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Important rock for hydrocarbon production.

Five types of important sedimentary rocks from the production of hydrocarbons. Sandstones Sandstones are clastic sedimentary rocks composed of mainly sand size particles or grains set in a matrix of silt or clay and more or less firmly united by a cementing material (commonly silica, iron oxide, or calcium carbonate). The sand particles usually consist of quartz, and the term “sandstone”, when used without qualification, indicates a rock containing about 85-90% quartz. Sandstone is good reservoir rock. Carbonates, broken into two categories , limestones and dolomites. Carbonates are sediments formed by a mineral compound characterized by a fundamental anionic structure of CO3-2. Calcite and aragonite CaCO3, are examples of carbonates. Limestones are sedimentary rocks consisting chiefly of the mineral calcite (calcium carbonate, CaCO3), with or without magnesium carbonate. Limestones are the most important and widely distributed of the carbonate rocks. Dolomite is ...
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the Rock Cycle

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The Rock Cycle Igneous, metamorphic, and sedimentary rocks are related by the rock cycle, the circular process by which each is formed from the others. Rocks are weathered to form sediment, which is then buried. During deeper and deeper burial, the rocks undergo metamorphism and/or melting. Later, they are deformed and uplifted into mountain chains, only to be weathered again and recycled.  Rocks do not remain in equilibrium and are forced to change as they encounter new environments. The rock cycle is an illustration that explains how the three rock types are related to each other, and how processes change from one type to another over time. The rock cycle never stops.
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Well test

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WELL TEST. In the Petroleum Industry, a   well test   is the execution of a set of planned   data acquisition   activities to broaden the knowledge and understanding of hydrocarbons properties and characteristics of the underground   reservoir   where   hydrocarbon   are trapped. The test will also provide information about the state of the particular   well   used to collect data. The overall objective is identifying the reservoir's capacity to produce hydrocarbons, such as   oil,   natural gas   and   condensate. Well test are various ways to categorize test types by its objectives, however two main categories only by objectives, these are productivity tests and descriptive tests.   According to   The Lease Pumper’s Handbook   of Oklahoma Commission on Marginally Producing Oil and Gas Wells, there are four basic well test types: potential tests, daily tests, productivity tests, and gas oil ratio...
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What Does a Geologist Do?

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What Does a Geologist Do? Geologists work to understand the history of our planet. The better they can understand Earth’s history, the better they can foresee how events and processes of the past might influence the future. Here are some examples. Geologists study Earth processes:   Many processes such as landslides, earthquakes, floods, and volcanic eruptions can be hazardous to people. Geologists work to understand these processes well enough to avoid building important structures where they might be damaged. If geologists can prepare maps of areas that have flooded in the past, they can prepare maps of areas that might be flooded in the future. These maps can be used to guide the development of communities and determine where flood protection or flood insurance is needed. Geologists study Earth materials:    People use Earth materials every day. They use oil that is produced from wells, metals that are produced from mines, and water that has been d...
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Temperature gradient and density

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Temperature gradient and density It is well known from deep mining operations that temperature increases downwards at an average rate of 300C per km. This rate is higher near a source of heat such as an active volcanic centre, and is also affected by the thermal conductivity of the rocks at a particular locality. Assuming for the moment that the temperature gradient continues at the average rate, calculation shows that at a depth of some 30 km the temperature would be such that most known rocks would begin to melt. The high pressure prevailing at that depth and the ability of crustal rocks to conduct heat away to the surface of the Earth result in the rock material there remaining in a relatively solid condition; but there will be a depth at which it becomes essentially a viscous fluid and this defines the base of the lithosphere (Greek: Iithos = stone). The mean mass density of the Earth, which is found from its size and motion around the Sun, is 5.527 gem"3. This is grea...
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IMPORTANCE OF CLAY IN PETROLEUM GEOLOGY

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IMPORTANCE OF CLAY IN PETROLEUM GEOLOGY Clay is the common name for a number of fine-grained, earthy materials that become plastic when wet. Chemically, clays are hydrous aluminums silicates, usually containing minor amounts of impurities such as potassium, sodium, calcium, magnesium, or iron. One of the commonest processes of clay formation is the chemical decomposition of feldspar. Clay consists of sheets of interconnected silicates combined with a second sheet-like grouping of metallic atoms, oxygen, and hydroxyl, forming a two-layer mineral such as kaolinite. Sometimes the latter sheet like structure is found sandwiched between two silica sheets, forming a three-layer mineral such as vermiculite. In the lithification process, compacted clay layers can be transformed into  shale . Under the intense heat and pressure that may develop in the layers, the shale can be metamorphosed into slate . Properties of clay minerals include plasticity, shrinkage under firi...
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Reservoir rock properties

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THE PROPERTIES OF RESERVOIR ROCKS According to Society of Petroleum Engineers Glossary, a reservoir rock is a rock containing porosity, permeability, sufficient hydrocarbon accumulation and a sealing mechanism to form a reservoir from which commercial flows of hydrocarbons can be produced. Porosity and permeability are the reservoir rock most significant physical properties.  A fundamental property of a reservoir rock between them is porosity. However, for explorationists, an effective reservoir rock, the most fundamental reservoir rock property is its permeability. Both of them are geometric properties are the result of its lithological, structural and compositional behaviour (composition). These physical compositions of a rock and the textural properties are geometric such as sizes and shapes of the rock grains, their arrangement system and packaging. The efficiency of reservoir rock account on different important properties. The reservoir content is estimated by means studyi...
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