Geology/Coring Point / Supervision
QUESTION: dear sir,
How Coring Point is select exploratory well ? and Geologist ask to supervise the Coring Operation onsite .
what is the silent feature that well-site Geologist is look and Note in Coring supervision.?
ANSWER: Dear Waqar,
Thanks for sending me your question.
The coring is an import process to get geological information about the drilled rock, either source rock or reservoir rock but generally, core happens to be in a reservoir and rarely in a source rock or a seal rock. The core point selection while drilling is the part of the well geological prognosis and the company geologist and geophysicist have to clearly define the objective of the core, the interval and depth and method to preserve after core comes to the surface.
Nearing the core point depth, wellsite geologist needs to be extra vigilant and sees the sample on shorter interval than usual and takes the help of LWD readings and smartly correlates ROP and lithology with nearby wells to ensure that required core point should not be missed.
Once core point is confirmed, core barrel to be run in hole while wellsite geologist needs to monitor lithology (usually very little volumes of cuttings come out but whatever comes out must be looked at and log should be prepared), ROP, gases and oil shows. Once core reaches to the surface Wellsite geologists take the chip of the core on any given interval (usually on every half meter or every foot) to examine and prepare core log.
A geologist is also responsible monitoring the proper labeling of the core with depth and boxes of core storage should be marked with well name and coring depth prior to transporting to the core analysis company or drilling warehouse. All documentation regarding core transportation should be correctly done, wich is usually a standard document of all operating companies
Hope this answer helps.
---------- FOLLOW-UP ----------
QUESTION: Which Fm or lithology is Suitable for coring and which are not ?
Unconsolitaed and highly fractured rocks are difficult to be preserved in cores whereas consolidated and moderate density rocks can be better preserved. Highly dense and hard rocks are time-consuming and expensive coring operation.
Hope, this may help