Changes

===Vibroseismic theory and vibration effect===

===Vibroseismic theory and vibration effect===

Vibration system is medium to save potential energy . this system have capability to save kinetic energy (massa or inertia). Vibration system involve ac-dc transfer energy beetwen potential and kinetic shape. In dimmed system some energy will be wrapped in each vibration cycle and must reaplacement from eksternal source, if the stabil vibration is hold. Although single pysic stucture can save kinetic and potential energy and can remove the energy. In translation move, replacement is distance, rotation as an angle move (Ralph, 1998)

Vibration system is medium to save potential energy . this system have capability to save kinetic energy (massa or inertia). Vibration system involve ac-dc transfer energy beetwen potential and kinetic shape. In dimmed system some energy will be wrapped in each vibration cycle and must reaplacement from eksternal source, if the stabil vibration is hold. Although single pysic stucture can save kinetic and potential energy and can remove the energy. In translation move, replacement is distance, rotation as an angle move.<ref>Ralph, B., 1998, Basic Vibration Theory: London.</ref>

[[FIG 2]]

[[FIG 2]]

In result of study analysts in laboratorium about core syntesis, vibration stimulation can repair the characteristic of rock physic that increase the porocity (φ) until 15.3% and absolute pearmeability (kabs) until 2.2% and decrease saturated oil remain (Sor) until 53.6%. From the result above need to do the reasearch that analysts the effect of vibration frequencyand pressure about porosity (φ), Kabs and Sor in corefield (Ridaliani et al., 2010)

In result of study analysts in laboratorium about core syntesis, vibration stimulation can repair the characteristic of rock physic that increase the porocity (φ) until 15.3% and absolute pearmeability (kabs) until 2.2% and decrease saturated oil remain (Sor) until 53.6%. From the result above need to do the reasearch that analysts the effect of vibration frequencyand pressure about porosity (φ), Kabs and Sor in cornfield.<ref name=Ridaliani_et_al>Ridaliani, O., T. Ariadji, and G. Handayani, 2005, Prediksi Perubahan Sifat Fisik</ref>

The analysts use the Hasler Permeameter tool with modification with vibrator. First model that designed with vibrator place above the core holder according vertical vibration direction. Meanwhile second model with vibrator that place beside core holder with horizontal vibration direction and direction beetwen vibrator and core holder closer than the first model. From the result of laboratorium study with second model tools in 15 core in the field, find that the the porocity before vibration is 4.84%-26.73% and after the vibration the porosity increase until 53.9% with average 36.6%. Kabs data before vibration is 231.46 m – 1113.59 mD and after vibration can reach 54.1% with average 39.4%. Sor Data before vibration is 0.15%-0.57%. and after vibration can reacht decrease Sor untul 68% with average 66.1 %. From the result above, there is the same result beetwen sysntesis core and field core that give the image about the same changing pattern in rock pysical properties (φ, kabs and Sor) because the effect of vibration stimulation with increase of porosity and kabs and the decrease of Sor. The effect of pressure in vibration stimulation make the system is confined, and the direction effect from the vibration source about core holder can as effective as radius from vibrator strength (Ridaliani et al., 2005)

The analysts use the Hasler Permeameter tool with modification with vibrator. First model that designed with vibrator place above the core holder according vertical vibration direction. Meanwhile second model with vibrator that place beside core holder with horizontal vibration direction and direction beetwen vibrator and core holder closer than the first model. From the result of laboratorium study with second model tools in 15 core in the field, find that the the porocity before vibration is 4.84%-26.73% and after the vibration the porosity increase until 53.9% with average 36.6%. Kabs data before vibration is 231.46 m – 1113.59 mD and after vibration can reach 54.1% with average 39.4%. Sor Data before vibration is 0.15%-0.57%. and after vibration can reacht decrease Sor untul 68% with average 66.1 %. From the result above, there is the same result beetwen sysntesis core and field core that give the image about the same changing pattern in rock pysical properties (φ, kabs and Sor) because the effect of vibration stimulation with increase of porosity and kabs and the decrease of Sor. The effect of pressure in vibration stimulation make the system is confined, and the direction effect from the vibration source about core holder can as effective as radius from vibrator strength.<ref name=Ridaliani_et_al />

In this era, the technology of vibroseismic can be useful in research that do in teoritic or laboratorium, aplication in field, and to predict the performance in the future that relate with economic evaluation. If mechanism that happen in reservoar applied in vibroseismic technology, there is a possibility to increase the production rate. But, the rate of success aplication in field cannot give the justification of description about mechanism yet (Ariadi et al., 2005)

In this era, the technology of vibroseismic can be useful in research that do in teoritic or laboratorium, aplication in field, and to predict the performance in the future that relate with economic evaluation. If mechanism that happen in reservoar applied in vibroseismic technology, there is a possibility to increase the production rate. But, the rate of success aplication in field cannot give the justification of description about mechanism yet (Ariadi et al., 2005)

On the otherhand, the generally term in oil industry before the application of a technology . firstly, the prediction of the work wether technically or economically have to be done. In order to do the prediction step several method will be needed such as Decline Curve Analysis, laboratory research or reservoir simulation. But, until now there are no such prediction method that accepted by the oil industry, at this level of knowledge, empirical approachment is the most suitable method of the field prediction. There is also a prediction method that has been recommended by the russian researcher (Institute of the Eart Physics and Institute of Oil and Gas Research below Russian Academy Society) based on previous datas of production and water cut. After that, this method is being examined, evaluated and then proposed to more reliable method (Ariadji et al., 2010).

On the otherhand, the generally term in oil industry before the application of a technology . firstly, the prediction of the work wether technically or economically have to be done. In order to do the prediction step several method will be needed such as Decline Curve Analysis, laboratory research or reservoir simulation. But, until now there are no such prediction method that accepted by the oil industry, at this level of knowledge, empirical approachment is the most suitable method of the field prediction. There is also a prediction method that has been recommended by the russian researcher (Institute of the Eart Physics and Institute of Oil and Gas Research below Russian Academy Society) based on previous datas of production and water cut. After that, this method is being examined, evaluated and then proposed to more reliable method.<ref name=Ariadji_et_al>Ariadji, T., H. Purwanto, and D. B. Scarboroug, 2005, Metode Peramalan Dan Evaluasi Keekonomian Teknologi Vibroseismik. Bandung: Petroleum Engineering Department.</ref>

==Step of experiment==

==Step of experiment==

[[FIG 3]]

[[FIG 3]]

The previous study indicate that vibration stimulation can change the coal properties, such as porosity and absolute permeability (kabs). Permeability is the main parameter of CBM reservoir in determining response of reservoir – reservoircoal – seam. The high value of permeability will increase the gas production rate related to the increase of gas desorption process speed (Ariadji, et al., 2010).

The previous study indicate that vibration stimulation can change the coal properties, such as porosity and absolute permeability (kabs). Permeability is the main parameter of CBM reservoir in determining response of reservoir – reservoircoal – seam. The high value of permeability will increase the gas production rate related to the increase of gas desorption process speed.<ref name=Ariadji_et_al />

However, the optimum value of frequency will be needed to meet the maximum permeability, there are two ways to determine the optimum value of frequency, there are analytical method and experimental method. To determine the optimum value of frequency analytically, there is formula to count the exact value of optimum frequency, the formula is :

However, the optimum value of frequency will be needed to meet the maximum permeability, there are two ways to determine the optimum value of frequency, there are analytical method and experimental method. To determine the optimum value of frequency analytically, there is formula to count the exact value of optimum frequency, the formula is :

[[TABLE 3]]

[[TABLE 3]]

Based on the data, we know that the value of optimum frequency is 10 – 15 Hz (Ariadji et al., 2010)

Based on the data, we know that the value of optimum frequency is 10 – 15 Hz<ref name=Ariadji_et_al />

==Application==

==Application==

==References==

==References==

 

* Batuan Reservoir Dengan Studi Laboratorium Stimulasi Vibrasi Terhadap Contoh Batuan Lapangan Pada Berbagai Tekanan Overburden. Department Petroleum Engineering: Institut Teknologi Bandung.

* Batuan Reservoir Dengan Studi Laboratorium Stimulasi Vibrasi Terhadap Contoh Batuan Lapangan Pada Berbagai Tekanan Overburden. Department Petroleum Engineering: Institut Teknologi Bandung.

* Seidle, John. 2011. Fundamentals of Coalbed Methane Reservoir Engineering. Oklahoma: Pennwell Corporation.

* Seidle, John. 2011. Fundamentals of Coalbed Methane Reservoir Engineering. Oklahoma: Pennwell Corporation.

* Sukandarrumidi. 1995. Batubara dan Gambut. Yogyakarta: Gadjah Mada University Press. Sukandarrumidi. 2006. Batubara dan Gambut, Pengantar Teknologi Batubara Menuju

* Sukandarrumidi. 1995. Batubara dan Gambut. Yogyakarta: Gadjah Mada University Press. Sukandarrumidi. 2006. Batubara dan Gambut, Pengantar Teknologi Batubara Menuju

* Lingkungan Bersih. Yogyakarta: Gadjah Mada University Press.

* Lingkungan Bersih. Yogyakarta: Gadjah Mada University Press.