INVESTIGATION OF WELLS IN THE WORKING FUND OF “AZNEFT” PU AND PROPOSAL OF ANTI-SAND MEASURES
Authors: Alesker Jabarov Alesker Jabarov 
Published: April 2022

One of the most common complications during the operation of wells in oil fields is the formation of sand. During the formation of sand wells, time stops, their repair takes a long time, as a result, there is a significant loss of production of the well. A floating sand with liquid entering the bottom of a well, destroys the working equipment, loses speed and breaks down at the bottom of the well, forming a sand plug. Removal of sand plugs requires a lot of labor, but sometimes leads to the loss of oil in many wells and the destruction of rocks in the subsurface zone of wells and deformation of the operating pipeline.
One of the most pressing problems in the oil industry today is to prevent rock particles from collapsing in the wellbore area and sand accumulation. Despite numerous scientific studies and mining experiments on the sand prevention mechanism, no universal method of sand control has been found. Studies show that the load on the walls of the protective pipeline is the main cause of failure of wells as a result of deformation of the pipeline within the operating facility. Sand block formation during the operation of fragile, poorly cemented reservoirs is an important factor in the close relationship between production line deformation and sand block formation in the well, which requires consideration of the geological and operational characteristics of the field an object.
The internal structure of the formation usually changes before the collector rocks are washed away by the infiltration stream. Changes in rock structure during the filtration process occur as a result of mechanical suffocation and compaction of rocks (separation of particles in the rock under the influence of pressure gradients during the movement of oils containing heavy particles in the formation). The most effective way to combat wellhead flushing and sand blockage is to reduce the amount of fluid removed from the formation. This is due to the regulation of the pressure drop in the wellbore. Rock collapse is accompanied by the introduction of sand grains into the wellbore, thereby continuously reducing the permeability of the wellbore zone. However, the sharp decline in well yields is not due to a decrease in the permeability of the formation, but to the high resistance created by the blockage, which closes the filter section and is formed by small sand grains.
Colmatization of mechanical mixtures in the wellbore area, contamination of the wellbore, increased vibrations and more intensive wear of the equipment inside the well create serious complications.
Despite the widespread use of rod depth pumps, their operation in sand wells is complicated. As a result, the voltage on the rods and the electric motor increases, the rods are stretched, broken, the pliers are idle, the electric motor is overloaded, and so on. occurs.
The formation of sand plugs is more pronounced in the final stages of field development. At the moment, due to the sand plugs in the wells, they often stop for repairs, which reduces of the time between repairs and increases the over-all operating costs. Therefore, one of the most pressing issues facing oil workers is to study the causes of sand plugs, to investigate the processes taking place in the plug zone and to develop effective methods to combat sand by analyzing the operation of such wells. If the sand completely closes the filter of the production casing and as a result the flow of liquid to the bottom hole is completely stopped, such a complication can be eliminated by either washing the bottom hole or strengthening the well hole zone. However, in many cases this technology does not work or is not cost-effective.
Based on the results of the study, indicator diagrams or graphs of changes in the percentage of oil, water, gas and sand are plotted depending on the pressure in the well or the dynamic level, as well as adjustment curves, i.e. graphs of the dependence of these indicators on the parameters of deep pumping. According to the results of studies carried out by measuring the dynamic level of a deep pump, an indicator diagram can be constructed using the method. This method consists of recording dynamic levels on the same scale selected on the vertical axis, plotting the level drops on the right axis, and recording the percentages of liquid, oil, water, gas, and sand on the horizontal axis. The amount of sand recovered can be expressed in volumes or units of weight. Liquid, oil and water debits should be taken on the same scale. They select the appropriate scale for gas and GOR as well as the percentage of sand, and the level drawdown (difference between static and dynamic levels) is also determined as fluid levels are measured from the wellhead.
In order to investigate the impact of mechanical mixtures on the operation of the pump and to determine the measures to be taken, information was collected on the repairs carried out in the shaft depth pump wells on the of “Azneft” PU.
Keywords: sand, pump, plunger, cylinder, pump-compressor pipes, mechanical particles, coagulation.