Prospecting for Oil and Natural Gas
Fast Facts About
Prospecting for Oil and Natural Gas
Prospecting is the very first stage of the oil and natural gas development process. It consists of two main steps: exploration and the acquisition of permits and leases.
Exploration encompasses the processes and methods involved in locating potential sites for oil and gas drilling and extraction. Geoscientists use many tools to identify and characterize “prospects” for oil and natural gas development. These tools range from basic geological and paleontological understanding of a reservoir to acoustic and magnetic seismography enhanced by 3D imaging. Other factors such as road access, topography, and prior drilling results (if any) are also considered. If available, data from existing wells in the reservoir help refine these assessments. This data can include well logs, cross-sections, and Estimated Ultimate Recovery (EUR), which is an estimate of the expected recovery of oil or gas from a producing well. Finally, the location must be economically and regulatorily available.
Permitting and Leasing are closely intertwined and follow exploration. Prior to drilling in hydrocarbon fields that were identified through the exploration process, permits and leases must be secured from the entity that owns the land and its associated mineral rights. In the United States, four types of land ownership influence this process: private, federal, state, and tribal. The federal government also manages leases for offshore activity on the outer continental shelf of the U.S. The U.S. is the only country in the world that allows private ownership of mineral rights. Outside the U.S., the permitting and leasing of mineral rights are generally a government-managed process.
Taken together, the processes of exploration, permitting and leasing may take years to decades to accomplish, depending on the location and nature of the prospecting activity.
See our Drilling, Completing, and Producing Oil and Natural Gas Wells page for information on the steps that follow prospecting. See our Oil and Natural Gas pages for information on processing, refining, and transporting oil and natural gas after they are produced.
Porosity vs Permeability
Porosity is the volume of pore space in a rock as a percentage of the total volume the rock occupies. The pore space is usually filled by water but may be filled with oil or natural gas.
Permeability is the ease with which fluids or gases can move through the interconnected pores of rock.
Both porosity and permeability are important factors for a productive oil or gas well.
Types of Oil and Gas
Oil
- Conventional oil (found in reservoirs with naturally high permeability)
- Unconventional oil (low permeability or high viscosity, requires stimulation or other enhanced methods, e.g., hydraulic fracturing). Types of unconventional oil include:
- Heavy oil: highly viscous crude oil that does not flow easily
- Tight oil: oil found in low-permeability, non-porous rock formations like shale
- Oil sands: a mixture of sand, clay, water, and bitumen (a dense, highly viscous, and sticky black hydrocarbon)
- Oil shale: sedimentary rock that contains solid bituminous materials which are released as petroleum-like liquids when the rock is heated
Gas
- Conventional gas (found in reservoirs with naturally high permeability)
- Unconventional gas (low permeability, requires stimulation). Examples of unconventional gas include:
- Shale gas
- Tight sands gas
- Coalbed methane
- Methane hydrates (not commercially viable)
Prospecting Tools
Paleontology
Fossil correlation and dating of different core samples
Seismography
Measuring of seismic waves to understand and map the subsurface
Well Logs
Logs that show the density, porosity, temperature, resistivity, and pressure at different depths
Mapping
Geologic mapping of potential sites and data analytics of current wells
Drivers
- Continuing demand for oil and gas
- Can reduce energy dependence on other countries by finding additional domestic resources
- Potential to find more economic reservoirs (e.g., with technological advances)
Barriers
- Geologic tools can be expensive
- Lack of certainty that new drilling permits will be given
- Strict regulations for oil and gas
- Land use restrictions
- Public opposition
Climate Impact: Low
- Emissions from exploratory wells
Environmental Impact: High
- Exploratory wells require the clearing of vegetation and land
- Seismic techniques of exploration disturb ecosystems
- Road construction to prospecting sites cuts through ecosystems
- Improper disposal of saline water pumped from the ground damages soil and groundwater
Updated December 2025
Our 10-Minute Take On
Prospecting for Oil and Natural Gas
If you're short on time, start by watching this video of key highlights from our lecture on Prospecting for Oil and Natural Gas.
Presented by: Diana Gragg, PhD; Core Lecturer, Civil and Environmental Engineering, Stanford University; Explore Energy Managing Director, Precourt Institute for Energy
Recorded: March 7, 2025
Duration: 12 minutes
If you liked this video, watch the other 10-Minute Takes here!
Curated Videos and Readings on
Prospecting for Oil and Natural Gas
We assign videos and readings to our Stanford students as pre-work for each lecture to help contextualize the lecture content. We strongly encourage you to review the Essential videos and readings below before watching our lecture on Prospecting for Oil and Natural Gas. Include selections from the Optional and Useful list based on your interests and available time.
Essential
- Conventional vs Unconventional Oil and Gas. Energy Training Resources. November 3, 2017. (5 min)
The difference between conventional and unconventional oil and gas wells, and how wells are designed to access these energy resources. - Using 3D Seismic Exploration to Find and Drill for Oil and Natural Gas Sources. PolarPetroleum. April 29, 2013. (3 min)
How 3D seismic exploration is used to find and drill for oil and natural gas. - Prospecting Petroleum: How It’s Done. OpenMind. October 22, 2014. (2 min)
A graphical overview of the processes and technology involved in offshore oil exploration. - How It Works: Offshore Exploration. Canadian Association of Petroleum Producers. February 16, 2022. (3 min)
With focus on Atlantic Canada, this video provides a brief overview of how companies find oil and natural gas under the sea. - Evolution of a Landman. American Association of Professional Landmen. January 4, 2023. (1 min)
A brief look at how the land profession has changed since the 1950s.
Optional and Useful
- Overview of the Oil and Gas Exploration and Production Processes (pages 4-10). E&P Forum/UNEP. 1997. (7 pages)
A summary of methodologies used in the exploration process. - Taking Care of Base Business. Chevron. April 7, 2015. (1 min)
A commercial perspective of the technical and business measures taken in the oil and gas industry to extend the life of oil and gas exploration investments. - Powered by Public Lands, BLM California’s Oil and Gas Program. California Bureau of Land Management. September 28, 2017. (3 min)
A history of oil exploration and production and lease management in the state of California.
Our Lecture on
Prospecting for Oil and Natural Gas
This is our Stanford University Understand Energy course lecture on oil and natural gas prospecting. We strongly encourage you to watch the full lecture to understand this important topic within the context of the oil and natural gas energy systems. For a complete learning experience, we also encourage you to watch / read the Essential videos and readings we assign to our students before watching the lecture.
Presented by: Jane Woodward, Adjunct Professor, Civil and Environmental Engineering, Stanford University; Founder and Managing Partner, WovenEarth Ventures; Founding Partner, MAP Energy
Recorded on: September 29, 2025 Duration: 27 minutes
Additional Resources About
Prospecting for Oil and Natural Gas
Government and International Organizations
- International Energy Agency (IEA) Oil, Natural Gas
- US Energy Information Administration (EIA). Petroleum, Natural Gas, Oil and Natural Gas Proved Reserves, Oil and Gas Exploration Maps
- US Energy Information Administration (EIA) Today in Energy Oil, Natural Gas
- US Department of Interior (DOI) Atlas of Oil and Gas Plays on American Indian Lands
- US Environmental Protection Agency (EPA) Oil and Gas Sector Information
- US Federal Energy Regulatory Commission (FERC) Oil, Natural Gas
- US Bureau of Land Management (BLM) Oil and Gas
- US Bureau of Indian Affairs (BIA) Division of Energy and Mineral Development
- US Bureau of Ocean Energy Management (BOEM) Oil and Gas Energy
- Each state manages the oil and gas drilling permitting, leasing, and oversight that occurs on state lands. Example state resources: