APPROVAL OF OPTIMAL PIPELINE`S CLEANING METHODS ACCORDING TO MULTIPHASE FLOW PATTERNS

The object of research is gathering and transmission system of gas and gas condensate fields. One of the major problem areas is the lack of an integrated approach and justification for choosing the optimal for pipeline cleaning methods (removing deposit) from the inner cavity of pipelines that form these systems. This leads to inefficient use of pipeline pigging equipment and significant operating costs without visible economic benefits. Based on analysis of gas-condensate life cycles, it is established that different stages of the field development are characterized by a proper gas-liquid flows pattern. During the research, the relief characteristics of the flow and trunk lines, which transmit the gas-liquid flow with different gas contents, are investigated. Based on the analysis of the criteria characterizing the flow pattern, mathematical models of overall pressure drop on the rising and declining sections are presented. The determined pressure differences are formed according to different structures of motion of gas-liquid flows under the influence of hydraulic resistance of each of the studied sections. The estimation of the hydraulic state of the system transporting a multiphase flow, based on a comparison of the actual measured pressure drop and its calculated value, is presented. By experimental researches it is established that the most dangerous factor in the operation of such systems is the possibility of slug moving when changing the baric regime of operation. In order to increase the reliability and efficiency of pipelines operation, an algorithm for determining the structural form of motion and actual hydraulic state of the gathering and transmission system of different types of field is proposed. And a sequence of choosing the optimal method for pipeline cleaning is developed. The proposed algorithm for choosing the best ways to drain liquid from the pipeline cavity will provide an opportunity to discard deliberately inefficient methods, as a result will save time and money for the Company