UNITED STATES DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY AND U.S. MINERALS MANAGEMENT SERVICE Summary report on the regional geology, petroleum potential, environmental consideration for development, and estimates of undiscovered recoverable oil and gas resources of the United States Gulf of Mexico Continental Margin in the area of proposed Oil and Gas Lease Sales Nos. 81 and 84 Edited by Richard Q. Foote U.S. GEOLOGICAL SURVEY OPEN-FILE REPORT 84- 33*} This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards and stratigraphic nomenclature. Use of trade names is for descriptive purposes only and does not constitute endorsement by the USGS. CONTENTS Page iW M . Introduction 0-1 References 0-4 J. xXiis tratxons - "*" - _ » _i - » __»m-r -i.. T- _i . _ .___ u <_,__ -. A.- -m (j j Chapter I: Regional Geologic Framework: Central and Western Gulf of Mexico OCS regions, by Ray G. Martin 1-1 Regional Geologic Setting 1-1 Origin and early evolution 1-2 Mesozoic and Cenozoic depositional history 1-5 Structural framework 1-7 Geologic Framework of Proposed Sale Areas 1-9 Stratigraphy 1-10 Structural features 1-14 ]?O'FOY"QTIV Cl. C I. CLlV*COtlf»d<3 . il~ "I ___ "I .^M -L-"l-__I__MI_ .m L^!_- ^^ «»M»M»^^_______ U__ -- ___WW«» ___U__- ^ - «___ - ___ __L--I ___ _T_U MLaLOL ML ___ ML _. OL J- T»J. fc*? UA Illustrations 1-32 Chapter II: Petroleum Geology: OCS Lease Sales 81 and 84 Planning Areas, by R.Q. Foote and R.G. Martin II-l Introduction II-l Source Beds and Maturation - II-2 Seals and Timing II-4 Mesozoic Reservoir Rocks II-6 Jurassic II-6 Lower Cretaceous II-7 Upper Cretaceous II-8 Cenozoic Reservoir Rocks II-9 ToT-f--{J. cL L-Ldi. a-r^r y .._^~____ . ~ .^ - . ___ _- __..^__.__^___________________ ___ ___ u-^x __._ _^.. ______ TTjLX Q:/ Quaternary 11-17 Structural and Stratigraphic Traps 11-20 Continental shelf 11-20 Continental slope and rise 11-23 Distribution of Oil and Gas Accumulations 11-26 Areas of Geologic Potential 11-29 Central Gulf of Mexico OCS (Sale 81) 11-29 Western Gulf of Mexico OCS (Sale 84) 11-32 T?O"Foi^OTir»OO£VC1. C I. Cli^.l3O M1 am-m - - l_. __"____ «J^ _LJMM LJMM .._ __I___T __i_ __r ~i_ _____ -mi«__-m _ ML __ «__ «__ __ »!«MI ~ __ - ^l^l-~- J^ «- i..^__ . T^FTl_____ __L ___ ..__.' TJ. TJ. * J*^ J^ Illustrations and Tables 11-40 Chapter III: Estimates of Undiscovered Recoverable Crude Oil and Natural Gas Resources, Proposed Lease Sale 81 and 84 Planning Areas, by Abdul S. Khan III-l Introduction III-l Area Assessed III-l Assessment Procedure III-2 Central Gulf Planning Area (OCS Sale 81) HI-4 Exploration history and petroleum potential HI-4 Western Gulf Planning Area (OCS Sale 84) HI-6 Exploration history and petroleum potential HI-6 Estimates of Resources HI-7 References HI-9 Illustrations and Table HI-10 Chapter IV: Environmental Consideration for OCS Development, Lease Sales 81 and 84 Planning Areas, by Louis E. Garrison IV-1 Introduction IV-1 Seafloor Instability IV-2 Upper continental slope IV-3 The Mississippi Delta IV-7 Gas Seeps and Shallow Gas Accumulations IV-8 Shallow Faulting IV-9 Texture of Surface Sediments IV-10 References IV-12 Illustrations IV-16 Chapter V: Unconventional Energy Resources: OCS Lease Sales 81 and 84 Planning Areas, by R.Q. Foote, L.M. Massingill and R.H. Wells V-l Geopressured-Geothermal Energy Resources V-l Geology of geopressured zones V-3 Trends and prospects V-4 Summary V-9 Unconventional Gas Resources: Gas From Gas/Water V-10 Industry activities V-ll Resource estimates V-13 References V-14 Illustrations V-17 Appendix: Environmental Geology Summaries, Introduction '- - -n"-^- -.... ._« -.. v.. -> . »!._ -» ..«... ___-. A J. Pleistocene Trend Area: Southeast Louisiana Shelf and Slope A-l Status of information A-3 South Texas Outer Continental Shelf A-8 Reports generated (1975-1980) A-9 Reference A^-15 SUMMARY REPORT ON THE REGIONAL GEOLOGY, PETROLEUM POTENTIAL, ENVIRONMENTAL CONSIDERATION FOR DEVELOPMENT, AND ESTIMATES OF UNDISCOVERED OIL AND GAS RESOURCES OF THE UNITED STATES GULF OF MEXICO CONTINENTAL MARGIN IN THE AREA OF PROPOSED OIL AND GAS LEASE SALES NOS. 81 AND 84 INTRODUCTION The first formal step in an Outer Continental Shelf (OCS) oil and gas lease offering is the preparation of a Resource Report (Summary Geology Report). The resource estimates developed for this report are then used in the preparation of the next required document, the Exploration and Development (E&D) Report. These two reports provide information needed in the selection of the Area of Geologic Potential, the area identified by the Under Secretary, Department of the Interior, in the formal Call for Information. The purpose of the Resource Report is to describe both narratively and graphically the general geology, petroleum geology, resource estimates and environmental geology of an entire planning area, such as the central Gulf of Mexico. The Resource Report is a synthesis of relevant publicly available data and reports; it is written in a style and format that is useful to geologists, economists, petroleum engineers, environmental scientists, and decision-makers. This report summarizes our general knowledge of the geologic framework, petroleum geology, and potential problems and hazards associated with development of petroleum resources in the Central and Western Gulf of Mexico OCS Planning Areas for proposed oil and gas lease sales 81 and 84, respectively. These areas encompass the submerged continental margin of the northern Gulf of Mexico from the vicinity of Mobile Bay to the ^io Grande and from State-Federal offshore boundaries to the deep Gulf floor along 0-1 latitude 26°N (Fig. 0-1). The Central Gulf Planning Area (Sale 81) lies offshore the states of Louisiana, Mississippi, and Alabama, and encompasses some 39 million acres of seabed. The Western Gulf Planning Area (Sale 84) lies principally offshore Texas, but includes deepwater tracts south of western Louisiana; approximately 33 million acres of seabed are contained in this area. Final sale sizes, however, are subject to exclusion of tracts selected on the basis of environmental concerns, military usage, low geologic potential, and other considerations. Water depths in the combined call-area range from about 60 to 10,200 feet; generalized bathymetry and physiographic features of the region are shown in Figure 0-2. The Gulf of Mexico OCS in the region of proposed lease sales 81 and 84, is the most productive offshore region in the United States. Over 94 percent of the petroleum liquids and 99 percent of the natural gas produced from the U.S. OCS in 1981 were taken from the central and western Gulf OCS off Louisiana and Texas (Havran and others, 1982). The U.S. Minerals Management Service Gulf of Mexico Regional Field Names Committee lists 521 active oil and gas fields in the Gulf of Mexico OCS as of December 31, 1982. An additional 16 fields have been depleted and abandoned. Estimates of original recoverable reserves for 468i/ active fields and 16 depleted fields amount to 3.56 billion barrels of oil (3BO) and 98.1 trillion cubic feet (TCF) of gas; remaining recoverable reserves in these fields, as of December 31, 1982, are estimated at 3.0 BBO and 39.8 TCF of gas (Hewitt and others, 1983). The following chapters are arranged to provide general information on the regional framework and petroleum geology of the central and western Gulf of Mexico, followed with information on petroleum potential and seafloor I/ Hewitt and others (1983) do not consider 53 of the 489 active fields to be sufficiently developed to permit reasonably accurate estimates of reserves at this time. 0-2 hazards more specifically tied to the areas proposed for leasing in Sales 81 and 84. References cited and illustrations have been included with individual chapters for convenience. 0-3 References Havran, K. J., Wiese, J. D., Collins, K. M., and Kurz, F. N., 1982, Gulf of Mexico Summary Report 3: A revision of Outer Continental Shelf oil and gas activities in the Gulf of Mexico and their onshore impacts; Gulf of Mexico Summary Report 2, August 1981: U.S. Geological Survey Open-file Report 82-242. Hewitt, J. E., Brooke, J. P., Knipmeyer, J. H., and Surcouf, R. M., 1983, Estimated oil and gas reserves, Gulf of Mexico Outer Continental Shelf and Continental Slope, December 31, 1982: U.S. Geological Survey Open-file Report 83-122, 17 p. 0-4 LOU ISIANA Lafayette Ewing Bonk Mississippi Canyon MEXICO 84 LEASE SALE 81 AREA Ztf1 - PLANNING AREA 50 100 NAUTICAL MILES I too ISO KILOMETERS Figure 0-1. Map of northwest Gulf of Mexico showing Central and Western Gulf OCS Planning Areas for proposed Lease Sales 81 (Central) and 84 (Western). 98' 96' 94* 92* O I 26' Figure 0-2. Map of northern Gulf of Mexico region showing bathymetry and principal physiographic feature in area of proposed Lease Sales 81 and 84. Contour intervals: 0 to 200 m in 20-m isobaths; greater than 200 m in 200-ra isobaths. From Martin and Bouma (1982). CHAPTER I REGIONAL GEOLOGIC FRAMEWORK: CENTRAL AND WESTERN GULF OF MEXICO OCS REGIONS by Ray G. Martin GENERAL Outer Continental Shelf Oil and Gas Lease Sales Nos. 81 and 84 are proposed for the central and western Gulf of Mexico regions lying principally off the states of Texas and Louisiana. These regions include the continental shelf and adjacent continental slope and the deep seabed of the north central and northwestern Gulf of Mexico generally west of longitude 88°W and north of latitude 26°N (Fig.