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Title: Operational report : 1976 USACRREL-USGS Subsea Permafrost Program, Beaufort Sea, Alaska
Authors: United States. Bureau of Land Management.
United States. National Oceanic and Atmospheric Administration.
Geological Survey (U.S.)
Sellmann, P. V. (Paul V.)
Lewellen, Robert Irl.
Ueda, Herbert T.
Chamberlain, Edwin J.
Blouin, Scott.
Keywords: Beaufort Sea
Offshore drilling
Continental shelves
Core sampling
Core drilling
Sea ice
Subsea permafrost
Frozen ground
Frozen soils
Prudhoe Bay, Alaska
Publisher: Cold Regions Research and Engineering Laboratory (U.S.)
Engineer Research and Development Center (U.S.)
Series/Report no.: Special report (Cold Regions Research and Engineering Laboratory (U.S.)) ; 76-12.
Description: Special Report
Abstract: During the spring of 1976, three holes were drilled offshore in the Prudhoe Bay area using the sea ice cover as a drilling platform. The objectives of this program were to obtain samples and subsurface information to aid in quantification of the engineering characteristics of permafrost beneath the Beaufort Sea as well as to conduct supporting thermal and geological studies. The results of the drilling and related investigations are being used in conjunction with data from other subsea pe'rmafrost projects to develop maps and models for the prediction of permafrost occurrence in this offshore environment. The project also provides a means of testing drilling, sampling, and in-situ measurement techniques in an offshore setting where material types and sea ice conditions make acquisition of undisturbed sam pies extremely difficult. This report documents the operational aspects of the spring 1976 field study; subsequent reports will cover the technical and research results. During the mobilization period in March 1976 mobile drilling and housing facilities were assembled at Prudhoe Bay. The drilling equipment was derived from a variety of sources including several Government organizations (NARL, ONR, USGS and CRREL), while the field housing and some logistics support were contracted in the Prudhoe area. An Acker Mountaineer rotary drill rig was utilized in order to evaluate rotary and drive sampling techniques. No sampling or drilling problems were encountered in the upper parts of the sections (5 to 9 m) which in all cases were fine-grained. and cohesive. In these materials conventional drive sampling techniques consistently provided the best results. The lower portions of all sections were coarse grained including sand and gravel. In these intervals drive sampling also afforded the best recovery and least equipment problems. Although preliminary thermal data indicated temperatures below 0°C throughout all the sections, bonded permafrost was not encountered. Thermal data were obtained periodically from the three holes after their completion and until ice conditions in early June no longer permitted site visits. The holes ranged in depth from 34.0 to 52.0 m from the drill collar. An additional study consisted of an evaluation of a probe device for measuring in-situ engineering properties of the subsea sediments. Probe soundings were made at the drill sites and near the ARCO dock. Probe design allowed side friction and point penetration resistance to be measured separately. Temperature data over the depth of the soundings were also obtained. The probe was advanced by using a hydraulic ram or a drop hammer. The results indicate significant correlation between the two penetration techniques and the general material types identified during the drilling operation.
Rights: Approved for public release; distribution is unlimited.
Appears in Collections:Special Report

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