Hydrocarbon Exploration Production
Hydrocarbon exploration (or oil and gas exploration) is the search by petroleum geologists and geophysicists for deposits of hydrocarbons, particularly petroleum and natural gas, in the Earth's crust using petroleum geology.
Hydrocarbon Exploration Production
Visible surface features such as oil seeps, natural gas seeps, pockmarks (underwater craters caused by escaping gas) provide basic evidence of hydrocarbon generation (be it shallow or deep in the Earth). However, most exploration depends on highly sophisticated technology to detect and determine the extent of these deposits using exploration geophysics. Areas thought to contain hydrocarbons are initially subjected to a gravity survey, magnetic survey, passive seismic or regional seismic reflection surveys to detect large-scale features of the sub-surface geology. Features of interest (known as leads) are subjected to more detailed seismic surveys which work on the principle of the time it takes for reflected sound waves to travel through matter (rock) of varying densities and using the process of depth conversion to create a profile of the substructure. Finally, when a prospect has been identified and evaluated and passes the oil company's selection criteria, an exploration well is drilled in an attempt to conclusively determine the presence or absence of oil or gas. Offshore the risk can be reduced by using electromagnetic methods [1]
A prospect is a potential trap which geologists believe may contain hydrocarbons. A significant amount of geological, structural and seismic investigation must first be completed to redefine the potential hydrocarbon drill location from a lead to a prospect. Four geological factors have to be present for a prospect to work and if any of them fail neither oil nor gas will be present.
Hydrocarbon exploration is a high risk investment and risk assessment is paramount for successful project portfolio management. Exploration risk is a difficult concept and is usually defined by assigning confidence to the presence of the imperative geological factors, as discussed above. This confidence is based on data and/or models and is usually mapped on Common Risk Segment Maps (CRS Maps). High confidence in the presence of imperative geological factors is usually coloured green and low confidence coloured red.[2] Therefore, these maps are also called Traffic Light Maps, while the full procedure is often referred to as Play Fairway Analysis (PFA).[3] The aim of such procedures is to force the geologist to objectively assess all different geological factors. Furthermore, it results in simple maps that can be understood by non-geologists and managers to base exploration decisions on.
Resources are hydrocarbons which may or may not be produced in the future. A resource number may be assigned to an undrilled prospect or an unappraised discovery. Appraisal by drilling additional delineation wells or acquiring extra seismic data will confirm the size of the field and lead to project sanction. At this point the relevant government body gives the oil company a production licence which enables the field to be developed. This is also the point at which oil reserves and gas reserves can be formally booked.
Sand injectites are described in scientific literature as an increasingly common occurrence in hydrocarbon reservoirs, in particular in deep-water clastic systems, where they are known to influence reserves distribution and recovery. Seismically-detectable injected sand bodies constitute targets for exploration and development wells and, subseismic sand bodies provide excellent intra-reservoir flow units that create field-wide vertical communication through depositionally extensive, low-permeability units. As sand injectites form permeable conduits in otherwise low-permeability units they facilitate the expulsion of basinal fluids; hence they act both as a seal risk and mitigate timing and rate of hydrocarbon migration. Injected sand bodies form intrusive traps, which are distinct from structural or stratigraphic traps. Included in this publication are 10 chapters on subsurface examination of sand injectites, 1 chapter on theoretical considerations, and 13 outcrop analogs in reservoirs across the world. Captured in this volume is at least a taste of the global and stratigraphic distribution of sand injectites, and an attempt to introduce readers to sand injectites and their significance in the context of hydrocarbon exploration and production. The book is not intended as a complete review of the field-based literature, but emphasizes high quality case studies from the surface and subsurface. The geographic scope of the book is large, and illustrates the diversity of geological settings in which these fascinating and economically significant features are found.
The Journal of Petroleum Exploration and Production Technology is an international open access journal that publishes leading edge studies in the field of petroleum engineering, petroleum geology and exploration geophysics and the implementation of related technologies to the development and management of oil and gas reservoirs from their discovery through their entire production cycle.
Denmark has a long history of exploration for and production of hydrocarbons which is marked by many unique events and successes, Modern exploration began in 1935 on land, and in 1966 offshore in the North Sea. To date, more than 160 exploration and appraisal wells have been drilled and in excess of 150 000 line-km of seismic data have been acquired. Exploration activity in the Central Trough of the North Sea has had considerable success and Denmark benefits from the production of four oil fields and one gas field.
Hydrocarbon exploration and production incorporate great technology challenges for the oil and gas industry. In order to meet the world's future demand for oil and gas, further technological advance is needed, which in turn requires research across multiple disciplines, including mathematics, geophysics, geology, petroleum engineering, signal processing, and computer science.
This book addresses important aspects and fundamental concepts in hydrocarbon exploration and production. Moreover, new developments and recent advances in the relevant research areas are discussed, whereby special emphasis is placed on mathematical methods and modelling. The book reflects the multi-disciplinary character of the hydrocarbon production workflow, ranging from seismic data imaging, seismic analysis and interpretation and geological model building, to numerical reservoir simulation. Various challenges concerning the production workflow are discussed in detail.
The upstream segment of the oil and gas industry contains exploration activities, which include creating geological surveys and obtaining land rights, and production activities, which include onshore and offshore drilling.
Natural gas is found in both associated formations, meaning it is formed and produced with oil, and non-associated reservoirs. Gas can either be dry (pure methane), or wet (exists with other hydrocarbons like butane). Although wet gas must be treated to remove the other hydrocarbons and other condensates before it can be transported, it can increase producers' revenues because they can sell those removed products.3
The advent of shale gas in the United States is one of the biggest breakthroughs in the history of the energy industry. Prior to its development, the United States was viewed as a growing natural gas importer. But, production from shale gas has catapulted the United States into being the world's largest producer of natural gas and a fast-growing exporter. The two primary technological advances that made production from shale and other tight formations economically possible were horizontal drilling and hydraulic fracturing.
Oil and gas exploration encompasses the processes and methods involved in locating potential sites for oil and gas drilling and extraction. Early oil and gas explorers relied upon surface signs like natural oil seeps, but developments in science and technology have made oil and gas exploration more efficient. Geological surveys are conducted using various means from testing subsoil for onshore exploration to using seismic imaging for offshore exploration. Energy companies compete for access to mineral rights granted by governments by either entering a concession agreement, meaning any discovered oil and gas are the property of the producers, or a production-sharing agreement, where the government retains ownership and participation rights.4 Exploration is high risk and expensive, involving primarily corporate funds.5 The cost of an unsuccessful exploration, such as one that consisted of seismic studies and drilling a dry well, can cost $5 million to $20 million per exploration site, and in some cases, much more. However, when an exploration site is successful and oil and gas extraction is productive, exploration costs are recovered and are significantly less in comparison to other production costs.6
Oil and gas production is one of the most capital intensive industries: It requires expensive equipment and highly skilled labors.11 Once a company identifies where oil or gas is located, plans begin for drilling. Many oil and gas companies contract with specialized drilling firms and pay for the labor crew and rig dayrates.12 Drilling depths, rock hardness, weather conditions and distance of the site can all affect the drilling duration.13 Tracking data using smart technologies can help with drilling efficiency and well performance by providing real-time information and trends.14 While every drilling rig has the same essential components, the drilling methods vary depending on the type of oil or gas and the geology of the location.15
In onshore drilling facilities, the wells are grouped together in a field, ranging from a half acre per well for heavy crude oil to 80 acres per well for natural gas.16 The group of wells are connected by carbon steel tubes which sends the oil and gas to a production and processing facility where the oil and gas are treated through a chemical and heating process.17 Onshore production companies can turn on and off rigs more easily than offshore rigs to respond to market conditions.18 041b061a72