The Experts below are selected from a list of 11952 Experts worldwide ranked by ideXlab platform
Ji Rongyi - One of the best experts on this subject based on the ideXlab platform.
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estimating sand shale Formation Pore Pressure
Petroleum Science and Technology, 2011Co-Authors: F. Honghai, Y Zhi, Ji RongyiAbstract:Abstract This article presents a comprehensive evaluation method of estimating sand–shale Formation Pore Pressure by using sonic velocity and other logging data. The method takes the influence of porosity, density, shale content, effective stress, and some other physical properties of sand–shale Formation on sonic velocity into account. The influence and related logging data are combined to estimate the effective stress, and then Pore Pressure can be obtained by the effective stress principle. Using this method, software was developed and it applied in the well site. Its applications indicate that this method can accurately estimate the abnormal Pressure of a sand–shale Formation.
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Estimating Sand–Shale Formation Pore Pressure
Petroleum Science and Technology, 2011Co-Authors: F. Honghai, Ji RongyiAbstract:Abstract This article presents a comprehensive evaluation method of estimating sand–shale Formation Pore Pressure by using sonic velocity and other logging data. The method takes the influence of porosity, density, shale content, effective stress, and some other physical properties of sand–shale Formation on sonic velocity into account. The influence and related logging data are combined to estimate the effective stress, and then Pore Pressure can be obtained by the effective stress principle. Using this method, software was developed and it applied in the well site. Its applications indicate that this method can accurately estimate the abnormal Pressure of a sand–shale Formation.
F. Honghai - One of the best experts on this subject based on the ideXlab platform.
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Estimating Formation Pore Pressure in Tectonic Compression Zones
Petroleum Science and Technology, 2012Co-Authors: Y Zhi, F. Honghai, L. Gang, W. YunlongAbstract:Abstract Accurate knowledge of Formation Pore Pressure is a key requirement for safe and cost-effective drilling in overPressured Formations. Tectonic compression is an important type of overPressure mechanism, in addition to undercompaction and fluid expansion. However, there is not a valid approach for overPressure estimation in tectonic compression zones. Actually, two lateral stresses are too large to be ignored in tectonic environments. As a consequence, the conventional overPressure estimation methods are not accurate enough for tectonic compression mechanism. This article presents a new approach called the root mean square (RMS) principal stress method that modifies the estimation of Pore Pressure for tectonic compression zones. The RMS method better considers the characteristics of a 3D stress state. It has been tested in the Kuqa thrust belt of Tarim oil field where significant tectonic compression commonly exists. Pore Pressure estimation of this region shows that the RMS method provides more pr...
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estimating sand shale Formation Pore Pressure
Petroleum Science and Technology, 2011Co-Authors: F. Honghai, Y Zhi, Ji RongyiAbstract:Abstract This article presents a comprehensive evaluation method of estimating sand–shale Formation Pore Pressure by using sonic velocity and other logging data. The method takes the influence of porosity, density, shale content, effective stress, and some other physical properties of sand–shale Formation on sonic velocity into account. The influence and related logging data are combined to estimate the effective stress, and then Pore Pressure can be obtained by the effective stress principle. Using this method, software was developed and it applied in the well site. Its applications indicate that this method can accurately estimate the abnormal Pressure of a sand–shale Formation.
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Estimating Sand–Shale Formation Pore Pressure
Petroleum Science and Technology, 2011Co-Authors: F. Honghai, Ji RongyiAbstract:Abstract This article presents a comprehensive evaluation method of estimating sand–shale Formation Pore Pressure by using sonic velocity and other logging data. The method takes the influence of porosity, density, shale content, effective stress, and some other physical properties of sand–shale Formation on sonic velocity into account. The influence and related logging data are combined to estimate the effective stress, and then Pore Pressure can be obtained by the effective stress principle. Using this method, software was developed and it applied in the well site. Its applications indicate that this method can accurately estimate the abnormal Pressure of a sand–shale Formation.
Mark D Zoback - One of the best experts on this subject based on the ideXlab platform.
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compressive and tensile failure of inclined well bores and determination of in situ stress and rock strength
Journal of Geophysical Research, 1995Co-Authors: Pavel Peska, Mark D ZobackAbstract:In this paper we investigate the occurrence of compressive and tensile failures of arbitrarily inclined well bores under a wide variety of stress conditions. The principal assumptions in this analysis are that the rock is isotropic and that it deforms elastically to the point of failure. As has been shown by previous investigators, for a given stress state and well bore orientation, it is straightforward to predict the orientation of the failures around the well bore as well as whether failure is likely to occur depending on such parameters as rock strength and borehole fluid Pressure. However, as the stress state is almost never known in situ, we demonstrate how observations of compressive and tensile wall failures in inclined holes can be used to constrain in situ stress orientations and magnitudes if there are independent data on the magnitude of the least principal stress from either leak-off or microfrac tests and on the Formation Pore Pressure. We further demonstrate how once the stress state is determined, it is possible to assess both an upper bound on the effective in situ rock strength and the degree to which increasing the borehole fluid Pressure (or mud weight) can reduce the likelihood of borehole failure. Through application of this methodology to an inclined well bore in an area of complex faulting in the Gulf of Mexico, we illustrate how it is possible to utilize observations of borehole failures to determine the magnitude and orientation of the stress tensor in areas such as offshore sedimentary basins where drilling inclined well bores is quite common.
Reza Looyeh - One of the best experts on this subject based on the ideXlab platform.
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In-Situ Stress
Petroleum Rock Mechanics, 2011Co-Authors: Bernt Sigve Aadnoy, Reza LooyehAbstract:In-situ stress data plays a crucial role in various stages of oil and gas well planning, construction, operation and production, in operations which include drilling, well completion, well stimulation, production, and wasted re-injection. Knowledge of in-situ stresses and mechanical properties of the rock Formation are vital for the assessment of wellbore construction and production. This chapter discusses the in-situ stress state, how it is determined and what one would expect the in-situ stresses to be. The importance of using the available techniques such as open hole logging data, Formation Pore Pressure measurements, leak-off test (LOT) or Pressure integrity test (PIT), mini-fracture (mini-frac) test, drilling performance data and caliper data is shown to determine the in-situ stress inFormation. Several techniques are available for measuring the magnitude and orientation of in-situ stresses. These techniques must estimate the minimum of six independent measurements that are required to complete a stress state tensor.
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Rock Strength and Rock Failure
Petroleum Rock Mechanics, 2011Co-Authors: Bernt Sigve Aadnoy, Reza LooyehAbstract:Rock strength is specified in terms of tensile strength, compressive strength, shear strength, and impact strength. This chapter uses the two criteria most used in the oil and gas industry. These are the Von Mises and Mohr-Coulomb failure criteria. Many correlations have been used in the oil industry to enable the transfer of knowledge from one well to another. Some of these are just empirical correlations whereas others are based on models or physical principles. A number of correlations are derived over the years to enable the prediction of fracture and Pore Pressures. There are several methods which can be used to measure and/or estimate Formation Pore Pressure. For most in-situ conditions, such as those that exist in the rock Formation at any point around a wellbore, the stress field is truly three-dimensional or multiaxial and therefore none of the uniaxial testing methods can be accurately used to evaluate the complex mechanical behavior of the rock.
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Wellbore Instability Analysis Using Inversion Technique
Petroleum Rock Mechanics, 2011Co-Authors: Bernt Sigve Aadnoy, Reza LooyehAbstract:This chapter shows a unique instability analysis, known as the inversion technique. This technique uses leak-off test data to predict stresses in the Formation. It is used to predict fracturing Pressures for newly drilled wells. Several input parameters are required in order to use this technique; these are fracture gradient, Formation Pore Pressure, overburden stress at each fracture location, and the directional data i.e. borehole azimuth and inclination. This chapter provides two real scenarios followed by a detailed numerical field example to demonstrate more in-depth application of the inversion technique. The advantages of the inversion technique are discussed as an effective tool to analyze various fields with different stress states. The input data may be grouped according to interpretation or quality.
Pavel Peska - One of the best experts on this subject based on the ideXlab platform.
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compressive and tensile failure of inclined well bores and determination of in situ stress and rock strength
Journal of Geophysical Research, 1995Co-Authors: Pavel Peska, Mark D ZobackAbstract:In this paper we investigate the occurrence of compressive and tensile failures of arbitrarily inclined well bores under a wide variety of stress conditions. The principal assumptions in this analysis are that the rock is isotropic and that it deforms elastically to the point of failure. As has been shown by previous investigators, for a given stress state and well bore orientation, it is straightforward to predict the orientation of the failures around the well bore as well as whether failure is likely to occur depending on such parameters as rock strength and borehole fluid Pressure. However, as the stress state is almost never known in situ, we demonstrate how observations of compressive and tensile wall failures in inclined holes can be used to constrain in situ stress orientations and magnitudes if there are independent data on the magnitude of the least principal stress from either leak-off or microfrac tests and on the Formation Pore Pressure. We further demonstrate how once the stress state is determined, it is possible to assess both an upper bound on the effective in situ rock strength and the degree to which increasing the borehole fluid Pressure (or mud weight) can reduce the likelihood of borehole failure. Through application of this methodology to an inclined well bore in an area of complex faulting in the Gulf of Mexico, we illustrate how it is possible to utilize observations of borehole failures to determine the magnitude and orientation of the stress tensor in areas such as offshore sedimentary basins where drilling inclined well bores is quite common.