The JOIDES office provides scientific direction and planning advice to the ODP prime contractor, Joint Oceanographic Institutions (JOI), Inc., the ODP Science Operator at Texas A&M University (TAMU), and the ODP Wireline Logging Services Operator at Lamont-Doherty Earth Observatory (LDEO) of Columbia University through an advisory structure of panels and committees. The two main committees are the Executive Committee (EXCOM), which oversees all policies and procedures, and the Science Committee (SCICOM), which oversees the science. These two committees and their associate subgroups forward recommendations to JOI for action. Recommendations concerning the science operator are forwarded to ODP/TAMU.
JOIDES service panels include the SSP, PPSP (also known as the Safety Panel), and Scientific Measurements Panel (SciMP), all of which provide advice to the advisory structure. The Technology and Engineering Development Committee (TEDCOM) provides advice to ODP through the Operating Committee (OPCOM) on technical matters, drilling tools, and techniques to meet scientific objectives as well as monitoring the progress of their development.
Scientific proposals are reviewed by the Science Steering and Evaluation Panels (SSEPs) for Environment and Interior, which select scientifically mature proposals for external review. SCICOM (with advice from the SSEPs) creates small, focused short-term Program Planning Groups (PPGs) to work with proponents to produce mature proposals that cover specific scientific themes.
Following reviews of proposals by external panels, the SSEPs forward scientifically mature proposals to SCICOM with a recommendation for inclusion in the drilling program. SCICOM ranks all the proposals and sends them to OPCOM. OPCOM receives reports from the SSEPs and PPGs and recommends the drilling program schedule to SCICOM for approval. The SSP provides advice to ODP through OPCOM on the adequacy of and need for site survey information relating to proposed drilling targets. The PPSP provides advice to ODP through OPCOM regarding potential safety and pollution hazards that may exist because of general or specific geology of the seafloor or as a consequence of human activities.
The JOIDES PPSP and the ODP/TAMU Safety Panel (TAMUSP) make recommendations that are considered in the final decision on specific drill sites, including advice on maximum penetration depths and required precautionary procedures. The Co-Chief Scientists typically attend the formal joint safety review with the PPSP ~9–12 months prior to the leg. During the safety review, Co-Chief Scientists or a delegate document potential safety issues extant at proposed sites and the safety panels examine these data.
The ODP/TAMU Drilling Services Department (DSD) provides ODP/TAMU management with a preliminary leg review, and ODP/TAMU management advises SCICOM and OPCOM on operational feasibility, time, cost, location, and environmental factors. SCICOM reviews and approves the proposed drilling schedule recommended by OPCOM and forwards it to EXCOM for approval. ODP/TAMU management assembles a ship schedule and assigns key personnel, and the ODP/TAMU DSD formulates a detailed operating plan in concert with the Staff Scientist/Leg Project Manager (LPM), Co-Chief Scientists, Transocean, and LDEO.
A precruise meeting is held with the Co-Chief Scientists at ODP/TAMU ~6–12 months prior to the leg, and the ODP/TAMU Operations Manager, Staff Scientist/LPM, and Laboratory Officer become involved in detailed planning with the Co-Chief Scientists. A detailed Scientific Prospectus that reflects the agreed-upon priorities and implementation strategies is prepared at the precruise meeting.
On notification from the JOIDES office, proponents of proposals that have been highly ranked by the SSEPs must submit supporting site survey data packages to the ODP Site Survey Data Bank for archiving (see "Safety and Site Survey Checklist" in "Appendix A"). These data packages are evaluated by the SSP and PPSP to determine if
The SSP reviews highly ranked proposals as advised by the JOIDES office and follows those placed on the drilling schedule until each leg sails. The PPSP, on the other hand, generally reviews only scheduled legs but will preview proposals that are identified as having potential safety concerns. The PPSP previews provide proponents an opportunity to address safety issues before the final PPSP review.
At their winter and summer meetings, the SSP reviews full proposals that have undergone external review. The SSP provides advice to proponents on specific data requirements for each proposed site. These requirements are based upon the objectives of each site and the local geologic environment. SSP only reviews data submitted to the ODP Site Survey Data Bank.
The time required for a proposal to become a scheduled drilling leg depends to a large degree on completeness of the site survey data package. Proponents are therefore urged to submit as much of the required data as early as possible, once they are notified to do so by the JOIDES Office. Data must be received in the Data Bank no later than 15 February or 1 July to be reviewed by SSP at their winter or summer meetings, respectively. If survey data are to be collected in the future, the proposal should note information on the timing of cruises, firmness of funding, and period required for data processing before submission.
The Site Survey Panel will review these proposals and the supplied data and provide advice to proponents on how to improve their data packages. SSP also provides comments to SCICOM and OPCOM on the status of the site survey data package with respect to its readiness for drilling. At the same time, the panel identifies those proposals that may have potential safety problems and passes this information along to the PPSP and the proponents. Proponents of these proposals may be asked to present their data to the PPSP for a safety preview at the panel's earliest convenience. The PPSP, on examination of the data package, will provide guidance on site selection and data processing to improve imaging of the sites and on modification of site locations so they will be safe to drill and still meet the scientific objectives.
Proponents should be aware that the comments below are only guidelines. The SSP's advice to SCICOM/OPCOM on the acceptability of a data set is based on scientific judgment. In particular, SSP seeks to determine (1) whether the regional and site-specific survey data are of sufficient quality and quantity that it will be possible to select the best sites at which to address the scientific questions posed in the proposal and (2) if a site is drilled, whether the regional and site-specific survey data are of sufficient quality and quantity that the results from this borehole could likely be extrapolated over a usefully broad portion of the ocean and/or applied to related questions and analogous sites worldwide.
Target categories describe broad types of drilling objectives (see Table T1). Individual sites with multiple objectives may be required to meet the standards of more than one of the target categories. For example, sites frequently have shallow advanced piston corer (APC) objectives (Target A) and deeper sedimentary and basement objectives (Targets D or E).
These guidelines cover drilling targets in >650 m of water. Proposed sites in <650 m of water, regardless of target type, are governed by additional shallow-water hazard survey requirements. See "Shallow-Water Operations" in "Principal Hazards" for details on these specialized requirements.
The most commonly used site survey techniques are conventional and swath bathymetry, magnetic and gravity field measurements, coring and dredging, heat flow, single- and multichannel seismic (SCS and MCS, respectively) reflection profiling, side-scan sonar, and crustal seismic refraction using ocean-bottom seismometer (OBS) and wide-angle reflection sonobuoy measurements. All survey methods are not appropriate for all sites, and specific combinations are chosen by proponents to obtain the maximum useful information for the minimum cost.
The following matrix (see Table T2) shows site survey guidelines for each target environment. Sites that lack a data type characterized as "X: required" will generally not be scheduled for drilling. Lack of a data type characterized as "Y: recommended" will not prevent scheduling drilling; however, if data of a recommended type do exist, the proponents are expected to submit the data for use by the ODP community in site selection and postdrilling interpretation. For data types marked as "X*" or "Y*," the SSP will advise, on a site by site basis, whether the specific data type is required or recommended to support the proposed science.
Data in support of each proposed site must be submitted to the ODP Site Survey Data Bank. For details on the proper format and annotation of the data packages, go to www.ldeo.columbia.edu/databank.
The major data categories are:
Proponents should be aware that in addition to SSP's data requirements they will eventually have to meet the additional requirements of the PPSP. For a brief overview of safety reviews, see "Pollution Prevention and Safety Panel (PPSP) Review," below. As part of a safety review, proponents should present maps of commercial well locations near their proposed drill sites and information regarding nearby hydrocarbon occurrences (production data, reservoir and source intervals, shows, etc.) to PPSP. Seismic ties to nearby commercial wells and heat flow data with which to assess potential hydrocarbon maturation may also be requested. As it can take considerable time to acquire such information from commercial sources, proponents are urged to begin the effort as early as possible. Leaks in existing wellbores can change previously unpressured zones.
The PPSP is composed of petroleum geologists, geophysicists, engineers, and organic geochemists drawn from industry, government, and academia who are recognized authorities in the fields of marine research and offshore oil exploration. They provide independent advice on the safety of drill sites to both JOIDES and ODP. The PPSP is actually composed of two separate groups, the JOIDES Safety Panel and the TAMUSP. In questioning presenters during a PPSP review, reviewing data, and discussing problems, there is no distinction between the two groups. After reviewing the site data and PPSP advice, ODP/TAMUSP makes a final recommendation regarding site safety and the operations plan.
The diverse sites planned for ODP drilling involve additional hazards not encountered in previous DSDP drilling. Holes are planned for deeper sediment penetration and/or in shallower water on continental margin sites. Moreover, the JOIDES Resolution continues to face drilling hazards inherent in operating without a drilling riser to the surface, return circulation, or standard blowout preventers. Although improved seismic surveys, an expanded borehole logging program, and advanced hydrocarbon monitoring capabilities help detect hazardous conditions during the cruise, the key to preventing an accident is the selection of safe drilling locations before the ship sails.
Once a full proposal has undergone SSP review and is placed onto the drilling program, it will be scheduled for further review by the PPSP at least 6 months prior to departure. Co-Chief Scientists (or their delegate) of the newly scheduled leg must prepare a written safety report that examines each site from the perspective of potential hazards, and they must also make an oral presentation of the existing data to the PPSP at their meeting. Failure by Co-Chief Scientists or their delegate to meet their responsibility of providing adequate data for review will result in rejection of drill sites by the PPSP.
Prior to the scheduled PPSP review, the Co-Chief Scientists (or their delegate) of the scheduled leg must produce a written synthesis of geological, geochemical, and geophysical data at each site, with an emphasis on hydrocarbon potential, possible trap structures, and other possible hazards. This report is submitted to the ODP Site Survey Data Bank, which then provides electronic versions on the World Wide Web site for access by PPSP members prior to the meeting. Safety reports are also required for proposals being previewed by the panel. Generally, the reports contain the information in Table T3.
Material submitted for each site should be indexed and annotated to enable ready identification of structural features, line locations, line directions, wells, grab samples, cores, etc.
The purpose of the written report is twofold. First, it requires the individuals to shift focus from the science of their sites to safety and operational issues. Second, by having the report in hand prior to the meeting, the PPSP members are able to locate additional data from their own sources that can be brought to the meeting to assist in site discussion. Contact the ODP Site Survey Data Bank at odp@ldeo.columbia.edu for assistance in preparation of the report.
At the PPSP meeting, Co-Chief Scientists or their delegate must make a formal presentation of pertinent data for each site and then discuss any safety issues with the panel. Most of the data needed for these safety reviews are also required for the SSP review; however, additional, safety-related items should be submitted to the ODP Site Survey Data Bank in an appropriate format prior to the PPSP meeting.
Based on the data presented, the PPSP will advise the presenter that a site (1) is recommended for approval as proposed, (2) should be moved to a safer location that is still compatible with the scientific objectives, or (3) is rejected because of inadequate data or inherent risk. The PPSP may recommend a preferred order of drilling if safety is a factor and may also specify conditions of approval, such as maximum depth of penetration or special monitoring requirements. It should be noted that proposing sites on structural highs will generally yield recommendations to relocate them onto the flank of the structure. The PPSP is also inclined to relocate drill sites to intersections of seismic lines, especially where sedimentary sections are thick and where traps could occur. In general, the panel will expect to see full-size copies of the information listed in Table T4.
During their October 1992 meeting, concern regarding potential for gas blowouts in shallow-water settings caused the JOIDES and ODP/TAMU Safety Panels to disapprove a number of proposed drill sites on the New Jersey shelf. The special blowout danger in shallow-water drilling is that gas, with its attendant threats of fire and explosion, will reach the sea surface at or in close proximity to the drilling vessel. In ODP drilling, this danger is compounded by the drillship's lack of a blowout preventer (BOP) and limited ability to use weighted drilling mud to contain gas release on a scale comparable to a standard oil and gas exploration rig.
JOIDES and ODP have seen an increasing number of drilling proposals with sites located in shallow water (<650 m) on the continental shelves. Shallow-water operations follow the recommendations adopted by the JOIDES panels of the Shallow-Water Drilling Working Group (SWDWG). These guidelines are as follows:
The guidelines developed by the SWDWG continue to be modified as necessary. Regulatory and scientific differences make change a necessity. Evolution of geophysical equipment used in high-resolution hazards surveys is continual. In general, state-of-the-art equipment will be required for ODP shallow-water surveys. The Shallow-Water Site Survey Guidelines are as follows:
A shallow-water hazard survey will have seven general requirements:
The current requirements for SWGHSs are described in detail in the Shallow-Water Drilling Working Group's Report. Proponents should consult the details of this report prior to planning any SWGHS.
Proponents must use the site summary forms (Fig. F1) to document the scientific objectives, available site survey information, logging plans, and safety at each proposed site. The set of forms uses a layered approach in describing each site, with the first page documenting basic site information and subsequent pages adding further details as the proposal matures and moves through the JOIDES review system. Proponents are instructed to fill out all parts of the form that are shaded in gray. Instructions for completing the forms are found below.
This form should be submitted for each site when submitting a preliminary proposal and whenever sites are moved or updated. The purpose of this form is to document each site's name, location, basic objectives, and drilling plan.
This form should be submitted for each site when submitting a full proposal and whenever survey data need to be updated. The purpose of this form is to document the available survey data for each proposed site. Include as much detail as possible for each data type. Please be specific regarding the locations of data on survey lines by indicating exact dates/times or shotpoints.
Check "New" when initially proposing the site. Check "Revised" for all updates and changes.
List proposal number, site number (e.g., SUBSAT-10A), and current date.
List all data available for data types 1 through 18 for the proposed drill site. Please give as much information as possible, including cruise names, line numbers when available, and specific date/time or shotpoint locations of sites on track line data. List as much data as possible and indicate survey cruises that may collect additional data and their expected dates. For details regarding site survey requirements for specific drilling environments, please see "Site Survey Target Types and Data Standards" in "Site Survey and Safety Panel Reviews."
This form should be submitted for each site when submitting a full proposal and whenever the logging plan is updated. The purpose of this form is to outline the logging program for the proposed drill sites.
Check "New" when initially proposing the site. Check "Revised" for all updates and changes.
List proposal number, site number (e.g., SUBSAT-10A), and current date.
List depths in meters.
Fill in as much detail as possible on the scientific objectives of each logging tool that will be run at this site. For details on what can be achieved with each tool, contact ODP/LDEO Wireline Logging Services (www.ldeo.columbia.edu/BRG/ODP).
This page should be submitted for each site once the proposal is placed on the drilling schedule. The newly scheduled leg will need to be reviewed by the PPSP. The information presented on this form will be used by PPSP to evaluate the safety of each drill site.
Check "New" when initially proposing the site. Check "Revised" for all updates and changes.
List proposal number, the site number (e.g., SUBSAT-10A), and the current date.
Please provide information requested in items 1 through 9 with as much detail as possible. The PPSP will use this information to evaluate the safety of each site. It is recommended that proponents begin to search for industry data on hydrocarbon occurrences even before the proposal becomes a leg, as this information is often difficult to obtain.
This page should be submitted for each site once the proposal is placed on the drilling schedule.
Check "New" when initially proposing the site. Check "Revised" for all updates and changes.
List proposal number, site number (e.g., SUBSAT-10A), and current date.
A sketch of the general lithologies proponent expects to encounter should be drawn on this page.
Whereas proposed drill sites are reviewed by both the SSP and the PPSP, their objectives are different. The SSP seeks to ensure that there are sufficient data of the appropriate kind to document a site's position and suitability for the proposed science. The PPSP then reviews these and other data to ensure that the drill site will be safe for ship operations and pose no pollution threat. Usually the data required for SSP review are sufficient for the PPSP review, but reprocessing or reformatting may be requested to enhance the data for use in hazard detection.
Site survey data requirements vary depending upon the type of environment in which the proposed drill site is located and the proposed depth of penetration. The SSP has defined eight target types, each with different data requirements, summarized in Table T1. If proposed sites fall into two classes, they may need to meet requirements of both target types. The data requirements for each of these target types are summarized in Table T2.
Details on each of the data types listed in the table can be found on the ODP Site Survey Data Bank Web pages (www.ldeo.columbia.edu/databank) along with guidelines on submitting data packages. Contact the Data Bank Manager (odp@ldeo.columbia.edu) with questions regarding data formats or presentation styles.
Twice per year the Site Survey Panel reviews the data packages of proposals referred to them and reports to OPCOM and the drilling proponents on the readiness of each package. If any potential pollution or safety hazards are noted during SSP review, sites may be referred to the PPSP for a preview. Flagging these hazards at an early stage allows site locations to be adjusted to avoid the problem or allows time for the location of additional data (such as from the petroleum industry) to further document and assess the hazard.
It is basic to pollution prevention and safety to make the best possible estimate of thickness of the sedimentary section at drill sites and to infer the nature of the rocks to be penetrated. Knowing the thickness of the sedimentary rock above igneous or metamorphic basement is most useful in deciding whether a drill site has potential petroleum hazards resulting from thermochemical action on organic matter in the sediments. It is difficult to predict whether there has been an adequate supply of organic matter in the section to have allowed substantial petroleum generation. However, seismic data usually provide adequate information on sedimentary rock thickness at a proposed drill site. If there is no definite information on the absence of petroleum source material, thick sedimentary sections (1500 m or more) must be considered possible progenitors of petroleum and should be drilled with appropriate caution.
For purposes of estimating petroleum hazards, ocean areas may generally be divided into those with >1000 m of sediment above basement (shelves, slopes, and rises adjacent to continents or islands; many small ocean basins and troughs; and a few sediment-filled basins far from land in the main oceans) and those with <1000 m of sediment (constituting most of the vast central areas of the major oceans, the mid-ocean ridges, and many trenches and local areas closer to land).
Sediment sections <1000 m thick usually have not experienced sufficient heating to generate abundant petroleum. An exception to this general rule is high heat flow areas near hydrothermal vents or mid-ocean ridges and gas hydrate or H2S deposits. Areas of thin sediments are therefore relatively free of petroleum hazards, provided the following conditions are also fulfilled:
In general, the PPSP considers central oceanic areas with 500 m or less sediment above basement to be nearly free of petroleum hazards. Even in such areas, however, consideration must be given to the possibility that older sedimentary sections may underlie acoustic basement or that biogenic methane may be present.
Obviously, hydrocarbon hazards are enhanced if good potential reservoir strata are present in the section (Pimmel and Claypool, 2001). This factor has an important modifying effect on safety conclusions based on sedimentary thicknesses and organic contents. Seismic data and regional geologic considerations may give helpful information on the probability of substantial reservoirs being present.
The presence of evaporites, overpressured shales, gas hydrate zones, and other seals below which hydrocarbons may be trapped also has an important bearing on the depth to which a drill hole can be safely carried. Presence of diapirs or flowing faults is a danger signal.
At least one continuous seismic profile must be obtained across any prospective drill site, and two profiles intersecting at approximately right angles must cross at prospective sites on shelves, slopes, and rises or at any site where a single profile suggests the possibility of a trap. Features of significance on seismic profiles include anticlines, faults, pinchouts, unconformities, etc. Any sort of structural or stratigraphic trap should be avoided in choice of drilling locations. Whereas reliance for identification of traps must rest primarily on seismic sections, gravity, magnetics, and bathymetric data may also be helpful.
Where thickness and character of rock sequences suggest adequate hydrocarbon source potential, quality of seismic data is critical. Migrated depth sections may be needed to evaluate faults as migration paths. Maps of key horizons may be necessary to document local structure and trapping configurations. Regional maps to ascertain relief on pinchouts may be needed to evaluate potential stratigraphic traps. Site proponents are urged to select sites off structure where desired objectives can be reached, even if this action means an increase in drilling depth.
Known Oil and Gas Presence. In planning a drilling leg, available information on oil and gas wells or seepages close to proposed sites, both on and offshore, must be obtained. This information is vital on continental margins. Shallow piston cores near proposed sites may provide information on hydrocarbon presence in surface sediments. Petroleum companies who hold or have held concessions in the general vicinity are good sources of information of this type. It must be noted that presence of an industry "dry hole" near a proposed site does not equate with a complete absence of hydrocarbons at that site. Drilled holes can breach seals and become a path for fluid migration and pressurization of shallow zones.
Abnormal Pressures. Areas and stratigraphic intervals containing fluids under greater than normal hydrostatic pressure should be avoided because of their common association with oil and gas and their tendency to cause blowouts. The presence of undercompacted shale is a warning that fluids may be encountered at greater than normal hydrostatic pressure. An undercompacted shale is one in which fluid expulsion has not kept pace with increased fluid pressure, so formation fluids in the shale and associated sands are not only under hydrostatic pressure but also bear part of the weight of the overlying rock column. Fluid pressures in such shales may also have a component of pressure generated internally by buoyant forces related to contained gas. Pressure-compacted shales may be identified by decreases in their interval velocities related to their abnormally high fluid content. They may also appear in seismic sections as distorted, convoluted reflections. Undercompacted shales may show up on gravity profiles because of their lower densities. Absence of velocity inversion does not preclude abnormal formation pressure, nor does its occurrence always result from an undercompacted shale section. Nevertheless, drill sites at which marked velocity inversions are detected should be avoided unless the inversion can be related to some other lithologic change.
Thermal Gradients. Heat flow data should be acquired at prospective drill sites to assess the possibility of migrated petroleum and because higher temperatures are commonly associated with abnormally high pressures and hydrocarbon accumulations.
Water Depth. Blowout danger to the ship diminishes greatly with increased water depth. Violent surface blowout may occur in water depths as great as 500 m, but there is little likelihood that such blowout danger exists in depths of 2000 m or more. Slow seepage of oil or gas into the sea, with consequent risk of pollution at remote downcurrent sites, can occur while drilling in any water depth.