油气井雷达成像测井仪改进及试验

传统的测井仪器探测深度基本在3 m以内, 大多也没有方位分辨能力, 无法实现油气井周围较大范围地层结构与构造的成像, 故不能解决隐蔽构造与油气储层的探测问题。针对上述问题, 将地表地质雷达成像技术移植到测井中, 研发了雷达成像测井仪。为提高雷达成像测井仪探测深度、方位分辨率和下井深度, 采用纳秒脉冲源与定向接收天线对井周地层进行探测和成像, 在增大探测距离的同时, 兼顾了分辨率; 采用磁环和光耦对脉冲板做隔离, 有效地压制了噪声; 通过在电路外增加保温瓶和优选耐高温元器件提高了仪器的耐高温性能; 最后利用模型井对仪器进行了测试和标定, 并在3口油井中进行了现场应用。改进后的雷达成像测井仪下井深度可达6 000 m, 最大探测深度可达12 m, 能够对井周5 m以外孔洞、裂缝进行定位和成像, 大大地拓宽了测井技术的横向预测能力。测试与应用结果表明:该仪器能够耐受油井下的高温高压环境, 探测深度大且分辨率高, 对钻孔周围地层界面、裂缝和孔洞构造成像效果较好。 

Improvement and test of radar imaging logging tool for oil and gas wells

The detection depth of traditional logging tools is basically less than 3 m, and without azimuth resolution, the formation structure in larger area around wells cannot be imaged. Therefore the problems arising in the detection of subtle structure and oil and gas reservoirs can not be solved. In response to such problems, radar imaging logging tool is developed by applying ground penetrating radar imaging technology to logging. In order to improve the detection depth, azimuth resolution and downhole depth of the tool, a nanosecond pulse source and directional receiving antennae are used to detect and image the formation around the well, increasing the detection distance while improving the resolution. Magnetic rings and optocouplers are used to isolate the pulse plate, which effectively suppresses the noise. The high temperature resistance of the tool is improved by adding thermos and selecting high temperature resistant components outside the circuit. Finally, the tool is tested and calibrated by using model wells, and has been applied in three oil wells. The downhole depth of the improved radar imaging logging tool can reach 6 000 m, and its maximum transverse detection depth can reach 12 m. It can locate and image holes and fractures 5 m away from the wellbore, significantly improving the lateral prediction ability of logging technology. The testing results show that as the tool can withstand high temperature and high pressure environment of oil wells with a large detection depth and high resolution, and it has a good imaging effect on the formation interface, fractures and pore structure around the borehole.