Survey costs and Risk Management (MWD Radio Theatre Episode 10)

D-MWD enters trailer after casing break

DD: "Welcome home !"

D-MWD: "Glad to see the A/C is still working. How was your break?"

DD: "OK. They had me doing some training back at the office."

D-MWD: " I've got a couple things to add to our chat from last week. It's amazing what a little time off can do to clear your head."

DD: "Fire away!"

D-MWD: " It's helpful to keep in mind that if the logs while drilling are only used for selecting perforating depths with simple geology, there is not much point in worrying about whether survey location or geo-steering more is 'accurate'. BUT if the logs will be used to update reservoir models, the situation is very different. Logs and seismic MUST all be tied to the same reference."

DD: "Why? I think I know but just to be sure."

D-MWD: "Because we have to assume that the reservoir model is based on best possible survey data and maybe even combined with some seismic data. Best practices require that reservoir models are based on accurate survey locations and that almost certainly requires post job multi-station survey management."

DD: "But what if we are not using real time multi-station corrections?"

D-MWD: Well, then you are comparing 'apples and oranges'. It is very unlikely that raw or simple single-shot corrected surveys will consistently 'agree' with the reservoir model. More likely to 'confuse' the model. Just another justification for the relatively small added cost of real-time survey management compared to the overall cost of good reservoir model-based well planning."

D-MWD: "and another thing, . . . I should have mentioned that there are times when 'relative positioning' is used other than just during geo-steering operations. For example, relief or replacement wells must be positioned 'relative' to a target casing string. In this situation MWD or other ranging methods are used to determine the location of the target, relative to the MWD sensors.

DD: "I'm thinking this all means that survey expense depends on how accurately you need to know 'where you are'."

D-MWD: " Exactly! . . . and believe it or not, not everybody in the office know the answer to the question How much is it worth to know within +/- 10, 50, 100 ft or whatever, where we are downhole? . . . of course this is just my opinion, right?"

DD: "Mine too!"

D-MWD: "So let's chat about this a little more before we get busy. Rig time and pad costs are a big factor with all the stress on ROP. But there is also a big investment in all the downstream facilities associated with pad drilling and reservoir production. All this depends in some way on accurate placement of the wells we drill. I wonder how the bean counter's spreadsheets take all this into account along with costs of individual well-bore 'construction' . .. . sorry, well-bore construction is a term I am hearing much more lately. We aren't a factory or construction site. Where are the inspectors you see on construction sites to oversee quality? WE are the inspectors. '

DD: "No problem, I am old school too."

D-MWD: . . .' wellbore construction' seems to be completely cost driven UNTIL something happens. How is cost of poor production, frac-hits, or even collision risk due to poor survey management added to to the overall project expenses by the corporate planners?

DD: " I think that survey management "centers" and the use of best possible survey management AND correction methods is being used by the larger operators, but not all companies I have worked for are able to do this. Pad drilling with remote operations centers and man-camps and so on are only cost-effective for major projects, my opinion.

D-MWD: "You know, it might be a good idea if ALL drilling projects, no matter how small have a serious DWOP built in at some point. Each project is different, and requires careful consideration of survey accuracy requirements. A DWOP would put some heat on the planners to tell management just how accurate they expect wellbore placement to ensure good production from each well. This could be relatively late in the planning process because survey practices can be 'upgraded' pretty quickly."

DD: " I'm all for that, but here comes the company man now. Shall we give him our free advice."

D-MWD: No. I'm having too much fun being an unpaid management consultant!!

CM:" You guys still talking?"

D-MWD: "Yep, solving all your problems."

DD (shaking his head): 'We're about reading to kick this one off. Do you want a gyro orientation? I'm thinking too much magnetic interference in this close spaced cluster to get a good magnetic survey. Near vertical, we can't orient accurately with gravity or magnetic toolface."

CM: "What does our survey genius here say?"

D-MWD: "I'm just packing up my kit, new guy is here, I see his truck. I've got an offshore call. Hoping food is better there."

DD: "Give me a break! Safe travels."

CM: "WHAT !!? Who do we call if there are problems with kickoff? Like DD said, we are in the middle of some congestion and there is likely a lot of magnetic interference once we are back on bottom !! "

(to be continued . .

Will our DD be able to orient and safely build angle on the plan in this tight cluster of 3 previous wells off this pad without a gyro orientation?

Stay tuned !!!)