What you're looking for is My Maps Editor by Google and the My Maps feature of Google Maps, and here's how you can use it:
1. Download the editor app to your phone, then go to Google Maps in a browser. Sign in, click on My Maps and create a new map. You can make it public, so that anyone can view it, or private, and you can share it by inviting others (coworkers for example, or whoever you want to). Name it, add comments if you want, create more than one map if you need to.
2. Now you can go to wherever the drilling equipment is and open up My Maps Editor. Select the map you created, and wait for it load. The feature you are looking for is "Mark my location" (menu -> add -> mark my... , or the big plus sign button -> mark my...). The GPS will zone in on you, and a marker will be added to the map. When you are satisfied with the accuracy of your GPS lock, press OK to accept the marker.
3. The editor will prompt you to tap on a word bubble to edit the marker. Do so, then click edit, and voil?! You can name the marker, add comments to it or even snap a photo to go along. The exact date and time is already handily noted for you, leave it in the comments if you like. As soon as you press save it is synced to the map, and is available for others to see, who are invited or know about your map.
4. Profit! You found another way Android is handy for you!
5. If you like to mark location info on My Maps you should hit up the My Tracks app also by Google. It can record your journeys by GPS, create and show statistic like speed, elevation and tons more, and upload your tracks to a map on My Maps, and your statistics to Google Docs. Maybe you'll find some use for this too, check it out!
edit:
6. I just realized you might not actually go to the point you want to mark. In that case, here's alternative #2: instead of mark my location, find the place you want to mark in My Maps Editor, then select add a marker from the menu. A marker will appear, drag it where you want it to be then click OK to place it. Resume original guide from #3.
