hello my name is Tim Clark founder of corizon willfield services welcome to coring 101 this week is episode one what is coring Coring in simple terms is the acquisition of intact samples of reservoir Rock which are more representative of the downhole environment than cuttings this can be done in two ways acquisition through a conventional rotary coring system or through sidewall coring conventional rotary coring is the running of a specialist drilling assembly to cut a column of reservoir Rock and bring it back to surface when running a coring BHA special drill bit called core head is run there's a drill bit without a center modern coring does not utilize roller cones but pdc's diamond and impreg bits above the core head is a core Barrel which is assembled from two major parts an inner and outer core Barrel the outer core Barrel is essentially a large diameter steel drill pipe for some systems as little as 38 of an inch under gauge and is regularly stabilized typically every 30 ft within the outer core Barrel is the inner core Barrel which is generally made of aluminium in order to minimize friction between the inner core barrel and the core the inner barrel is suspended from the inner head bearing assembly which allows the outer Barrel to rotate while keeping the inner barrel stationary as the core head Cuts away the formation it leaves a cylinder of reservoir Rock while the core head makes hole the inner core Barrel moves over the core to provide protection upon completion of coring the drill pipe is tripped and the core Barrel is recovered to surface cores typically range in diameter from 1 and 3/4 in to 5 and 1/4 in they're usually cut in 30 ft increments cores in excess of 600 ft have been successfully cut though 90 to 180 ft is more usual depending on factors such as formation size and Coring BHA used why line sidewall coring is the acquisition of plug samples from the wall of the bore hole taken as part of the openhole wi line logging program and can be acquired from multiple zones of Interest sidewall cores typically measure from 1 and 1/8 of an inch to 1 and 3/4 in in length and 1116 of an inch to 1 in in diameter sidewall cores are typically taken after logs have been run usually near the end of the openhole Wireline logging operation this gives the geologists time tock core depths after Consulting the logs to identify zones of interest in which to take the samples in the next episode we'll look at why we core but in the meantime remember core is our only opportunity to touch the reservoir