Figure 2. Photographs of the ACORK head showing the three instrument bays. The ACORK head is a 30 in. diameter cylindrical frame fabricated from in. steel around a section of 11 in. casing. It houses components in each of three 120° wide, 60 in. high bays that are bounded above and below by circular horizontal bulkheads and divided from one another by radial webs. (A) Bay #3 (left) houses the ROV connector, data logger, and pressure gauges. Bay #1 (right) houses the T-handle valves and ports and connecting tubing to downhole screen sections. (B) Bay #2 houses a sample port valve manifold for geochemical sampling and six three-way sensor valves. The sensor valves are tied in to the pumping valves and ports on Bay #1 to protect the pressure gauges from pressure surges when pumping or sampling fluids. Photographs by Adam Klaus.