加气站地下储气井应力分析与现场试验

Stress analysis of underground gas storage wells at gas filling stations and field tests

储气井具有占地少、相对安全、成本较低等明显优势,目前已经成为天然气汽车加气站的首选储气设备,并逐步进入调峰站、企业储气库、城镇储配站等领域,但长期以来关于固井水泥环对储气井影响的研究甚少,相关的试验研究几乎为空白。为此,建立了地下储气井的受力模型,分析计算了固井水泥环与井筒之间的界面压力,计算结果显示储气井的固井水泥环对储气井井筒具有较大的加固作用。同时,建造了储气井试验井,进行了固井质量检测,并对地下储气井实施了应力测试,分别测试了固井前和固井后井筒的应力。结果表明:①固井后的井筒环向应力较固井前的井筒环向应力降低,固井后井筒环向应力最多降低了16%;②随着井筒内压的逐渐增加,固井水泥环对井筒的加强作用日益明显。该试验结果与理论分析结论基本一致,可对储气井设计、制造、使用和检验提供参考。

With obvious advantages such as little space occupation, relative security, rather low cost, etc. , underground gas storage wells have become the first option of gas storage equipment for gas filling stations, and also have entered into the fields like peak shaving stations, gas storage of enterprises, urban storage and distribution stations, and so on. However, rare research has ever been done for a long time on how the cement sheath influences the gas storage well and there is still a blank space in the relevant ex perimental studies. In view of this, a mechanical model was established of an underground gas storage well to analyze and calculate the interfacial pressure between the cement sheath and the well bore. From the calculated results, the reinforcement of the cement sheath is evident on the well bore of such wells. Then, an experimental gas storage well was built, and the cement quality was detected while stress tests were made on the well bore respectively before and after the cementing operation. The following results were obtained. First, the hoop stress after cementing is lower than that before cementing and drops by 16% at the most. Second, with the increasing internal pressure in the well bore, the reinforcing role of the cement sheath is increasingly apparent. The above experimen tal results agree well with the theoretical analysis and can provide a reference to the design, manufacture, usage and inspection of underground gas storage wells.