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Structural Traps

Explorer Article

Conventional wisdom regarding basin-centered gas accumulations has sparked a geologic debate in Colorado.

American Association of Petroleum Geologists (AAPG)
Explorer Emphasis Article

There's more to Alaska than Prudhoe Bay: New technology and some surprising geological discoveries are helping to reawaken Alaska's petroleum promise.

American Association of Petroleum Geologists (AAPG)
Explorer Article

Timing, teamwork and technology contributed to the success stories of the lives of the lives of the featured lecturers at the Michel T. Halbouty Lecture.

American Association of Petroleum Geologists (AAPG)
Explorer Article

Go east, young geologist, go east? Thanks in part to Cold War era surveillance work, offshore East Africa is garnering renewed scientific and industrial interest.

American Association of Petroleum Geologists (AAPG)
Explorer Article

Shallow water, deep gas: In the scramble to find and produce new gas resources, operators are looking to the Gulf of Mexico to save the day.

American Association of Petroleum Geologists (AAPG)
Explorer Emphasis Article

State-of-the-art seismic acquisition, processing and interpretation techniques continue to be keys that unlock the treasure for Forest Oil in South Africa.

American Association of Petroleum Geologists (AAPG)
Explorer Article

What does past and present activities on the world's deepwater provinces tell us about the future? (Hint: The answer is 'a lot.')

American Association of Petroleum Geologists (AAPG)
Explorer Emphasis Article

A global assessment of undiscovered conventional oil and gas resources has led to some surprising geologic insights regarding petroleum systems.

American Association of Petroleum Geologists (AAPG)
Explorer Emphasis Article

Companies eyeing exploration in the National Petroleum Reserve-Alaska see prospects there as good to great, despite a scarcity of previous drilling there.

American Association of Petroleum Geologists (AAPG)
Explorer Emphasis Article

Coming soon: A new USGS resource assessment of the National Petroleum Reserve-Alaska, an area that may hold the key to Alaska's exploration future.

American Association of Petroleum Geologists (AAPG)
VG Abstract

Production from unconventional petroleum reservoirs includes petroleum from shale, coal, tight-sand and oil-sand. These reservoirs contain enormous quantities of oil and natural gas but pose a technology challenge to both geoscientists and engineers to produce economically on a commercial scale. These reservoirs store large volumes and are widely distributed at different stratigraphic levels and basin types, offering long-term potential for energy supply. Most of these reservoirs are low permeability and porosity that need enhancement with hydraulic fracture stimulation to maximize fluid drainage. Production from these reservoirs is increasing with continued advancement in geological characterization techniques and technology for well drilling, logging, and completion with drainage enhancement. Currently, Australia, Argentina, Canada, Egypt, USA, and Venezuela are producing natural gas from low permeability reservoirs: tight-sand, shale, and coal (CBM). Canada, Russia, USA, and Venezuela are producing heavy oil from oilsand. USA is leading the development of techniques for exploring, and technology for exploiting unconventional gas resources, which can help to develop potential gas-bearing shales of Thailand. The main focus is on source-reservoir-seal shale petroleum plays. In these tight rocks petroleum resides in the micro-pores as well as adsorbed on and in the organics. Shale has very low matrix permeability (nano-darcies) and has highly layered formations with differences in vertical and horizontal properties, vertically non-homogeneous and horizontally anisotropic with complicate natural fractures. Understanding the rocks is critical in selecting fluid drainage enhancement mechanisms; rock properties such as where shale is clay or silica rich, clay types and maturation , kerogen type and maturation, permeability, porosity, and saturation. Most of these plays require horizontal development with large numbers of wells that require an understanding of formation structure, setting and reservoir character and its lateral extension. The quality of shale-gas resources depend on thickness of net pay (>100 m), adequate porosity (>2%), high reservoir pressure (ideally overpressure), high thermal maturity (>1.5% Ro), high organic richness (>2% TOC), low in clay (<50%), high in brittle minerals (quartz, carbonates, feldspars), and favourable in-situ stress. During the past decade, unconventional shale and tight-sand gas plays have become an important supply of natural gas in the US, and now in shale oil as well. As a consequence, interest to assess and explore these plays is rapidly spreading worldwide. The high production potential of shale petroleum resources has contributed to a comparably favourable outlook for increased future petroleum supplies globally. Application of 2D and 3D seismic for defining reservoirs and micro seismic for monitoring fracturing, measuring rock properties downhole (borehole imaging) and in laboratory (mineralogy, porosity, permeability), horizontal drilling (downhole GPS), and hydraulic fracture stimulation (cross-linked gel, slick-water, nitrogen or nitrogen foam) is key in improving production from these huge resources with low productivity factors.

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American Association of Petroleum Geologists (AAPG)

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