Analysis of mechanical impurities contained in pumped liquids at the fields of Western Siberia

Annotation. Purpose of the study : analyze the mechanical impurities contained in the pumped liquids. To achieve this goal, the paper set the task of conducting a physicochemical analysis of the composition of solid deposits on parts that come into contact with an aggressive liquid. Scientific hypothesis Improving the reliability of field pipeline and pumping hydraulic systems is one of the most important tasks in oil production. In addition to oil, a significant amount of corrosive fluid is increasingly released from the reservoir during production, damaging the parts through which it passes. This naturally leads to the appearance of the most important complication during operation - deposits of paraffins and hydrates. The article is devoted to the study of the mineralogical and granulometric composition of mechanical impurities that destroy the pipeline network and pumping hydraulic system in the fields of Western Siberia. In this paper, mechanical impurities contained in pumped liquids at the Samotlor and Khokhryakovskoye fields are analyzed. Premature failure of the productive operation of the equipment is due to the aggressiveness of groundwater injected into the reservoir. A physicochemical analysis of the compositions of solid deposits on damaged parts of oilfield equipment was carried out - a laboratory analysis of the granulometric and mineralogical composition of mechanical impurities was carried out. Appropriate conclusions are drawn . Proposed measures to prevent the processes of salt deposition.


Introduction
Since the development of Western Siberia, pipeline transport in the oil and gas industry has become significantly outdated.Injection wells maintain reservoir pressure by injecting wastewater into the reservoir, which is then pumped through pipelines.Oil fields in the Far North have completely changed -their water cut is more than 95%.This liquid has an aggressive environment, causing the destruction of the pipeline network and the pumping and hydraulic system.The mineralization and granulometric composition of the pumped liquid are the cause of the destruction of oilfield pipes and equipment.
The purpose of this work is to analyze the effect of mechanical impurities on the destruction of the pipeline network and the pumping-hydraulic system.
Tasks of this work: 1) Determine the causes of equipment failures -destruction and failure of parts and assemblies; 2) Conduct a laboratory analysis of the content of mechanical impurities; 3) Analyze the granulometric and mineralogical composition of mechanical impurities and draw the appropriate conclusions.

Results and discussions
The mineralogical and granulometric composition is measured in the control laboratory of the Nizhnevartovsk Research Institute ( NIPIneft ).An emergency situation occurred at an oil production field -salt deposits were found on the impellers of a centrifugal pump (Figure 1).In the laboratory of NIPIneft, under a microscope, the size of the particles of the destroyed metal that came from the field for research is measured.Microscopic analysis makes it possible to determine the characteristics of the fracture surface.
Less than 1 mg of material is required for examination under a microscope.Such and measurements of spherical particles give reliable and accurate values.
Particle size is measured using an ocular micrometer (Figure 2).From the Samotlor field, the laboratory received a pump part -a dark-colored tip.The extension cable was heated as a result of electrical breakdown in the cable entry sleeve.According to the results of laboratory analysis of sample No. 1, the highest content of carbonate was revealed -81%, an admixture of barite -12% and iron hydroxides -7%.Micrograins are less than 0.02 mm in size, irregular and isometric in shape with jagged jagged edges.Barite micrograins have a size of no more than 0.15 mm.They present themselves in the form of thin lamellar, needle-shaped and scaly aggregates.Micrograins of iron hydroxides are up to 0.03 mm in size, rusty-brown in color, observed in the form of colloidal and amorphous accumulations.Referring to Table 3, we can conclude that iron carbonate and hydroxides are a pelitic coarse-grained fraction, and barite is a silty fine-grained fraction.The mineralogical composition of mechanical impurities is represented by carbonate, iron hydroxides and carbonaceous matter.We also note the high content of carbonate -82%.It is distributed in the form of grains with uneven sinuous edges, up to 0.03 mm in size.Microparticles of iron hydroxides are distributed unevenly in the form of clusters and have a size of up to 0.05 mm.The carbonaceous substance is distributed in shapeless smears, up to 0.05 mm in size.According to the results of laboratory analysis of sample No. 2, the highest content of carbonate was revealed -82%, an admixture of iron hydroxides -11% and carbonaceous substances -7%.Referring to Table 1.6, we can conclude that carbonate, iron hydroxides and carbonaceous substances belong to the pelitic coarse-grained fraction.
Deposits of calcium carbonate CaCO3, calcium sulfate, barium, chloride and other salts occur in wells and equipment during the development and operation of oil fields.The deposition of inorganic salts occurs with all methods of well operation, but most of all with pumping .
The aggressiveness of groundwater is formed by the presence of certain chemical compounds -dissolved components that contribute to the leaching of the rock.They affect the chemical composition and concentration of chemical components.The temperature and filtration rate of the reservoir fluid have a significant effect.
The considered samples with a clear advantage of one or another type of deposits indicate the corresponding process of formation of solid particles.Carbonate salts are present in all types of deposits, which indicates that the process of deposition of carbonate salts takes place at all sampling points.

Conclusions
1) The presence of samples with a clear advantage of one or another type of deposits indicates the corresponding process of formation of solid deposits; 2) Carbonate salts are present in all types of sediments, which indicates that the process of deposition of carbonate salts takes place at all sampling points, but with different reaction rates of their formation; 3) To combat deposits of the carbonate type, measures are necessary to prevent salt deposits, namely, the use of inhibitors of salt deposits LEYSAN 3003 grade 3, IPRODENT.

Fig. 1 .
Fig. 1.Deposition of salts on the impellers of a centrifugal pump.

Fig. 2 .
Fig. 2. Ocular micrometer Sample No. 1 Reason for failure and defects:From the Samotlor field, the laboratory received a pump part -a dark-colored tip.The extension cable was heated as a result of electrical breakdown in the cable entry sleeve.

Fig. 4 .
Fig. 4. Sample photo #1 Sample No. 2 A pump shutdown occurred at the Khokhryakovskoye field.The NIPIneft laboratory received pump parts subjected to scaling.Reason for failure and defects: 1. Washers are completely worn out; 2. The bushings are worn out; 3. Wheels working average wear; 4. The guide devices are completely worn out.

Table 1 .
Characteristics of the pump part

Table 4 .
Characteristics of pump parts