Innovative Technology for Multi-Phase Pumping

Abstract

Abstract Multi-phase pumps (MSPs) have been successfully used to accelerate production from wellheads and reduce well intervention costs. As multi-phase pumps are essentially hybrids of a pump and a compressor they face challenges from variations in GVF, changing flow conditions and from the gas-compression effect. MSPs can also be complex, have large capex/opex and consume a lot of power. Surface jet pumps, innovatively combined with novel compact separation, provide a cost effective and simpler method for multi-phase pumping. Surface jet pumps (SJPs) are simple, low cost, passive devices that use a high pressure (HP) fluid as the motive force to boost the pressure of the LP well and deliver it for processing. The LP multi-phase flow is separated by a compact separator and the separated liquid pumped by a single phase pump while the gas is boosted by the surface jet pump. The power required to drive the single phase pump is a fraction of the power consumed by the multiphase pump. The high pressure fluid that is needed for the motive flow for the SJP can come from a HP well, the discharge of a compressor or from the export gas line. Advantages of using SJPs with compact separators include no moving parts, zero maintenance, zero power or fuel gas usage, small footprint and varying layout configurations. SJPs are well suited to changes in process conditions, liquid ingestion and variations in GVF (without affecting performance). This paper discusses the use of Surface Jet Pumps and compact separators as an alternative to multi-phase pumps and cites several case studies of where this technology has been utilised. The design and operational criteria of SJPs, as well as the economics are also highlighted. Introduction As oil and gas fields reach maturity, production becomes restricted for a variety of reasons such as increased water-cut and deterioration of the inflow characteristics of wells. If nothing is done, the low pressure wells will be loaded with liquids and seize production prematurely. Multiphase pumps have been used successfully to boost production from low pressure oil wells. One of their benefits is that they can handle multiphase flow, a mixture of gas and liquids without the need to separate the two phases. Multiphase pumps however consume big power as they need to boost the pressure of both gas and liquids. There is however an alternative solution in cases where a high pressure source is available. This paper describes the use of surface jet pumps (SJPs) to revive oil and gas wells and prolong their production life. The challenge related to both oil and gas production is handling multiphase flow, a mixture of gas-oil and water by the boosting system. SJPs are capable of handling multiphase flow similar to multiphase pumps, but selection of the SJP system depends on the available source of HP motive flow. The use of surface jet pumps (SJPs) is one of the simplest and most cost effective ways to revive low pressure oil and gas wells, or boost production from such wells. A high pressure (HP) fluid is needed as the motive flow and the source of energy for the SJP. The paper describes the various solutions using the SJP system and provides some guidelines for selecting the best candidate LP wells. The paper also refers to several recent field examples. The economics of using the SJP system is very attractive and all field applications to date have shown the recovery of capital from the added revenue ranging from only ten days to a few months.