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The Standard Oil Company of California's well K.C.L. 20-13 attained a depth of 16,246 feet in 1944. The section penetrated includes 3560 feet of combined Tulare and San Joaquin formations, 3110 feet of Etchegoin formation, 1630 feet of the Reef Ridge shale, 1000 feet of McLure shale above the Stevens sand, 880 feet of Stevens sand, and 1875 feet of McLure shale below Stevens and above Pulvinulinella gyroidinaformis. The interval from P. gyroidinaformis at 12,056 feet to the top of the Santos shale at 15,230 feet consists mostly of cemented sandstone and firm, nearly barren, silty shale. Middle Miocene foraminifers were found at 13,423 feet and the Olcese and Rio Bravo-Vedder sand zones are recognized in the intervals 13,906-14,073 and 14,900-15,230 feet respectively. The antos shale is very hard and dense below 15,800 feet where the electric-log character changes. A decrease of about 25 millivolts from the normal shale line and an increase in resistivity of 2 to 3 times that of the overlying shale are noted. Shale porosities drop from 3.4% and 2.3% at 15,539 feet and 15,651 feet to 1.03% and 0.29% at 15,981 feet and 16,166 feet. Petrographic studies by Taliaferro are incomplete and can not be reported in time for this presentation.
Core dips are low (3°-10°) to 13,000 feet, then gradually rise to 65° at 16,166 feet. The maximum temperature at 16,186 feet was 400°F.
Subject to possible modification by the petrographic study, it is tentatively concluded that no metamorphic minerals have been formed by the load and shearing stresses of folding involved, but the rock at bottom is approaching the limit to which fine-grained sediments can be compressed without such changes.
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