Released News: Cuba Block 9 Operations Update, page-6

It isn't strange.

If Alameda-1 showed oil on the shakers (which it did), you would think Alameda-3 would also show oil on the shakers (since Alameda-3 is drilling very close to the Alameda-1 well and is mirroring Alameda-1's trajectory).

Sometimes people get confused and they think if any oil at surface is detected this is a sign of danger/blow out. This is wrong.

What happens is this:
"Drilling fluids are integral to the drilling process and, among other functions, serve to lubricate and cool the drill bit as well as convey the drilled cuttings away from the bore hole. These fluids are a mixture of various chemicals in a water or oil based solution and can be very expensive to make. For both environmental reasons and to reduce the cost of drilling operations, drilling fluid losses are minimized by stripping them away from the drilled cuttings before the cuttings are disposed of." source: https://en.wikipedia.org/wiki/Shale_shakers#:~:text=Shale%20shakers%20are%20the%20primary,it%20begins%20to%20be%20processed.

"In addition to lifting the rock cuttings out of the hole, drilling mud also helps to stabilise the hole, cool the drill bit and control downhole pressure." source: https://youtu.be/eBOtXD_UQSo?si=KIBA1JndWpBX-Wj-&t=190


source: https://www.solidscontrolshaker.com/types-shale-shaker.html

Therefore, as the oil laden rock cuttings come up out of the hole, they are separated from the drilling fluids in order to prevent drilling fluid losses. This means if there is enough oil in the rock being drilled, and it has been detected, visually, in the mud coming back over the shale shakers, this tells us they are drilling through oil bearing rock. This is a good sign for the likelihood of positive appraisal tests in my opinion.