Practice to drill the well at near balance condition in conjunction with well control precaution

In some situation, where you drill with mud weight that is very close to balance condition (near formation pressure) and you don’t have much room to weight up due to fracture gradient limitation, from the well control perspective, you may need to drill one stand, then circulate bottom up and perform flow check. If everything is static, you can go ahead and drilling. Moreover, you need to look at the peak gas after going back to drill because it indicates how well of mud weight is. If you don’t see any gas peak, it means that your mud weight at the static condition is good. However, if you see any gas peak while drilling but it does not come from formations that you are drilling, this situation indicates that you don’t have or just enough mud weight to control the well in the static condition. You can check where the gas coming from by using a lag stroke calculation.

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