ENHANCED OIL RECOVERY THROUGH THE USE OF VIBRO SEISMIC IMPACT TECHNOLOGY (VSIT) - A CASE STUDY FROM MERBAU TREND AND JENE OILFIELD

摘要

Declining production in oil recovery operations is a major concern in the oil producing industry. Typically, natural pressure in the reservoir generally results in 5 - 15% recovery of the existing oil contained in the formation and secondary recovery generally results in a 20 - 45% recovery factor. The residual oil is difficult to produce because of its very low mobility. To improve the recovery factor, some enhanced oil recovery (EOR) methods are commonly applied. These methods, in the most successful cases, can enhance the oil recovery by up to 50 - 70% of the total oil in place. Vibro Seismic Impact Technology (VSIT) is an alternative EOR method using seismic waves, which are generated by means of a surface seismic vibrator to stimulate the reservoir. The mechanisms responsible for improved recovery remain the subject of further research. However, the following mechanisms have been proposed to explain the change in fluid flow characteristics resulting from the seismic wave stimulation, that is, changes in wettability, coalescence and/or dispersion of oil drops, reduced viscosity and surface tension, and increased permeability. The surface excitation method of reservoir stimulation requires significant further testing. The number of field tests or applications conducted is, as yet, insufficient. Attempts to use surface sources for oil production stimulation show both positive and negative results, depending on the formations/ reservoir characteristics. In Indonesia, VSIT field tests or applications are still rare. This paper will discuss VSIT field application in Merbau Trend and Jene Oilfield, both located in Sumatera. These fields have different formations, i.e. sandstone and limestone. This paper will provide invaluable information about the results of VSIT application on different formations.