It was difficult to drill and complete the wells in the Kenkiak Under-Saltdome oilfield in Kazakhstan due to complicated geological conditions. Among 42 wells which had been drilled by former operator 40 wells were abandoned; amid 40 abandoned wells 12 were engineering abandoned; only 2 wells were capable of production with 38 to 69 tons of oil per day. Because of low drilling rate of success, long cycle of drilling, and low production, the former operator regarded the field an unable to be developed one. Consequently the field had not been put into production since its discovery 30 years ago.
In order to increase the productivity, near balance drilling and open hole completion have been accepted for vertical wells in the beginning in high pressure low permeability fractured carbonate reservoir. The first trial met with success and initial day rate of production was as high as up to 480 tons of oil. Subsequently, near balance drilling and open hole completion have been adopted for other vertical and high-angle wells, average day rate of production exceeds 300 tons per well.
However, a few wells completed open hole encountered tubing blocked when put into production, which resulted in those wells off production. To prevent the wells from tubing blocked during putting into production, as well as to maintain high productivity, subsequent wells that are not suitable for open hole completion have been liner completed. Average day rate of production of those wells completed with liners also exceeds 300 tons per well.
Production of some wells completed open hole or liner exceeds 1000 tons per day per well. Open hole completion and liner completion have greatly increased productivity as compared to those wells completed perforation, turning it from an unable to be developed marginal field into one with annul capacity of 2 million tons of oil.