Study of Reservoir Heterogencities and Structural Features Affecting Production in the Shallow Oil Zone, Eastern Elk Hills Area, California

PDF Version Also Available for Download.

Description

Late Neogene (Plio-Pleistocene) shallow marine strata of the western Bakersfield Arch and Elk Hills produce hydrocarbons from several different reservoirs. This project focuses on the shallow marine deposits of the Gusher and Calitroleum reservoirs in the Lower Shallow Oil Zone (LSOZ). In the eastern part of the study area on the Bakersfield Arch at North and South Coles Levee field and in two wells in easternmost Elk Hills, the LSOZ reservoirs produce dry (predominantly methane) gas. In structurally higher locations in western Elk Hills, the LSOZ produces oil and associated gas. Gas analyses show that gas from the eastern LSOZ ... continued below

Creation Information

Gillespie, Janice November 1, 2004.

Context

This report is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided by UNT Libraries Government Documents Department to Digital Library, a digital repository hosted by the UNT Libraries. More information about this report can be viewed below.

Who

People and organizations associated with either the creation of this report or its content.

Publisher

Provided By

UNT Libraries Government Documents Department

Serving as both a federal and a state depository library, the UNT Libraries Government Documents Department maintains millions of items in a variety of formats. The department is a member of the FDLP Content Partnerships Program and an Affiliated Archive of the National Archives.

Contact Us

What

Descriptive information to help identify this report. Follow the links below to find similar items on the Digital Library.

Description

Late Neogene (Plio-Pleistocene) shallow marine strata of the western Bakersfield Arch and Elk Hills produce hydrocarbons from several different reservoirs. This project focuses on the shallow marine deposits of the Gusher and Calitroleum reservoirs in the Lower Shallow Oil Zone (LSOZ). In the eastern part of the study area on the Bakersfield Arch at North and South Coles Levee field and in two wells in easternmost Elk Hills, the LSOZ reservoirs produce dry (predominantly methane) gas. In structurally higher locations in western Elk Hills, the LSOZ produces oil and associated gas. Gas analyses show that gas from the eastern LSOZ is bacterial and formed in place in the reservoirs, whereas gas associated with oil in the western part of the study area is thermogenic and migrated into the sands from deeper in the basin. Regional mapping shows that the gas-bearing LSOZ sands in the Coles Levee and easternmost Elk Hills area are sourced from the Sierra Nevada to the east whereas the oil-bearing sands in western Elk Hills appear to be sourced from the west. The eastern Elk Hills area occupied the basin depocenter, farthest from either source area. As a result, it collected mainly low-permeability offshore shale deposits. This sand-poor depocenter provides an effective barrier to the updip migration of gases from east to west. The role of small, listric normal faults as migration barriers is more ambiguous. Because our gas analyses show that the gas in the eastern LSOZ reservoirs is bacterial, it likely formed in-place near the reservoirs and did not have to migrate far. Therefore, the gas could have been generated after faulting and accumulated within the fault blocks as localized pools. However, bacterial gas is present in both the eastern AND western parts of Elk Hills in the Dry Gas Zone (DGZ) near the top of the stratigraphic section even though the measured fault displacement is greatest in this zone. Bacterial gas is not present in the west in the deeper LSOZ which has less measured fault displacement. The main difference between the DGZ and the LSOZ appears to be the presence of a sandpoor area in the LSOZ in eastern Elk Hills. The lack of permeable migration pathways in this area would not allow eastern bacterial gas to migrate farther updip into western Elk Hills. A similar sand-poor area does not appear to exist in the DGZ but future research may be necessary to verify this.

Language

Item Type

Identifier

Unique identifying numbers for this report in the Digital Library or other systems.

  • Report No.: none
  • Grant Number: FG26-03NT41916
  • DOI: 10.2172/886857 | External Link
  • Office of Scientific & Technical Information Report Number: 886857
  • Archival Resource Key: ark:/67531/metadc875360

Collections

This report is part of the following collection of related materials.

Office of Scientific & Technical Information Technical Reports

Reports, articles and other documents harvested from the Office of Scientific and Technical Information.

Office of Scientific and Technical Information (OSTI) is the Department of Energy (DOE) office that collects, preserves, and disseminates DOE-sponsored research and development (R&D) results that are the outcomes of R&D projects or other funded activities at DOE labs and facilities nationwide and grantees at universities and other institutions.

What responsibilities do I have when using this report?

When

Dates and time periods associated with this report.

Creation Date

  • November 1, 2004

Added to The UNT Digital Library

  • Sept. 21, 2016, 2:29 a.m.

Description Last Updated

  • Dec. 2, 2016, 1:02 p.m.

Usage Statistics

When was this report last used?

Yesterday: 0
Past 30 days: 1
Total Uses: 4

Interact With This Report

Here are some suggestions for what to do next.

Start Reading

PDF Version Also Available for Download.

Citations, Rights, Re-Use

Gillespie, Janice. Study of Reservoir Heterogencities and Structural Features Affecting Production in the Shallow Oil Zone, Eastern Elk Hills Area, California, report, November 1, 2004; United States. (digital.library.unt.edu/ark:/67531/metadc875360/: accessed October 23, 2017), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.