致密储层束缚水干化反应及干化效应差异分析与评价

通过向致密储层中注入干化剂,使其与地层水发生干化反应能够消耗地层水、降低储层含水饱和度,从而提高气体渗流能力。以致密气藏干化原理为基础,对所选干化剂进行原理性干化实验发现,干化剂实际耗水量大于理论耗水量。分析认为,干化剂实际干化效果还受化学反应热效应的影响。本文以热化学理论为基础,研究了干化剂与水反应的热效应及其对干化效果的影响。并考虑到实际地层往往处于不同的温度和压力条件下,故对干化反应热效应随体系温度和压力的变化情况做了研究。结果表明,所选干化剂与水反应能够放出约5.28k J/g的热量,放出的热量能够使反应速率加快和使部分水分子蒸发成气相从而提高干化效率;干化剂化学反应热随温度和压力的升高而增加,但增加速率较小;温度和压力的变化对热蒸发耗水量影响较小。

Analysis and Evaluation of Bound Water Drying Reaction and Drying Effect in Tight Reservoir

By injecting drying agent into tight reservoir and drying formation water can reduce water saturation and raise gas seepage capacity of reservoir. On the basis of drying principle of tight gas reservoir, the principle drying experiment of selected drying agent showed that the actual water consumption of drying agent is larger than theoretical water consumption. According to analysis, the actual drying effect is also affected by the thermal effect of chemical reaction. Based on thermochemical theory, this paper studies the thermal effect of reaction between drying agent and water, and the affection of thermal effect for drying tight gas reservoir. Considering the fact that the formation is often under different temperature and pressure, the variation of thermal effect with the temperature and pressure of system is also studied. The results showed that the reaction between selected drying agent and water release about 5.28 kJ/g of heat, it accelerates the reaction speed and also makes the water molecules into vapor phase so as to improve the drying efficiency. The heat of chemical reaction of drying agent is increased with temperature and pressure. The change of temperature and pressure has little influence on the water consumption of heat evaporation.