The results of application of zonal isolation technology of wellbores (ZITW) at the instance of Tatarstan field

Isolation of zones of loss, tightening and collapse in the wellbore with ZITW (Zonal Isolation Technology in Wellbore) is mentioned in the article. The investigations were mainly about wellbore stability problems in Veryski, Bashgir, and Serpukhov horizons in Republic of Tatarstan. Wellbore issues regularly occur while drilling zones of loss and tightening. Therefore to proceed the drilling process these intervals have to be cemented or isolated with specially prepared casing called ZITW (Zonal Isolation Technology in Wellbore). Initially loss intervals should be clarified. After clarifying intervals of losses, underreaming of those intervals, running in hole of ZITW (Zonal Isolation Technology in Wellbore) and enlarging under pressure to isolate and measurement with caliper log, Gamma log and Neutron-Gamma log have been conducted. Finally, after isolating those intervals with ZITW (Zonal Isolation Technology in Wellbore) restoration of fluid circulation within the wellbore is 90–95 % provided and next drilling operations can be proceeded. Additionally, ZITW can be used to isolate the deformed and collapsed sections in the wellbore.