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<br />1 the nuclei in the formation. Hydrogen plays a predominant role in slowing down and capturing <br />' the neutrons. Low neutron counts are therefore indicative of water bearing zones or hydrated <br />minerals such as gypsum or clays, Electromagnetic (EM) conductivity measures the materials <br />' ability to conduct electricity. This physical property is strongly dependent on the moisture <br />content and the total dissolved solids level of the pore fluids. Hence, dry materials tend to have <br />' low conductivity values. Copies of the geophysical logs run in well M-14 are presented in <br />Appendix A. <br />' The neutron log for well M-14 shows a distinct shifr to lower counts below 142 feet. This is <br />' responding to the saturated versus unsaturated zone, with static water level measured at 142 feet <br />below ground surface prior to logging. The high peak just prior to this shift is a reflectance <br />' phenomena from the water surface. The other distinctive feature on that log is a dramatic low <br />between 23 and 27.5 feet. This interval coincided with a noticeable drilling break; but the return <br />cuttings did not indicate any change in lithology or the presence of water. Tha gamma log is <br />fairly uniform from the surface to 140 feet, where a noticeable shift occurs. This change is <br />attributable to the sand pack/grout interface. The most distinctive feature on the EM conductivity <br />log is a low between 20-28 feet followed by a high interval between 28-37 feet. The low <br />conductivity response is coincident in part with the low neutron response, while the high interval <br />corresponds to increased silt and clay content in the subsurface. It should be opted that minor <br />' depth discrepancies are attributable to datuming errors, cable stretch or slippage, and tool vertical <br />resolution. <br />The geophysical logs from wells M-9, M-12, and M-]3 were also reviewed in an attempt to <br />correlate beds within the Santa Fe Formation in this locale. Due to the repetitious and localized <br />depositional sequence of the Santa Fe sediments, however, definitive cotrelatioas could not be <br />t made between these wells. <br /> <br /> <br />' -6- <br />1 <br />