Determining the Appropriate Sealing Conditions through a Permeability and Groutability Evaluation: A Case Study of Sivaki Dam, Iran

The Sivaki Dam is an earth dam that is located near Yasuj city, 5.3 km northwest of Sepidar village. During excavations at the dam construction site, the high potential of water seepage from the foundation and its abutments has been proven. Some cavities and dissolution have been observed on both sides of the dam, suggesting the possibility of Karstification at greater depths. Most of the outcropping rocks in the study area comprise Asmari Limestone. These rock masses, despite their medium to high strength, have provided unfavorable conditions in terms of permeability and weathering. In this study, the foundation and both abutments of the dam were evaluated and analyzed to determine the permeability and groutability characteristics. To achieve this goal, the engineering characteristics of the rock mass of the construction site were examined by performing rock mass rating (RMR) and geological strength index (GSI) classifications. Moreover, the Lugeon test, secondary permeability index (SPI), rock quality designation (RQD), and monitoring hydraulic flows were used for this purpose. According to the results of this study, for abutments of the dam and in the case of alluvial substrates, grout curtain and the cutoff wall are respectively the best and most compatible methods available.

Investigation of Oil Recovery in Fractured Carbonate Rock by

The purpose of the three experiments described in this paper is to investigate the efficiency of secondary andtertiary gas injection in fractured carbonate reservoirs, focusing on the effect of equilibrium gas,re-pressurization and non-equilibrium gas. A weakly water-wet sample from Asmari limestone which is the mainoil producing formation in Iran, was placed vertically in a specially designed core holder surrounded withfracture. The unique feature of the apparatus used in the experiment, is the capability of initializing the samplewith live oil to obtain a homogeneous saturation and create the fracture around it by using a special alloy whichis easily meltable. After initializing the sample, the alloy can be drained from the bottom of the modified coreholder and create the fracture which is filled with live oil and surrounded the sample. Pressure and temperaturewere selected in the experiments to give proper interfacial tensions which have been measured experimentally.Series of secondary and tertiary gas injection were carried out using equilibrium and non-equilibrium gas.Experiments have been performed at different pressures and effect of reduction of interfacial tension werechecked by re-pressurization process. The experiments showed little oil recovery due to water injection whilesignificant amount of oil has been produced due to equilibrium gas injection and re-pressurization. Results alsoreveal that CO2 injection is a very efficient recovery method while injection of C1 can also improve the oilrecovery.

Assessing and Mapping the Vulnerability of Karstic Aquifer Using GIS and COP Model

<p>Vulnerability assessment and production of the risk map of the contamination is considered as a managerial significant technique in the conservation of Karstic water resources. Karst aquifers in semi-arid regions of the West of Iran with respect to the region&rsquo;s natural conditions are prone to contamination. The present paper aims to estimate the value of vulnerability and to produce the map of the Karst aquifer of Gilan-e-Gharb in the West of Iran against the pollution diffusion, using COP model. The model estimates the vulnerability of the Karst&#39;s water resources against the contamination using three parameters: overlying layer (O), density of current (C), precipitation regime (P). The results show that 0.25% of the region&#39;s area is located in a very low vulnerability domain, and 25.5% of the region&#39;s area is in a low vulnerability domain, which represents a low vulnerability of this Karst aquifer against pollution. Most regions with a low and moderate vulnerability - in the dominion of developed Karsts of the Asmari limestone formation - are located in the high lands. The dominant vegetation of the region is mostly covered by forest and dense pastures, and its total amount of precipitation is more than 600mm. In general, C, P and O parameters play the most significant role in reducing the value of the vulnerability over the area of study, respectively. The C factor plays the most important role in lessening the vulnerability of the region due to the little area of developed Karsts, high district of non-Karst regions, and lack of suitable vegetation. On the other hand, the region&rsquo;s precipitation is relatively low which results in a decrease in the amount of contamination permeation. The map of (O) factor shows a high and very high vulnerability of the region, which represents the expansion of permeable structures in the region. The high vulnerability value of this factor is adjusted by other two factors, and on the whole, the vulnerability amount of region is kept down through these factors.</p>