Investigation of Temperature Drop Characteristics During the Throttling Process of Ultra-High-Pressure Condensate Gas

The southern margin block of the Xinjiang Oilfield represents a typical ultra-high-pressure condensate gas field. Existing surface throttling practices rely heavily on empirical experience, with the underlying throttling mechanisms remaining unclear and lacking systematic theoretical support. In this study, the TW1 Well is selected as the research subject. Based on the principle of equal total enthalpy before and after throttling—and with particular attention to the effects of condensate gas heavy components and water on enthalpy calculations—a mathematical model for throttling-induced temperature drop, tailored to ultra-high-pressure condensate gas, is developed. The model enables a systematic analysis of temperature variations throughout the throttling process. Results indicate that the pre-throttle temperature is the primary factor controlling the magnitude of temperature change, and that post-throttle temperature rise may occur due to the Joule–Thomson coefficient becoming negative under ultra-high-pressure conditions. By integrating hydrate-formation prediction with differential pressure calculations across the throttling valve, a rational production scheme is proposed. This study provides a theoretical basis for understanding the mechanisms of ultra-high-pressure condensate gas well throttling and delivers critical technical support for the scientific design and optimization of surface throttling operations.