Geology/importance of carbonate mud
Dear Sir Tariq.
Sorry for keep the question private. My mistake.
I'm second year student, studying degree in Petroleum geoscience in Universiti Teknologi Petronas.
I would like to ask you about exploration of petroleum in deep marine. And what is the importance of carbonate mud in deep marine environment?
Dear Siti Norliana,
Thanks for sending me your question.
Her is the answer of the first part of your question is about deep marine petroleum exploration or exploration in offshore. (for second question please send another question)
As we all know that geological features and geological structures are present every where in our Earth, from high mountains to deep marine conditions where water depth exceeds 10 km.
These features are rocks of various types (igneous, metamorphic and Sedimentary) which housed minerals whereas sedimentary rocks have oil and gas reserves as well and still be looked into deep water. Unlike exploration on land where we have an ability to see the rock itself, the method of exploration in deep or shallow marine is is always through seismic data which can imaged rocks geometry and structural pattern present below the sea level.
The marine reelection seismic data is acquired by ships which are equipped with all those standard tools as in land seismic data acquisition. Geophone, hydrophone recording tools and energy producing devices. Once acquired seismic data is acquired, filtered and processed then interpretation needs to be carried out in order to identify those structures where oil and gas may present if the petroleum system analysis results are also supportive.
Drilling is the ultimate test to determine if the identified structures have any oil or gas or not. Offshore drilling equipment is a drilling rig which depends upon the water depth.
Following is a summary of the offshore drilling rigs type;
Ship for drilling for oil in deep water (3,300 ft and more); it is more mobile but less stable than a semisubmersible or jack-up platform.
Movable structure that is anchored to the seabed and used at depths of 350 to 1,650 ft; it is mounted on pontoons submerged at about 100 ft to provide stability.
Structure that is mainly used at moderate depths (up to 1,300 ft); it rests on the seabed on pillars buried deep in the sea floor.
JACK UP RIGS
Movable structure that is used in shallow water (between 65 and 330 ft); it is raised above sea level on retractable pillars resting on the ocean floor.
Exploration cost in offshore greatly varies and depend upon the sea water depth.
Offshore deep drilling is at least 2 to 10 time more expensive than shallow water or onshore drilling.
Hopefully, this answer will be helpful.