注化学试剂法开采天然气水合物研究综述

Review on exploitation of natural gas hydrates by chemical injection method

摘要:

天然气水合物高效开采是实现其商业化利用的基础与前提。注化学试剂法通过改变水合物相平衡条件、破坏笼型结构促进其分解，是重要开采技术之一。本文综述了注醇类、盐类及热酸液开采水合物方法的研究进展，分析了各类化学试剂的作用机理、水合物分解效率及联合开采过程。结果表明，注醇类试剂开采主要通过亲水羟基降低水活度实现热力学抑制，但开采过程面临环境污染严重、注剂量大等难题；盐类试剂成本低且环境友好，但单一应用开采潜力较低，联合降压或热激可显著提升近50%的储层产气效率；注热酸液通过化学溶蚀与热传递协同增产，但机理研究不够全面。海洋泥质粉砂水合物储层细颗粒占比大、黏土含量高与渗透率低的特点导致注化学试剂法开采面临注入困难，注剂种类、浓度与储层适配性亟待研究。本研究可为注化学试剂法高效开采水合物提供思路。

Abstract:

Efficient exploitation of natural gas hydrates constitutes the foundation and prerequisite for their commercial utilization. As one of the vital exploitation technologies， the chemical reagent injection method facilitates hydrate dissociation by altering hydrate phase equilibrium conditions and destroying cage structures. This paper reviews the research progress of hydrate exploitation including injected alcohols， salts and hot acid solutions， and analyzes the action mechanism of various injected chemical reagents， hydrate dissociation efficiency and combined exploitation processes. The results demonstrate that alcohol-based reagents achieve thermodynamic inhibition mainly by reducing water activity via hydrophilic hydroxyl groups， yet their application suffers from severe environmental pollution and large injection dosage. Salt reagents feature low costs and environmental friendliness， while exhibiting limited exploitation potential when used alone， and combination with depressurization or thermal stimulation can boost reservoir gas production efficiency by nearly 50%. Hot acid injection enhances gas production through the synergy of chemical dissolution and heat transfer， whereas relevant mechanism research remains incomplete. Marine argillaceous silty hydrate reservoirs are characterized by high fine particle and clay contents as well as low permeability， which brings about injection obstacles for the chemical reagent injection method. The compatibility between reagent type， concentration and reservoir conditions requires urgent investigation. This study can provide references for the efficient exploitation of natural gas hydrates via chemical reagent injection.