大牛地气田下古生界含硫气井脱硫工艺适应性分析

Adaptability of desulfurization technologies to the Lower Paleozoic sour gas wells,Daniudi gasfield

自2016年以来,鄂尔多斯盆地大牛地气田陆续实施了井筒除硫工艺、雾化除硫工艺、小型撬装除硫和集中除硫工艺,通过各种除硫工艺试验释放了下古生界含硫气井产能,为气田上产做出了贡献。但在试验过程中也暴露出除硫成本较高、经济效益不佳,部分工艺导致气井采气管线结垢严重、影响产量安全释放等问题。为了充分认识和准确把握大牛地气田下古生界气藏H_(2)S浓度高低对脱硫工艺适应性的影响,同时也为科学制定大牛地气田下古生界气藏含硫气井除硫工艺发展提供决策参考,以现有大牛地气田除硫工艺中所处理天然气中H_(2)S的含量为基准,分析了不同除硫工艺的适应性及其效果,综合评价了井筒脱硫、井口雾化、井口撬装和地面集中脱硫工艺的适应性,明确了井筒加药除硫、井口雾化除硫、井口小型撬装脱硫和地面集中除硫4种方式为大牛地气田现有的主要除硫方式。研究结果表明:4种除硫方式具有操作简单,成本较低,除硫效果较为显著的特点。结论认为:结合大牛地气田含硫气井发展部署规划,依据含硫气井的分布特点、H_(2)S浓度含量高低差异,结合"效益优先"的原则,综合分析评价井筒除硫、井口雾化除硫、井口撬装除硫和地面集中除硫工艺的适应性,为大牛地气田下古生界气藏经济开发提供参考。

Since 2016, four technologies such as wellbore, atomization, small skid-mounted, and centralized desulfurization have been applied successively to Daniudi gasfield in Ordos Basin. And the productivity in the Lower Paleozoic sour gas wells has been released by means of various chemical test, contributing to production increase in this field. In the test process, however, desulfurization cost is higher, economic benefit is not good, and serious scaling in pipelines may affect safe release. In order to sufficiently and accurately understand the influence of H_(2)S concentration in these reservoirs on the technological adaptability and provide decision-making reference for scientific development, both adaptability and application effect were analyzed for different desulfurization technologies by taking the H_(2)S content in natural gas treated by existing desulfurization as the reference value. In addition, the adaptability of wellbore, wellhead atomization, wellhead skidmounted, and surface centralized desulfurization technologies was evaluated comprehensively. It is ascertained that, in Danniudi gasfield, there are four main desulfurization modes, including chemical adding in the wellbore for desulfurization, atomization at the wellhead for desulfurization, wellhead small skid-mounted desulfurization, and surface centralized desulfurization. In conclusion, the adaptability of these four desulfurization modes is analyzed and evaluated comprehensively based on the distribution characteristic of sour gas wells and the difference of H_(2)S content, combined with the development and deployment plan of sour gas wells and the principle of "benefit priority", so as to promote economic feasibility on the development of Lower Paleozoic gas reservoirs.