scholarly journals The Effect of Sand Plug at the Gas Well Bottom-hole on its Productive Characteristics

Author(s):  
R. М. Kondrat ◽  
N. S. Dremliukh

The reasons that lead to the destruction of the bottomhole zone during the operation of wells with unstable reservoirs are considered. The negative effects of the sand carry-over from the formation into the wellbore are shown. The review of scientific and technical literature on the effect of the sand plug on well productivity is presented. It indicates that the studies have mainly considered oil wells, but the effect of the sand plug on well productivity has not been studied sufficiently. For most gas wells, Darcy's law is primarily violated while filtering gas to the bottom-hole of the well, especially at high gas flow rates. The authors have studied theoretically the effect of a sand plug at the bottom of a gas well with permeability variations on the productive characteristics.  According to the results of theoretical studies, the authors construct and analyze graphical dependencies in the form of the ratio of gas flow with and without a sand plug to the ratio of the reservoir permeability and the plug, on condition that the plug blocks the reservoir completely and the plug height exceeds the reservoir thickness. The scientists work a formula for indicating the flow rate of a gas well with a sand plug at the well bottom, on condition that the plug blocks the reservoir completely and the plug height exceeds the reservoir thickness while filtering gas in the reservoir according to the binominal law. On the basis of the research, it is established that on condition of the identical height of the sand plug and the identical ratio of reservoir permeability and the plug, the productivity of the gas well with the sand plug increases with the increase of the reservoir permeability. If the height of the plug exceeds the reservoir thickness, the flow rate of the gas well will be the smaller, the greater is the height of the sand plug compared to the reservoir thickness.

Author(s):  
R. М. Kondrat ◽  
N. S. Dremliukh ◽  
L. І. Haidarova

The negative consequences of sand production from the formation into the wellbore during the operation of wells with unstable rocks are characterized. A highly effective method of preventing sand from entering the well from the formation is the use of gravel packs, which are used in Ukraine and abroad. The types of gravel packs, the conditions for their application, the choice of the diameter of gravel grains for creating gravel pack are given. The types of gravel pack installation are considered depending on the geological and technical conditions of the reservoir. Calculations have been performed using Schlumberger's PipeSim software to assess the effect of gravel pack size and permeability on the performance specification of a gas well. Based on the research results, graphical de-pendences of gas flow rates in the presence of gravel pack on the permeability of the gravel pack at its various thicknesses have been constructed and analyzed. It has been found that the gas flow rate increases with an increase in the thickness of the gravel pack in the considered interval of its variation up to 0.9 m. The effect of the thickness of the gravel pack on the gas flow rate increases with an increase in its permeability. Based on the results of statistical processing of the calculated data using the least-squares method, the optimal values of the gravel pack permeability for various values of its thickness have been determined. The optimal values of the thickness and permeability of the gravel pack have been determined, beyond which the value of the gas flow rate practically does not change. The calculation of the pressure distribution along the bore of a gas well in the presence of gravel pack with certain optimal values of its permeability and thickness is performed. Using the PipeSim software, the influence of the de-gree of relative formation penetration on the productivity of a gas well in the presence of gravel packing has been investigated for determining certain optimal values of permeability and thickness of gravel packing.


Author(s):  
Antonio J. Mele´ndez-Rami´rez ◽  
Miguel A. Reyes-Gutie´rrez ◽  
Luis R. Rojas-Solo´rzano ◽  
Juan C. Mari´n-Moreno ◽  
Jose´ Colmenares

New data of the experimental performance of a Gas-Liquid Cylindrical Cyclone (GLCC) separator are presented. The data were collected using a 2 3/4” (0.07m) ID GLCC model working with an air-glycerin mixture. The inlet liquid flow rate, the inlet gas flow rate, the tangential liquid velocity inside the separator body and the gas carry under were measured for an operation regime without liquid carry over. The influence of the first three parameters over the gas carry under was established. Results show the separator efficiency is mainly affected by the inlet gas flow rate for the explored conditions with slug flow at the GLCC entrance.


Author(s):  
B.S. Soroka ◽  
V.V. Horupa

Natural gas NG consumption in industry and energy of Ukraine, in recent years falls down as a result of the crisis in the country’s economy, to a certain extent due to the introduction of renewable energy sources along with alternative technologies, while in the utility sector the consumption of fuel gas flow rate enhancing because of an increase the number of consumers. The natural gas is mostly using by domestic purpose for heating of premises and for cooking. These items of the gas utilization in Ukraine are already exceeding the NG consumption in industry. Cooking is proceeding directly in the living quarters, those usually do not meet the requirements of the Ukrainian norms DBN for the ventilation procedures. NG use in household gas stoves is of great importance from the standpoint of controlling the emissions of harmful components of combustion products along with maintenance the satisfactory energy efficiency characteristics of NG using. The main environment pollutants when burning the natural gas in gas stoves are including the nitrogen oxides NOx (to a greater extent — highly toxic NO2 component), carbon oxide CO, formaldehyde CH2O as well as hydrocarbons (unburned UHC and polyaromatic PAH). An overview of environmental documents to control CO and NOx emissions in comparison with the proper norms by USA, EU, Russian Federation, Australia and China, has been completed. The modern designs of the burners for gas stoves are considered along with defining the main characteristics: heat power, the natural gas flow rate, diameter of gas orifice, diameter and spacing the firing openings and other parameters. The modern physical and chemical principles of gas combustion by means of atmospheric ejection burners of gas cookers have been analyzed from the standpoints of combustion process stabilization and of ensuring the stability of flares. Among the factors of the firing process destabilization within the framework of analysis above mentioned, the following forms of unstable combustion/flame unstabilities have been considered: flashback, blow out or flame lifting, and the appearance of flame yellow tips. Bibl. 37, Fig. 11, Tab. 7.


1998 ◽  
Vol 63 (6) ◽  
pp. 881-898
Author(s):  
Otakar Trnka ◽  
Miloslav Hartman

Three simple computational techniques are proposed and employed to demonstrate the effect of fluctuating flow rate of feed on the behaviour and performance of an isothermal, continuous stirred tank reactor (CSTR). A fluidized bed reactor (FBR), in which a non-catalytic gas-solid reaction occurs, is also considered. The influence of amplitude and frequency of gas flow rate fluctuations on reactant concentrations at the exit of the CSTR is shown in four different situations.


Author(s):  
Pengju Huo ◽  
Xiaohong Li ◽  
Yang Liu ◽  
Haiying Qi

AbstractThe influences of loose gas on gas-solid flows in a large-scale circulating fluidized bed (CFB) gasification reactor were investigated using full-loop numerical simulation. The two-fluid model was coupled with the QC-energy minimization in multi-scale theory (EMMS) gas-solid drag model to simulate the fluidization in the CFB reactor. Effects of the loose gas flow rate, Q, on the solid mass circulation rate and the cyclone separation efficiency were analyzed. The study found different effects depending on Q: First, the particles in the loop seal and the standpipe tended to become more densely packed with decreasing loose gas flow rate, leading to the reduction in the overall circulation rate. The minimum Q that can affect the solid mass circulation rate is about 2.5% of the fluidized gas flow rate. Second, the sealing gas capability of the particles is enhanced as the loose gas flow rate decreases, which reduces the gas leakage into the cyclones and improves their separation efficiency. The best loose gas flow rates are equal to 2.5% of the fluidized gas flow rate at the various supply positions. In addition, the cyclone separation efficiency is correlated with the gas leakage to predict the separation efficiency during industrial operation.


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