Unconventional Reservoir Research Papers - Academia.edu (original) (raw)

Asphaltene is a component of crude oil that has been reported to cause severe problems during production and transportation of the oil from the reservoir. It is a solid component of the oil that has different structures and molecular makeup which makes it one of the most complex components of the oil. This research provides a detailed review of asphaltene properties, characteristics, and previous studies to construct a guideline to asphaltene and its impact on oil recovery. The research begins with an explanation of the main components of crude oil and their relation to asphaltene. The method by which asphaltene is quantified in the crude oil is then explained. Due to its different structures, asphaltene has been modeled using different models all of which are then discussed. All chemical analysis methods that have been used to characterize and study asphaltene are then mentioned and the most commonly used method is shown. Asphaltene will pass through several phases in the reservoir beginning from its stability phase up to its deposition in the pores, wellbore, and facilities. All these phases are explained, and the reason they may occur is mentioned. Following this, the methods by which asphaltene can damage oil recovery are presented. Asphaltene rheology and flow mechanism in the reservoir are then explained in detail including asphaltene onset pressure determination and significance and the use of micro-and nanofluidics to model asphaltene. Finally, the mathematical models, previous laboratory, and oilfield studies conducted to evaluate asphaltene are discussed. This research will help increase the understanding of asphaltene and provide a guideline to properly study and model asphaltene in future studies.

- by and +2
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- Enhanced Oil Recovery, Unconventional Reservoir, Petroleum Engineering

many countries in the world are producing there Gas from tight reservoir as the conventional reservoirs are mostly explored. Pakistan contain more than 40TCF of tight gas reservoir that is proven in some areas of Pakistan. tight gas requires advance techniques for its production. In Pakistan production from tight reservoir is not common as it is not much economical. but in future gas will be produced from tight reservoir as unconventional reservoirs are the new future of oil and Gas Industries.

Reserve forecasting using the Arps empirical rate-decline relations has been standard practice in the petroleum industry for decades. However, the forecasting of reserves in unconventional reservoirs using the Arps relations is usually challenging and more often than not produces ambiguous results. The low to ultra-low permeability plays that make up unconventional reservoirs display behaviour that runs contrary to the assumptions that underlie the Arps relations. Because of this, when the typically long-term transient flow data is used with the Arps relations, it results in substantial underestimation or overestimation of reserves when the relations are extrapolated unconstrained. To address the shortcomings of the traditional relations, a Modified Hyperbolic Decline Model was introduced that merges a hyperbolic equation with an exponential tail. In this paper the development of this model is analysed and compared with the traditional Arps relations using synthetic data of a tight gas well. After analysing the data, it was concluded that the Modified Hyperbolic Relation presents an alternative that addresses the shortcomings of the traditional Arps relations and also provides for flexibility in the forecast as more data becomes available.

- by Ammar Mohsen
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- Unconventional Reservoir

Executive Summary Unconventional reservoir development involves extensive hydraulic fracturing to create a Stimulated Reservoir Volume (SRV) connected to the wells, which will drive both the well productivity and associated development strategy. Once a well is hydraulically fractured, the next step is to clean it up by flowing it back to remove water from the wellbore and adjacent fracture network before putting it on production. Currently, characterization of Multi-Fractured Horizontal Wells (MFHW) productivity is commonly performed with Rate Transient Analysis (RTA) of online production data after a significant production history, which also provides some indication of the SRV geometry. One of the main challenges today is to characterize the SRV geometry and productivity as early as possible and at the lowest cost possible. Recent studies have demonstrated a valuable opportunity to gain information from early fluid production and flowing pressures gathered during the flowback operation that can be used to assess long-term well productivity; however such information is rarely exploited quantitatively. Several uses of flowback data include: completion design and flowback sequence optimization, choke strategy adjustment, SRV characterization and production forecasting. Clarkson and Williams-Kovacs introduced a pseudo-analytical model for analyzing two-phase flowback to estimate key hydraulic fracture and reservoir properties, notably fracture half-length and conductivity. The base model assumes cylindrical fracture tanks in which three flow regimes occur: (1) transient radial flow of water within the fracture, (2) fracture depletion (boundary dominated flow of water while fracture pressure remains above formation pressure), and (3) coupled formation linear flow and multi-phase fracture depletion after formation fluid breakthrough (when fracture pressure drops below formation pressure). They established that Before Breakthrough (BBT) single-phase RTA and analytical modeling can provide an estimation of frac properties BBT and ABT. This workflow has been applied to Vaca Muerta wells drilled in different fluid windows (from dry gas to light oil), in different landing points, and with different frac designs. The analysis has been carried out with FLOAT ("Flowback Analysis Tool"), an excel-based software developed initially by Clarkson and Williams-Kovacs for tight oil reservoirs, and later modified for shale gas by Williams-Kovacs and Clarkson. This paper presents the main results obtained and the lessons learned on the impact of frac design and flowback process, and the applicability/predictability of the model.

Shale-gas resource plays can be distinguished by gas type and system characteristics of geo-mechanics. Mineralogy appears to be a key factor characterizing the best wells. The brittleness of the shale is key to stimulation whereby a fracture network is created, providing linkage between the wellbore and the microporosity. The Barnett Shale is considered to be the best type of shale gas reservoirs produced as its mineralogical and mechanical conditions are discussed to farther knowledge about the shale gas characterizations with a comparison of different productive types of shale like Marcellus Shale. The best Barnett Shale production comes from zones with 45% quartz and only 27% clay (Bowker, 2003), Barnett shale can be defined as a mixed siliceous mudstone, and mostly clay rich Siliceous mudstone according to a Ternary-based classification. The study of minerals aspects in Barnett shale defined clearly that the main clay mineral that could takes control on Barnett shale is the Illite and minor Smectite which could probably be the best clay mineral to describe shale gas reservoir that will be deduced later. The Barnett Shale produces so much gas because it is brittle and responds to stimulation (and because it has high gas contents). This brittleness is related to mineralogy, and the Barnett Shale contains high percentages of quartz derived from biogenic silica (data from Gas Research Institute, 1991). The Hydraulic Fracturing with appropriate proppant is also provided.

- by Basma Ahmed
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- Clay Minerals, Black shales, Shale gas, Unconventional oil and gas

La evaluación final se realizó por medio de la interpretación estratigráfica y estructural de los PayShales arrojando como resultado la zona 4 al NW del área de estudio como la mejor para profundizar la evaluación de un yacimiento del... more

- by Miguel Angel Manjarrez Cantú
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- Geology, Geophysics, Assessment, Petroleum

The thick Eocene carbonate deposits that are newly ascribed as Radwany Formation (previously Thebes Formation) in the October basin within the Gulf of Suez region, are of particular interest for hydrocarbon exploitation. However, no efforts have been directed to investigate their petrophysical characteristics and pore system. This study aims to investigate the petrophysical characteristic, pore system and formation potentiality as a reservoir rock. Thirteen sidewall core samples and sixty thin sections from OCT-X well were studied in order to investigate the lithological characteristics, porosity network. In addition, well logging data and petrophysical and geochemical laboratories measurements including Nuclear Magnetic Resonance (NMR) porosity technique were used to define the petrophysical characteristics. The investigated work revealed that: 1) the pore system is a combination of depositional and diagenetic processes. 2) the dominant porosity types include fracture, interparticle, intra-particle and moldic porosity; NMR indicates mesopores to macropores, 3) petrophysical evaluation and geochemical analysis indicates a self-sourced unconventional reservoir based on its organic richness characteristics unconventional resource opportunity as tight carbonate reservoir, 4) the basal part of the Radwany Formation has a high potential to store hydrocarbon, and it is a potential conventional resource. 6) The linking trends between the petrophysical parameters with sediment microfacies were defined in the studied section, where a significant increasing trend line has been inferred in the direction from wackestone microfacies to packstone microfacies. Finally, the diagenetic process through time has greatly controlled the petrophysical parameters of the Radwany Formation. The gap between Source and Reservoir rocks has been defined based on integrated geochemical and petrophysical characteristics. The studied section has unique multiscale characterization as unconventional and conventional resource.

- by Ahmed E. Radwan
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- Sedimentology, Petrophysics, Reservoir Engineering, Petroleum geology

Roseaneath and Murteree shale in Cooper basin, South Australia are proven seal, source as well as shale gas reservoir rock. Source rock characterization as a potential gas requires extensive understanding about the geomechanical properties for optimization of stimulation treatment and in order to avoid well bore instability and sand production during drilling and completion stages. Fifteen samples were selected from Moomba 191 well (depth 8473-8475 ft) drilled in Cooper Basin by DSD, Australia. The Triaxial compression and unconfined compression tests were performed on samples in order to find static geomechanical properties. The wireline logs like sonic and density were used to find dynamic mechanical properties. The calibrations were carried out between static and dynamic parameters in order to get reliable calibrated values. The 1-D Mechanical Earth Model (MEM) was developed based on elastic parameters (Young's modulus, Poison's ratio), failure parameters (Cohesion, internal friction angle, compressive strength and tensile strength), in-situ stresses, pore pressure and mud weight. The calibrated Young's modulus and Poison's ratio were ranging from 15 GPa to 30 GPa and 0.20 to 0.3 respectively. Brittleness analysis (BI) (ranges from 0.2-0.78) exhibited brittle and ductile layers within the whole shale interval. The Brittle index (BI), Young's modulus and poison's ratio on brittle layers were range from 0.4 to 0.78, greater than 25 GPa and <0.3 respectively for brittle layers. Based on failure parameters, insitue stresses and mud weight three possible locations for wellbore breakouts, fractures, has been identified where special considerations are needed to select the mud weight in order to avoid the problems i.e. sand production, wellbore instability. The strongest depths for minimum wellbore stability have been identified that have also high BI (0.6 to 0.69) and can be potential target for stimulation. Based on results, it has been concluded that this Roseneath shale interval of Moomba 191 well have many critical zones based on limits of upper and lower safe mud weight window where extra care need to be taken. The normal stress regime exhibited that fractures orientation will be perpendicular to minimum horizontal stresses.

- by Omer Iqbal
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- Unconventional Reservoir

Portland cement is used by the construction industries, which is known to be a heavy contributor of carbon dioxide emissions and environmental damage. Adding of industrial wastes like demolished old concrete OF structures, silica fume (SF) fly ash (FA) as additional cementing materials (SCMs) could result in a substantial reduction of the overall Carbon dioxide trace marks of the final concrete product. Use of these additional materials in construction industry especially in the making of concrete is highly challenging. Remarkable research efforts are needed to study about the engineering properties of concrete incorporating such industrial wastes. Present research is an effort to study the properties of concrete adding industrial wastes such as demolished concrete, FA and SF The improvement of properties of RCA concrete with the incorporation of two ureolytic-type bacteria, Bacillus subtilis and Bacillus sphaericus to improve the properties of RCA concrete. The experimental investigations are carried out by experts evaluate the improvement of the compressive strength, capillary water absorption and drying shrinkage of RCA concrete adding bacteria. Seven concrete mixes are manufactured using Portland slag cement (PSC) partially changed with SF ranging from 0 to 30%. The mix proportions were obtained as per Indian standard IS: 10262-2009 with 10% extra cement when SF is taken as per the above the construction practice by experts. Optimal dosages of SF for maximum values of compressive strength, tensile splitting strength and flexural strength at 28 days are determined.

- by IJRASET Publication
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- Unconventional Reservoir, Mix Design

The distinction between conventional and unconventional hydrocarbon accumulations depends on whether oil or gas are hosted within a well-defined trap and whether they can be produced economically by wells. The unconventional oil and gas resources cannot be extracted economically by using conventional methods and technologies, while the conventional accumulations refer to technically and economically recoverable hydrocarbons. The unconventional accumulations are characterized by large resources but poor reservoir properties. Conventional hydrocarbons only account for less than 20% of the world’s fossil fuel resources, whereas unconventional hydrocarbons account for at least 80%. On the Romanian territory, 10 petroleum basins with different hydrocarbon richness have been identified: Moesian Platform, Transylvanian Basin, Eastern part of Pannonian Basin, Eastern Carpathians Flysch, Moldavian Platform, Carpathian Foredeep, Schythian Platform, Maramures Basin, North-Dobrogean Promontory and the Romanian shelf of the Black Sea. In these basins more than 18 petroleum systems have been identified. Almost all these petroleum basins contain unconventional hydrocarbon resources like shale gas, shale oil, heavy oil, tar sands, tight sands gas, gas hydrates and coal bed methane (CBM).

- by Bogdan NICULESCU and +1
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- Oil and gas, Petroleum geology, Gas Hydrates, Black shales

This study presents the effects of equations of state (EOSs) on methane adsorption capacity, sorption hysteresis and initial gas reserves of a medium volatile bituminous coal. The sorption experiments were performed, at temperatures of 25 • C and 40 • C and up to 7MPa pressure, using a high-pressure volumetric analyzer (HPVA-II). The measured isotherms were parameterized with the modified (three-parameter) Langmuir model. Gas compressibility factors were calculated using six popular equations of state and the results were compared with those obtained using gas compressibility factors from NIST-Refprop ® (which implies McCarty and Arp's EOS for Z-factor of helium and Setzmann and Wagner's EOS for that of methane). Significant variations were observed in the resulting isotherms and associated model parameters with EOS. Negligible hysteresis was observed with NIST-refprop at both experimental temperatures, with the desorption isotherm being slightly lower than the adsorption isotherm at 25 • C. Compared to NIST-refprop, it was observed that equations of state that gave lower values of Z-factor for methane resulted in "positive hysteresis", (one in which the desorption isotherm is above the corresponding adsorption curve) and the more negatively deviated the Z-factors are, the bigger the observed hysteresis loop. Conversely, equations of state that gave positively deviated Z-factors of methane relatively produced "negative hysteresis" loops where the desorption isotherms are lower than the corresponding adsorption isotherms. Adsorbed gas accounted for over 90% of the calculated original gas in place (OGIP) and the larger the Langmuir volume, the larger the proportion of OGIP that was adsorbed.

- by Jamiu Ekundayo
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- Equations of State, Adsorption, Hysteresis, Coal bed methane

Aquifer Systems and Hydrogeologic Conceptual Models: evaluation tools of hydric resources for sustainable use in Upstream. Examples.
Water is a strategic resource to explore and produce hydrocarbons. The study of groundwater resources to characterize/ define "aquifer systems" and the elaboration of hydrogeologic conceptual models that allow their knowledge, are the main tools to understand the hydrogeology of any region. When the zone is more arid and its geology more complex, the systems are more difficult to understand and thus the models to elaborate. When more data and results are obtained and evaluated systematically with experience in hydrogeologic conceptual models, they are elaborated with increasing certainty and detail. With them, decisions can be taken with more certitude from the points of view of the "sustainable use of the resource" and the "environmental" one, applying the paradigm of Integrated Water Resource Management (IWRM), within the Sustainable Development. If there is not a previous hydrogeologic conceptual model, it is impossible to make a mathematical model for simulation, because there is not a reliable base to elaborate it. The characterization and definition of an aquifer system should have its classic components: aquifers themselves (porous, high to medium permeability), aquitards (porous, low permeability), aquicludes (porous, impermeable), aquifugues (nonporous, impermeable), fractured aquifers (originally may have been aquicludes/ aquifugues, but by fracturing they have transformed in aquifers due to secondary porosity and permeability); recharge, circulation and discharge areas; flow systems of different scales (regional, subregional, local). When the knowledge reached allows it, they may include: hydrogeochemistry zonations, evolution with groundwater flow and increasing depth, isotopic characterization, origins and ages of water. The characterization of aquifer systems and hydrogeologic conceptual models allow to elaborate maps and vertical sections useful as tools to make decisions. If the studied region/ zone of an aquifer system is large and variable, there may be differences between distinct areas, each of them having a particular hydrogeologic conceptual model, compatible with the regional one. There may be zones where the aquifer system acts in general as one complex flow unit, and others where it is compartmentalized: divided by aquicludes ("seals") and/or aquitards ("semiseals") which allow to discriminate distinct bodies/ thicknesses with different characteristics. If the knowledge reached and the data/ results are enough, hydrogeologic conceptual models can be expressed in Petrel or Sahara format or similar, allowing to be managed with friendly tools by geologists and other professionals of hydrocarbon industry not specialists in hydrogeology. Examples of aquifer systems and hydrogeologic conceptual models from argentine hydrocarbon basins in arid/ semiarid regions are presented, with different levels of knowledge and scales.
Keywords: sistema acuífero, modelo hidrogeológico conceptual, uso sostenible, SANeRa

Oil sands, or technically called bitumen, is an unconsolidated sandstones that contained water and oil in a thick form. Extra-heavy oil and natural bitumen are formed gradually through the process, which is generated and degraded from remnants of immense volumes of conventional oils. Based on the texture, extra-heavy oil and natural bitumen are identical with the residue of light oil from refinery distillation. The resource of extra-heavy oil and natural bitumen is quite enormous and possible to encourage the reserve of the future oil supply. In Indonesia, one of the promising resources is located in Central Sumatra. Based on the data of USGS (2007), Central Sumatra held 40,6 BBO from 49,827 BBO in Indonesia. Furthermore, we can know that Central Sumatra is the biggest holder of extra-heavy oil and natural bitumen in Indonesia. The production method that technically feasible for oil recovery is open-pit mining. Open-pit mining would apply to deeper reservoir of heavy oil and obtain the overburden and heavy oil from its deepening pit until the base of the oil storage. And because of that, this open-pit mining method holds the potential of oil recovery greater than 80 percent of the Original Oil In Place (OOIP) than the most of conventional oil reservoirs that just have 30-40 percent of the recovery. Production continues to the bitumen extraction stage using hot water extraction.
From the geological aspects, Central Sumatra Basin is one of a series rift basins whose position is currently in the back-arc position which extends along the edge of Sundaland. This area led to Upper Telisa and Lower Telisa Formation that was buried from Early to Middle Miocene. The thickness of the bitumen layer is approximately about 144 meters (Ilyas, 2003). Bitumen flakes that have been developed are believed by experts as a potential source of hydrocarbons. With the increasing demand for oil supplies and the decrease in oil production in Indonesia, it is time for Indonesia to move to optimize the use of unconventional reservoirs. By seeing its potential and excellence, oil mining is a golden opportunity and hope for Indonesia to boost national sustainable energy.

- by Rizqy Syarif Muhammad and +1
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- Bitumen (Petrochemical Product), Unconventional oil and gas, Bitumen, Unconventional Reservoir

The late Carboniferous-Middle Triassic, intracratonic Cooper basin in northeastern South Australia and southwestern Queensland is Australia's foremost onshore hydrocarbon producing region. The basin compromises Permian carbonaceous shale like lacustrine Roseneath and Murteree shale formation which is acting as source and reservoir rock. The source rock can be distinguished from non-source intervals by lower density, higher transit time, higher gamma ray values, higher porosity and resistivity with increasing organic content. In current dissertation we have attempted to compare the different empirical approaches based on density relation and Δ LogR method through three overlays of sonic/resistivity, neutron/resistivity and density/resistivity to quantify Total organic content (TOC) of Permian lacustrine Roseneath shale formation using open hole wireline log data (DEN, GR, CNL, LLD) of Encounter 1 well. The TOC calculated from fourteen density relations at depth interval between 3174.5-3369 meters is averaged 0.56% while TOC from sonic/resistivity, neutron/resistivity and density/resistivity yielded an average value of 3.84%, 3.68%, 4.40%. The TOC from average of three overlay method is yielded to 3.98%. According to geochemical report in PIRSA the Roseneath shale formation has TOC from 1 – 5 wt %.There is unpromising correlations observed for calculated TOC from fourteen density relations and measured TOC on samples. The TOC from average value of three overlays using Δ LogR method showed good correlation with measured TOC on samples.

- by Omer Iqbal
- •
- Unconventional Reservoir

La identificación en el subsuelo de cuerpos concordantes y discordantes de origen subvolcánico, se ha transformado en un tema de interés en la industria petrolera y en particular en el desarrollo de Vaca Muerta. Los mismos se presentan con propiedades mecánicas y calidades de roca muy diferentes, y su caracterización es de importancia estratégica, entre otras razones, para el diseño de terminación de los pozos horizontales.
Mucho se ha estudiado en los últimos años respecto de la Formación Vaca Muerta desde el punto de vista de la sismo-estratigrafía, la caracterización de sus facies (Crouse et al., 2018) fracturas naturales (Delpino y Bermudez, 2011; Estrada et al, 2018), la composición mineralógica y la evolución de la materia orgánica contenida través de la cuantificación del TOC o contenido orgánico total (Palacio et al., 2018). Al menos en el área del engolfamiento neuquino donde presenta los mayores espesores, la Formación Vaca Muerta se presenta como una variedad de margas y fangolitas, y en algunos casos, han sido descriptas como facies subordinadas rocas volcaniclásticas, niveles calcitizados, beefs y concreciones (Kietzmann et al, 2016; Rosemblat et al, 2016). Sin embargo, con las nuevas tecnologías de registros asistidos y técnicas de geonavegación, se ha podido estudiar a través de super pozos horizontales y documentar de una manera más precisa las variaciones laterales de esta formación.
El presente trabajo trata sobre la utilización de registros de pozo asistidos que permitan caracterizar estos cuerpos: las imágenes resistivas tanto en lodo base agua como lodos base aceite, son ideales para la identificación de cuerpos texturalmente diferentes, precisando su correspondiente relación geométrica y estructural respecto de la roca de caja. Además, los mismos pueden ser caracterizados combinando otros registros de pozo abierto disponibles y de LWD (Logging while drilling), como el de rayos gamma espectral y los registros acústicos tanto monopolares como dipolares que proveerán información tanto referida a su composición, sus características mecánicas como así también de calidad de roca.
Esta información, validada por dos casos de estudio influenciados por el Complejo Volcánico de Auca Mahuida (Fig. 1), enfatiza el desafío de caracterizar cuerpos volcánicos, sub-volcánicos y depósitos volcaniclásticos que no fueron discriminados en el control geológico y la importancia estratégica de tener un modelo interpretativo; la utilización de su conocimiento predictivo puede influenciar críticamente a la hora de tomar decisiones y evitar costos invisibles tanto durante la perforación como la completación o terminación del pozo.

- by Marta DAngiola and +1
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- Unconventional Reservoir, Petrophysics and Image Logging, volcaniclastics, Sills

Indonesia has a reserve potential of 453 TCF CBM (Coalbed Methane) which spread across the nation, it is divided into 11 basin which include Sumatera, Kalimantan, and Java Island. CBM is a reliable and inexpensive source of natural gas in some other country like Russia, Australia, Canada, and United States of America. Indonesia was indicated are having coal which was thicker and greater than CBM that spread in Powder River Basin (United States of America). Hereby, Indonesia is expected to be able to sustain the energy in the upcoming future. In the past 20 years since the development of CBM in Indonesia, not even a single prospect area can produce CBM optimally. It’s recorded that CBM in Indonesia only reached about 1 MMSCFD in that period of time. Therefore, strategic study and identification of potential problems that occur globally also further review about field techniques are needed to optimize the production of the unconventional gas. CBM wellbore starts the production with a low Gas / Water Ratio (GWR) which increases along the time. This event resulting to process and disposal water facilities caused by CBM production must be built at the beginning of the project so a selected method must be precise because will be the determining factor for the economics project. Besides that, it requires an effective and efficient Artificial Lift that suitable with the condition of formation to fasten the drainage and to decrease the pressure at the reservoir also to decrease the blockage in the Artificial Lift because of the coal characteristics after dewatering. CBM is generally founded at shallow coal bed, therefore it makes the exploration costs are cheaper. Also, the combustion from CBM does not produce toxic, it does not emit ash and only releases a little CO2 per unit compared with oil. Coal bed can store 6-7 times more gas than conventional gas reservoirs, so the CBM resource is very large and promising to be developed. By seeing its potential and excellence, CBM is a golden opportunity and hope of Indonesia to increase national sustainable energy.

- by Rizqy Syarif Muhammad and +1
- •
- Sustainable Energy, Hydrocarbon, Unconventional oil and gas, Unconventional Reservoir

Carbon dioxide (CO 2) injection is one of the most applied enhanced oil recovery methods in the hydrocarbon industry, since it has the potential to increase oil recovery significantly and can help reduce greenhouse gases through carbon storage in hydrocarbon reservoirs. Carbon dioxide injection has a severe drawback, however, since it induces asphaltene precipitation by disrupting the asphaltene stability in crude oil that bears even the slightest asphaltene concentration. This can result in severe operational problems, such as reservoir pore plugging and wellbore plugging. This research investigates some of the main factors that impact asphaltene stability in crude oil during CO 2 injection. Initially, asphaltene precipitation, flocculation, and deposition were tested using visual tests without CO 2 in order to evaluate the effect of oil viscosity and temperature on asphaltene stability and content in the crude oil. The results obtained from the visualization experiments were correlated to the Yen-Mullins asphaltene model and were used to select the proper chemical to alter the oil's viscosity without strongly affecting asphaltene stability. After performing the visual asphaltene tests, a specially designed filtration vessel was used to perform the oil filtration experiments using filter membranes with a micron and nanometer pore size. The effect of varying CO 2 injection pressure, oil viscosity, filter membrane pore size, and filter membrane thickness on asphaltene stability in crude oil was investigated. The results were then correlated with the Yen-Mullins asphaltene model to characterize the asphaltene size within the oil as well. Results showed that as the oil viscosity increased, the asphaltene concentration in the oil also increased. Also, the asphaltene concentration and filter cake thickness increased with the decrease in filter membrane pore size, since the asphaltene particles either plugged up the smaller pores, or the asphaltene nanoaggregates were larger than the pore sizes, and thus the majority of them could not pass. This research studies asphaltene instability in crude oil during CO 2 injection in different pore sizes, and correlates the results to the principle of the Yen-Mullins model for asphaltenes. The results from this research can help emphasize the factors that will impact asphaltene stability during CO 2 injection in different pore sizes in order to help reduce asphaltene-related problems that arise during CO 2 injection in hydrocarbon reservoirs.

The late Carboniferous-Middle Triassic, intracratonic Cooper basin in northeastern South Australia and southwestern Queensland is Australia's foremost onshore hydrocarbon producing region. The basin compromises Permian carbonaceous shale like lacustrine Roseneath and Murteree shale formation which is acting as source and reservoir rock. The source rock can be distinguished from non-source intervals by lower density, higher transit time, higher gamma ray values, higher porosity and resistivity with increasing organic content. In current dissertation we have attempted to compare the different empirical approaches based on density relation and Δ LogR method through three overlays of sonic/resistivity, neutron/resistivity and density/resistivity to quantify Total organic content (TOC) of Permian lacustrine Roseneath shale formation using open hole wireline log data (DEN, GR, CNL, LLD) of Encounter 1 well. The TOC calculated from fourteen density relations at depth interval between 3174.5-3369 meters is averaged 0.56% while TOC from sonic/resistivity, neutron/resistivity and density/resistivity yielded an average value of 3.84%, 3.68%, 4.40%. The TOC from average of three overlay method is yielded to 3.98%. According to geochemical report in PIRSA the Roseneath shale formation has TOC from 1-5 wt %.There is unpromising correlations observed for calculated TOC from fourteen density relations and measured TOC on samples. The TOC from average value of three overlays using Δ LogR method showed good correlation with measured TOC on samples.

- by Askury Abd Kadir
- •
- Unconventional Reservoir

Unconventional Hydrocarbon Reservoirs
Unconventional reservoir is becoming a large resource potential gradually and making explorationists shift their attention to this area. Unconventional reservoir have been attached great importance by countries and companies all over the world. It will become the inevitable trend of industry development that the extension from the conventional oil and gas exploration to unconventional oil and gas in oil and gas exploration and development field. This chapter introduces unconventional reservoir resources and its importance in improving quality of life Basic concept and terms used in the oil and gas industry are introduced, defined and explained to different oil and gas types, transportation and it usage and the properties of the petroleum system.

More than seventy percent of the world's undiscovered reserves are reportedly held in unconventional reservoirs. As such, these fracture dependent plays are becoming the focus of E&P companies globally. Higher risk in these plays hampers success. ION has made advances in acquisition, processing, and interpretation techniques to address unconventional reservoirs and help E&P companies lower this risk.

- by Ahmed Seree
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- Geology, China, Multicomponent Alloys, Unconventional Reservoir

A statistical technique for the pore-scale analyses of heterogeneity and representative elemental volume (REV) in unconventional shale rocks is hereby presented. First, core samples were obtained from shale formations. The images were scanned using microcomputed tomography (micro-CT) machine at 6.7 lm resolution with voxels of 990 9 990 9 1000. These were then processed, digitised, thresholded, segmented and features captured using numerical algorithms. This allows the segmentation of each sample into four distinct morphological entities consisting of pores, organic matter, shale grains and minerals. In order to analyse the degree of heterogeneity, Eagle Ford parallel sample was further cropped into 96 subsamples. Descriptive statistical approach was then used to evaluate the existence of heterogeneity within the subsamples. Furthermore, the Eagle Ford parallel and perpendicular samples were analysed for volumetric entities representative of the petrophysical variable, porosity, using corner point cropping technique. The results of porosity REV for Eagle ford parallel and perpendicular indicated sample representation at 300 lm voxel edge. Both pore volume distribution and descriptive statistical analyses suggested that a wide variation of heterogeneity exists at this scale of investigation. Furthermore, this experiment allows for adequate extraction of necessary information and structural parameters for pore-scale modelling and simulation. Additional studies focusing on re-evaluation at higher resolution are recommended.

- by James O Adeleye
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- Geology, Oil Shale, Shale Gas Technology, Unconventional Reservoir

A field trial was carried out to investigate the performance of different unconventional geosynthetic materials in unpaved road construction over soft ground.The test site comprises of 25 m long, by 3 m wide test sections, built on a subgrade of undrained shear strength approximately 45 kPa. One isunreinforced and serves as a control section in the study, three sections includea geotextile, and one includes a geogrid. Each test section incorporated avariable thickness of sandy gravel base course material, between25 and 45 cmthick. They were loaded in sequence by a vehicle of standard axle load.Performance of the test sections was evaluated from measurements of rut depth, base course thickness, base course deformations, geosynthetic strain, and deformed profile of the geosynthetic, with increasing number of vehicle passes.The four geosynthetic materials used exhibited a broad range of stiffness and material properties ,but the general performance of the four reinforced sections was similar on the base course layers. On contrary thinner subgrades showed a significant difference between the geosynthetics

- by IJRASET Publication and +1
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- Civil Engineering, civil Engineer, Unconventional Reservoir

- by Askury Abd Kadir
- •
- Unconventional Reservoir

Modern data analytic techniques, statistical and machine-learning algorithms have received widespread applications for solving oil and gas problems. As we face problems of parent–child well interactions, well spacing, and depletion concerns, it becomes necessary to model the effect of geology, completion design, and well parameters on production using models that can capture both spatial and temporal variability of the covariates on the response variable. We accomplish this using a well-formulated spatio-temporal (ST) model. In this paper, we present a multi-basin study of production performance evaluation and applications of ST models for oil and gas data. We analyzed dataset from 10,077 horizontal wells from 2008 to 2019 in five unconventional formations in the USA: Bakken, Marcellus, Eagleford, Wolfcamp, and Bone Spring formations. We evaluated well production performance and performance of new completions over time. Results show increased productivity of oil and gas since 2008. ...

- by Marshal Wigwe
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- Environmental Science, Data Mining, Data Analysis, Spatio Temporal Analysis

Hydraulic fracturing is widely accepted technology to unlock unconventional reservoirs and produce the hydrocarbon fluids at feasible rates, but reaching these rates requires an optimal designing of the hydraulic fracturing treatment. This study presents an approach to design an appropriate hydraulic fracture with proper material selection and optimized fracture half-lengths. In this approach, initially, a hydraulic fracture model is selected for fracture design while considering formation stresses and fracture propagation. After that, the proppants and fracturing fluids are selected based on in-situ stresses, hydraulic fracture permeability and conductivity, the sensitivity of formation with water, pressure and temperature conditions of the reservoir. After the selection of the above materials, five hydraulic fractures with fracture half-lengths of 318 ft, 415 ft, 539 ft, 618 ft, and 724 ft are selected based on the amounts of proppants pumped, and their production responses are plotted. After comparing the selected fractures, the optimal fracture treatment is achieved at fracture half-length of 618 ft due to its high fluid recovery, along with the low amount of proppant pumped (127 klbs), which ultimately increases revenue and puts less burden on the economics of the project. The approach used in this study will, therefore, help design future hydraulic fracture treatment with an optimized hydraulic fracture, resulting in high hydrocarbon production rates, and reduce the overall cost by selecting the compatible fracturing fluids and adequate amounts of proppants.

- by Temoor Muther
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- Geology, Fracture Mechanics, Hydraulic Fracturing, Unconventional Reservoir

- by Edwyn Bougre
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- Data Mining, Data Analysis, Spatio Temporal Analysis, Big Data Analytics

A statistical technique for the pore-scale analyses of heterogeneity and representative elemental volume (REV) in unconventional shale rocks is hereby presented. First, core samples were obtained from shale formations. The images were scanned using microcomputed tomogra-phy (micro-CT) machine at 6.7 lm resolution with voxels of 990 9 990 9 1000. These were then processed, digi-tised, thresholded, segmented and features captured using numerical algorithms. This allows the segmentation of each sample into four distinct morphological entities consisting of pores, organic matter, shale grains and minerals. In order to analyse the degree of heterogeneity, Eagle Ford parallel sample was further cropped into 96 subsamples. Descriptive statistical approach was then used to evaluate the existence of heterogeneity within the subsamples. Furthermore , the Eagle Ford parallel and perpendicular samples were analysed for volumetric entities representative of the petrophysical variable, porosity, using corner point cropping technique. The results of porosity REV for Eagle ford parallel and perpendicular indicated sample representation at 300 lm voxel edge. Both pore volume distribution and descriptive statistical analyses suggested that a wide variation of heterogeneity exists at this scale of investigation. Furthermore, this experiment allows for adequate extraction of necessary information and structural parameters for pore-scale modelling and simulation. Additional studies focusing on re-evaluation at higher resolution are recommended.

- by James O Adeleye
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- Shale Gas Technology, Unconventional Reservoir