Figure 2. Lott 19 #4 well log with core photographs and photomicrographs of reservoir interval at Happy Spraberry field. The productive interval (A) consists of oolitic grainstones and packstones with well-developed skel- and oomoldic porosity which approach 1 cm. B is lithoclastic rudstone with in situ Tubiphytes bindstone in the right portion of the core photograph. Large bryozoan fragments and replacive anhydrite are visible in the photomicrograph. C is a quartz siltstone with primary intergranular porosity. D is matrix-dominated lithoclastic floatstone with large, complete fossils present. Scalebar: Core photographs = 1 cm, photomicrographs = 100 mµ.