Published September 2013
On complications while well drilling
D.S. AkhundovWhile well drilling on squares Garadagh, Gizildash, Lokbatan, Galmaz via drilling mud with density higher than 2.0.104 H/m3 in the depth 22002600 m, with the balance in the wellformation system the decreasing of drilling mud density to 12501300 kg/m3 with following open gas flows is observed. The gas, entered into the well via diffusion is generally exhaled while washout after the trip. In the keyseats occur the elements of gas-cut mud, the density of which is for several times higher than the circulated one earlier. The diffusion is the occurrence stipulated with the molecule movement. The principal reason of gas diffusion is the presence of concentration gradient. The diffused gas ingress from the layer into the well will take place unless gas molecules move from the high concentration zone towards the zones with low concentration, i.e. into the well. Entering the drilling mud diffuzing gas lifting together with the muds and passes from the high pressure zones into the zones with lower pressure, enhances, in the results of which its density decreases, which in its turn causes the hydraulic pressure decrease in well bottom and serious complications. In order to prevent the complications in the well it is required to conduct the washout in the closed preventer with reciprocated drilling string.
