Drilling fluid technology for salt-gypsum zones and high pressure saltwater zones in Azores Area, Turkmenistan

The interval between 2230 m and 2860 m of Zhebie Oilfield in Azores of Turkmenistan is difficult to drill due to many challenges, such as existence of multiple salt-gypsum zones and high pressure saltwater zones, high salinity and narrow safety pressure windows. Through researching and applying calcium treated compound saltwater drilling fluid system, anti-pollution capacity against high concentration of Ca2+ and Mg2+ of drilling fluid is enhanced and its stability is guaranteed. Combined near-balance pressure drilling with plugging while drilling, technical problems of lost circulation and narrow safety pressure windows were resolved by using time lagged swelling compound plugging technology. As a result of above technologies, four wells are finished successfully, providing technological guarantee for future drilling in the area.