Influence of viscoplastic oil properties on well performance in the presence of a sand plug at the bottomhole

UDK: 622.276.5:665.613.2
DOI: 10.24887/0028-2448-2019-2-58-60
Key words: viscousplastic oil, sand plug, oil well, radial two-dimensional flow, filtration rate
Authors: S.D. Mustafayev (Azerbaijani State University of Oil and Industry, Azerbaijan, Baku), S.A.-G. Gasymova (Azerbaijani State University of Oil and Industry, Azerbaijan, Baku)

The authors consider the work of the well producing viscoplastic oil in case of a sand plug at the bottomhole. In a drainage zone of the well there is a radial two-dimensional flow which takes place in many operational wells which have opened all power formation thickness. In a sand plug upward parallel flow occurs. Filtration of viscoplastic oil in a drainage zone and in a plug follow the generalized Darcy’s law which is two-parameter model: the first parameter is the plastic viscosity, and the second one is the initial pressure gradient that typifies the movement of viscoplastic oil in the porous medium. The porous medium is uniform formation; lateral and vertical reservoir permeability doesn't change and remains constant. The current surface of filtration in a drainage zone is cylindrical and the less is radius-vector the less is area of the current cylindrical surface. The current surface of filtration in a sand plug is a circle which remains constant. For definition of key parameters of the oil well operation were used a formulas for oil production rate in a drainage zone and in a sand plug. From the equality of these oil production rates, a formula was derived for the pressure at the bottomhole, i.e. under the sand plug. Using formulas of the areas of filtration surfaces in drainage zone and in sand plug, formulas were derived for the filtration rates in the layer and in the sand plug. Formulas are also derived for the law of pressure distribution in the drainage zone of the layer. The relationship between the average true speed of oil movement in the porous channels of the reservoir rocks and the speed of filtration is used. The depth of the oil level above the sandy cork was determined with the help of an echometer of the Kvantor-4mikro hardware and software complex.

References

1. Aleskerov S.S., Alibekov B.I. et al., Vliyanie vyazko-plastichnykh svoystv zhidkosti na debit skvazhiny pri rabote ee cherez filʹtr chastichno perekrytyy peschanoy probkoy (In Russ.), Ehkspluatatsiya skvazhin v oslozhnennykh usloviyakh, 1971, pp. 18–20.

2. Əliyev İ.İ., Ştanqlı dərinlik nasos quyularında qum tıxacının hündürlüyünün təyin edilməsi üsulu (Method for determining the thickness of a sand plug formed in a well with a sucker-rod pump), ANT, 2004, no. 11, pp. 16–20.

3. Samedov T.A., Mustafaev S.D., Guliev R.A., Some method applied to determine frequency of sand plugs washing in oil wells (In Russ.), Neftepromyslovoe delo, 2015, 7 p.

The authors consider the work of the well producing viscoplastic oil in case of a sand plug at the bottomhole. In a drainage zone of the well there is a radial two-dimensional flow which takes place in many operational wells which have opened all power formation thickness. In a sand plug upward parallel flow occurs. Filtration of viscoplastic oil in a drainage zone and in a plug follow the generalized Darcy’s law which is two-parameter model: the first parameter is the plastic viscosity, and the second one is the initial pressure gradient that typifies the movement of viscoplastic oil in the porous medium. The porous medium is uniform formation; lateral and vertical reservoir permeability doesn't change and remains constant. The current surface of filtration in a drainage zone is cylindrical and the less is radius-vector the less is area of the current cylindrical surface. The current surface of filtration in a sand plug is a circle which remains constant. For definition of key parameters of the oil well operation were used a formulas for oil production rate in a drainage zone and in a sand plug. From the equality of these oil production rates, a formula was derived for the pressure at the bottomhole, i.e. under the sand plug. Using formulas of the areas of filtration surfaces in drainage zone and in sand plug, formulas were derived for the filtration rates in the layer and in the sand plug. Formulas are also derived for the law of pressure distribution in the drainage zone of the layer. The relationship between the average true speed of oil movement in the porous channels of the reservoir rocks and the speed of filtration is used. The depth of the oil level above the sandy cork was determined with the help of an echometer of the Kvantor-4mikro hardware and software complex.

References

1. Aleskerov S.S., Alibekov B.I. et al., Vliyanie vyazko-plastichnykh svoystv zhidkosti na debit skvazhiny pri rabote ee cherez filʹtr chastichno perekrytyy peschanoy probkoy (In Russ.), Ehkspluatatsiya skvazhin v oslozhnennykh usloviyakh, 1971, pp. 18–20.

2. Əliyev İ.İ., Ştanqlı dərinlik nasos quyularında qum tıxacının hündürlüyünün təyin edilməsi üsulu (Method for determining the thickness of a sand plug formed in a well with a sucker-rod pump), ANT, 2004, no. 11, pp. 16–20.

3. Samedov T.A., Mustafaev S.D., Guliev R.A., Some method applied to determine frequency of sand plugs washing in oil wells (In Russ.), Neftepromyslovoe delo, 2015, 7 p.


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