National Geothermal Data System (NGDS)

The steel pipe experiment conducted in the lab was using 6 meter low-carbon steel pipe. We tested it with both dry and in-water condition. In the dry experimental setup, a coaxial cable acting as a return path in the air. Data associated with TDR experiment on the steel pipe with open termination when the pipe is in the water tank.

The coaxial-cable experiment conducted in the lab was with 80 m coaxial cable( RG-85). This experiment compares the TDR response between damaged and undamaged cable. For the damaged cable, the damaged section is in the middle (40 m). The amplitude of the data is mV with time(us).
Summary of the experiment. The amplitude of the data is mV.

The coaxial-cable experiment conducted in the lab was with 80 m coaxial cable( RG-85). This experiment compares the TDR response between damaged and undamaged cable. For the damaged cable, the damaged section is in the middle (40 m). The amplitude of the data is mV with time(us).
TDR response of the undamaged 20m coaxial cable with shorted termination. The amplitude of the data is mV with time(us).

For the model calculation we applied EM3D using completion diagram of CaMI site and a background resistivity consistent with the borehole logs. It was also important to use the accurate position of the return electrode. We note that for the data fit the code also incorporated well casings for well INJ and the other observation well, either OB1 or OB2, in the calculation.

In summary, we demonstrate here, for this particular case, that the DC results may be a reasonable approximation to the low frequency EM data collected at CaMI. If this approximation continues to hold, then the extreme computational efficiency offered by the hierarchical modeling used in the DC simulations will permit us to explore far more model complexity, especially the pervasive and troublesome data artifacts that arise when doing EM surveys in mature, culturally developed sites.

In Brief, both the low frequency and DC simulation codes provided very consistent results that match the field data really well, indicating their capability to help monitoring borehole integrity with the low frequency EM method. Field low frequency EM data for excitation of Observation Well 2 using a 5 Hz source frequency. Data is provided as distance form wellhead (m), Ex field amplitude (V/m), and Ex phase (degrees)..

Cymric oil field frequency domain electromagnetic (FEM) data with two parts of data labeled Part 1 and Part 2. Part 1 utilizes an electrical source line parallel to the receiver line, while Part 2 utilizes an electrical source line at a 75 deg angle to the receiver line. Data are plotted and compared to numerically modeled data to observe electric field response to well structure. In two configuration files are diagrams of the experiment layout.
Cymric field numerical modeling data using a 5 Hz source frequency. Data is provided as distance form wellhead (m) and Ex field amplitude (V/m).

The objective of this field test is to validate several technologies for non-invasive well integrity assessment using existing wells with a known completion. The tests were made at the Cymric oil field, which is a steam flood operation. The wells therefore undergo similar downhole conditions as geothermal wells. The Cymric field is mainly a cyclic steam operation where wells are 1000-15-00 ft in depth and the reservoir occupies the bottom 400ft. The maximum temperatures can exceed 500 degrees F and the well spacing is very close, often less than 50m. The field plan consisted of applying the Time Domain Reflectometry (TDR) method to the wells. The input voltages were set as 70 V shows the TDR responses at frequencies of 450 kHz, 2500 kHz, and 4500 kHz. There is a summary report will full information about the field tests. TDR response of 4500 kHz were made on the final morning in well TO15-5, using TO15-6 as a return electrode. The input voltage was set as 70V. We can set a TDR return at 1.8 – 2 µs, which is the reflection at about 738—862 ft deep. The shape of the TDR return indicates this is an open termination. Based on our knowledge of the well structure, this return is from the end of the production string.

Cymric oil field frequency domain electromagnetic (FEM) data with two parts of data labeled Part 1 and Part 2. Part 1 utilizes an electrical source line parallel to the receiver line, while Part 2 utilizes an electrical source line at a 75 deg angle to the receiver line. Data are plotted and compared to numerically modeled data to observe electric field response to well structure. In two configuration files are diagrams of the experiment layout.
Field data versus finite element solution for electric field data from Part 2 using a 1 Hz source frequency