다양한 종류의 암석에 대한 물-암석 상호작용 용해 실험을 통한 지하수 성분 영향 평가

조호정 전북대학교 일반대학원 2020 국내석사

Chemical composition of groundwater is primarily influenced by geogenic origins, and thus water-rock interaction is one of the most essential factors in regulating geogenic groundwater chemistry. The study was aimed for assessing the effects of geogenic origin on groundwater chemistry by conducting water-rock dissolution experiments for South Korea's representative rocks. Ten different kinds of representative rocks in total used in the experiments were as follows: carbonates (limestone and dolostone), volcanic rocks (basalt, andesite, and tuff), metamorphic rocks (phyllite and gneiss), and sedimentary rocks (mudstone, siltstone, and mudstone). Water-rock interaction was systemically evaluated for the representative rock samples (63-250 μm) in various pH conditions (2, 5, and 9.03) through batch equilibrium and kinetic experiments. The batch equilibrium experiments were conducted to monitor and determine the characteristics of major elements (Ca, Mg, Na, K, and Si) released from the rock samples through a dissolution reaction of 24 hours. The kinetic experiments were conducted to determine the changes in concentrations and dissolution rates of the elements over the 24 hours reaction time, by monitoring the geochemical changes at different times. For the characterization of rock samples, mineralogy, geochemistry, particle size distribution and specific surface area were analyzed and determined using X-ray diffraction (XRD), microscope, X-ray fluorescence (XRF), particle size analyzer and surface area analyzer. Based on the results of the analyses, the rock samples were classified into three types as follows: C-type of carbonate rocks with high contents of CaO and MgO, S-type of silicate rocks with high content of SiO2 and M-type of calc-silicate or calcite bearing rocks. The results of the batch equilibrium and kinetic experiments showed that the dissolution of elements is mainly controlled by mineralogy and geochemistry of the rock samples and pH of the reacting solution. The concentrations of elements dissolved from the rocks were high in the order of Ca>Mg>Si>Na>K. The concentrations of elements (particularly, Ca and Mg) in the early time of the reaction increased rapidly for the rocks of C- and M-types, making it difficult to find significant changes in concentrations until the reaction was completed. This is believed to be because carbonate rocks (C- and M-type (except basalt)) consist of the minerals that are more soluble (e.g., calcite, dolomite, and gypsum) than silicate rocks (basalt and S-type). The dissolution of Na and K in the silicate rock (S-type) samples was identified, but the dissolution rates of those two elements were relatively slow compared to those for the other types of rock samples. In addition, silicate rocks’ dissolution rates were slowly increased as parabolic forms. Si was detected under pH 2, whereas dissolution was negligible under the other pH conditions. The dissolution elements in the aqueous solution in pH 5 were not much different from those in pH 2; however, the concentrations of most elements were relatively low compared to those in pH 2, and some elements were not released to the solutions. In conclusion, it is thought that mineralogy and geochemistry of rocks are more crucial factors than genesis of rocks (i.e., igneous, metamorphic, and sedimentary rocks), and they determine the geogenic chemical composition of groundwater by water-rock interactions. Among the minerals investigated, highly soluble minerals (i.e., calcite, dolomite, gypsum, and calc-silicate minerals) contributed mostly the composition of water. Silicate minerals such as feldspar and mica also contributed to the chemical composition of groundwater corresponding to the increases in concentrations of Na, K and Si. These results will contribute to understanding the geochemical characteristics of actual groundwater and to comprehend the relationship between rock and groundwater quality.

Geochemical Fluid-rock Interactions in Energy Systems: An Investigation of Coupled Physical and Chemical Processes in Low-permeability Rocks

Herz-Thyhsen, Ryan J University of Wyoming ProQuest Dissertations & The 2019 해외박사(DDOD)

In both natural and engineered systems, fluids are often in geochemical disequilibrium with the surrounding rocks. In this context, low-permeability rocks (tight rocks) have become a focus of attention because they inhibit fluid flow in the earth’s crust. These rocks can harbor large amounts of thermal energy as hydrocarbons or heat, and they act as seals for storage reservoirs. Recovering energy in these rocks requires increasing permeability to enhance fluid flow while storing waste and fluids requires maintenance of naturally low permeability. We engineer hydraulic fracturing in the subsurface to produce hydrocarbons from unconventional reservoirs of oil and gas. However, hydraulic fracturing is a controversial process that uses large volumes of water and has been linked with harmful effects to the environment. To assess the efficiency, safety, and usability of hydraulic fracturing, processes that govern the fate of fluids must be understood at a quantitative level. This dissertation investigates coupled chemical and physical alteration during interaction between engineered fluids and low-permeability rocks to better understand how these processes affect fluid storage and transport. Chapter 2 characterizes both hydraulic fracturing fluids (HFF) and two different rocks that harbor unconventional reservoirs of hydrocarbons. The collected rock and fluid data are used to develop numerical simulations that predict mineral dissolution and precipitation reactions that may occur during hydraulic fracturing. Chapter 3 reports findings of hydrothermal experiments that use rocks and fluids evaluated in Chapter 2 and gives insight into mineral dissolution and precipitation reactions that occur during hydraulic fracturing. Chapter 4 investigates these reactions at the interface between fractures and the rock surrounding stimulated fractures. This interface is important because water moves into the rock surrounding fractures before hydrocarbons pass through this area of rock during hydrocarbon production. Findings of Chapter 4 suggest that that mineral dissolution and precipitation occurs at the nanoscale in a reaction halo surrounding stimulated fractures. Chapter 5 presents results of a novel technology used to assess the geometry and nanoscale porosity of rocks after interaction with hydraulic fracturing fluids. Results suggest that rock alteration at the nanoscale is crucial for understanding the behavior of fluids in low-permeability rocks.

(The) U.S. position on the liancourt rocks issue

정희승 Graduate School of International Studies, Korea Un 2020 국내석사

One of the most significant issues in international relations is territorial dispute and territorial control, which is an ongoing problem for states that strive to legitimize their authority, security, and sovereignty over claimed and unclaimed territories. In East Asia, the United States has become a bastion of maintaining the “status quo” and strategically watches over emerging powerful players. While the U.S. attempts to resolve its allies’ grievances and tensions, Japan and South Korea are struggling to resolve past historical issues. One of these key issues involves the Liancourt Rocks islet. This paper seeks to analyze the U.S. position in the Liancourt Rocks dispute, conceptualizing and interpreting the trilateral relations of Japan, South Korea, and the U.S. This research further identifies how territorial disputes of the Liancourt Rocks affect the U.S. maintenance of regional peace and security. Lastly, the paper concludes with an analysis of how the United States’ involvement in the Liancourt Rocks issue is evolving, where its political and economic interests are influencing Asia. The methods of this research mainly utilize the U.S. government sources from the U.S. Department of State Foreign Relations, Congressional Records, and U.S. Court of Appeals, as well as supplementary materials relating to territorial rights. With these sources, this research will attempt to answer questions regarding the U.S. trilateral relations with South Korea and Japan as well as the U.S. position in dealing with South Korea and Japan’s territorial dispute over the Liancourt Rocks.

光陽-南海地域에 分布하는 深成岩類에 對한 岩石地域化學的 硏究

박천영 全南大學校 1993 국내박사

광양-남해지역은 지리산편마암복합체인 화강편암, 반상변정질편마암류가 기저를 이루고 이를 관입하는 백악기 화강암류인 섬록암, 섬록반암, 화강섬록암, 석영섬록암, 각섬석흑운모화강암, 흑운모화강암, 미문상화강암, 염기성 암맥으로 구성되어 있다. Marker 변화도, AFM 삼각도, Al₂O₃와 normative Pl(An+Ab) 상관도, SiO₂대 알카리 상관도, 알카리 지수 및 알카리-lime 지수에 의하면 연구지역 심성암류는 calc-al-kaline rock series 영역에 속하는 마그마로부터 형성되었음을 시사해 주며 Fe₂O₃대 FeO 상관도, ACF 삼각도, Na₂O 대 K₂O 관계도, normative corundum 및 대자율측 정치에 의하면 연구지역 심성암류는 I-type 또는 magnetite series에 속한다. 연구 지역의 심성암류의 관입환경은 Rock/ORG와 미량원소, SiO₂대 Nb, Y 및 Yb 상관도, Y 대 Nb 상관도, Rb 대 Y+Nb 상관도에 의하면 대체로 WPG나 VAG+COLG+ORG 영역에 도시되어 연구지역의 심성암류의 마그마 관입과 지구조적 환경은 대륙주변부나 호상열도로 추정된다. 섬록암에 대한 전암시료와 흑운모 분리시료에 의한 Rb-Sr 절대연령은 101.±4.7Ma으로서 백악기 중기에 해당되고 ^(87)Sr/^(86)Sr 초생치는 0.709로서 비교적 높게 나타난다. 이는 섬록암을 형성시킨 마그마가 상부맨틀에서 형성되어 지각에 관입 정치되는 과정에서 주위의 모암에 의해 얼마간의 혼화작용을 받은 것으로 사료된다. Au원소 대 주성분원소 및 미량원소의 상관도에서 Au원소가 증가함에 따라 Fe₂O₃, FeO, CaO, Co, V, Cl등의 원소는 증가하는 경향을 보여 주는 반면에 K₂O와 Rb등의 원소는 감소하는 경향을 나타낸다. 광산이 밀집분포하는 본정지역의 심성암체에서 Au와 Ag의 상관계수가 0.93, Au와 Cu의 상관계수가 0.89, Au와 F는 0.66, Ag와 F는 0.75, Pb와 Cd는 0.91, Pb와 Cl은 0.77로서 정(+)의 관계를 보여 주며, Au-Ag, Au-Cu, Au-F, Ag-F, Pb-Cd, Pb-Cl등의 원소들이 광화작용을 받은 암체에서 양호한 상관성을 보여 주고 있다. Cl함량 700 ppm에서 Au함량 1ppb 이상과 이하가 뚜렷이 구분되는데 이는 Au를 운반하는데 Cl의 영향이 컸음을 시사해 주고 있다. 도수분포에 의하면 광양지역에서 Au, Ag, As, Zn, Ni, Cu, Pb, Cr, Bi, Mo, Cd등의 원소가 남해지역에 비하여 이상분포 현상을 보여주고 있다. 분산분석과 판별분석에 의하면 광화된 암체와 비광화된 지역의 암체는 Fe₂O₃, MnO, CaO, MgO, Nb, Au, Sb, Mo등의 원소에 의하여 81.4%(주성분원소)와 95.4%(미량원소)로 구분되고 있으며 본정지역의 섬록암체와 남해지역의 섬록암체를 비교하면 Na₂O, CaO, K₂O, Al₂O₃, MgO, Eu, Nb, Nd, Cd, Mo, Sm등의 원소에 의하여 주성분원소와 미량원소가 각각 100%로 구분되고 있다. 상관계수, 군집분석, 요인분석에 의하면 광양지역의 심성암류는 Ni-Cr, V-Co, Mo-Zn-Pb, As-Sb, Ag-Cu-Cd등의 원소가 상관성이 유사함을 보여주고, 남해지역의 심성 암류에서는 Ni-Cr-Sc-V-Co, As-Sb, Cd-Pb-Zn-Ag등의 원소가 상관성이 유사하게 나타나는데 이는 상기의 원소군들이 광양지역에서는 광화작용의 영향인 것으로 사료되고 남해지역에서는 심성암체의 화학조성이 중성암류에서 반려암까지 변화하기 때문인 것으로 사료된다. 연구지역의 광화지역 심성암체(본정 심성암체)와 비광화심성암체(광양 심성암체, 남해 심성암체)를 구분하여 주는 원소는 Fe₂O₃, CaO, MgO, Co, K₂O, Rb, Cr, Ni, Y, Zr, Sm. Dy, Yb, Pb, F, Cl등의 원소와 K₂O/Na₂O, Li/Mg, Rb/Sr, K/Rb, Ni/Co등인데 비광화지역에서 광화지역으로 갈수록 낮은 함량을 보여주는 원소는 Fe₂O₃, CaO, MgO, Co, Cr, Ni, Y, Zr, Sm, Dy, Yb, Pb 및 F등의 원소와 K/Rb 및 Ni/Co인 반면 Kc₂O, Rb 및 Cl원소와 K₂O/Na₂O, Li/Mg 및 Rb/Sr은 비광화대지역에서 광화지역 심성암체로 갈수록 부화되어 높게 나타난다. Geochemical studies were carried out on the plutonic rocks distributed Kwangyang-Namhae area. Features for alkalinity versus silica and the AMF triangular diagram if studied area suggest the possibility that these rock facies are a cale-alkaline rock serise of differentiation by fractional crystallization. And magnetic susceptibility, ACF triangular diagram Na₂O versus K₂O diagram and Fe₂O₃verses FeO diagram of the plutionic rocks indicate that they belong to I-type or magnetite series. The Rb-Sr isotopic systems of whole rock and biotite for the diorite in the Kwangyang district suggested that the emplacement age was 101.1±4.7Ma, corresponding to the igneous activity of the Bulgugsa Disturbance periods in the area. Minor elements, such as Ag, Au, As, Cd, Hg, Sb, Cu, Mo, Pb, Zn, Ga, Cl, F, Ba, Li, Nb, Ni, Sr, V, Y and Rb were statstically analyzed in order to investigate relationship with Au contents. It is observed that Au content has positive correlation with Fe₂O₃, FeO, CaO, V and Cl contents, but negative correlation with K₂O and Rb contents. Plutonic rocks related to Au-Ag mineralization in the Beongjeong area show higher Au, Li, Ni and Zn values, compared with non-nonmineralized plutonic rocks distributed in Namhae, Jinkyo, Hadong plutonic rocks. And geochemical correlation coefficients of Au and Ag, Au and Cu, Au and F, Ag and F, Pb and Cd, Pb and Cl are 0.93, 0.89, 0.66, 0.75, 0.91, 0.77 respectively, in the Beongjeon stock. In discriminant analysis, it is classified into two groups of mineralized plutonic rock(Beongjeon diorite) and nonmineralized rocks(Kwangyang diorite) by the Fe₂O₃, MnO, CaO, Nb, Au, Sb and Mo elements. And Na₂O, CaO, K₂O, Al₂O₃, MgO, Eu, Nb, Nd, Cd, Mo and Sm elements divided into Beonjeong diorite and Namhae diorite(nonmineralized rocks). By the R-mode cluster analysis, Mo-Pb-Zn, As-Sb, Ag-Cd-Cu, Cr-Ni(row data) and Y-F-Nb, As-Sb-Au, Cd-Pb-Ag-Bi, Sc-Hg-Ga, Ni-Sr-Cr-Cu(log10 transform data) are closely correlated in the Kwangyang plutonic rocks, and Nb-F, Co-Cr-Ni, Au-Cl, As-Sb, Cd-Pb-Zn-Ag(row data) and Nb-F, Cd-Pb-Zn-Mo, As-Sb-Cu-Ag, Ba-Au(log10 transform data) closely correlated in the Namhae plutonic rocks. Diorites in the Beongjeong were characterastics of enrichment of K₂O, Rb and Cl, and depletion of Fe₂O₃, MgO, CaO, TiO₂, P₂O_5, Co compared with those in the Kwangyang and Namhae. The geochemical characteristics of the Beonjeong diorites were indicative of mineralization, with particular reference to the ratios of selected elements such as K₂O/Na₂O, Li/MgO, K/Rb, Rb/Sr and Ni/Co.

Paleomagnetic and rock-magnetic studies for the volcanic rocks in the Northern region of the Jeju Island, Korea

오지혜 Graduate School, Korea University 2012 국내석사

Paleomagnetic and rock-magnetic investigations were carried out on volcanic rock units from the northern half region of Jeju Island, in order to determine directional variations of the geomagnetic field in the Brunhes chron (~780 ka). Reliable paleomagnetic directions were obtained from a total of 515 oriented samples taken from 21 sites in seven volcanic rock units. The average paleomagnetic direction (D/I=0.3°/45.7°, k=63.2, α95=5.2°) was derived from the site-mean directions of 17 sites excluding four sites showing anomalous directions. The distinctive anomalous directions were observed as D/I=33.3°/74.0° (k=282.6, 95=3.3°) and D/I=1.2–8.1°/-5.1 to -7.9° (k =144.5–449.4, 95=1.5–2.8°) in the Eodori Basalt and the three sites of Gwanghaeak Basalt, respectively. Results of the rock-magnetic experiment indicated that magnetite grains of single domain or pseudo-single domain size were main magnetic carrier. Most of virtual geomagnetic poles (VGPs) were located near the geographic North Pole, while VGP latitude of four sites with anomalous directions corresponds to the relatively low range of 52–57°N, being deviated by more than 30° from the geographic North Pole. Thus, the VGPs located at 52–57°N were determined as the records of geomagnetic excursions in the Brunhes chron. Based on the reported age data, three VGPs of the Gwanghaeak Basalt (260–150 ka) are correlated with one of the excursions, including Calabrian Ridge 0 (~260 ka), Pringle Falls (~211 ka) and Iceland Basin (~188 ka) excursion. Although Eodori Basalt has never been dated, it could be interpreted as the record of an older (or same) excursion than those recorded in the Gwanghaeak Basalt because it is lower rock unit than the Gwanghaeak Basalt. As a result of comparison with model for latitudinal VGP dispersion (SB) of Brunhes-age volcanic rocks, the value (SB=13.6°) of VGP dispersion is closest to the expected value (SB≈13–16°) at the latitude of the Jeju Island when the excursional records are excluded from the analysis, indicating that the obtained data average out paleosecular variation. The paleomagnetic pole position (Lat./Long.=83.7°N/304.1°E; N=17, A95=5.3°) for this study statistically coincides with the reported pole positions in the Jeju Island and the Far East Asia. The paleomagnetic data suggest that Sanbangsan trachyte (802–747 ka) which has been previously reported as recording the reversed directions of the Matuyama reversed polarity chron could be erupted earlier than the seven units shows the dominant occurrence of the normal paleomagnetic directions. For the Gwanghaeak Basalt, the western parts extruded at the different time with the northeastern parts showing normal directions because the anomalous directions were observed only at outcrops in the western parts of island. 브륀 정자극기(Brunhes normal polarity chron: ~780 ka) 동안의 지구자기장의 방향 변화를 알아보기 위하여 제주도 북부 지역에 분포하는 화산암에 대한 고지자기 및 암석자기 연구를 수행하였다. 7개 화산암층의 21개 지점에서 채취된 총 515개의 정향시료에 대해 단계별 소자실험을 적용한 결과, 신뢰성 있는 고지자기 방향을 획득하였다. 대부분의 지점별 평균방향은 제주도에서 기대되는 지자기 방향과 유사하였으며, 이들의 평균 고지자기방향은 D/I=0.3°/45.7° (k=63.2, α95=5.2°)이다. 어도리 현무암과 광해악 현무암의 일부 지점에서는 각각 D/I=33.3°/73.0° (k=282.6, α95=3.3°)와 D/I=1.2~8.1°/-5.1~-7.9° (k=144.5~449.4, a95=1.5~2.8°)의 이상방향이 관찰되었다. 암석자기 실험 결과, 단자기구역(single domain)에서 위단자기구역(pseudo-single domain) 입자크기의 자철석이 주요 자성광물임을 확인하였다. 각 지점의 평균방향으로부터 계산된 가상지자기극(VGP)들 중 대부분은 지리적 북극 주변에 분포하였으나, 이상방향을 기록한 4개 지점의 VGP들은 지리적 북극으로부터 30° 이상 떨어진, 상대적으로 낮은 범위(52-57°N)의 위도상에 위치하여 지자기 회유(geomagnetic excursion)의 일부 과정을 기록한 것으로 판단된다. 기존의 연대측정결과에 근거하여, 광해악 현무암(260~150 ka)에서 확인되는 지자기회유 기록은 Calabrian Ridge 0 (~260 ka), Pringle Falls (~211 ka), Iceland Basin (~188 ka) excursion 들 중 하나와 관련된 것으로 해석된다. 어도리 현무암의 경우, 보고된 연대측정자료는 없으나 광해악 현무암보다 하부의 층으로 해석되었으므로, 광해악 현무암과 동일하거나 그 이전 시기의 브륀 정자극기 내 지자기 회유와 관련된 것으로 판단된다. 본 연구의 VGP 분산도(SB)를 브륀 정자극기 연대를 갖는 화산암의 자료들로부터 계산된 위도별 VGP 분산도 모델과 비교한 결과, 지자기 회유를 기록한 지점을 제외시켰을 때(SB=13.6°)가 제주도의 위도에서 기대되는 모델 값(SB≈13~16°)에 가장 근사하며, 이 값은 지자기 영년변화가 상쇄되었음을 의미한다. 지자기 회유 기록을 제외하고 계산된 고지자기극의 위치(Lat./Long.=83.7°N/304.1°E; N=17, A95=5.3°)는 기 보고된 제주도와 극동 아시아 지역의 고지자기극과 통계적으로 일치한다. 고지자기 방향자료를 제주도 화산층서와 대비시킨 결과, 선행 연구에서 마쓰야마 역자극기(Matuyama reversed polarity chron)를 기록한 것으로 확인된 산방산 조면암(802~747ka)이 전체적으로 정상방향을 기록한 7개 화산암층보다 이전에 형성되었을 가능성이 제시된다. 이후에 형성되었을 가능성이 제시된다. 광해악 현무암의 경우, 서쪽에 분포하는 암체의 노두에서만 이상방향이 관찰되었으므로, 정상방향이 관찰된 북동쪽 암체와는 다른 시기에 형성된 것으로 해석된다.

Geomechanics of Disturbances in Pore Fluid Pressure of the Subsurface Rocks With Applications in Stability Analysis of Infill Wells in Depleted Reservoirs

Su, Xing The Pennsylvania State University ProQuest Dissert 2023 해외박사(DDOD)

The crustal stress state of the earth is a primary parameter to be considered in virtually any engineering operation that involves subterranean drilling or exploitation of subsurface resources. The change in magnitude and rotation of the subsurface in-situ stress upon reservoirs depletion (or injection) is studied in this dissertation. The outcome is applied to the practical problem of wellbore stability during drilling operations to obtain the safe mud weight window of infill wells drilled through depleted rock formations.Due to simplicity, uniaxial strain model is commonly used to predict the depletion- or injection-induced changes in the subsurface stress. However, field evidence and numerical studies on the subject have demonstrated the inaccuracy of uniaxial models in predicting the in-situ stress change of depleted rocks. Analytical solutions for axisymmetric models of the subsurface rock layers are herein developed to offer improved mechanistic rigor and accuracy in estimation of in-situ stress change upon reservoir depletion. Due to the inherent coupling of solid phase stress and pore fluid pressure in the considered problem, Biot’s theory of poroelasticity is adopted to model the mechanical behavior of rocks undergoing simultaneous changes in pore pressure and bulk stress. The cases of homogenous and inhomogeneous configuration of rock layers are considered, separately. The solution for homogenous case is derived using Green’s function approach and by adopting axisymmetric fundamental solutions for an analogous thermoelastic problem. The inhomogeneous case is solved using Hankel integral transform method. The obtained analytical solutions are compared against numerical simulation using COMSOL Multiphysics®.Results for the case of uniform pore fluid pressure change within the porous layer are presented in terms of rock deformation, as well as changes in the magnitude and orientation of principal stresses, inside and outside a depleted rock layer. Variations of these results with key problem parameters including the contrast in stiffness of rock layers and the aspect ratio of disturbed pore pressure volume are presented. Findings indicate substantial error rates that uniaxial strain models may produce in estimating the stress path of both the reservoir and surrounding rocks. Layers heterogeneity is shown to largely affect redistribution and reorientation of the in-situ stress, yet, less significantly the deformation of depleted layer.The developed analytical solutions for in-situ stress variations upon depletion are used to study the stability of infill wellbores inside and outside depleted rock formations. The approach for such analysis involves obtaining the shear failure and tensile failure limits of the rock surrounding the wellbore. Different faulting regimes are considered for this purpose. Results indicate that reservoir depletion decreases the tensile failure gradient and shear failure gradient of infill wells both inside and outside the reservoirs. Again, uniaxial models do fall short in accurate prediction of the tensile or shear failure gradients of infill wells and the advocated safest wellbore orientation would be different from the one obtained in this work. These errors are more substantial for wells that are closer to reservoir boundary.

An Experimental Study of the Impact of Injection Water Composition on Oil Recovery from Carbonate Rocks

Alshakhs, Mohammed J ProQuest Dissertations & Theses Stanford Universit 2015 해외박사(DDOD)

Evidence from laboratory studies and field tests suggests that implementing certain modifications to the ionic composition of the injection brine leads to greater oil recovery from sandstone rocks. More recent studies indicate that salinity and ionic composition impact oil recovery from carbonate rocks. The mechanisms that take place and techniques of altering the salinity may be different from those experienced in clastic systems. This work examines experimentally the factors that influence oil recovery from carbonate rocks when the salinity is altered. It also investigates mechanisms that lead to greater oil recovery. A series of forced imbibition experiments were conducted at different total salinity and ionic composition using reservoir limestone cores and crude-oil. Brines of different salinities were injected sequentially into a core with realistic initial oil and water saturation. Additional incremental oil recovery of 4.4-6.4% of the original oil in place (OOIP) was observed, during the tertiary stage, when the injection seawater, that has a salinity of 55 kppm, was replaced by a new brine (MgSO4) of similar total salinity (45 kppm) and rich in Mg2+ and SO42- ions. The effect of reducing the total salinity was evaluated using outcrop limestone cores and another crude- oil. An incremental oil recovery increase of 3.2-6.5% was observed when twice-diluted seawater (29 kppm) was injected during the tertiary stage following seawater injection. Direct measurements of crude-oil contact-angles on smooth calcite surfaces suggest that the release of oil is caused by a wettability shift toward water wetness. The static water contact-angle was reduced from 92.9 to 58.7 when the brine was switched from seawater to MgSO4 solution of similar salinity. Similar reduction was observed when measurements were conducted using the fluids of the second system. The static water contact-angle was reduced from 70.1 to 58.9 when the brine was switched from seawater to twice-diluted seawater. The contribution of each component of the rock/brine/oil system to the wettability was evaluated by measuring zeta potential of water/oil and water/solid interfaces. DLVO (Derjaguin, Landau, Verwey, and Overbeek) theory of surface forces uses the measurements to predict disjoining pressure and contact-angle. The results rationalized observations of recovery and crude-oil adhesion to solids. They also show that Mg2+ ions play a key role in the wettability alteration process when MgSO4 brine was used and no significant contribution was observed for SO42- ions. For tests that used the twice diluted seawater, the wettability alteration was attributed to the additional Ca2+ ions that added to the brine from the rock dissolution. Conventional fluid flow simulation was able to predict the additional oil recovery that was observed in the core-flood experiments. The input relative permeabilities for each brine were generated using pore network modeling that simulated flow in a carbonate system under different wettability conditions.

綾州盆地의 中生代 白堊紀 堆積岩類에 對한 堆積岩石學, 層序 및 堆積環境에 關한 硏究

김정길 全南大學校 1990 국내박사

이 硏究의 對象地域은 百惡紀 慶尙累層群이 分布하는 綾州盆地 一帶이다. 本域은 全羅南道에 位置하는 綾州盆地內에서 北北東-南南西와 南北方向에 따라 隔離된 長城-新安 長山島, 潭陽-和順-長興 有治와 大德 및 求禮-昇州 송치재와 海龍에 이르는 小盆地들로 이루어져 있다. 本 硏究目的은 野外 地質調査를 하고, 堆積岩類에서 主로 역암에 대한 堆積岩石學的 硏究를 遂行하여 本域과 慶尙盆地 堆積岩層과의 關係 및 綾州盆地內의 各 地域間 相互關係, 對北, 層序와 堆積環境을 糾明하는데 있다. 그 結果는 다음과 같다. 1. 本域의 基盤岩은 선캠브리아기의 變成岩複合體 및 쥬리기의 花崗岩, 堆積岩類는 主로 凝灰岩, 셰일, 砂岩 및 礫岩이며, 火山岩類는 主로 安山岩과 流紋岩 등 이다. 이중 자색 셰일과 砂岩은 互層을 이루며, 礫岩은 長興 大德을 除外하고는 複成礫岩이다. 2. 本域의 層序는 下部로부터 基盤岩, 인곡凝灰岩, 西酉里層, 壯東凝灰岩, 有治礫岩, 茶道凝灰岩 및 無等山火山岩類로 設定할 수 있다. 3. 本域의 堆積岩類는 堆積岩相에 의한 層序로 보아 慶尙盆地 慶尙累層群의 楡川層群에 對比된다. 4. 本域의 礫岩은 잔자갈 역암이고, 大部分의 礫은 亞圓狀이 우세하고 disk와 spheroid 模樣이 全般的으로 우세하다. 礫岩의 역은 주로 花崗岩, 安山岩, 流紋岩, 硅岩 및 맥석영 등으로 구성되나 地域에 따라 片麻岩, 凝灰岩, 礫岩, 砂岩, 셰일 및 長石 등이 含有되어 있다. 礫의 根源地는 堆積盆地 北東 내지 南東 方向에 位置했던 것으로 推定된다. 5. 本域의 堆積環境은 湖成, 河成 및 沖積扇狀地에서 2段階 模型 設定이 可能하였다. The study area of this paper is the Neungju Basin of the southeastern part of Jeollanam-do, in which the strata of Cretaceous System, Meozoic, is distributed. The Neungju Basin occupies the types of isolated minor basins which are Jangseong-Sinangun Jangsando, Damyang-Hwasun-Jangheunggun Daedeog, Gurye-Seungjungun Songchijae-Seungjugun Haeryong trending NS and NNESSW in Neungju Basin. The main purposes of this study are to carry out the geological survey, the sedimentary petrologic study on conglomerate, the stratigraphic correlation and the stratigraphy and interpret the depositional environment. The results of this study are as follows ; 1. Bed rocks in the study area are gneisses, schists, quartzite, schistose grantie and granite, sedimentary rocks are mainly tuff, shale, sandstone, and conglomerate, and igneous rocks are mainly andesite, and rhyolite. Also, the reddish shale and the sandstone are alternated and conglomerates are polygenetic ones in all localities except Jangheunggun Daedeog locality. 2. The Stratigraphy of the study area can be established in ascending order ; Bed rocks, Ingog tuff, Seoyuri formation, Jangdong tuff, Uchi conglomerate, Dado tuff and Mudeungsan volcanic rocks. 3. The geologic age of the study area is upper cretaceous and is correlated with the Yucheon Formation of the Gyeongsang Supergroup. 4. The conglomerates in the study area belong to pebble conglomerate. The clasts in conglomerates are mainly subrounded in roundness and disk or spheroid in shape. The composition of the clasts are mainly granite, andesite, rhyolite, quartzite and vein quartz, in some localities those are gneiss, tuff, conglomerate, sandstone, shale and feldspar. The provenance, which clast were driven, seems to be located in the noutheastern to southeastern parts of the study area. 5. The depositional environment of the study area can be established the type of two stages and interpreted to be fluvial, lacustrine and alluvial fan environments.

群山地域 變成岩에 關한 硏究

모진석 전북대학교 교육대학원 1982 국내석사

1. This area is the geosyncline belt of OK-Cheon group that was not surveyed. 2. This area shows the geologically complicated structures due to serious diastrophism and intrusion of igneous rocks. 3. Schists and quartzites distributed in this area are sedimented on late-Paleozoic and synchronized with those of Ham-Yeol system judging from the view point of rock facies and rock forming minerals. 4. Gneiss and serpentinite distributed in this area intruded on Dae-Dong period of Mesozic and were metamorphosed by diastrophism on mid-Dae Dong period of Mesozic. 5. Volcanic breccia distributed in this area were sedimented on late-Dae Dong period of Mesozic. 6. Coal seams distributed in Eo-Eumli were synchronized with Ham-Ra mountain formation of Ham-Yeol system. 7. It is considered that granite gneiss was metamorphosed regionally at relatively high temperature inferring from the development of gneissosity containing most feldspar and little quartz and biotite.

경기육괴 남서부 고군산군도 지역의 지구조진화사 및 남중국과의 지구조대비

김원정 전북대학교 일반대학원 2021 국내석사

동북아시아의 신원생대 지구조 진화사 해석에 정보를 제공할 것으로 생각되는 로디니아 초대륙과 관련된 신원생대 암석이 한반도의 여러 지역에서 인지되었다. 경기육괴 남서부 경계에 위치한 고군산군도는 신원생대 화성암과 퇴적암으로 구성되어있다. 말도층은 1156-896 Ma 사이 퇴적되었고 화산호 환경에서 형성된 염기성 및 산성 화성암에 의해 930-894 Ma에 관입되었다. 말도층은 충돌을 지시하는 중압 변성(3.2-5.5 kbar and 454-480 °C)을 경험했다. 방축도층은 충돌 후 열곡 환경에서 792-763 Ma 이후 퇴적되었다. 고군산군도의 신원생대 화강암류의 TDM(2.14-1.57 Ga와 2.72-1.08 Ga)연령은 옥천변성대 내 신원생대 화강암류의 TDM(2.2-1.6 Ga)연령, 장난 조산대와 난후아 열곡의 TDM(2.4-0.8 Ga)연령과 유사하다. 이러한 자료들은 고군산군도와 옥천변성대가 각각 로디니아 초대륙의 봉합 전 섭입과 로디니아 초대륙의 분열에 의해 형성되었으며 각각 남중국의 장난 조산대와 난후아 열곡에 대비될 수 있음을 지시한다. 화산호와 열곡 관련 화성암의 연령은 한반도에서 중국까지 서쪽으로 향할수록 더 젊어지는 경향이 있으며 이는 충돌이 한반도에서 시작해 서쪽으로 향했을 것을 지시하는 것으로 생각된다. In the Korean Peninsula, the Neoproterozoic rocks related to the Rodinia supercontinent were recognized in several locations, providing information about the Neoproterozoic tectonic process in northeastern Asia. The Gogunsan Islands locate on the southwestern margin of the Gyeonggi Massif and consist of the Neoproterozoic igneous and sedimentary rocks. The Maldo Formation was deposited between 1156 Ma and 896 Ma and intruded by mafic and felsic igneous rocks during 930-894 Ma in arc tectonic environment. The Maldo Formation experienced intermediate-P/T metamorphism (3.2-5.5 kbar and 454-480 °C) which indicates the collision event. The Bangchukdo Formation was deposited after 792-763 Ma in rift tectonic environment after the collision. The TDM age of 2.14-1.57 Ga and 2.72-1.08 Ga from Neoproterozoic granitic rocks in the Gogunsan Islands are similar to those of Neoproterozoic granitic rocks in the Okcheon Metamorphic Belt (ca. 2.2-1.6 Ga TDM age) and the Jiangnan Orogen and Nanhua rift (ca. 2.4-0.8 Ga TDM age) in the South China Craton. The data in this and previous studies suggest that the Gogunsan Islands and Okcheon Metamorphic Belt formed during subduction before the amalgamation of the Rodinia supercontinent and during breakup of the Rodinia supercontinent, repectively. They can be correlated to the Jiangnan Orogen and the Nanhua rift in the South China Craton. The age of arc and rift related igneous rocks tend to be younger westward from the Korean Peninsula to South China Craton, indicating that the collision may have propagated westwards.