulose with a low hydrolysis rate. Chitobiose, chitotriose, chitotetraose, and chitopentaose were fairly resistant to the enzyme action and while, chitohexaose and the higher chitooligosaccharides were hydrolyzed easily. The enzyme had maximum activity against 81.9% deacetylated chitosan and also showed 83.3% activity against even 39.2% deacetylated chitosan. It produced chitooligosaccharides ranging from chitotriose to chitooctaose as major end-products from chitosan.
최연진,김은정,신용철,김종진,윤영철,최치만,김영수 한국키틴키토산학회 1998 한국키틴키토산학회지 Vol.3 No.3
Fermentation conditions and purification processes for chitosanase production from Bacillus sp. KCTC0337BP were optimized using 50 liter jar fermentor. Maximum 70U/ml of chitosanase was produced from the bacterium under optimized conditions. From the culture supernatant, chitosanase was purified 28-fold by a series of purification steps containing membrane filtration, ultrafiltration, and ion exchange chromatography. The specific activity and recovery yield of the purified enzyme was 1,009U/mg and 68%, respectivety. Chitosanase activity of lyophilized enzyme was 200,000U/g for desalted enzyme and 45,000U/g for non-desalted enzyme. The purified chitosanase was characterized and its applicability for chitin and chitosan oligomer productions was examined. Our results indicated that the enzyme can be applied to commercial production of chitosan oligomer with high degree of polymerization, low viscosity or water-soluble chitosans, and chitin oligomer from partially deacetylated chitin.