Freedman R, Anand V, Grant B, Ganesan K, Tabrizi P, Torres R, Catina D, Ryan D, Borman C, Krueckl C
Schlumberger Technology Corp., 110 Schlumberger Drive, Sugar Land, Texas 77478, USA.
Grant Innovation, 618 Mesquite Drive, Cedar Creek, Texas 78612, USA.
Rev Sci Instrum. 2014 Feb;85(2):025102. doi: 10.1063/1.4863857.
We discuss an innovative new high-performance apparatus for performing low-field Nuclear Magnetic Resonance (NMR) relaxation times and diffusion measurements on fluids at very high pressures and high temperatures. The apparatus sensor design and electronics specifications allow for dual deployment either in a fluid sampling well logging tool or in a laboratory. The sensor and electronics were designed to function in both environments. This paper discusses the use of the apparatus in a laboratory environment. The operating temperature and pressure limits, and the signal-to-noise ratio (SNR) of the new system exceed by a very wide margin what is currently possible. This major breakthrough was made possible by a revolutionary new sensor design that breaks many of the rules of conventional high pressure NMR sensor design. A metallic sample holder capable of operating at high pressures and temperatures is provided to contain the fluid under study. The sample holder has been successfully tested for operation up to 36 Kpsi. A solenoid coil wound on a slotted titanium frame sits inside the metallic sample holder and serves as an antenna to transmit RF pulses and receive NMR signals. The metal sample holder is sandwiched between a pair of gradient coils which provide a linear field gradient for pulsed field gradient diffusion measurements. The assembly sits in the bore of a low-gradient permanent magnet. The system can operate over a wide frequency range without the need for tuning the antenna to the Larmor frequency. The SNR measured on a water sample at room temperature is more than 15 times greater than that of the commercial low-field system in our laboratory. Thus, the new system provides for data acquisition more than 200 times faster than was previously possible. Laboratory NMR measurements of relaxations times and diffusion coefficients performed at pressures up to 25 Kpsi and at temperatures up to 175 °C with crude oils enlivened with dissolved hydrocarbon gases (referred to as "live oils") are shown. This is the first time low-field NMR measurements have been performed at such high temperatures and pressures on live crude oil samples. We discuss the details of the apparatus design, tuning, calibration, and operation. NMR data acquired at multiple temperatures and pressures on a live oil sample are discussed.
我们讨论了一种创新的新型高性能装置，用于在非常高的压力和温度下对流体进行低场核磁共振（NMR）弛豫时间和扩散测量。该装置的传感器设计和电子规格允许在流体采样测井工具或实验室中进行双重部署。传感器和电子设备设计为在两种环境中均能正常工作。本文讨论了该装置在实验室环境中的使用情况。新系统的工作温度和压力极限以及信噪比（SNR）远远超过了目前的水平。这一重大突破得益于一种革命性的新型传感器设计，该设计打破了许多传统高压NMR传感器设计的规则。提供了一种能够在高压和高温下运行的金属样品架，用于容纳所研究的流体。该样品架已成功测试到36 Kpsi的操作压力。缠绕在开槽钛框架上的螺线管线圈位于金属样品架内部，用作发射射频脉冲和接收NMR信号的天线。金属样品架夹在一对梯度线圈之间，这对梯度线圈为脉冲场梯度扩散测量提供线性场梯度。该组件位于低梯度永久磁铁的孔中。该系统可以在很宽的频率范围内运行，无需将天线调谐到拉莫尔频率。在室温下对水样测量的信噪比比我们实验室的商用低场系统高15倍以上。因此，新系统的数据采集速度比以前快200倍以上。展示了在高达25 Kpsi的压力和高达175°C的温度下，对含有溶解烃类气体的原油（称为“活油”）进行的实验室NMR弛豫时间和扩散系数测量。这是首次在如此高的温度和压力下对活原油样品进行低场NMR测量。我们讨论了装置设计、调谐、校准和操作的细节。还讨论了在多个温度和压力下对活油样品采集的NMR数据。
