The basic functionality and performance of a new Schlumberger active wireline heave compensation system on the JOIDES Resolution was evaluated during the sea trial and a 3-year period of the IODP Phase II operations. A suite of software programs was developed to enable real-time monitoring of the dynamics of logging tools, and assess the efficiency of wireline heave compensation during downhole operations. The evaluation of the system effectiveness was performed under normal logging conditions as well as during stationary tests. Logging data were analyzed for their overall quality and repeatability, and to assess the reliability of high-resolution data such as formation microscanner (FMS) electrical images. This revealed that the system reduces 65-80 % of displacement or 88-98 % variance of downhole tool motion in stationary mode under heave conditions of ±0.2-1.5 m and water depths of 300-4,500 m in open holes. Under similar water/heave conditions, the compensator system reduces tool displacement by 50-60 %, or 75-84 % variance in downhole tool motion during normal logging operations. Such compensation efficiency (CE) is comparable to previous compensation systems, but using advanced and upgradeable technologies, and provides 50-85 % heave motion and heave variance attenuation. Moreover, logging down/up at low speeds (300-600 m/h) reduces the system's CE values by 15-20 %, and logging down at higher speeds (1,000-1,200 m/h) eliminates CE values by 55-65 %. Considering the high quality of the logging data collected, it is concluded that the new system can provide an improved level of compensation over previous systems. Also, if practically feasible, future integration of downhole cable dynamics as an input feedback into the current system could further improve its compensation efficiency during logging operations.
Integrated Ocean Drilling Program Expedition 342 was designed to recover Paleogene sedimentary sequences with unusually high deposition rates across a wide range of water depths (Sites U1403-U1411). The drilling area is positioned to capture sedimentary and geochemical records of ocean chemistry and overturning circulation beneath the flow of the Deep Western Boundary Current in the northwest Atlantic Ocean. In addition, two operational days were dedicated to a sea trial of the Motion Decoupled Hydraulic Delivery System developmental tool (Site U1402).Expedition 342 Preliminary Report 9 posits include the early Eocene to late middle Eocene, the late Eocene to early Oligocene, the late Oligocene and early Miocene, the later Miocene to probable late Pliocene, and the Pleistocene. Widespread hiatuses are present near the Paleocene/Eocene boundary into the middle early Eocene and the middle Oligocene. The Eocene/ Oligocene boundary is a period of slow sedimentation at most sites but is expanded at Site U1411. A marked change in the geometry of drift formation is observed in the ?late Pliocene, as has been observed in drift deposits elsewhere.An unexpected finding was the recovery of a number of Cretaceous "critical boundaries." These include the K/Pg boundary, the Campanian-Coniacian interval, the Cenomanian-Turonian boundary and oceanic anoxic event (OAE) 2, and the Albian/ Cenomanian boundary OAE 1d. These intervals were drilled opportunistically when they were encountered near or above our target depth for a given site. The K/Pg boundary was recovered at Site U1403, where it proved to have a well-preserved, normally graded spherule bed and unusually well preserved earliest Danian planktonic foraminifer community. The Campanian-Coniacian interval was cored at Site U1407 and is unusual mainly for the relative biostratigraphic completeness of a sequence that elsewhere commonly shows hiatuses in the early Campanian. The Cenomanian-Turonian transition was also cored at Site U1407 and consists of a series of organic black shales in nannofossil chalk with as much as 11 wt% total organic carbon (TOC). The Cenomanian-Turonian sequence at Site U1407 is broadly similar in biostratigraphy, sequence of black shales, and sediment color to classic Italian and northern German outcrop sections. Finally, coring at Site U1407 also recovered a lower Cenomanian nannofossil chalk and nannofossil claystone record that extends into the biozones associated with OAE 1d. The Albian-Cenomanian sequence is notable for the generally high quality of microfossil preservation and its gradational contact with underlying Albian shallow-marine carbonate grainstone and packstone.We created high-quality spliced records of most of the sites on Southeast Newfoundland Ridge that penetrate sequences with carbonate-rich lithologies. As anticipated, the task of creating spliced records in the more clay-rich lithologies in some sites was not straightforward due to intervals of low-amplitude change in some physical properties data sets. All sites also proved ...
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