煤层气与常规油气共采可行性探讨——深部煤储层平衡水条件下的吸附效应

DISCUSSION ON RELIABILITY FOR CO-MINING THE COALBED GAS AND NORMAL PETROLEUM AND NATURAL GAS: ABSORPTIVE EFFECT OF DEEP COAL RESERVOIR UNDER CONDITION OF BALANCED WATER

在分析煤层气与常规油气共采可行性问题的基础上,采用物理模拟方法,结合地质条件分析,研究了深部煤储层在平衡水条件下的吸附效应,并初步得出一些新的认识:地层温度、埋藏深度、煤级等条件的组合,可能对煤储层平衡水含量发生不同程度的影响;深部地层条件的具体特征,可能会导致深部煤储层吸附性与浅部煤储层有所不同;在地层条件下,煤饱和吸附量随埋藏深度增大而变化的趋势在一定深度发生反转,存在一个“吸附饱和临界深度”,且临界深度随煤级的变化而有所不同,这是地热场深部增温效应与煤储层自身特性共同作用的必然结果;深部较高地层温度与较高地层压力的配置关系可能有利于煤层气的开采,存在实现深部煤层气资源与常规油气资源共采的可能性;深部较高流体压力和较高受热温度的“双重”控制效应,可能是导致深部煤储层吸附性与浅部存在较大差异的根本原因。

Based on suggesting the problems for co-mining the coalbed gas and normal petroleum ＆. natural gas, the absorptive effect of the deep coal reservoir under the condition of the balanced water was studied using the physical simulating test with the analysis of the geological setting, and some new viewpoint were suggested. The results showed that the content of the balanced water in coal reservoir could be controlled by the combination of the strata temperature with the its burial depth and coal rank. The conditions of the deep strata could result in the difference of the absorption between the deep and sallow reservoirs. The relationship of the saturated gas-absorbing content to the burial depth of the reservoir could be reversed at a certain depth （named as the critical depth of absorptive saturation） in the strata, and the critical depth is varied with coal rank, which is deservedly derived from the co-action of the temperature-enhancing effect and self-characteristics of the deep reservoir. The match of the higher temperature with the flow pressure in the deep reservoir could be favorable of mining the coalbed gas, and, in another word, there is the reliability of co-mihing the deep coalbed gas and petroleum ＆. natural gas. The difference of the absorption between the deep and sallow reservoirs could be radically derived from the double controls of the higher flow pressure and temperature in the deep reservoir.