# Susceptibility and Remanent Magnetization Estimates from Orientation Tools in Borehole Imaging Logs
## 3 Results
### Magnetic Susceptibility Estimates
The declination estimates show small values dispersion ranging from around \(112^{\circ}\) to \(118^{\circ}\), values that are very different from today's field at well location, which is around \(24^{\circ}\). However, the geomagnetic field reversal simulations of [32] indicates that during a reversal the field not only becomes weaker, but also multiple poles may appear in different parts of the globe. The low field intensity associated to the unusual declination angle may support the hypothesis that the igneous rocks may have acquired magnetization during a period of intense magnetic field changes, as illustrated by the geomagnetic polarity scale of Figure 7b (Hauterivian stage). As no remanent inclination \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & & \multicolumn{4}{c}{**Interval (m)**} \\ \hline
**Estimates** & **6211–6300** & **6305–6495** & **6500–6535** & **6540–6570** & **6585–6605** & **6620–6681** \\ \hline \(\chi_{x}\) & \(2.3\times 10^{-1}\) & \(8.7\times 10^{-1}\) & \(5.5\times 10^{-1}\) & \(8.6\times 10^{-1}\) & \(5.6\times 10^{-1}\) & \(7.2\times 10^{-1}\) \\ \(\chi_{y}\) & \(-8.2\times 10^{-1}\) & \(-9.3\times 10^{-1}\) & \(-7.0\times 10^{-1}\) & \(-5.9\times 10^{-1}\) & \(-5.0\times 10^{-1}\) & \(-9.3\times 10^{-1}\) \\ \(\chi_{z}\) & \(1.0\times 10^{0}\) & \(9.9\times 10^{-1}\) & \(3.8\times 10^{-1}\) & \(5.0\times 10^{-1}\) & \(9.2\times 10^{-1}\) & \(1.0\times 10^{0}\) \\ \(\chi\) & \(1.4\times 10^{-1}\) & \(3.1\times 10^{-1}\) & \(7.8\times 10^{-2}\) & \(2.6\times 10^{-1}\) & \(3.3\times 10^{-1}\) & \(2.6\times 10^{-1}\) \\ \hline \(M_{R_{x}}\) (A/m) & \(-7.9\times 10^{-1}\) & \(-1.4\times 10^{0}\) & \(-1.2\times 10^{0}\) & \(-1.8\times 10^{0}\) & \(-1.9\times 10^{0}\) & \(-2.1\times 10^{0}\) \\ \(M_{R_{y}}\) (A/m) & \(1.7\times 10^{0}\) & \(2.8\times 10^{0}\) & \(3.1\times 10^{0}\) & \(3.4\times 10^{0}\) & \(3.7\times 10^{0}\) & \(4.3\times 10^{0}\) \\ \(M_{R_{x}}\) (A/m) & \(-1.1\times 10^{0}\) & \(-1.7\times 10^{0}\) & \(-1.9\times 10^{0}\) & \(-2.1\times 10^{0}\) & \(-2.1\times 10^{0}\) & \(-2.5\times 10^{0}\) \\ \(M_{R}\) (A/m) & \(2.2\times 10^{0}\) & \(3.6\times 10^{0}\) & \(3.8\times 10^{0}\) & \(4.4\times 10^{0}\) & \(4.7\times 10^{0}\) & \(5.4\times 10^{0}\) \\ \hline \end{tabular}
\end{table} 
Table 2: Magnetic susceptibility (\(\chi\)) and remanence (\(M_{R}\)) estimates for the six igneous intervals of well 1-RJS-755-RJ. and declination measures are available to compare, it is difficult to extend this discussion since, in the worst hypothesis, we may be speculating upon not valid results. As mentioned in Section 3.2, magnetic susceptibility laboratory measurements were made in 58 rock samples distributed along the analyzed interval. The laboratory values are plotted together with the susceptibility estimates in Figure 14. For the carbonate interval estimate, results show values one order of magnitude higher than those measured in the lab. It is possible that the close presence of igneous rocks may be influencing the measured field and, consequently, the susceptibility estimates. Estimates for the igneous rocks presented better results when compared with the lab analysis. The first igneous interval, for instance, shows estimates that are very close to the measurements. For second and third interval estimates are a little lower than the measures while the predictions for the remaining intervals show higher values than the measurements. Taken into account that the process uses only the magnetic field acquired inside the well for its estimates, we consider these results as satisfactory to provide susceptibility and remanence values for forward magnetic modeling purposes.