目前降低井底压差的工具存在作业复杂、对井底降压效果有限等问题,而射流泵钻头则存在过度依赖井壁间隙的问题。针对以上问题,研制出了一种新型的环流射吸降压差钻头。该钻头采用一种变形设计的射流泵,并在射吸喷嘴外加装射吸套,利用钻...目前降低井底压差的工具存在作业复杂、对井底降压效果有限等问题,而射流泵钻头则存在过度依赖井壁间隙的问题。针对以上问题,研制出了一种新型的环流射吸降压差钻头。该钻头采用一种变形设计的射流泵,并在射吸喷嘴外加装射吸套,利用钻头内部的射流泵组及反向喷射的射吸管,实现了涡流-射吸复合降压的效果,并将多个射流泵在钻头内并联共同作用,有效的实现降低井底压差,提高机械钻速。在实际生产应用中,结合邻井钻井效果对比,新型215.9 mm STS636LGRS射吸钻头在部分岩段中具有一定提速效果。展开更多
A high-accuracy,low-dropout （LDO） voltage regulator is presented. Using the slow-rolloff frequency compensation scheme, the LDO effectively overcomes the stability problem, facilitates the use of a ceramic capacitor...A high-accuracy,low-dropout （LDO） voltage regulator is presented. Using the slow-rolloff frequency compensation scheme, the LDO effectively overcomes the stability problem, facilitates the use of a ceramic capacitor, and improves the output voltage accuracy, which is critical for powering high-performance analog circuitry. The slow-rolloff compensation scheme is realized by introducing three pole-zero pairs, including the proposed polezero pair and sense zero. The post-layout simulation results demonstrate that this LDO has robust system stability, a high open-loop gain, and a high unit-gain frequency,which lead to excellent regulation and transient response performance. The line and load regulation are 27μV/V and 3.78μV/mA, and the overshoots of the output voltage are less than 30mV,while the dropout voltage is 120mV for a 150mA load current.展开更多
文摘目前降低井底压差的工具存在作业复杂、对井底降压效果有限等问题,而射流泵钻头则存在过度依赖井壁间隙的问题。针对以上问题,研制出了一种新型的环流射吸降压差钻头。该钻头采用一种变形设计的射流泵,并在射吸喷嘴外加装射吸套,利用钻头内部的射流泵组及反向喷射的射吸管,实现了涡流-射吸复合降压的效果,并将多个射流泵在钻头内并联共同作用,有效的实现降低井底压差,提高机械钻速。在实际生产应用中,结合邻井钻井效果对比,新型215.9 mm STS636LGRS射吸钻头在部分岩段中具有一定提速效果。
文摘A high-accuracy,low-dropout （LDO） voltage regulator is presented. Using the slow-rolloff frequency compensation scheme, the LDO effectively overcomes the stability problem, facilitates the use of a ceramic capacitor, and improves the output voltage accuracy, which is critical for powering high-performance analog circuitry. The slow-rolloff compensation scheme is realized by introducing three pole-zero pairs, including the proposed polezero pair and sense zero. The post-layout simulation results demonstrate that this LDO has robust system stability, a high open-loop gain, and a high unit-gain frequency,which lead to excellent regulation and transient response performance. The line and load regulation are 27μV/V and 3.78μV/mA, and the overshoots of the output voltage are less than 30mV,while the dropout voltage is 120mV for a 150mA load current.
