| Title | Pressure Transient Analysis of Geothermal Wells with Phase Boundaries |
|---|---|
| Authors | Horne, R.N., Satman, A., and Grant, M.A. |
| Year | 1980 |
| Conference | New Zealand Geothermal Workshop |
| Keywords | |
| Abstract | The analysis of pressure tests in geothermal This paper investigates the effect of a reservoirs is often complicated by two-phase effects. boundary at a constant radial distance from the well, produced, for example, by the flashing of a water reservoir during production or by the injection of water into a steam or two-phase reservoir. This configuration may be recognized from a time shift in the buildup (or falloff) semilog straight line, and, in some cases, the distance to the phase boundary can be estimated by plotting the transition pressure response against time on Cartesian coordinates. Field data from the Broadlands geothermal field in New Zealand confirms the applicability of the technique and demonstrates that the injected volume (which is known) may be used with the buildup data to calculate porosity and ''swept" volume. The analysis also indicates the possibility of compressibility and permeability contrasts across the phase boundary. estimation of the reservoir porosity and relative permeabilities in the two-phase region. In a few cases, wellbore storage effects can disguise the pressure response and make parameter determination more difficult. These cases are discussed. |