High Gas-Oil Ration Separator Units

Abstract

Abstract The aim of this work is to analyze the separator unit design advantages and disadvantages for fields with high gas-oil ratio. As a matter of course the following tasks have been set: –Analysis of the commonly accepted design, consisting of three separate units: preliminary gas treatment device (PGTD), two or three phase separator and the gas separator;–Analysis of the two modernized input separation unit design approaches suggested by authors. Operation of oil and gas-condensate fields is complicated by significant gas factor and the slug or plug flow. According to the commonly accepted design, at the beginning gas-liquid mixture (GLM) enters preliminary gas treatment device intended for extraction of free gas released from the well stream in the pipeline and for liquid pulsations removal. After preliminary gas treatment device gas, oil and mixture flows in three phase separator. The gas released in PGTD and three phase separator flows to cleaning from capillary liquid in the gas separator and then distributed to the consumers. The disadvantage of the commonly accepted design is significant metal consumption and large size of the site. The advantage of this design is the ability of one separator shutdown without stopping another. Instead of PGTD, three phase and gas separator standalone usage, authors suggest to use a combined input separation unit, modifications of which are discussed below. For each option PGTD has been improved, it began to play the role of the input inclined pipelines. The first option is for gas condensate fields. Gas-liquid mixture flows through preliminary gas treatment device to centrifugal gas separator (GSC) located directly on three phase separator, which immediately separates and cleans gas from liquid that is drained by gravity force into the underlying vessel. The second option is designed for oil and gas fields or oil with high gas-oil ratio. A key feature of the second modification from the first is the flow of a GLM after preliminary gas treatment device not to a GSC, but to a centrifugal input device that is made in form of cap installed on three-phase separator and designed for gas-liquid separation. Final cleaning of gas takes place in the centrifugal gas separator that is also located on unit.