scholarly journals Volcanic Reservoir Rocks and Reservoir Pressure in Nagaoka District, Niigata Prefecture

1966 ◽  
Vol 31 (1) ◽  
pp. 22-29
Author(s):  
Kinji MAGARA
Keyword(s):  
Reservoir Pressure ◽  
Reservoir Rocks ◽  
Volcanic Reservoir ◽  
Niigata Prefecture

Numerical Simulation of Oil Production With Simultaneous Ground Subsidence

1975 ◽  
Vol 15 (05) ◽  
pp. 411-424 ◽  
Author(s):  
A. Finol ◽  
S.M. Farouq Ali
Keyword(s):  
Oil Production ◽  
Oil Field ◽  
Oil Fields ◽  
Ground Subsidence ◽  
Bottom Surface ◽  
Reservoir Pressure ◽  
Reservoir Rocks ◽  
Reservoir Compaction ◽  
Fluid Production ◽  
Production Behavior

Abstract A two-phase, two-dimensional black oil simulator was developed for simulating reservoir production behavior with simultaneously occurring reservoir formation compaction and ground subsidence at the surface.The flow equations were solved by both alternating direction implicit procedure and strongly implicit procedure. Reservoir compaction was described on the basis of the experimental data reported. The magnitude of areal subsidence at the surface was calculated using reservoir compaction, utilizing the recently developed theory of poroelasticity. poroelasticity. Computer runs were used to generate a variety of data, such as reservoir Pressure variation with oil production, for different reservoir compaction production, for different reservoir compaction coefficients. It was found that the average reservoir pressure increased with the Compaction coefficient pressure increased with the Compaction coefficient for a given cumulative oil production.The model was used for generating the reservoir formation profiles, as well as the ground subsidence bowls for a variety of conditions. It was found that the subsidence behavior strongly depends on the depth of burial. For example, with an increase in the depth, the reservoir bottom surface may actually uplift, while the top surface subsides.The model was also used for studying the effect of subsidence on pressure buildup behavior. The calculated reservoir pressure was higher in a compacting than in a noncompacting reservoir, taking into account the variation of permeability with compaction.Another phase studied was the effect of rebound on reservoir performance when gas is injected into the formation. Even though rebound is small in practice (on the order of 10 percent of subsidence), practice (on the order of 10 percent of subsidence), the effect was clearly evident in the reservoir pressure-production behavior. However, when there pressure-production behavior. However, when there was no rebound, gas injection simply inhibited compaction.Finally, the model was used for simulating the reported oil production and subsidence history of one of the Bolivar Coast oil fields in the Western Venezuela. Fair agreement was obtained between the observed and the predicted behavior. Introduction The phenomenon of ground subsidence associated with production of oil or gas from underground hydrocarbon reservoirs is not common; however, it does present environmental problems in a few oil-producing areas around the world. Notable examples are the Wilmington oil field, below Long Beach, Calif. where almost 30 ft of subsidence have been recorded, and the oil fields near and under Lake Maracaibo in Venezuela, where the surface has subsided as much as 10 ft. Other cases have been reported in Harris County, Tex., in the Niigata district of Japan, and in the Po Delta in Italy.Numerous causes may give rise to ground subsidence, either natural or as a result of man's activities. However, as far as the problem at hand is concerned, the observed land subsidence is considered to be a result of reservoir compaction, resulting from pore pressure decline in reservoirs that meet certain specific geometrical and structural conditions. The changes in the petrophysical properties of reservoir rocks caused by compaction properties of reservoir rocks caused by compaction have been studied to some extent, as well as the influence of such changes on the fluid production behavior of the reservoir. However, very little has been accomplished in relating the compaction of the underground reservoir with the subsidence occurring at the surface. Among the few studies conducted on this problem, the most realistic are those that consider subsidence above a disk-shaped reservoir, in which a uniform pressure reduction has occurred. These studies do not simulate the fluid production behavior of the compacting reservoir as such; this is considered to be known and is used to determine the compaction of the reservoir and the accompanying subsidence. SPEJ P. 411

scholarly journals Choosing the optimal operating mode of a gas condensate well taking into account the relaxation deformation of rocks

2021 ◽  
Vol 134 (3) ◽  
pp. 50-54
Author(s):  
Т. А. Samadov ◽  
◽  
B. Z. , Кazymov ◽  
S. H. Novruzova ◽  
◽  
...  
Keyword(s):  
Operation Mode ◽  
Operating Mode ◽  
Optimal Operation ◽  
Gas Condensate ◽  
Reservoir Pressure ◽  
Optimal Operating ◽  
Reservoir Rocks ◽  
Bottom Hole ◽  
Sand Accumulation ◽  
Current Operating

The article proposes a method for selecting the optimal operation mode of a gas condensate well without sand accumulation in the bottom, taking into account the relaxation deformation of reservoir rocks during the development of a gas condensate deposit in the depletion mode. This method simultaneously allows you to determine the required current operating volume of produced condensate (as well as gas), as well as bottom-hole and contour values of reservoir pressure, condensate saturation and porosity of the reservoir, corresponding to the selected optimal operation mode of the well.

Ciecze robocze – ich właściwości technologiczne i rola w procesie rekonstrukcji odwiertów

2021 ◽  
Author(s):  
Małgorzata Uliasz
Keyword(s):  
Hydraulic Conductivity ◽  
Solid Phase ◽  
Additional Treatment ◽  
Reservoir Rock ◽  
Porous Space ◽  
Reservoir Pressure ◽  
Technological Properties ◽  
Reservoir Rocks ◽  
Wide Range ◽  
Reservoir Conditions

A workover fluid is a type of special liquids used at the end of borehole drilling, i.e. during well operation or during reconstruction works. Such works, carried out at various stages of borehole operation, are aimed at maintaining or increasing the production of a specific well and at maintaining its proper technical condition. They may be carried out only after injecting the workover fluid into the borehole, which should generate counterpressure on the reservoir, preventing the inflow of reservoir media into the borehole, and should enable the maintaining of the hydraulic conductivity of the reservoir rock. To ensure that the basic requirements are satisfied by the workover fluid injected into the borehole, its physical and chemical properties must correspond to the geological and reservoir conditions of the specified level of reservoir rocks. Due to this, the composition of the workover fluid should be determined based on the reservoir pressure gradient, mineralogical composition of reservoir rocks and of their binder, as well as the chemical composition of reservoir waters. These are the basic criteria for selection of the composition and evaluation of the quality of the workover fluid, which enable control of the physicochemical processes occurring within the borehole zone, such as clogging of the porous space of rocks, hydration of clay minerals, capillary effects and changes in the surface tension at the interface, as well as the interaction of fluid with reservoir waters. Limitation of the intensity of occurrence of such processes, which affect the degree of damage to the permeability of the reservoir rocks in horizons featuring normal or reduced reservoir pressure, largely depends on the type of workover fluid used, i.e. brine without a solid phase and brine containing a solid phase or a liquid with density below 1.0 kg/dm3. The composition and technological properties of the workover fluid, properly selected to the specific geological and reservoir conditions, allow one to maintain the productivity of the well to a degree that does not require application of additional treatment, such as acid-treatment, fracturing and reperforations. The aim of the monograph is to show the role of a workover fluid in the conducted reconstruction treatments, as well as the importance of its technological properties in limiting damage to the permeability of reservoir rocks within the borehole zone. The presented issues comprise: • causes and threats to the deterioration of reservoir rock permeability resulting from the application of an improperly selected workover fluid; • tasks of the workover fluid and methods to improve its technological properties in terms of protecting the hydraulic conductivity of reservoir rocks; • types of workover fluids developed, the methodology for determination and assessment of their technological properties, as well as usability under reservoir conditions. The monograph also includes a short description of other special liquids used in the preparation of a well for exploitation. These are: washing and cleaning liquids, packer fluids and those used for perforation, as well as buffers for rope operations and pipe cleaning prior to packer fluid injection. The presented issue is a synthesis of a wide range of research and development works carried out at the INiG - PIB. It has been prepared based on the obtained results of laboratory tests carried out for geological and reservoir conditions existing in the productive horizons of the Carpathian Foredeep, as well as of the Carpathians and the Polish Lowlands. Keywords: borehole reconstruction, geological and reservoir conditions, workover fluid tasks, workover fluid properties, chemicals, blockers, permeability

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