Key technologies of acid-fracturing for ultra-deep reservoirs with high temperature and high fracture pressure

The external blocks of Tahe oilfield mainly include Tuofutai, Bamai, Yuqi, and TaZhong and so on, which are characterized with ultra-deep burial depth（6300 m）, high reservoir temperature（140 ℃）, great fracturing pressure gradient （0.021 MPa/m）and poor developed fracture-cavity comparing to Tahe Block 4 and other developing zones. With the study and application of relative technologies, such as reducing fracturing pressure, reducing filtrate, optimizing design and integrated techniques, the success treatment rate and stimulation effect of acid-fracturing are notably enhanced. And the applications of these techniques effectively promote the reserves producing of freshly developed blocks.