Application of Composite Jet-Rod Pumping System in a Deep Heavy-Oil Field in Tarim China

Abstract

Abstract Great challenges had been faced in the design and selection of artificial lift methods at Lungu reservoir of Tarim field in the North West China due to the extremely deep reservoir and extra-viscous crude. The average depth of the reservoir is about 5500m. The initial reservoir temperature is about 127°C, and pressure ranges from 57 to 64 MPa. With very high content of resins and asphaltenes, the oil from this reservoir has a viscosity of about 10×104mPa.s at 50°C and density varying from 0.95 to 1.08 g/cm3. Thanks to the high reservoir temperature along with high pressure, the oil has fairly enough mobility to flow into the well bore under reservoir conditions. However, as it flows towards the surface, the decrease in temperature along the well bore causes dramatic increase of viscosity. Both calculations and field experience suggested that it is not possible to meet the required production rate with only one particular available mechanical lift method, such as rod pump, jet pump, or other individual lifting method. To overcome the lifting difficulty and achieve the production volume, a composite pumping system which combines both jet and rod pumps was proposed and practiced in this field. The proposed composite jet-rod pumping system was proven to be a great success, which significantly increased and maintained production volume in the wells tested. This paper discusses the working mechanisms involved in the composite jet-rod pumping system, the lifting parameter optimization methodology and workflow, and the field application experience. This composite jet-rod pumping system was demonstrated to be the most promising mechanical lift system for Lungu reservoir and it can be potentially used in the other deep heavy oil fields world wide.