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The occurrence and morphology of mudstones happens in distinct environments. Some of the environments include river, marine beach, lacustrine beach, Barrier Island, volcaniclastic terrain and deep-sea slope. There have been other mudstones reported in shoreline, submarine channel, shallow marine, marine beach, glacial outwash and fluvial channel. However, the later occurrences are not very common and permanent because they experience low preservation potential and very limited conditions of outcropping. They are subject to external pressures that dismantle the existing mudstones and inhibit any further processes of formation. Therefore, it is difficult to find mudstones in these regions.
To determine immediate source of the mudstone constituents or its crystalline rock sources, there are several techniques used. The provenance information obtained for the mudstones depends strongly on the technique used. Each type of mudstone has different components depending on the depositions. Suggested components of mudstones come from different weathering intensities and tectonic settings. Tectonic setting usually moderates the weathering process. This includes the pressures in the shores that facilitate the formation of the stones. The intensity of tectonic forces is relevant in the formation because it determines its relative success. A geologic study done on three different belts in Turkey showed that the mélange units in the respective belts formed resulting from a process of gravity sliding in the respective basins underlain by the layers of continental basement rather than by the crushing of trenches through tectonic forces. Mafic volcanic activity is a feature of these basins, which are on continental margins flanking to tectonically active belts.
Drilling in mudstones is a difficult task especially for petroleum drillers. The mudstone formation has great significance in the petroleum industry. The mudstones make the task of drilling quite cumbersome for the drillers and use many resources. The rock behavior issues determine the success of the drilling process. The stability of the borehole analyses use varying analytical models evaluating the pressures, stresses, and temperatures within the boreholes. Mudstones do not have constant material properties. This makes it harder to determine the safety of drilling in a particular borehole. The mechanical properties of the mudstones depend on time because of the change in pore moisture content, pressure, and temperature in the borehole. Mudstones with high surface areas exhibit high sensitivity to major changes in chemical and physical properties of the pore fluids. Concentration and Pressure diffusion during the process of drilling change the pore fluids ionic composition continuously. This makes it a cumbersome task to drill boreholes to derive petroleum in mudstones.
Moon (2002) wrote that fine-grained materials are “reactive” in nature. It is evident that a “reactivity coefficient” is necessary to determine the physic-chemical sensitivity of mudstones. Coupling between mechanical and chemical properties may build up in reactive mudstones resulting to changes in their respective mechanical parameters. Experimental data from odometer tests is a presentation of time-dependent chemical properties within the borehole environments. This determines the drilling process either making it difficult or an easy process.