I first applied through Geoservices and Schlumberger, and was later contacted by both separately. Once they realized both were interviewing the same applicant, GSS cancelled their interview and referred me to just stick with the Schlumberger interview process in which I was already engaged. First I received an email from a recruiter asking me to respond within 3 days if I was interested. I was ecstatic, and responded quickly. Then I received two more emails. I had to get a reprieve for the 3 day response, because I was in the midst of a difficult out of state move, and couldn't fill out and send back all the necessary forms right away. The recruiter was understanding and obliging.
I was worried about the outcome of my phone interview, because I had only known about it for 2 hours beforehand. I read the previous advice on glassdoor and just tried to stay poised and give reasonable answers. At the end of the interview, the recruiter gave me the chance to ask questions of my own. I would strongly advise candidates to ask some questions here. I think the recruiters gauge your interest level and whether you would be a low-risk hire by if you seem enthusiastic by asking questions about the job (besides, there's a reasonable chance you'll get it if you're this far along). I asked about 4 questions, about as many relevant ones I could think of off the cuff, such as "would plans for graduate school be a problem?" "would the job provide a company car?"
Luckily I got an email stating I had passed the phone interview, and then had to prepare for the 2nd round group interview in Houston. This was better because I had a good bit of time to prepare for it. I took notes on Geoservices' and Schlumberger's websites. Much of the group interview is Schlumberger presentations introducing you to the company. I would recommend asking questions here as well, to cement your name / face in the recruiter's mind.
The group interview is in the evening. After presentations, we had a group project. There were 5 trivia questions about Schlumberger and Geoservices (know the stock price of a share of Schlumberger stock, the name and nationality of the current CEO, how to draw the Geoservices logo). Then we had to construct something with plastic straws, paper, scotch tape, rubber bands, and toothpicks. They gave each group one question to ask. "What is the outcome?" is a good one to ask. It turned out we had to build a ramp to move a golf ball across the carpet.
Then we went to the lounge of the hotel and hung out. SLB opens up a tab. I got a bottled water and talked to some of the other candidates. It couldn't hurt to chum it up with some of the recruiters here.
The next morning you go down for breakfast and then put on Schlumberger blue jumpsuits and steel-toed boots to tour the facility in Sugar Land. There's not much chance to use the bathroom during the tour, so be sure not to drink too much or go beforehand. Ask questions while touring the training / simulation on-site rig.
After this we went back to the hotel to change into business casual clothes and have 2 on 1 interviews. My guys were pretty laid back, one was eating lunch during the interview. It helped that I had relocated to Houston already and evidently impressed them with my answer to a question about conflict resolution. It took about 15 minutes, seemed entirely positive. Ask questions at the end of this too. Do you see a recurring motif?
They told me I'd hear something within 2 weeks. I wound up getting the offer 4 or 5 days later, and accepting it. Later there is a drug test and functional capacity test. They hair test and urine test, be forewarned. The functional capacity test is just a physical with some exercise routines thrown in, to make sure you can carry weights up and down steps, hang onto a rope, deadlift small weighted objects, crawl on all 4s, etc.
