Development of a bottom-hole gamma-ray diagnostic capability for high-level environments, during CTBT on-site inspection drilling
- Schlumberger-Anadrill, Sugarland, TX (United States)
The verification regime of the Comprehensive Test Ban Treaty (CTBT) provides for the possibility of on-site inspections (OSI`s) to resolve questions concerning suspicious events which may have been clandestine nuclear tests. The initial phase of an OSI may provide enough evidence to justify a request to the CTBT Organization for allowing drilling, so as to recover further evidence of a nuclear event. The equipment that was used for such `re-entry` drilling in the days of U.S. underground nuclear testing is considered too heavy and cumbersome for OSI deployments. So, an effort was initiated in 1995 to define, assemble, and demonstrate a new OSI drilling capability. Coiled-tubing (C-T) was selected as the most attractive technology because of its portability and its directional drilling capability (1). Following this selection, a preliminary engineering design was performed in 1996 for a Rapid Deployment Drilling System (RDDS). This system must have capabilities for downhole diagnostics of temperature and gamma-rays, since both types of data could be used to confirm the presence of an underground nuclear explosion. The study then identified two candidate downhole diagnostic systems operating with CT: the VIPER system of Schlumberger-Anadrill, and the Transocean system (2). In the current phase of this continuing effort the VIPER system has been retained as the first candidate because, everything else being equal, it is readily accessible domestically. One project, conducted by Maurer Engineering of Houston, TX, is specifying the details of the proposed CT system, its footprint, its modalities of air transport, and its costs of deployment and operation. The expected rate-of-penetration in rocks with unconfined compressive strength up to 14,500 psi (100 MPa) is also being estimated, based on laboratory-scale drilling tests on rock cores. Another project, which is the object of this report, has for an objective to develop and calibrate a downhole gamma-ray diagnostic capable of operating in the expected high-intensity environment near an underground nuclear cavity. The commercially available Anadrill VIPER logging assembly is calibrated to operate at levels of 0 to 250 American Petroleum Institute (API) units. These levels are much smaller than those necessary to confirm a clandestine nuclear explosion. The scope of the project is to make the necessary modifications to the VIPER gamma-ray module to meet minimum detection requirements of 50,000 API. At such a level, which is more than two orders of magnitude higher than seen in natural formations, the origin of gamma-rays could only be from underground nuclear test products. 2 refs, 2 figs, 2 tabs
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 675012
- Report Number(s):
- UCRL-CR-130663; INIS-XA-N-326; ON: DE98057873; BR: GJ1200000
- Resource Relation:
- Other Information: PBD: 1 May 1998
- Country of Publication:
- United States
- Language:
- English
Similar Records
Investigation of CTBT OSI Radionuclide Techniques at the DILUTED WATERS Nuclear Test Site
Aerial and ground-based inspections of mine sites in the Western U.S.-implications for on-site inspection overflights, under the CTBT