含硫页岩气井溶硫剂的应用进展

The Application Progress of Sulfur-Containing Shale Gas Well Sulfur-Reducing Agents

摘要: 含硫页岩气井在开发过程中常伴随H₂S/有机硫分解与压力–温度(P-T)路径突变，引发元素硫(S₈)在井筒–近井地带析出、沉积与迁移聚集，造成孔隙/裂缝有效流通截面缩减、管柱与地面集输受限，表现为产量骤降、井口压差异常、频繁解堵与安全环保风险叠加。大量研究表明，硫沉积具有“可逆溶解–再沉积”的动态特征，单纯依赖机械清理或短周期酸化难以形成稳定治理。溶硫剂作为将固/液态单质硫转化为可流动、可携带、可回收形态的关键化学手段，已从常规酸性气井的“事后救治”逐步发展为含硫页岩气长水平井的“事前预防 + 在线维护”技术。本文围绕溶硫剂类型(物理溶剂、化学溶剂、复合/新型体系)、作用机理(溶解–分散–络合/亲核开环)、现场应用模式(批次浸泡解堵、连续加注预防、与压裂/酸化协同)、效果评价与环境经济性进行系统梳理。综合分析认为：当前工程上以DMDS等有机硫化物物理溶剂体系与胺类/含硫亲核试剂化学溶剂体系为两大支柱，连续加注正在成为主流预防工艺；但在长水平段输运、配伍与返排处置方面仍存在瓶颈，未来需向智能化监测–自动加注与绿色分子设计融合演进。

Abstract: During the development of sulfur-containing shale gas wells, H₂S/organic sulfur decomposition and pressure-temperature (P-T) path mutations often occur, leading to the precipitation, deposition, and migration-aggregation of elemental sulfur (S₈) in the wellbore and near-well areas, resulting in a reduction of the effective flow cross-section of pores/fractures, and restrictions on the tubing string and ground gathering and transportation. This manifests as a sudden drop in production, abnormal wellhead pressure difference, frequent unclogging and the accumulation of safety and environmental risks. Numerous studies have shown that sulfur deposition has a “reversible dissolution-re-deposition” dynamic characteristic, and relying solely on mechanical cleaning or short-term acidizing is difficult to achieve stable treatment. Sulfurating agents, as a key chemical means for converting solid/liquid elemental sulfur into a flowable, transportable, and recyclable form, have gradually evolved from “post-treatment” in conventional acidic gas wells to “prevention + online maintenance” technologies for sulfur-containing shale gas long horizontal wells. This paper systematically reviews the types of sulfurating agents (physical solvents, chemical solvents, composite/new systems), their action mechanisms (dissolution-dispersion-complexation/nucleophilic ring-opening), on-site application modes (batch soaking for unclogging, continuous injection for prevention, and coordination with fracturing/acidizing), effect evaluation and environmental economy. Comprehensive analysis suggests that currently, the engineering field relies on organic sulfur-containing physical solvent systems (such as DMDS) and chemical solvent systems (such as amines/sulfur-containing nucleophilic reagents) as the two main pillars, and continuous injection is becoming the mainstream prevention process; however, there are still bottlenecks in long horizontal section transportation, compatibility and flowback disposal, and in the future, it is necessary to evolve towards intelligent monitoring - automatic injection and green molecule design integration.