Tight reservoirs organic rich shale reservoirs oil shale cbm. Unconventional resources n owadays, unconventional resources have been brought into the forefront of the energy future due to the increase in demand of hydrocarbon and decline of production from conventional reservoirs. In the hydrocarbon industry, units for stress are usually pounds per square inch psi or some variation of pascals megapascals mpa, gigapascals gpa, etc. Unconventional resources from exploration to production request. Purchase unconventional gas reservoirs 1st edition.
Platt gives the example of the mississippi lime play. Generic viagra online, levitra for sale halliburtonblog. The course is built around the role of the reservoir engineer and, hence, concerns itself. Unconventional resource is an umbrella term for oil and natural gas that is produced by means that do not meet the criteria for conventional production. Unconventional gas, on the other hand, is impounded in porous, lowpermeability features that act like a sponge, such as shale rock, sandstone, and coal seams. Unconventional datadriven methodologies forecast performance in unconventional oil and gas reservoirs keith r.
By contrast, unconventional resources are trapped in reservoirs with low permeability, meaning little to no ability for the oil or natural gas to flow through the rock and into a wellbore. For unconventional reservoirs, these techniques continue to evolve according to our improved understanding of the physics of fluid storage and flow. Unconventional resources are oil or gasbearing units where the permeability and porosity are so low that the resource cannot be extracted economically through a vertical well bore and instead requires a horizontal well bore followed by multistage hydraulic fracturing to achieve economic production. I suspect the terms have an origin based on quick decisions about how best to communicate to board members and bankers.
Unconventional reservoirs have burst with considerable force in oil and gas production worldwide. The projects are designed to reduce technical risks in enhanced oil recovery and expand application of eor methods in conventional and unconventional reservoirs. North american unconventional gas conference and exhibition, 1416 june, the woodlands, texas, usa. Because tight gas and shalegas reservoirs generally are.
This approach seems to offer the most comprehensive petrophysical analysis for unconventional reservoirs as it seeks an integrated characterization of mineralogy, organic content, porous volume, and fluid distribution. Yes, the definitions conventional versus unconventional are confusing. Petroleum resource triangle the relationship between conventional and unconventional resources is illustrated by a resource triangle. Unconventional reservoirs are very complex and most are considered as statistical plays. Unconventional gas resources from tight sand and shale gas reservoirs have received. The buoyancy forces does not succeed because of the low permeabilit y jail. Only in very rare cases will work be considered for regrading. Natural gas is currently the most promising source for providing sustainable, affordable and lowcarbon energy for the economic development of the world.
Unconventional resources inherent several specific characteristics, such as very low porosity, permeability, nondarcy flow, rock surface desorption. In order to extract unconventional gas economically, well operators make use of a combination of horizontal drilling and hydraulic fracturing. Talk about conventional and unconventional oil has led to the misunderstanding that these methods are in competition with each other. Reservoir management for unconventional reservoirs. Development, technology, and policy issues congressional research service summary in the past, the oil and gas industry considered gas locked in tight, impermeable shale uneconomical to produce. There is every reason to believe that enhanced oil recovery through huffandpuff injections in us tightoil plays could be a technical success across large numbers of wells. After decades of conventional drilling, this play has been revived with.
Power law exponential decline ple stretched exponential production decline sepd. A big part of the decisionmaking process in the oil and gas industry is certainty or rather, uncertainty. Both ple, sepd are good for production history over 3 year s, for tightunconventional wells. Request pdf unconventional resources from exploration to production in this chapter we present an overview of unconventional resource evaluation and. This approach seems to offer the most comprehensive petrophysical analysis for unconventional. Petrophysics of unconventional reservoirs training course. D06a9ec93bbe46772e12 filesshalegaseconomicimpactdec2011. Often enhanced recovery techniques, such as fracture stimulation or steam injection etc.
Tentative syllabus and administrative procedures fall 2009 class meetings. Unconventional gas and oil in north america page 4 of 24 glossary barrel oil. This course in unconventional reservoir management is aimed at all petrotechnical professionals who have little experience with these resource types but who wish to quickly learn some key elements and issues associated with the exploitation of unconventional reservoirs tight gas, tight oil and shales. What has qualified as unconventional at any particular time is a complex function of resource characteristics, the available exploration and production technologies, the economic environment, and the scale, frequency and duration of production.
The fundamental understanding of gas flow behaviours in unconventional gas reservoirs is essential to elevate the potential gas resource recovery. Highpermeability reservoirs that can be produced by traditional methods unconventional low permeability reservoirs immature source rocks production of adsorbed hydrocarbons heavy oil that will not flow naturally hydrocarbons in weird forms. To achieve commercial production, these reservoirs should be stimulated through massive hydraulic fracturing and, frequently, through horizontal wells as a. Hydraulic fracturing in unconventional reservoirs 1st edition. Unconventional gas reservoirs louisiana state university. Spe 145080 reservoir engineering for unconventional gas. Shale gas reservoirs require fracture stimulation to unlock gas from extremely lowpermeability formations. I suspect the terms have an origin based on quick decisions about how best to communicate to board members and bankers i will add to the confusion. Heavy oil and oil sands are also unconventional resources and many of these deposits are in reservoirs with permeability exceeding 500 nd. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext.
Jeff hamman, john sneider, carl sondergeld petrophysics is central to the integration of a wide spectrum of related geoscience and engineering disciplines. Naik summary with the decline of production and increase in demand of fossilfuel, economically producing gas from unconventional sources tight gas, coal bed methane cbm, and gas hydrate is a great challenge today. Thus, unconventional resources include both low and high permeability reservoirs with both low and high viscosity fluids. International development of unconventional resources accenture. The shales are both the source of and the reservoir for natural gas, unlike conventional petroleum reservoirs. To correct for this drawdown effect, a correction factor, f cp, is implemented in the gas constant pressure module, allowing for a more accurate determination of x f vk. Hydraulic fracturing in unconventional reservoirs 1st. Highpermeability reservoirs that can be produced by traditional methods unconventional low permeability reservoirs immature source rocks production of adsorbed hydrocarbons heavy oil that will not flow naturally hydrocarbons in weird forms what are the unconventional. Hydraulic fracturing in unconventional shale gas reservoirs. Spe 163609 a generalized framework model for simulation of gas. Comparative study of formation evaluation methods for unconventional shale gas reservoirs. On the characterization of unconventional oil reservoirs. Pete 4241 spring 2011 main instructor arash dahi, phd department of petroleum engineering office.
Tight gas reservoirs an unconventional natural energy source. As fracture stimulation is an important aspect of well completions. The term is used to make a distinction from shale and other unconventional reservoirs, in which gas might be distributed throughout the reservoir at the basin scale, and in. Industry has defined long time ago that unconventional reservoirs are those that have permeability to gas lower than 0. From hydraulic fracture mapping to seismicity and reservoir monitoring, our passive monitoring services and advanced analysis products are unmatched in the marketplace. Unconventional reservoirs are these source rocks where oil andor gas remained. Besides being a nondestructive technique, a clear advantage of sas techniques over lpa and mip is the possibility to investigate psds and their variation using relevant fluids i. The ability to economically produce natural gas from unconventional shale gas reservoirs has been made possible recently through the application of horizontal drilling and hydraulic fracturing. Tight gas reservoirs an unconventional natural energy. Conventional versus unconventional oil and gas conventional resources are concentrations of oil or gas that occur in discrete accumulations or pools. What are unconventional resources unconventional resources are hydrocarbon reservoirs that have low permeability and porosity and so are difficult to produce. Reservoir engineering focuses on the fundamental concepts related to the development of conventional and unconventional reservoirs and how these concepts are applied in the oil and. Once it approaches the depth of the targeted oil or gas reservoir, the shaft. An unconventional reservoir consists of an ultra tight source rock, trap and seal containing organic rich matter that has reached thermal maturity without migration.
Unconventional gas including tight, shale, and coal seam gas production has led to a drastic change of global energy landscape. Petrophysics of unconventional reservoirs robert m. Unconventional resources chapter kappa engineering. The basic reservoir parameters of unconventional reservoirs are often unknown or very difficult to determine with a high degree of accuracy. Unconventional oil and gas reservoirs are being explored significantly around the globe nowadays. A reservoir in which buoyant forces keep hydrocarbons in place below a sealing caprock. For unconventional gas reservoirs, x f vk departs from its analytical value as the pressure drawdown, d d, becomes higher. However, advances in directional well drilling and reservoir. Unconventional oil and gas resources handbook evaluation and development edited by y. Shale gas is one of them, with intense activity taking place in regions like north america. Lectures tth 10am, 3 credits, grading midterm exam 25%. Reservoirs tight gas sands coalbed methane gas hydrates heavy oil bitumen oil shale g y modified from holditch, jpt nov.
Specifically, a hybrid modeling approach is presented by combining discrete. To mine unconventional shale gas stimulation of the reservoir rock becomes necessary for a profitable gas production hydraulic fracturing is used to create a large and complex network of fractures which connects the production wells with the greatest possible volume of reservoir rocks horizontal well driven in the reservoir layer. These energy sources are a fastgrowing market and are recognized as having huge future potential for production worldwide. The term is used to make a distinction from shale and other unconventional reservoirs, in which gas might be distributed throughout the reservoir at the basin scale, and in which buoyant forces or the influence of a water column on the location of hydrocarbons within the reservoir are not significant. Abstract recent advances in drilling technologies have allowed some operators to reevaluate the economic. The economical production of hydrocarbons from these unconventional oil and gas reservoirs requires very advanced and cost effective technologies. In order to produce from unconventional reservoirs, industry uses a stimulation technique like hydraulic fracturing to create cracks in the underground rock. Bob cluff is a geologist and petrophysicist with over 35 years experience in oil.
Rock formations hosting these pools traditionally have high porosity and permeability and are found below impermeable rock formations. Unconventional gas much of the technically recoverable natural gas in north america is present in unconventional reservoirs such as tight sands, shale, and coal beds. Continuous d eposition, low permeability and bo th traditional and basin center settings. The gas is usually produced by pumping water from the coal seam to reduce pressure and release the gas. As fracture stimulation is an important aspect of well completions, production companies need to know basic. Holdaway, louis fabbi, and dan lozie, sas institute inc. Unconventional gas shales are fine grained, organic rich, sedimentary rocks. Reservoir management for unconventional reservoirs training. The reality for unconventional gas reservoirs ugrs, including.
Unconventional reservoirs require some form of stimulation to obtain commercial production. Geomechanical principles for unconventional reservoirs. Tight gas reservoirs an unconventional natural energy source for the future g. Theories, operations, and economic analysis introduces the basic characteristics and theories surrounding hydraulic fracturing and the main process of fracturing in shale, including the main workflow, the details in case analysis, and the fundamental differences between theory, study, and practical operation. These impervious layers form barriers to hydrocarbon migration. Reservoir and fluid characteristics of conventional reservoirs typically permit oil or natural gas to flow readily into wellbores. While any reservoir that is deemed to be shale may seem to be firmly in the unconventional bucket, there are different definitions of the term shale and it is important to know that not all shales are found in unconventional reservoirs. Petrophysics is central to the integration of a wide spectrum of related geoscience and engineering disciplines. P ractical geomechanics for unconventional resources. Unconventional datadriven methodologies forecast performance. Unconventional drilling methods for unconventional.
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