Print this pageABSTRACT: Interference test of Sibayak geothermal field North Sumatra, Indonesia
Harun, Mochamad1 and Tavip Dwikorianto2
(1)
Pertamina Area Panasbumi EP Sibayak, Sumatra Utara, Indonesia
(2) Pertamina Area Panasbumi
Sibayak
Interference test has been recognized as a valuable technique for evaluating reservoir
properties
such as permeability thickness and storativity over an area where active and
observation wells are located. Interference test can also provide qualitative indications
of reservoir heterogenities and communication between two or more wells. The availability
of sophisticated pressure recorders encourages providing reliable data and improved
accuracy.
Interference test of Sibayak geothermal field that has been carried out in December
1998 to September 1999 is examined to prove two major fault which are predicted supporting
permeability of this area. The presence of linear boundary can be determined by using a
new semi-log type curve matching (Sageev et al, 1985). Log-log type curve (Theis Curve)
can also be employed to determine the interwell properties i.e. transmisivity and
storativity.
The first test that conducted by measuring SBY-8 response to SBY-5 discharge does not
reflect presenting of either fault F1 or fault F4 which is predicted supporting the
permeability before. The second test of well SBY-7 response to SBY-5 discharge indicates
shifting of the pressure response to the constant pressure linear boundary curve. It is
shown in a log-log plot matching (Theis curve
) and more clearly in new semi-log. For
Sibayak geothermal field the area between SBY-8 and SBY-5, permeability thickness is 40.3
x 10-12 m3 and
storativity is 2.64 x 10-8 m/Pa. The area between SBY-7 and SBY-5, permeability thickness is 48.3 x 10-12 m3 and storativity is 1.63 x 10-8 m/Pa.
AAPG Search and Discovery Article #90913©2000 AAPG International Conference and Exhibition, Bali, Indonesia