A key part of drilling and tapping new oil wells is the use of specialized cements to line the borehole and prevent collapse and leakage of the hole. To keep these cements from hardening too quickly before they penetrate to the deepest levels of the well, they are mixed with chemicals called retarders that slow down the setting process.
Click here for original story, Techniques for observing concrete as it sets could facilitate the development of new cements
Source: Phys.org