Key Laboratory of Continental Dynamics and Mineralization Prediction of Central Asian Orogenic Belt, Xinjiang University
College of Geology and Mining Engineering, Xinjiang University
College of Energy and Safety, Anhui University of Science &Technology
Xinjiang Uygur Autonomous Region Coalfield Geology Bureau 156 Coalfield Geological Exploration Team
216 Group, China Bureau of Nuclear Geology
Xinjiang Uygur Autonomous Region EnergySecurity Monitoring Center

我国煤层气资源开发具有广阔的前景,煤储层水的演化过程及其在煤层气开发过程中的运移规律对煤层气的富集和产能有重要影响。文章阐明了煤储层水的组成、性质、来源及同位素年代学研究进展;分析了煤储层水运移过程中压降漏斗的扩展规律和井间干扰机理,探讨了煤储层水运移过程中可能造成的储层伤害,并根据煤储层水的演化过程及其在煤层气开发中的运移规律,对煤层气开发提出几点建议。研究总结表明:①煤储层水来源于原始沉积水、渗入水、深成水以及成岩水,原始沉积水的钠氯系数 (rNa+/rCl−)< 0.5,肖勒系数 IBE>0.129,矿化度>10 000 mg/L;渗入水则与原始沉积水相反,深层水的 δD 介于−80‰~+40‰,δ18O 介于+7‰~+9.5‰,成岩水 δD 介于−65‰~−20‰,δ18O 介于+5‰~+25‰;②煤储层水地球化学特征对煤层气的富集、开发有重要指示意义,煤层气高含气区通常具有钠氯系数、脱硫系数、镁钙系数小,变质程度高的特点,低含气区反之;③煤储层水运移过程中形成的压降漏斗以及井间干扰有利于提高煤层气井产量,我国煤层气井大多采用矩形或菱形井网部署,最优井距通常在 250~400 m;④煤储层水运移会引起水锁伤害、水敏伤害及速敏伤害等,通过实施合理排采强度、开展井网优化以及向入井流体中加入防水锁剂和煤粉分散剂方式等降低储层伤害。研究成果可为提高我国煤层气勘探效率和产量提供一定的理论依据。

The development of coalbed methane resources in China has broad prospects, and the evolution process of coalbed water and itstransportation law has important impacts on coalbed methane production capacity. This paper clarifies the composition, properties, sourcesand isotopic chronology of coal reservoir water, analyzes the expansion law of the pressure drop funnel and the inter-well interferencemechanism during the water transport process, discusses the reservoir damage that may be caused by the water transport during drainage,and puts forward several suggestions for coalbed methane development according to the evolution of coal reservoir water and its transportand migration law during production. The results show that: (1) coal reservoir water is originated from primary sedimentary water, infiltration water, deep-forming water and diagenetic water, and the sodium-chlorine coefficient (rNa+/rCl-), Scholler coefficient (IBE), and mineralization degree of the original sedimentary water is<0.5, >0.129, and >10000 mg/L, respectively; corresponding values of infiltration water are the opposite of these relations; the δD and δ18O of deep-forming water is ranged from −80‰ to+40‰ and +7‰ to +9.5 ‰, respectively; the δD and δ18O of diagenetic water is ranged from −65‰ to −20‰ and +5‰ to+25‰, respectively; (2) the geochemical characteristics of coal reservoir water have important indicative significances for the enrichment and development of coalbed methane, and the highgas-containing areas of coalbed methane usually have the characteristics of low sodium-chlorine coefficient, low desulfurization coefficient, low magnesium-calcium coefficient, and high degree of metamorphism, correspondingly, the low gas-containing areas have the opposite characters; (3) the pressure drop funnel propagation during coal reservoir water transport and migration and the interference betweenwells are conducive to improve the coalbed methane production, and most of the coalbed methane wells in China are deployed by rectangular or diamond-shaped well networks, and the optimal well space is usually ranged between 250m and 400m; (4) the water transport ofcoal reservoirs can cause pulverized coal to block the formation, water lock damage, water sensitive damage, and velocity sensitive damage. To reduce reservoir damage, implementing reasonable drainage strength, optimizing the well network, and adding waterproof lockingagent and pulverized coal dispersant to the incoming fluid are suggested. The research results can provide a certain theoretical basis for improving the exploration efficiency and coalbed methane yield in China.

国家自然科学基金资助项目(42062012)

赵馨悦, 韦波, 袁亮, 等. 煤储层水文地质特征及其煤层气开发意义研究综述[J]. 煤炭科学技术, 2023, 51(4): 105-117.

ZHAO Xinyue, WEI Bo, YUAN Liang. Hydrological characters of coal reservoir and their significances on coalbed methanedevelopment: A review[J]. Coal Science and Technology, 2023, 51(4): 105-117.