Geophysical prospecting methods
AssigneeContinental Oil Company
InventorsKenneth H. Waters, George W. Rice
Life of this patent
Estimating the term…
Abstract
A method for deriving seismic information from over a relatively large expanse of land to determine relevant strike, dip, velocity and related information. The method consists of the utilization of a plurality of strike, dip, velocity (SDV) cross patterned source-receiver arrays disposed at spaced known locations over a selected terrain, thereafter to derive localized and offset seismic data relative to selected pairs of groups of the SDV cross patterns with further signal processing to smooth and integrate strike, dip and velocity information over a specific substratum. The method utilizes information as derived from each SDV cross pattern, as well as offset seismic signal information derived from source/receiver combinations spanning two selected SDV cross patterns.
Claims28
A method of geophysical prospecting to derive strike, dip, velocity and related data for a selected stratum underlying an earth area comprising the steps of:
- disposing first and second source-receiver cross patterns at first and second spaced positions of said earth area, said cross patterns each including a plurality of aligned seismic energy sources with a plurality of seismic energy receivers positioned transversely thereto;
- obtaining first and second local seismic trace data establishing reflection times for events reflected from said selected stratum underlying said first and second spaced positions;
- obtaining offset seismic trace data establishing reflection times for events reflected from said selected stratum underlying said earth area at a position intermediate to said first and second spaced positions, said offset seismic trace data resulting from seismic energy emanating from one source-receiver cross pattern and detected at the other source-receiver cross pattern;
- utilizing the first and second local trace data to produce parameter signals which define first and second planes under said first and second earth positions which best fit the reflection times of the first and second trace data, respectively, and
- utilizing the offset seismic trace data to produce parameter signals which define a third plane under said intermediate earth position which best fits the reflection times of the offset trace data,
- said first, second and third planes thereby representing the configuration of said selected stratum underlying said three earth positions, from which strike and dip of said selected stratum may be derived together with velocity of seismic energy between the earth's surface at said positions and the selected stratum.
A method of geophysical prospecting to derive strike, dip, velocity and related data for a selected stratum underlying an earth area comprising the steps of:
- disposing first and second source-receiver cross patterns at first and second spaced positions of said earth area, said cross patterns each including a plurality of aligned seismic energy sources with a plurality of seismic energy receivers positioned transversely thereto;
- obtaining first and second local seismic trace data for events reflected from said selected stratum underlying said first and second spaced positions;
- obtaining offset seismic trace data for events traveling from said selected stratum underlying said earth area at a position intermediate to said first and second spaced positions, said offset seismic trace data resulting from seismic energy emanating from one source-receiver cross pattern and detected at the other source-receiver cross pattern;
- utilizing the first and second local trace data to produce parameter signals which define velocity of seismic energy and first and second planes under said first and second earth positions which best fit the reflection times of the first and second trace data, respectively, and
- utilizing the offset seismic trace data to produce parameter signals which define velocity and a third plane under said intermediate earth position which best fits the reflection times of the offset trace data,
- said first, second and third planes thereby representing the configuration of said selected stratum at portions respectively underlying said three earth positions and the velocity used in the best fit determinations providing the actual velocity of seismic energy at each of said three earth positions.
A method of geophysical prospecting to derive the configuration of substrata underlying the earth's surface, comprising steps of:
- positioning a first line of seismic energy receivers in generally perpendicular intersection with a first line of sources and forming a first array at a first location on the earth's surface;
- positioning a second line of seismic energy receivers in generally perpendicular intersection with a second line of sources and forming a second array at a second location on the earth's surface spaced from said first location,
- energizing said sources sequentially and recording in the form of trace data seismic energy reflected from reflection points at substrate received by all said receivers upon each source energization to provide local trace data from said first and second arrays and offset trace data from seismic energy emanating from sources at one of said arrays and received by receivers at the other of said arrays;
- and
- selecting portions of said offset trace data and said local trace data relating to a defined region of said substrata to provide a combination of both local and offset trace data for deriving the configuration of said region of said substrata by analysis of said combination of trace data.
A method of geophysical prospecting to derive the configuration of substrata underlying the earth's surface, comprising steps of:
- positioning a first line of seismic energy receivers in generally perpendicular intersection with a first line of sources and forming a first array at a first location on the earth's surface;
- positioning a second line of seismic energy receivers in generally perpendicular intersection with a second line of sources and forming a second array at a second location on the earth's surface spaced from said first location,
- energizing said sources sequentially and recording in the form of trace data seismic energy reflected from reflection points at substrata received by all said receivers upon each source energization to provide local trace data from said first and second arrays and offset trace data from seismic energy emanating from sources at one of said arrays and received by receivers at the other of said arrays;
- and
- utilizing portions of said offset trace data and said local trace data relating to a defined region of said substrate for deriving the configuration of said region of said substrata by analysis of said portions of trace data in combination.
A method of geophysical prospecting to derive the configuration of substrata underlying the earth's surface, comprising steps of:
- positioning a first array of seismic energy receivers and sources at a first location on the earth'surface;
- positioning a second array of seismic energy receivers and sources at a second location on the earth'surface spaced from said first location,
- energizing said souces sequentially and recording in the form of trace data seismic energy reflected from reflection points at substrata received by all said receivers upon each source energization to provide local trace data from said first and second arrays and offset trace data from seismic energy emanating from sources at one of said arrays and received by receivers at the other of said arrays;
- and
- utilizing portions of said offset trace data and said local trace data relating to a defined region of said substrata for deriving the configuration of said region of said substrata by analysis of said portions of trace data in combination.
Dependencies are inferred from the claim text.