دولوميت

 

دولوميت

 

يکي از کاني هاي رايج سازنده سنگهاي رسوبي با ساختار شيميايي متشکل از کربنات کلسيم و منيزيم CaMg (CO3) 2 مي باشد که در سيستم رومبوئدريک متبلور شده و در سه جهت رخ کامل دارند . اکثر دولوميت ها به رنگ هاي خاکستري مايل به کرم و سفيد مايل به خاکستري يافت مي شوند ولي برخي به رنگ هاي چون سفيد ، زرد ، سبز و سياه هم ديده مي شوند .
وزن مخصوص اين ماده معدني حدود 6/2 گرم بر سانتيمترمکعب ، سختي آن 4-5/3 و داراي جلاي شيشه اي يا مرواريدي است.

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Survey of the diagenesis process and effect these process on
reservoir quality of the Kangan formation in South Pars Field

Kangan and Upper Dalan formations are forming reservoir sequence of the South Pars field. Litology of the kangan formation is carbonate and (limestone and dolomite with anhydrite intervals), so digenetic processes were very active in this formation and these processes have changeed the reservoir quality. Importances of the digenetic process are including dissolution, calcite cements, dolomitization, anhydritization, physical and chemical compaction and fracturing.

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تصاویری از دیاژنز در سنگهای کربناته

Diagenesis of Carbonate Rocks

This photograph illustrates a case of grain-to grain pressure-solution. Before the pores of a rock are filled by cement, stress is consentrated at the points where the grains meet and part of one or both the grains dissolves. In the example, ooids have undergone solution. The later cement is a mauve-stained, slightly ferroan sparite. Note the small rhombic areas of fine calcite spare.g. midway up, half-way between center and left-hand edge. These are calcite pseudomorphs after dolomite

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