ANALYSIS OF DEPOSITS OF INORGANIC SALTS IN THE SYSTEM OF COLLECTION OF NSP «B», BPS-5 «А»

Abstract

Relevance. Currently, the problem of salt deposits formation is very relevant and important. Oil production becomes difficult with the advent of inorganic deposits, which are formed in the well bottom zone, and in the systems for collecting and preparing well products. The consequences of salt deposits are a decrease in the well productivity coefficient, which causes a significant loss of oil. Also, due to insufficient inflow, there is a risk of failure of downhole pumping equipment, a decrease in time between failures of this equipment appears due to occurrence of seizures of electric centrifugal pump and sucker rod pump valves. For these reasons, oil companies suffer significant losses, as large expenditures on measures to prevent and combat salt deposits become necessary. The aim of the research is to study this problem in details; to identify sediment prevention and control methods; to determine whether a precipitate will fall out as a result of defining the coefficient of supersaturation, by the method of Skilmen–McDnald–Stiff; to analyze the studies in definition of sediments composition. The methods. The Skilmen–McDnald–Stiff technique was used in calculations. The inorganic part of the sediments was determined by X-ray diffraction on a Shimadzu XRD-6000 powder diffractometer. The results. Analysis of the results of determining the macro- and microcomponent composition of water showed that the samples of passing-extracted water taken from production wells and automated group metering installation of deposit X contain significant amounts of calcium ions and sulfate ions, which can lead to formation of insoluble salts, such as calcite and plaster. In the wells 5 and 311, the supersaturation coefficient is 1 (there is supersaturation of formation water with gypsum). In these wells, gypsum has the ability to fall out both in volume and on the heat exchange surface itself. In the well 158 the supersaturation coefficient is 1. With unsaturation or formation water, there will be no precipitation in the volume. However, on the heat exchange surface, due to partial evaporation, the solution is especially saturated with gypsum. Because of this, the gypsum is able to be postponed even with some undersaturation of the produced water with it – with a decrease in the coefficient to 0,9. It is necessary to prevent in advance gypsum deposits not to allow them complicating oil production. To prevent deposits formation it is necessary to select an effective inhibitor of scaling for conditions of deposits collecting at NSP «B». To protect the oil gathering system, it is recommended to organize the supply of a scale inhibitor.

Keywords

• deposits
• sedimentation
• inorganic salts
• calcite
• gypsum
• scale inhibitor