Exploration
With the development of incredibly modern, imaginative technology in the previous 20 years, the practice of detecting natural gas resources has changed considerably. The only way to locate underground petroleum and natural gas reserves in the early days of the industry was to look for surface indications of these underground formations. Those hunting for natural gas deposits had to comb the Earth for seepages of oil or gas discharged from underneath before they even knew there were deposits beneath. Due to the fact that only a small portion of petroleum and natural gas reservoirs naturally rise to the surface, the process of exploration has historically been arduous and inefficient. However, as the demand for fossil fuel energy has drastically increased in recent times, there is now a greater need for more precise techniques to locate these deposits.
Energy corporations fight for access to mineral rights granted by governments by engaging in a concession deal, which states that any discovered oil and gas is the property of the producers, or a production-sharing agreement, which states that the government retains ownership and participation rights. Exploration is a high-risk, high-cost endeavour that primarily involves corporate financing. An unsuccessful exploration, such as one including seismic investigations and drilling a dry well, can cost anywhere from $5 million to $20 million per exploration site and, in some circumstances, much more. When an exploration location is successful, and oil and gas extraction is profitable, exploration costs are recovered and are much lower than other production costs.
Proven reserves are the amount of oil and gas that a business believes it can produce economically with existing technologies at a certain point in time. Projections of proved reserves are frequently revised throughout the duration of a lease. These estimates can be affected by technological advancements, as seen in the case of the Marcellus Shale, where the proven reserves were raised by the U.S. Geological Survey by 40 times the initial figure due to innovations in hydraulic fracturing and horizontal drilling. Along with technology, reserve estimations are also influenced by prevailing prices and the existing infrastructure.
The exploration phase typically lasts 5 to 10 years and includes field discovery and field evaluation. This is normally accomplished by a combination of geological and geophysical investigations, as well as an assessment of the feasibility of exploiting the reservoir for production.
Field Discovery
Field discovery refers to the identification of a significant deposit of oil or gas in a particular geographic location. This typically occurs after an exploration company has conducted a series of geological and geophysical surveys, drilled exploratory wells, and evaluated the potential of the area.
The initial phase of upstream oil and gas production involves the exploration process of searching for and identifying potential locations to drill for gas deposits. This involves conducting numerous surveys, analyses, and tests on areas of interest.
Types of Surveys Used In The Exploration of Natural Gas.
Seismographic techniques: Seismic prospecting is a geophysical method used to explore and evaluate subsurface structures and properties of the Earth's crust. It involves measuring and analysing the response of rock and soil layers to artificially generated seismic waves.
Seismic waves are created by generating a controlled source of energy, such as a small explosion, a mechanical impact, or a vibrating plate. These waves propagate through the subsurface and are recorded by sensors called geophones or seismometers, which are placed on the ground surface or in boreholes.
The data collected from seismic prospecting is processed to create images of the subsurface layers, revealing the location and geometry of geological features such as faults, folds, and stratigraphic boundaries. This information is used in a variety of applications, consisting of oil and gas exploration, mineral exploration, engineering and environmental studies, and earthquake hazard assessment.
Earth gravity: The Earth gravity method, also known as gravity surveying, is a geophysical technique used in oil and gas exploration to determine the density variations of subsurface rock layers. Gravity surveys rely on the fundamental concept that the Earth's gravity field is influenced by the distribution of rocks below the surface. During such surveys, precise readings of the intensity and direction of gravitational force are taken at multiple locations on the ground surface or within boreholes. These readings are then used to generate a map of the gravity field in the surveyed area, which is subsequently scrutinized to detect any variations in the density of the underlying rock strata.
In oil and gas exploration, the Earth gravity method can be used to identify areas where there may be accumulations of hydrocarbons, as these typically have lower densities than the surrounding rock formations. By analysing the gravity data and combining it with other geological and geophysical information, exploration companies can determine where to drill exploration wells and assess the potential for finding oil and gas reserves.
The Earth gravity method is a valuable tool in oil and gas exploration, but it is not always sufficient on its own. It is generally used in combination with other geophysical techniques, such as seismic surveying and magnetic surveying, to provide a more complete picture of the subsurface geology.
Surface method: The surface method can be used to study the geology and other surface features of an area to gain insights into the underlying rock formations and the potential for hydrocarbon deposits. For example, researchers may examine the types of rocks and minerals present on the surface to gain an understanding of the underlying geology, including the types of formations that could potentially contain oil or gas. In addition, the surface method can be used to identify areas where hydrocarbon seepage has occurred, which can indicate the presence of an underground reservoir. By studying the surface features and geology of an area, researchers can gain valuable information that can help guide further exploration efforts, including drilling and other subsurface investigations.
The goal of the survey is to identify the potential reservoir called "Prospects." Once a field discovery is made, the exploration company will assess the size and quality of the oil or gas deposit and determine whether it is economically viable to develop the field for production.
