Drilling and completion technology for dual branch horizontal well H8309 of Khasakstan

The Kenkiyak Oilfield in Kazakhstan is one of the world-recognized blocks difficult to be produced. This block has small individual-well oil control area and high developmentcosts. Therefore, it is determined that the technical difficulties in this Block be tackled by branch well drilling technologies. Well H8309 is the first overseas dual branch horizontal well of PetroChina, which has the deepest sidetracking point among overseas dual branch hozizonal wells.In order to overcome high pressure in deep wells and ensure wellbore stability, high density drilling fluid （1.98 g/cm3）was used in this well; in order to reduce well control risks, this well used the sectional whipstock fishing technology for branch wells and completion string release technology for deep branch wells for the first time. The dual branch holes were both acid fractured. The H8309 Well flowed at a rate of 180 tons of oil a day and maintained smooth production for 138 days, which is three times of daily production of adjacent horizontal wells. The success in this well provides experiences for the efficient development of difficult blocks, provides new approaches to the development of oil and gas in Kenkiyak oil province and provides strong support for developing faulted edge reservoirs, improving oil recovery and reducing development costs.