| Abstract |
In evaluating geothermal resources we are primarily interested in data on the distribution of temperature and fluid conductivity within the reservoir, the total volume of the productive formations, recharge characteristics and chemical quality of the thermal fluids. While geophysical exploration by surface methods may furnish some data on the temperature field and give indications as to the reservoir volume, they furnish practically no information on the fluid conductivity and production characteristics. Such information will generally have to be obtained by tests performed within the reservoir, primarily by production tests on sufficiently deep wells. Reservcir testing is therefore one of the most important tasks in a general exploration program. I n principle, reservoir testing has much in common with conventional geophysical exploration. A1 though the physical fields applied are to some extent different, we face the same type of selection between controlled and natural drives, forward and inverse problem setting, etc. The basic philosophy (Bodvarsson,, 1966) is quite similar. In the present paper, we will discuss some fundamentals of the-theory of reservoir testing where the fluid conductivity field is the primary target. The emphasis is on local and global aspects of the forward approach to the case of liquid saturated (dominated) Darcy type formaticns. and natural driving pressure or strain fields are to be considered and particular emphasis will be placed on the situation resulting from the effects of a free liquid surface at the top of the reservoir. |