The Experts below are selected from a list of 678 Experts worldwide ranked by ideXlab platform
John Townend - One of the best experts on this subject based on the ideXlab platform.
-
Seismic Response to Injection Well Stimulation in a High‐Temperature, High‐Permeability Reservoir
Geochemistry Geophysics Geosystems, 2019Co-Authors: Chet Hopp, Steven Sewell, Stefan Mroczek, Martha K. Savage, John TownendAbstract:Author(s): Hopp, C; Sewell, S; Mroczek, S; Savage, M; Townend, J | Abstract: ©2019. American Geophysical Union. All Rights Reserved. Fluid injection into the Earth's crust can induce seismic events that cause damage to local infrastructure but also offer valuable insight into seismogenesis. The factors that influence the magnitude, location, and number of induced events remain poorly understood but include injection flow rate and pressure as well as reservoir temperature and permeability. The relationship between injection parameters and injection-induced seismicity in high-temperature, high-permeability reservoirs has not been extensively studied. Here we focus on the Ngatamariki geothermal field in the central Taupō Volcanic Zone, New Zealand, where three stimulation/injection tests have occurred since 2012. We present a catalog of seismicity from 2012 to 2015 created using a matched-filter detection technique. We analyze the stress state in the reservoir during the injection tests from first motion-derived focal mechanisms, yielding an average direction of maximum horizontal compressive stress (SHmax) consistent with the regional NE-SW trend. However, there is significant variation in the direction of maximum compressive stress (σ1), which may reflect geological differences between wells. We use the ratio of injection flow rate to overpressure, referred to as Injectivity Index, as a proxy for near-well permeability and compare changes in Injectivity Index to spatiotemporal characteristics of seismicity accompanying each test. Observed increases in Injectivity Index are generally poorly correlated with seismicity, suggesting that the locations of microearthquakes are not coincident with the zone of stimulation (i.e., increased permeability). Our findings augment a growing body of work suggesting that aseismic opening or slip, rather than seismic shear, is the active process driving well stimulation in many environments.
Chet Hopp - One of the best experts on this subject based on the ideXlab platform.
-
Seismic Response to Injection Well Stimulation in a High‐Temperature, High‐Permeability Reservoir
Geochemistry Geophysics Geosystems, 2019Co-Authors: Chet Hopp, Steven Sewell, Stefan Mroczek, Martha K. Savage, John TownendAbstract:Author(s): Hopp, C; Sewell, S; Mroczek, S; Savage, M; Townend, J | Abstract: ©2019. American Geophysical Union. All Rights Reserved. Fluid injection into the Earth's crust can induce seismic events that cause damage to local infrastructure but also offer valuable insight into seismogenesis. The factors that influence the magnitude, location, and number of induced events remain poorly understood but include injection flow rate and pressure as well as reservoir temperature and permeability. The relationship between injection parameters and injection-induced seismicity in high-temperature, high-permeability reservoirs has not been extensively studied. Here we focus on the Ngatamariki geothermal field in the central Taupō Volcanic Zone, New Zealand, where three stimulation/injection tests have occurred since 2012. We present a catalog of seismicity from 2012 to 2015 created using a matched-filter detection technique. We analyze the stress state in the reservoir during the injection tests from first motion-derived focal mechanisms, yielding an average direction of maximum horizontal compressive stress (SHmax) consistent with the regional NE-SW trend. However, there is significant variation in the direction of maximum compressive stress (σ1), which may reflect geological differences between wells. We use the ratio of injection flow rate to overpressure, referred to as Injectivity Index, as a proxy for near-well permeability and compare changes in Injectivity Index to spatiotemporal characteristics of seismicity accompanying each test. Observed increases in Injectivity Index are generally poorly correlated with seismicity, suggesting that the locations of microearthquakes are not coincident with the zone of stimulation (i.e., increased permeability). Our findings augment a growing body of work suggesting that aseismic opening or slip, rather than seismic shear, is the active process driving well stimulation in many environments.
Jim Combs - One of the best experts on this subject based on the ideXlab platform.
-
A Study of Production/Injection Data from Slim Holes and Large-Diameter Wells at the Okuaizu Geothermal Field, Tohoku, Japan
2002Co-Authors: Joel Lawrence Renner, Sabodh K. Garg, Jim CombsAbstract:Discharge from the Okuaizu boreholes is accompanied by in situ boiling. Analysis of cold-water injection and discharge data from the Okuaizu boreholes indicates that the two-phase productivity Index is about an order of magnitude smaller than the Injectivity Index. The latter conclusion is in agreement with analyses of similar data from Oguni, Sumikawa, and Kirishima geothermal fields. A wellbore simulator was used to examine the effect of borehole diameter on the discharge capacity of geothermal boreholes with two-phase feedzones. Based on these analyses, it appears that it should be possible to deduce the discharge characteristics of largediameter wells using test data from slim holes with two-phase feeds
-
Use of slim holes with liquid feedzones for geothermal reservoir assessment
Geothermics, 1997Co-Authors: Sabodh K. Garg, Jim CombsAbstract:Abstract Production and injection data from slim holes and large-diameter wells at four geothermal fields (Oguni, Japan; Sumikawa, Japan; Takigami, Japan; Steamboat Hills, U.S.A.) were analyzed in order to establish relationships (1) between Injectivity and productivity indices, (2) between productivity/Injectivity Index and borehole diameter, and (3) between discharge capacity of slim holes and large-diameter wells. The productivity and Injectivity indices for boreholes with liquid feedzones are more or less equal. Except for the Oguni boreholes, the productivity and Injectivity indices display no correlation with borehole diameter. Thus, the productivity Index (or, more importantly, the Injectivity Index in the absence of discharge data) from a slim hole with a liquid feed can be used to provide a first estimate of the probable discharge capacity of a large-diameter geothermal production well. The large-diameter wells at the Oguni, Sumikawa and Steamboat Hills geothermal fields have a more or less uniform inside diameter, and the discharge capacity of these wells (with liquid feedzones) can be predicted using Pritchett's “scaled maximum discharge rate” in conjunction with discharge data from slim holes. Because of the non-uniform internal diameter for large-diameter Takigami wells, it is not possible to use a simple scaling rule to relate the discharge capacities of slim holes and large-diameter wells at Takigami; therefore, a numerical simulator was used to model the available discharge data from Takigami boreholes. The results of numerical modeling indicate that the flow rate of large-diameter Takigami production wells with liquid feedzones can also be predicted using discharge and injection data from slim holes.
-
A study of production/injection data from slim holes and large-diameter wells at the Takigami Geothermal Field, Kyushu, Japan
1996Co-Authors: Sabodh K. Garg, Jim Combs, Fumio Azawa, Hiroki GotohAbstract:Production and injection data from nine slim holes and sixteen large-diameter wells at the Takigami Geothermal Field, Kyushu, Japan were analyzed in order to establish relationships (1) between Injectivity and productivity indices, (2) between productivity/Injectivity Index and borehole diameter, and (3) between discharge capacity of slim holes and large-diameter wells. Results are compared with those from the Oguni and Sumikawa fields. A numerical simulator (WELBOR) was used to model the available discharge rate from Takigami boreholes. The results of numerical modeling indicate that the flow rate of large-diameter geothermal production wells with liquid feedzones can be predicted using data from slim holes. These results also indicate the importance of proper well design.
Pavel Bedrikovetsky - One of the best experts on this subject based on the ideXlab platform.
-
Injectivity decline during low-salinity waterflooding due to fines migration
Journal of Petroleum Science and Engineering, 2018Co-Authors: Larissa Chequer, Alexandre S.l. Vaz, Pavel BedrikovetskyAbstract:Abstract Injectivity damage by fines migration during low-salinity water injection can highly affect field-scale waterflooding projects. In this paper, we develop novel analytical models for one-dimensional linear and radial suspension-colloidal flows accounting for detachment, mobilisation, migration, and straining of natural reservoir fines. We also perform laboratory corefloods by water with piecewise constant decreasing salinity, and with monitoring the breakthrough particle concentration and pressure drop across the core. The analytical model for linear flows matches the laboratory data with high accuracy, and tuned model coefficients belong to the common-value intervals for those coefficients. The analytical model for radial flows predicts well behaviour; the experimental-data-tuned coefficients are used for reliable laboratory-based prediction of Injectivity Index decline. The calculations show a significant decline of injection-well Index due to fines migration during low-salinity water injection.
-
Injectivity formation damage due to fines migration
The APPEA Journal, 2018Co-Authors: Larissa Chequer, Mohammad Bagheri, Abbas Zeinijahromi, Pavel BedrikovetskyAbstract:Formation damage by fines migration during low-salinity water injection can greatly affect field-scale waterflooding projects. In this paper, we present the basic governing equations for single-phase flow with detachment, migration and straining of natural reservoir fines. We perform laboratory corefloods with low-salinity water injections and monitor the breakthrough particle concentration and pressure drop across the core. The analytical model for linear flow matches the laboratory data with high accuracy. The analytical model for radial flow predicts well behaviour from laboratory-tuned coefficients. The calculations show that fines migration during low-salinity water injection causes significant Injectivity decline. For typical values of fines-migration model coefficients, Injectivity Index declines 2–8 times during 10−3 pore volumes injected and the radius of the damaged zone does not exceed a few metres. We present two field cases on waterflooding and low-salinity water injection. The radial model presents good agreement with well Injectivity field data.
-
Injectivity Impairment During Produced Water Disposal into Low-Permeability Völkersen Aquifer (Compressibility and Reservoir Boundary Effects)
Day 2 Thu February 25 2016, 2016Co-Authors: Zhenjiang You, Azim Kalantariasl, Kai Schulze, Joerg Storz, Christian Burmester, S. Künckeler, Pavel BedrikovetskyAbstract:Compressibility needs to be accounted for when estimating Injectivity decline for water disposal in gas reservoirs and in closed aquifers, and for waterflooding of gas-condensate fields. The problem with given wellbore pressure at the injector aims avoiding the reservoir fracturing. An analytical model is developed that provides well Injectivity Index decline with time. Under this model, the solution of damage-free compressible flow in a closed reservoir is asymptotically matched with the impedance growth formulae for incompressible flow in the well vicinity. For the well regime of a given wellbore pressure, the injection rate decline is described by a nonlinear integro-differential equation that is solved iteratively. The solution under the field conditions investigated shows that well impedance grows faster during deep bed filtration than during external cake formation. This unusual pattern is explained by low permeability of the reservoir. Well impedance is more sensitive to the effect of formation damage than to the compressibility effect of rock and water. Lower formation damage, higher compressibility, or lower injected particle concentration results in larger total injection volume into a closed reservoir.
-
Formation-Damage Evaluation From Nonlinear Skin Growth During Coreflooding
SPE Reservoir Evaluation & Engineering, 2011Co-Authors: Pavel Bedrikovetsky, A.s.l.. S.l. Vaz, C.. Furtado, A.l.s.. L.s. De SouzaAbstract:Summary Injectivity decline of oilfield injection wells is a widespread phenomenon during seawater/produced-water injection. The decline may result in significant cost increase of the waterflooding project. Reliable modeling-based prediction of Injectivity-Index decrease is important for waterflood design as well as for the planning of preventive injected-water treatment. One of the reasons for well Injectivity decline is permeability decrease caused by rock plugging by solid/liquid particles suspended in the injected water. The mathematical model for deep-bed filtration contains two empirical functions: the filtration coefficient and the formation-damage coefficient. These empirical coefficients must be determined from laboratory coreflood tests by forcing water with particles to flow through the core samples. A routine laboratory method determines the filtration coefficient from expensive and difficult particle-concentration measurements at the core effluent; then, the formation-damage coefficient is determined from inexpensive and simple pressure-drop measurements. An alternative three-point-pressure method uses pressure data at an intermediate point of the core, supplementing pressure measurements at the core inlet and outlet. The method provides unique and stable values for constant-filtration and formation-damage coefficients. In the current work, we consider a more complex case in which both coefficients are linear functions of retained-particle concentration. In this case, the model is fully determined by four constants. The three-point-pressure method furnishes unique values for the four model parameters. A new semianalytical model for axisymmetric suspension filtration was developed to predict well-Injectivity decline from the linear coreflood data with pressure measurements in three core points.
-
Taking advantage of Injectivity decline for improved recovery during waterflood with horizontal wells
Journal of Petroleum Science and Engineering, 2011Co-Authors: Pavel Bedrikovetsky, Antonio Luiz Serra De Souza, Thi Nguyen, Andrew Hage, John R. Ciccarelli, Mohammad Afiq Ab Wahab, Gladys Chang, Claudio Jose Alves FurtadoAbstract:Abstract Injectivity formation damage with waterflooding using sea/produced water has been widely reported in the North Sea, the Gulf of Mexico and the Campos Basin in Brazil. The damage is due to the capture of solid and/or liquid particles by reservoir rock that consequently leads to the permeability decline. Another reason for the permeability decline is the formation of a low permeable external filter cake. However, moderate Injectivity decline is not too damaging for a waterflood project with long horizontal injectors, where the initial Injectivity Index is high. In this case, the injection of raw or poorly treated water may significantly reduce the cost of water treatment, which is a cumbersome and expensive procedure in offshore projects. In this paper we investigate the effects of injected water quality on waterflooding using horizontal wells. An analytical model for Injectivity decline, which accounts for particle capture and a low permeable external filter cake formation, has been implemented into black oil reservoir simulator. It was found that induced Injectivity damage results in a noticeable reduction of water cut and in increased (although delayed) sweep efficiency.
Martha K. Savage - One of the best experts on this subject based on the ideXlab platform.
-
Seismic Response to Injection Well Stimulation in a High‐Temperature, High‐Permeability Reservoir
Geochemistry Geophysics Geosystems, 2019Co-Authors: Chet Hopp, Steven Sewell, Stefan Mroczek, Martha K. Savage, John TownendAbstract:Author(s): Hopp, C; Sewell, S; Mroczek, S; Savage, M; Townend, J | Abstract: ©2019. American Geophysical Union. All Rights Reserved. Fluid injection into the Earth's crust can induce seismic events that cause damage to local infrastructure but also offer valuable insight into seismogenesis. The factors that influence the magnitude, location, and number of induced events remain poorly understood but include injection flow rate and pressure as well as reservoir temperature and permeability. The relationship between injection parameters and injection-induced seismicity in high-temperature, high-permeability reservoirs has not been extensively studied. Here we focus on the Ngatamariki geothermal field in the central Taupō Volcanic Zone, New Zealand, where three stimulation/injection tests have occurred since 2012. We present a catalog of seismicity from 2012 to 2015 created using a matched-filter detection technique. We analyze the stress state in the reservoir during the injection tests from first motion-derived focal mechanisms, yielding an average direction of maximum horizontal compressive stress (SHmax) consistent with the regional NE-SW trend. However, there is significant variation in the direction of maximum compressive stress (σ1), which may reflect geological differences between wells. We use the ratio of injection flow rate to overpressure, referred to as Injectivity Index, as a proxy for near-well permeability and compare changes in Injectivity Index to spatiotemporal characteristics of seismicity accompanying each test. Observed increases in Injectivity Index are generally poorly correlated with seismicity, suggesting that the locations of microearthquakes are not coincident with the zone of stimulation (i.e., increased permeability). Our findings augment a growing body of work suggesting that aseismic opening or slip, rather than seismic shear, is the active process driving well stimulation in many environments.