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The fiber-optic distributed temperatrue sensor (DTS) has been used for flow profiling in horizontal multi-stage fractured wells, and several reservoir/wellbore coupled thermal models were developed. Although these theoretical models are applicable only to some specific scenarios, the industry has realized the great potential of DTS for production prediction in unconventional resources. This paper presents a DTS flow profiling case for a horizontal multi-stage fractured well in tight gas reservoirs with open-hole packer completion scenarios by applying a newly improved theoretical model. In this paper, we extended the conventional semi-analytical wellbore-fracture-reservoir coupled flow/thermal model which have been developed for cased, perforated, and multi-stage fractured wells, by considering the special feature of the openhole packer completion scenario. Since the formation fluid flows first through the fracture into the open-hole annular space between the formation and the production liner, and then flow along the annular space until meeting the frac port on the production pipe, a simulation sub-region was added for representing the open-hole annular space, which helps to understand the flow and heat transfer inside it. The presented model successfully simulated the two-segment flow regime caused by the simultaneous flow and heat transfer in the annular space and the production pipe. In each stage, the DTS temperature data possibly show double drops due to the Joule-Thompson cooling effects at the fractures and frac ports if their locations are not consistent. With the improved model, the synthetic cases were firstly used for studying the temperature characteristics and the effects of gas production rate and frac port location. Then the DTS monitoring data during a three-rate production test in a horizontal multi-stage fractured well in the Erdos Basin of China was simulated and analyzed. The open-hole packer completion was taken into account in the simulation and the gas rate prediction is satisfactory. • Open-hole packer completion style causes a featured DTS data profile. • Double temperature drops observed at the fracture and frac port locations. • A simulation sub-region representing the open-hole annular space is essential. • Gas production rate and frac port location dominate temperature data behavior. [ABSTRACT FROM AUTHOR]

Soft plunger pumps have attracted the attention of many oil fields in China and other countries due to their advantages, such as their anti-scaling feature, simple structure, and convenient maintenance. The soft plunger pump has good adaptability to the well conditions of alkaline surfactant polymer (ASP) flooding technology. However, the short inspection period of soft plunger pumps in production hinders their further popularization and limits their application. To explore the relationship between the leakage rate of the pump and the structural parameters, a vertical annular slit flow model of a multistage soft plunger and a pump barrel was proposed. Using Lagrange-Euler to describe the problem of the interface displacement between fluid and solid, the deformation of the soft plunger was solved in an iterative manner, and the deformation cloud diagram and leakage distribution of the multistage soft plunger pump were obtained. On the basis of the fluid mechanics and the law of mass conservation, the relevant factors affecting leakage were analyzed, including the length and thickness of the soft plunger and the initial clearance between the soft plunger and pump barrel pair. The influences of these factors on leakage were explored by combining theoretical analysis and numerical simulation. Results show that under different initial clearance conditions of the soft plunger and pump barrel pair, the leakage of the oil pump is negatively correlated with the length of the soft plunger, that is, the longer the soft plunger is, the smaller the leakage will be. An exponential relationship exists between leakage and the thickness of the soft plunger. The leakage increases with the initial clearance between the soft plunger and pump barrel pair, and the relationship between the leakage of the oil pump and the initial clearance of the soft plunger--pump barrel pair is approximately at third power. Under the condition of satisfying the conservation of mass, from the fluid inlet to the fluid outlet, the length of the soft plunger decreases and the thickness and the initial clearance between the soft plunger and pump barrel pair increase. This study provides a theoretical basis for improving the pumping efficiency of the soft plunger pump and optimizing the structural parameters of the soft plunger. [ABSTRACT FROM AUTHOR]