Abstract: Pressure transient testing is an important dynamic monitoring technique for obtaining reservoir information and strata parameters. The pressure build-up test and the pressure drawdown test to acquire the formation parameters are usually adopted in the oilfield. But the methods have to need certain closed-in time, which has a great influence to the production, especially to the high-yielding oil well and high-rate water injection well. Hence, a new technique of pressure transient testing is requested to overcome the disadvantage and acquire accurate information of the reservoir. The case study named variable rate transient testing in the ultra-deep horizontal well of the unsaturated sandstone reservoir of Tarim H field shows that the theory is correct, the application condition is specific, the field response is good, indicating that such a horizontal well test technique is a powerful support to the development scheme adjustment while keeping the high-yielding and the production stable in the oilfield.

Key words: unsaturated reservoir, ultra-deep well, horizontal well, pressure transient testing