Abstract:
In order to determine the potential of electrical energy a geothermal well drilled that have been completed, there should be a series of production tests to determine precisely and accurately the characteristics of the geothermal production wells in terms of physical and chemical properties. There are several methods in geothermal well testing, but there are two commonly used methods, lip pressure and separator method. Lip pressure method can be performed in an upright (vertical discharge) or in a flat (horizontal discharge). Basically, both methods have the same purpose, its to clean the drill cutting or mud drilling and to get potential electrical energy that can be generated by these wells. In the progress of the production test, the separator method can present the data characteristics that have more comprehensive than lip pressure. However, separator method need longer preparation, larger cost, more man power and more complicated calculations than the method of lip pressure. From that background, the comparative analysis between the two methods by using statistical tools, in this case used the t-test method. The comparisons were done on eight wells at Lahendong (North Sulawesi) and Ulubele (Lampung) geothermal fields. The comparison was conducted on the rate of vapor and enthalpy for both the production test method. By calculating the error value and the standard deviation at 95% confidence level obtained by the normal distribution curve. Acceptance range for enthalpy of 596 kJ/kg to 1850 kJ/kg and steam rate of 23 tons/hour to 98 tons/hour. In other words, when used the lip pressure method and the results in that range, then we can say it's accurate with a confidence level of 95%.
