Physical and Chemical Geotechnologies

Purpose

To investigate the technology of cleaning flowlines of gas-condensate wells with foam, to perform feasibility study on the prospect of its application in practice.

Methodology

The technology of cleaning flowlines of gas-condensate wells with foam has been investigated to objectively evaluate its application and to determine the effectiveness of this measure.

Findings

During the operation of gas condensate wells, gas moves from reservoir to borehole bottom, and then with the help of a column of elevator pipes and a flowline to a gas treatment unit (GTU). Along with gas there is a movement of liquid. Under certain conditions, the fluid gradually accumulates in the flowlines, which results in decrease in their throughput and, consequently, in the flow rate and production of hydrocarbons. To solve this problem, one should periodically clean the inner cavity of the flowline using various methods.

Using the example of the wells of the Yuliivske oil and gas condensate field, the operating parameters were measured and the pressure losses along the length of the flowlines were calculated. According to the results of calculations at two wells (No.85 and No.60) a significant excess of the actual value of the flow friction characteristic over the theoretical was established. To reduce excessive pressure losses due to the presence of fluid and to improve the hydraulic characteristics of the wells, their inner cavities were cleaned using foam of expansion ratio from 40 to 100.

According to the results of production research, due to the cleaning flowlines of wells (No.85 and No.60) from the accumulation of fluid, the coefficients of their hydraulic efficiency increased by 12 % and 7 %, respectively. Measures taken to clean the inner cavity of the flowlines from the liquid have proven their efficiency and can be recommended for other flowlines of wells at other production fields.

The research was carried out within the framework of research and development work by specialists of the Ukrainian Scientific Research Institute of Natural Gases.

Keywords: well, flowline, fluid, cleaning of the internal cavity, hydraulic efficiency.

References

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