In a stratigraphic trap, the geometry allowing the accumulation of hydrocarbons is of sedimentary origin and has not undergone any tectonic deformation. In a stratigraphic trap, variations within the rock strata themselves e. Stratigraphic traps have commonly a structural dips pdf, epub, mobi total read. Please check out my latest geoscience instructional video. Structural trap is a type of geological trap that forms as a result of. The premise is that effective stratigraphic trap exploration consists of the following steps. Structural traps, in contrast, consist of geologic structures in deformed strata such as faults and folds whose geometries permit retention of hydrocarbons. This file is licensed under the creative commons attributionshare alike 3. For an update on activity of hurricane exploration please see the link at the end of this article. Search for the subtle trap download ebook pdf, epub. Exploring for stratigraphic traps schlumberger mafiadoc. The deliberate search for the stratigraphic trap download. The cross section documents stratigraphic relationships previously unreported and contrasts with earlier interpretations in two ways. A second major class of oil traps is the stratigraphic trap.
Structural traps combination traps stratigraphic traps fig. Oct 14, 2015 hydrocarbon traps that result from changes in rock type or pinchouts, unconformities, or other sedimentary features such as reefs or buildups are called stratigraphic traps. Hydrocarbon traps that result from changes in rock type or pinchouts, unconformities, or other sedimentary features such as reefs or buildups are called stratigraphic traps. Allan et al, 2006 all facts and figures true on date of original publication. This study analyses 271 exploration wells worldwide that targeted stratigraphic traps in clastic reservoirs since 2008, to investigate if this perception is justified. This year we had seventy two attendees from ten different countries. Digital tabulation of stratigraphic data from oil and gas. Structural traps successful exploration starts here. The prediction of trap capacity for stratigraphic traps must consider both the seal capacity of the rocks above and below the reservoir and the seal capacity of lateral rocks. Structural plays in ellesmerian sequence and correlative strata of the national petroleum reserve, alaska by thomas e. A petroleum reservoir or oil and gas reservoir is a subsurface pool of hydrocarbons contained in porous or fractured rock formations. Pdf historically, stratigraphic traps have been perceived to be. This site is like a library, use search box in the widget to get ebook that you want. Stratigraphic traps have commonly a structural dips stratigraphic traps of pinchout type may perform prolific petroleum locations in iraq.
Trapping is by a combination of both structural and stratigraphic mechanisms. It is related to sediment deposition or erosion and is bounded on one or more sides by zones of low permeability. In stratigraphic traps, the concavedown shape is due to changes in rock type. The new structure, which has been mapped with twodimensional seismic, covers a twentyfivesquaremile area and is a structural rather than a stratigraphic trap, which means gasbearing reservoir sands would likely be thicker and more productive than thinner layers of reservoir more likely in a stratigraphic trap. Notice the common co occurrence of arching and faulting. Chapter 21 exploring for stratigraphic traps by john c. There are two main prospect of finding stratigraphic traps, one is in the sand fill lowstand incised valley and another is in regressive highstand sand that truncated against shalefilled channel. Stratigraphic and subtle combination traps are those which cannot be defined by structural closure alone. Exploring for stratigraphic traps schlumberger limited. Pdf stratigraphic traps of pinchout type may perform prolific petroleum locations in iraq. Many other such reservoirs are waiting to be located by the drill. Diagrams of structural and stratigraphic traps a trap is a geologic structure or a stratigraphic feature capable of retaining hydrocarbons. The book, an addition to the handbook set of the treatise of petroleum geology, focuses on procedures and proven petroleum exploration techniques that are critical for generating viable prospects. Jan 07, 2004 the item beaufortian stratigraphic plays in the national petroleum reservealaska npra, david w.
Stratigraphic trap a second major class of oil traps is the stratigraphic trap. Stratigraphic traps have commonly a structural dips stratigraphic traps, it is likely that only heavy hc might be discovered as the seals cannot contain the light fraction of hc. Paleontological research institution and its museum of the earth schlumberger. Discussions and examples show how to use sequence stratigraphy to integrate seismic and geologic data. Seismic expression of a subtle stratigraphic trap, lexington field, clark county, kansas larry j. In contrast, the driving forces for unconventional tight accumulations are forces of expulsion which are produced by high pressures. Sequence stratigraphy as a sequence stratigraphy as a. The driving forces for conventional accumulations structural or stratigraphic traps are forces of buoyancy which are due to differences in densities of hydrocarbons and water. While dissolution of the co 2 stored in these traps reduces the longterm leakage risk, the dissolution process remains poorly understood in systems that reflect the appropriate subsurface geometry. This collection of papers examine a number of themes related to exploration for stratigraphic traps, ranging from play and risk assessment, through regional assessments of stratigraphic trapping potential, specific exploration. The item beaufortian stratigraphic plays in the national petroleum reservealaska npra, david w. Several avenues are available for members of the uva community needing library resources, including hathitrusts newlyreleased trove of ed digital material, open educational resources, online journals, databases, and ebooks. Pdf locating of promising stratigraphic traps of pinchout type in.
Stratigraphic traps are created by any variation in the stratigraphy that is independent of structural deformation, although many stratigraphic traps involve a tectonic component such as tilting of strata. We have subdivided struc tural traps into fold traps, traps associated with faults, traps associated with piercement features. Capillary pressures between oil and water in rock pores are responsible for trapping oil, and the height of oil column, z o, in a reservoir may be calculated from the hobson equation modified as follows. In conventional reservoirs, the naturally occurring hydrocarbons, such as crude oil or natural gas, are trapped by overlying rock formations with lower. Stratigraphic trap definition of stratigraphic trap by. Figure 2 illustrates in map view how dip rate affects stratigraphic trap size. Stratigraphic trap article about stratigraphic trap by. Structural traps are anticlines, fault blocks, and domes. This collection of papers examine a number of themes related to exploration for stratigraphic traps, ranging from play and risk assessment, through regional assessments of stratigraphic trapping potential, specific exploration programmes targeted. The 8th conference on the petroleum geology of nw europe was held in september 2015 and marked. Reconnaissance of their expected locations, depth, and geometry was the main task of the paper. Houseknecht, electronic resource represents a specific, individual, material embodiment of a distinct intellectual or artistic creation found in indiana state library. Carbon dioxide dissolution in structural and stratigraphic traps.
Success rates and finding costs can match or better structural traps in some areas, especially for gas plays. Structural and stratigraphic traps are well established in geological literature. Stratigraphic traps of pinchout type may perform prolific petroleum locations in iraq. Major recent discoveries like buzzard, an upper jurassic stratigraphic pinchoutdip trap, are obvious analogues for future synrift targets, but these require the development of a strong conceptual model. One of the more difficult tasks in categorizing an oil or gas accumulation into a. Onlap valley fill channels onlaps stratigraphic traps meandering stream fluvial environments rivers braided stream meandering stream sandstone mudstone 3d seismic slice fluvial meander at 2. Beaufortian stratigraphic plays in the national petroleum reserve alaska npra. Such traps can be found in clinoforms, in a pinchingout sedimentary structure, under an unconformity or in a structure created by the creep of an evaporite. For example, a dipping reservoir may pinch out between two layers of. Pdf locating of promising stratigraphic traps of pinch. Petroleum reservoirs are broadly classified as conventional and unconventional reservoirs.
Stratigraphic trap definition and meaning collins english. Structural and stratigraphic traps are attractive sites for co2 sequestration. The geologic sequestration of carbon dioxide co 2 in structural and stratigraphic traps is a viable option to reduce anthropogenic emissions. This one took me longer to create as i found a few sources which had slightly different information to sift through. Exploring for oil and gas traps geoscienceworld books. Lexington field is located in northeastern clark county, kansas, principally in secs. Stratigraphic traps american association of petroleum. This file contains additional information such as exif metadata which may have been added by the digital camera, scanner, or software program used to create or digitize it. Shumaker abstract stratigraphic information from 694 oil and gas exploration wells from the onshore santa maria basin and. As there are different types of stratigraphic traps, understanding of the stratigraphy is. Stratigraphic traps had low finding costs overall at c. Analyze seal, reservoir, and show to find and evaluate traps. Stratigraphic traps, prevalent on the central basin platform, are.
Because tectonics ultimately control deposition and erosion, however, few stratigraphic traps are completely without structural influence. Today, fully 40% of the oil found in mature hydrocarbon provinces is being found in stratigraphic traps. Click download or read online button to get search for the subtle trap book now. Learn critical techniques for generating viable prospects. Stratigraphic trap article about stratigraphic trap by the. Exploring for stratigraphic traps exploring for oil and gas. Stratigraphic trap definition is a natural reservoir in which oil or gas may be confined because of changes in porosity and permeability of the strata rather than as. Search for the subtle trap download ebook pdf, epub, tuebl. Stratigraphic traps are those traps whose geometry is formed by changes in lithology. Hydrodynamic traps occur where the downward movement of water prevents. Published by the geological society on behalf of pgc ltd.
Geological survey editorial standards or with the north american stratigraphic code. Reconnaissance of their expected locations, depth, and. As structural dip steepens, the need for highquality seals increases, raising the probability of trap failure. Study of a stratigraphic trap of paleocenelate cretaceous. Large stratigraphic traps are most common in basins with gentle structural dip, where small hydrocarbon columns can be areally extensive. A stratigraphic trap holds the oil because of a decrease in permeability of the subsurface beds. Other articles where stratigraphic trap is discussed. Stratigraphic traps were first identified in pennsylvania in 1880, but exploring for them remained a mystery until the mid1930s, when seismology began to be applied in the petroleum industry. Sequence stratigraphy as a concrete stratigraphic discipline abstract sequence stratigraphy is a stratigraphic discipline in which stratigraphic surfaces that represent changes in depositional trend are used for correlation and for defining specific types of sequence stratigraphic units. Historically, stratigraphic traps have been perceived to be more risky than structural traps. Two main groups can be recognized primary stratigraphic traps result from variations in facies that developed during sedimentation. What is the difference between stratigraphic traps and. Stratigraphic traps do not appear to be inherently riskier, although success in these plays relies on using the right geoscience tools and ensuring. Sequence stratigraphy combines the strengths of seismic stratigraphy with litho and biostratigraphy to enhance the effectiveness of stratigraphic trap exploration.
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