Application of Multiphase Pumps in a Remote Oil Field Onshore Abu Dhabi

Abstract

Abstract A multiphase pump was recently commissioned in a satellite oil field onshore Abu Dhabi. The pump is used to boost the flow from a well, located in a remote desert location, to a crude oil gathering centre, which is located 27 km away. This paper describes the multiphase pump installations and the unique features of these facilities. Pump specifications and key design considerations are discussed. The paper also addresses the project implementation strategy as well as early operating experience. Introduction Huwaila field is an undeveloped oil reservoir in a remote desert location in the south of Abu Dhabi. The field was discovered in 1965. The closest production facilities to Huwaila are in a gathering centre in the near by Bu Hasa field. The gathering centre, which is called RDS-3, is located 27 km north of Huwaila field. The terrain is hilly with undulating sand dunes. Access is only by four-wheel drive vehicles. Production from the field began using one well Hu-44. The well was initially produced through natural flow to the surface [1] and through the 27 km, 8 inch flowline to RDS-3. Since 1996, an electric submersible pump was used to produce the well. Well production during the first years of ESP was characterized by rapidly increasing water cut. Following a single well reservoir simulation study, well Hu-44 was side-tracked as an 1800 ft horizontal well. Various options to flow the well to RDS-3 were evaluated. A project was approved to try multiphase pumping technology. The objectives of the project are :Produce well Hu-44 via the gathering centre at RDS-3.Evaluate the performance of multiphase pumps as a potential technology for full development of Huwaila field.Monitor and better understand water behavior in the reservoir. Both dynamic and positive displacement pumps were considered. A discussion on the merits of each type and the gas volume fraction GVF is given in Appendix 1 and Appendix 2. Based on the actual flow rates and GVF at Huwaila, it became clear that the process parameters are more suited to positive displacement pumps rather than to dynamic pumps. Vendor Scope of Supply The multiphase pump, together with the associated electrical and control systems were tendered as one package. This was done to ensure single point responsibility and to avoid interface problems between the different vendors. In developing the technical requirements of the tender documents, several vendors and end users were approached for their experience. There are no industry standards to cover the design and manufacture of multiphase pumps. For twin screw pumps, the design is usually in compliance with API 676, which deals with positive displacement liquid pumps [2] As the pump vendor was German, it was agreed in the pre-award meeting that DIN standards would be adopted for some components in-lieu of API standards. For example, the load calculation of the timing gears were in accordance with DIN 3990 and not AGMA standard 6010 as stipulated in API 676. Also, the performance test procedures were not in accordance with API 675 as will be discussed later.