AN OVERVIEW OF TEST TECHNIQUE AND THEORY STUDY OF SLUG TEST

Slug test is an important hydraulic test technique to evaluate the local hydraulic properties of formation. Slug test has become such a frequently used technique as a result of its considerable logistical and economic advantages such as relatively low cost,simplicity,short duration of test,no water actually removed from or added to the well. There are more than fifty years of development history of this test in foreign countries;and its development is summarized as technique development and theoretical model development. Slug test technique can be divided into simple slug test,packer slug test and shut-in slug test. The theoretical models for slug test include exponential decay model,underdamped model and nonlinear model. The parameters obtained from slug test have been widely used in a variety of aspects,such as contamination hydrogeology,water supply investigations, near-surface agricultural hydrogeology,petroleum and coalbed-methane. The influential range of slug test is very small;and it is only possible to determine the characteristics of small volume of aquifer material surrounding the well due to intrinsic limitation of this technique. Recently,slug test is considered as an important technique to evaluate the spatial variations of aquifer seepage parameters and seepage characteristics of rock mass with low, even extremely low permeability. Shut-in slug test technique is utilized to in-situ measurement of rock mass permeability with permeability coefficient lower that 10-13 m/s.