Predictive model for sulfur precipitation in high-sulfur gas wells considering phase change

doi:10.3969/j.issn.1006-6535.2025.02.016

Abstract

Abstract: To accurately predict the wellbore pressure,temperature,and sulfur precipitation patterns in high-sulfur gas reservoirs,based on the law of conservation of mass,momentum and energy,a predictive model for wellbore pressure,temperature,and sulfur precipitation in high-sulfur gas reservoirs was established with the comprehensive considerations of the influence of well deviation angle and gas-liquid-solid phase characteristics of sulfur;the finite difference method and iterative techniques model were used to solve the model;the compressibility factor algorithm was optimize based on field data;predictions of wellbore pressure,temperature,and sulfur precipitation trends were made after validating the accuracy of the model;and the influencing factors of wellbore pressure and sulfur precipitation patterns were studied.The results show that using the DPR algorithm for calculating the compressibility factor yields the smallest average relative errors in predicting wellbore pressure and temperature,at 0.93% and 1.06%,respectively.The fluid flow inside the wellbore is characterized as either single-phase gas or gas-solid two-phase flow,with no gas-liquid two-phase flow present.With the increase of gas production rates,H₂S content,initial solubility of sulfur particles,and the decrease of well inclination,the variation range of wellbore pressure changes mounts gradually.Higher gas production rates result in sulfur precipitation closer to the wellhead with larger volumes of precipitated sulfur;higher H₂S content leads to sulfur precipitation closer to the wellhead with smaller volumes of precipitated sulfur;larger initial solubilities of sulfur particles and greater well inclinations push the precipitation location further from the wellhead,resulting in larger volumes of precipitated sulfur.This research provides technical support for the efficient development of high-sulfur gas reservoirs.

Key words: high-sulfur gas well, wellbore, gas-liquid-solid three-phase, wellbore pressure, wellbore temperature, sulfur precipitation prediction model

CLC Number:

TE375

LI Peng, DENG Hucheng, ZHANG Chuyue, LU Jie, ZHANG Xiaoju, HUANG Liang. Predictive model for sulfur precipitation in high-sulfur gas wells considering phase change[J]. Special Oil & Gas Reservoirs, 2025, 32(2): 123-130.

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