Geomechanical characterization of a caprock-reservoir system in the Northern Appalachian Basin: Estimating spatial variation of in situ stress magnitude and orientation

2018 ◽  
Vol 6 (3) ◽  
pp. T759-T781 ◽  
Author(s):  
Samin Raziperchikolaee ◽  
Mark Kelley ◽  
Neeraj Gupta
Keyword(s):  
Mechanical Properties ◽  
Horizontal Stress ◽  
Appalachian Basin ◽  
In Situ Stress ◽  
Complex Nature ◽  
Well Log ◽  
Reservoir System ◽  
Maximum Horizontal Stress ◽  
Northern Appalachian Basin

Assessing the mechanical integrity of the caprock-reservoir system is necessary to evaluate the practical storage capacity for geologic [Formula: see text] storage. We used a combination of well-log and experimental data to estimate the statistical distribution (mean and variance) of rock mechanical properties of Cambrian-Ordovician strata within the Northern Appalachian region of Ohio and studied their heterogeneity throughout the study area. Empirical correlations between static-dynamic moduli of carbonate and sandstone formations of the Northern Appalachian Basin were developed. The state of stress (the orientation and magnitude of the maximum horizontal stress) for caprock and reservoir formations in the Cambrian-Ordovician sequence was determined at multiple well locations to understand the regional variability of these properties throughout the study area. The maximum horizontal stress ([Formula: see text]) azimuth was estimated from image logs for six wells and S-wave anisotropy data for five wells. The [Formula: see text] magnitude was estimated by analytical and numerical modeling of stresses around the wellbore calibrated to the occurrence of wellbore breakouts and drilling-induced fractures in three wells as a function of depth. The results of assessing the [Formula: see text] magnitude and stress regime in the caprock and reservoirs in the Cambrian-Ordovician sequence using rock mechanical data acquired in this study, well-log data, and drilling data indicate that both parameters vary throughout the study area. In this work, we determined how integrating different types of data from multiple wells allowed us to estimate mechanical properties and characterize the spatial variability (laterally and vertically) of in situ stress for Cambrian-Ordovician caprock and reservoirs throughout the study area. A combination of different methods — numerical, analytical, and stress polygon — is used to estimate the in situ stress magnitude, especially [Formula: see text], regionally on a formation-by-formation basis. The results of this work can be used to improve our understanding the complex nature of stress in the Northern Appalachian Basin.

scholarly journals In Situ Stress and Stress Regime in the Onshore Part of the Northeast Java Basin

2021 ◽  
Vol 44 (2) ◽  
pp. 95-105
Author(s):  
Agus M. Ramdhan
Keyword(s):  
Petroleum Industry ◽  
Horizontal Stress ◽  
In Situ Stress ◽  
Vertical Stress ◽  
Stress Regime ◽  
Severe Erosion ◽  
Tectonically Active ◽  
Minimum Horizontal Stress ◽  
Maximum Horizontal Stress

In situ stress is importance in the petroleum industry because it will significantly enhance our understanding of present-day deformation in a sedimentary basin. The Northeast Java Basin is an example of a tectonically active basin in Indonesia. However, the in situ stress in this basin is still little known. This study attempts to analyze the regional in situ stress (i.e., vertical stress, minimum and maximum horizontal stresses) magnitude and orientation, and stress regime in the onshore part of the Northeast Java Basin based on twelve wells data, consist of density log, direct/indirect pressure test, and leak-off test (LOT) data. The magnitude of vertical (  and minimum horizontal (  stresses were determined using density log and LOT data, respectively. Meanwhile, the orientation of maximum horizontal stress  (  was determined using image log data, while its magnitude was determined based on pore pressure, mudweight, and the vertical and minimum horizontal stresses. The stress regime was simply analyzed based on the magnitude of in situ stress using Anderson’s faulting theory. The results show that the vertical stress ( ) in wells that experienced less erosion can be determined using the following equation: , where  is in psi, and z is in ft. However, wells that experienced severe erosion have vertical stress gradients higher than one psi/ft ( . The minimum horizontal stress ( ) in the hydrostatic zone can be estimated as, while in the overpressured zone, . The maximum horizontal stress ( ) in the shallow and deep hydrostatic zones can be estimated using equations: and , respectively. While in the overpressured zone, . The orientation of  is ~NE-SW, with a strike-slip faulting stress regime.

New constraints on stress and fracture orientations in the Shipwreck Trough, Otway Basin: implications for conventional and unconventional exploration and production

2012 ◽  
Vol 52 (2) ◽  
pp. 697
Author(s):  
David Tassone ◽  
Simon Holford ◽  
Rosalind King ◽  
Guillaume Backé
Keyword(s):  
Stress Tensor ◽  
Test Data ◽  
Sedimentary Basins ◽  
Horizontal Stress ◽  
In Situ Stress ◽  
New Method ◽  
Natural Fracture ◽  
Log Data ◽  
Maximum Horizontal Stress

A detailed understanding of the in-situ stress tensor within energy-rich basins is integral for planning successful drilling completions, evaluating the reactivation potential of sealing faults and developing unconventional plays where fracture stimulation strategies are required to enhance low permeability reservoirs. Newly available leak-off test results interpreted using a new method for analysing leak-off test data constrains the minimal horizontal stress magnitude for the offshore Shipwreck Trough wells to be ∼20 MPa/km, which is similar to the vertical stress magnitude derived from wireline data for depths shallower than ∼2–2.5 km. Breakouts interpreted from image log data reveal a ∼northwest–southeast maximum horizontal stress orientation and formation pressure tests confirm near-hydrostatic conditions for all wells. The new method for analysing leak-off test data has constrained the upper limit of the maximum horizontal stress magnitude to be the greatest, indicating a reverse-to-strike-slip faulting regime, which is consistent with neotectonic faulting evidence. Petrophysical wireline data and image log data to characterise extant natural fracture populations within conventional reservoirs and stratigraphic units that may be exploited as future unconventional reservoirs have also been used. These fracture sets are compared with possible fracture populations recognised in contiguous, high-fidelity 3D seismic datasets using a new method for identifying fracture systems based on attribute mapping techniques. This study represents the first of its kind in the Otway Basin. Combined analysis of the in-situ stress tensor and fracture density and geometries provides a powerful workflow for constraining fracture-related fluid flow pathways in sedimentary basins.

scholarly journals Study on In Situ Stress Distribution Law of the Deep Mine: Taking Linyi Mining Area as an Example

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Xuelong Li ◽  
Shaojie Chen ◽  
Sheng Wang ◽  
Meng Zhao ◽  
Hui Liu
Keyword(s):  
Coal Mine ◽  
Mining Area ◽  
Horizontal Stress ◽  
Geological Structure ◽  
In Situ Stress ◽  
Distribution Law ◽  
Principal Stresses ◽  
Stress Regime ◽  
Maximum Horizontal Stress

The variation of the in situ stress state is closely related to various factors. In situ stress state is also an important indicator to guide mining production. The study of in situ stress measurement and its distribution characteristics has always been a basic and very important work in mine production. In this study, the deep mines of Linyi Mining Area were considered as the research object. In this regard, the stress distribution law of each mine was studied. We found that the relationship between principal stresses was σH >  σ v  > σh, which belongs to the strike-slip stress regime. In this stress regime, the lateral Earth pressure coefficient was greater than one, and the magnitude of the three principal stresses all showed an increasing trend with the increase of depth. The maximum horizontal stress direction of the Gucheng Coal Mine, Guotun Coal Mine, and Pengzhuang Coal Mine was NW-SE under the influence of regional geological structure, while the maximum horizontal stress direction of Wanglou Coal Mine was NE-SW under the influence of local geological structure. Besides, the relationship between mine in situ stress and mine geological structure, the impact of original rock stress on stope stability, and the effect of original rock stress on floor water inrushing were also investigated. We believe that the research results are beneficial to mine disaster prevention and safety production.

scholarly journals In Situ Stress and Stress Regime in the Onshore Part of the Northeast Java Basin

2021 ◽  
Vol 44 (2) ◽  
pp. 83-95
Author(s):  
Agus M. Ramdhan
Keyword(s):  
Petroleum Industry ◽  
Horizontal Stress ◽  
In Situ Stress ◽  
Vertical Stress ◽  
Stress Regime ◽  
Severe Erosion ◽  
Tectonically Active ◽  
Minimum Horizontal Stress ◽  
Maximum Horizontal Stress

In situ stress is importance in the petroleum industry because it will significantly enhance our understanding of present-day deformation in a sedimentary basin. The Northeast Java Basin is an example of a tectonically active basin in Indonesia. However, the in situ stress in this basin is still little known. This study attempts to analyze the regional in situ stress (i.e., vertical stress, minimum and maximum horizontal stresses) magnitude and orientation, and stress regime in the onshore part of the Northeast Java Basin based on twelve wells data, consist of density log, direct/indirect pressure test, and leak-off test (LOT) data. The magnitude of vertical (  and minimum horizontal (  stresses were determined using density log and LOT data, respectively. Meanwhile, the orientation of maximum horizontal stress  (  was determined using image log data, while its magnitude was determined based on pore pressure, mudweight, and the vertical and minimum horizontal stresses. The stress regime was simply analyzed based on the magnitude of in situ stress using Anderson’s faulting theory. The results show that the vertical stress ( ) in wells that experienced less erosion can be determined using the following equation: , where  is in psi, and z is in ft. However, wells that experienced severe erosion have vertical stress gradients higher than one psi/ft ( . The minimum horizontal stress ( ) in the hydrostatic zone can be estimated as, while in the overpressured zone, . The maximum horizontal stress ( ) in the shallow and deep hydrostatic zones can be estimated using equations: and , respectively. While in the overpressured zone, . The orientation of  is ~NE-SW, with a strike-slip faulting stress regime.

Analysis of Casing Strength after Casing Wear in Ultra-Deep Rock Salt Formation

2012 ◽  
Vol 616-618 ◽  
pp. 538-542 ◽  
Author(s):  
Fu Xiang Zhang ◽  
Wei Feng Ge ◽  
Xiang Tong Yang ◽  
Wei Zhang ◽  
Jian Xin Peng
Keyword(s):  
Rock Salt ◽  
Coupling Effect ◽  
Equivalent Stress ◽  
Horizontal Stress ◽  
In Situ Stress ◽  
Attrition Rate ◽  
Salt Formation ◽  
Salt Creep ◽  
Casing Wear

To alleviate the problems of casing collapse induced by the coupling effect of rock salt creep and casing wear, the effects of salt creep, attrition rate and casing abrasive position on the equivalent stress on casings in non-uniform in-situ stress field is analyzed by finite-difference model with worn casing, cement and salt formation. It indicates that, creep reduces the yield strength of worn casing to a certain extent; Equivalent stress on casings is bigger and more non-uniform when the abrasion is more serious; Wear position obviously changes the distribution of equivalent stress on casing, and when the wear located along the direction of the minimum in-situ stress, equivalent stress on casing could be the largest that leads to the casing being failed more easily. Equivalent stress on casings increases gradually with creep time increasing and will get to balance in one year or so; In addition, new conclusions are obtained which are different from before: the maximum equivalent stress on casings is in the direction of the minimum horizontal stress, only when the attrition rate of the casing is little; otherwise, it is not. This method could help to improve the wear prediction and design of casings.

Experiment on Mechanical Properties and Seepage Capability of Deep Tight Sandstone Under True-Triaxial Stresses Environment

2021 ◽  
Author(s):  
Jiaying Li ◽  
Chunyan Qi ◽  
Ye Gu ◽  
Yu Ye ◽  
Jie Zhao
Keyword(s):  
Mechanical Properties ◽  
In Situ Stress ◽  
Stress Sensitivity ◽  
Stress Conditions ◽  
Tight Sandstone ◽  
Gas Reservoir ◽  
True Triaxial ◽  
Strain Behavior ◽  
Triaxial Stresses

Abstract The characteristics of seepage capability and rock strain during reservoir depletion are important for reservoir recovery, which would significantly influence production strategy optimization. The Cretaceous deep natural gas reservoirs in Keshen Gasfield in Tarim Basin are mainly buried over 5000 m, featuring with ultra-low permeability, developed natural fractures and complex in-situ stress states. However, there is no comprehensive study on the variation of mechanical properties and seepage capability of this gas reservoir under in-situ stress conditions and most studies on stress-sensitivity are conducted under conventional triaxial or uniaxial stress conditions, which cannot truly represent in-situ stress environment. In this work, Cretaceous tight sandstone in Keshen Gasfield was tested under true-triaxial stresses conditions by an advanced geophysical imaging true-triaxial testing system to study the stress-sensitivity and anisotropy of rock stress-strain behavior, porosity and permeability. Four groups of sandstone samples are prepared as the size of 80mm×80mm×80mm, three of which are artificially fractured with different angle (0°,15°，30°) to simulate hydraulic fracturing. The test results corresponding to different samples are compared to further reveal the influence of the fracture angle on rock mechanical properties and seepage capability. The samples are in elastic strain during reservoir depletion, showing an apparent correlation with fracture angles. The porosity decreases linearly with stress loading, where the decrease rate of effective porosity of fracture samples is significantly higher than that of intact samples. The permeabilities decrease exponentially and show significant anisotropy in different principal stress directions, especially in σH direction. The mechanical properties and seepage capability of deep tight sandstone are successfully tested under true-triaxial stresses conditions in this work, which reveals the stress-sensitivity of anisotropic permeability, porosity and stress-strain behavior during gas production. The testing results proposed in this paper provides an innovative method to analyse rock mechanical and petrophysical properties and has profound significance on exploration and development of tight gas reservoir.

Geomechanical Approach in Classification of Borehole Failures in Fractured Carbonates of Boca De Jaruco Field

2021 ◽  
Author(s):  
Anna Vladimirovna Norkina ◽  
Iaroslav Olegovich Simakov ◽  
Yuriy Anatoljevich Petrakov ◽  
Alexey Evgenjevich Sobolev ◽  
Oleg Vladimirovich Petrashov ◽  
...  
Keyword(s):  
Stress State ◽  
Horizontal Wells ◽  
Horizontal Stress ◽  
In Situ Stress ◽  
Vertical Wells ◽  
Stress Regime ◽  
Geophysical Information ◽  
The Republic ◽  
Maximum Horizontal Stress

Abstract This article is a continuation of the work on geomechanically calculations for optimizing the drilling of horizontal wells into the productive reservoir M at the Boca de Haruco field of the Republic of Cuba, presented in the article SPE-196897. As part of the work, an assessment of the stress state and direction was carried out using geological and geophysical information, an analysis of the pressure behavior during steam injections, cross-dipole acoustics, as well as oriented caliper data in vertical wells. After the completion of the first part of the work, the first horizontal wells were successfully drilled into the M formation. According to the recommendations, additional studies were carried out: core sampling and recording of micro-imager logging in the deviated sections. Presence of wellbore failures at the inclined sections allowed to use the method of inverse in-situ stress modeling based on image logs interpretation. The classification of wellbore failures by micro-imager logging: natural origin and violations of technogenic genesis is carried out. The type of breakout is defined. The result of the work was the determination of the stress state and horizontal stresses direction. In addition, the article is supplemented with the calculation of the maximum horizontal stress through the stress regime identifier factor.

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