Liquid Unloading with Multiphase Pumping

Abstract

In production of natural gas, often liquids (water and condensate) tend to collect in the production tubing of a typical gas well. Additionally, with horizontal wells stretching thousands of feet the liquids including flow back liquids get trapped in low laying sections and in the toe and heel of the tubing. When the gas flow velocity drops below critical velocity as result of drop in natural pressure, the liquids cannot escape the tubing and finally blocks the gas flow. In typical tight formations the wells natural pressure drops quickly, sometime in just months after start-up. As result the well will shut in or behave erratically with surging and slugging as result. Present methods using plungers, velocity strings, gas lift or ESP's are sometimes inefficient or need low back pressure to work which require blow down tanks, venting or flaring. Multiphase pumping has taken giant leaps since it was first introduced to the industry in the mid 1990s. The technology has received recognition in supporting oil and gas production from declining assets as well as being a tool to support and enhance the effectiveness of artificial lift systems of different types. Today more than thousand pumps are installed in onshore conventional as well as shale and tight formations, in steam assisted heavy oil production, topsides on platforms and subsea in deep water plays all over the world. From limited size pumps with a few hundred HP to large units with way over thousand HP, now some are in parallel operation to boost an entire oil field. Multiphase pumping has shown to provide great benefits to the operator as a tool for boosting and enhancing recovery from low-pressure reservoirs, minimizing topside facilities and comply with ESG considerations as well as significantly extending and accelerating oil and gas recovery. (Ref 4) Boosting with multiphase pumps is an efficient tool for continuous plateau production and for transporting the untreated or comingled well flow from the production pad to the process facility. The hydrocarbon production returns are essentially determined by the efficiency and capacity of the artificial lift system. When a surface installed multiphase pump is lowering the tubing and annulus gas pressure, it is possible to make the down-hole pumps, plungers or gas lift work under best possible conditions and thereby improving performance and reliability, which enhance production and the ultimate recovery from the formation.