scholarly journals An approach to constrain maximum horizontal stress magnitude using wellbore Failure observations from image logs

2017 ◽  
Vol 20 (K4) ◽  
pp. 39-47
Author(s):  
Khanh Quang Do

The magnitude of the maximum horizontal stress is generally the most challenging term in estimating the full stress tensor. In this paper, an approach to constrain the magnitude of the maximum horizontal stress using the frictional limits to stress and wellbore failure observations (drilling-induced tensile fractures DITFs and/or breakouts BOs) from image logs is presented. This approach is applied to constrain the magnitude of the maximum horizontal stress at some interest depths (3900 m, 4100 m, 4300 m and 4500 m) of the basement reservoirs at the White Tiger field, Cuu Long basin, Vietnam from the program STRESS POLYGON. The occurrence of DITFs and/or BOs proved to be useful in estimating stresses around the wellbore, especially the maximum horizontal stress magnitude.

2012 ◽  
Vol 52 (2) ◽  
pp. 697
Author(s):  
David Tassone ◽  
Simon Holford ◽  
Rosalind King ◽  
Guillaume Backé

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.


2021 ◽  
Author(s):  
Abu M. Sani ◽  
Hatim S. AlQasim ◽  
Rayan A. Alidi

Abstract This paper presents the use of real-time microseismic (MS) monitoring to understand hydraulic fracturing of a horizontal well drilled in the minimum stress direction within a high-temperature high-pressure (HTHP) tight sandstone formation. The well achieved a reservoir contact of more than 3,500 ft. Careful planning of the monitoring well and treatment well setup enabled capture of high quality MS events resulting in useful information on the regional maximum horizontal stress and offers an understanding of the fracture geometry with respect to clusters and stage spacing in relation to fracture propagation and growth. The maximum horizontal stress based on MS events was found to be different from the expected value with fracture azimuth off by more than 25 degree among the stages. Transverse fracture propagation was observed with overlapping MS events across stages. Upward fracture height growth was dominant in tighter stages. MS fracture length and height in excess of 500 ft and 100 ft, respectively, were created for most of the stages resulting in stimulated volumes that are high. Bigger fracture jobs yielded longer fracture length and were more confined in height growth. MS events fracture lengths and heights were found to be on average 1.36 and 1.30 times, respectively, to those of pressure-match.


2020 ◽  
Author(s):  
Velio Coviello ◽  
Lucia Capra ◽  
Gianluca Norini ◽  
Norma Dávila ◽  
Dolores Ferrés ◽  
...  

Abstract. The M7.1 Puebla-Morelos earthquake that occurred on 19 September 2017, with epicenter located ∼ 70 km SW from Popocatépetl volcano, severely hit central Mexico. Seismic shaking of the volcanic edifice induced by the earthquake triggered hundreds of shallow landslides on the volcanic flanks, remobilizing loose pyroclastic deposits and saturated soils. The largest landslides occurred on the slopes of aligned ENE-WSW-trending ravines on opposite sides of the volcanic cone, roughly parallel to the regional maximum horizontal stress and local volcanotectonic structural features. This configuration may suggest transient reactivation of local faults and extensional fractures as one of the mechanisms that has weakened the volcanic edifice and promoted the largest slope failures. The seismic records from a broadband station located at few kilometers from the main landslides are used to infer the intensity of ground shaking that triggered the slope failures. The material involved in the larger landslides, mainly ash and pumice fall deposits from late Holocene eruptions with a total volume of about 106 cubic meters, transformed into two large debris flows on the western slope of the volcano and one on its eastern side. The debris flows were highly viscous and contained abundant large woods (about 105 cubic meter). Their peculiar rheology is reconstructed by field evidences and analyzing the grain size distribution of samples from both landslide scars and deposits. This is the first time that such flows were observed at this volcano. Our work provides new insights to constrain a multi-hazard risk assessment for Popocatépetl and other continental active volcanoes.


2021 ◽  
Author(s):  
Anna Vladimirovna Norkina ◽  
Iaroslav Olegovich Simakov ◽  
Yuriy Anatoljevich Petrakov ◽  
Alexey Evgenjevich Sobolev ◽  
Oleg Vladimirovich Petrashov ◽  
...  

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.


Geophysics ◽  
2021 ◽  
pp. 1-97
Author(s):  
kai lin ◽  
Bo Zhang ◽  
Jianjun Zhang ◽  
Huijing Fang ◽  
Kefeng Xi ◽  
...  

The azimuth of fractures and in-situ horizontal stress are important factors in planning horizontal wells and hydraulic fracturing for unconventional resources plays. The azimuth of natural fractures can be directly obtained by analyzing image logs. The azimuth of the maximum horizontal stress σH can be predicted by analyzing the induced fractures on image logs. The clustering of micro-seismic events can also be used to predict the azimuth of in-situ maximum horizontal stress. However, the azimuth of natural fractures and the in-situ maximum horizontal stress obtained from both image logs and micro-seismic events are limited to the wellbore locations. Wide azimuth seismic data provides an alternative way to predict the azimuth of natural fractures and maximum in-situ horizontal stress if the seismic attributes are properly calibrated with interpretations from well logs and microseismic data. To predict the azimuth of natural fractures and in-situ maximum horizontal stress, we focus our analysis on correlating the seismic attributes computed from pre-stack and post-stack seismic data with the interpreted azimuth obtained from image logs and microseismic data. The application indicates that the strike of the most positive principal curvature k1 can be used as an indicator for the azimuth of natural fractures within our study area. The azimuthal anisotropy of the dominant frequency component if offset vector title (OVT) seismic data can be used to predict the azimuth of maximum in-situ horizontal stress within our study area that is located the southern region of the Sichuan Basin, China. The predicted azimuths provide important information for the following well planning and hydraulic fracturing.


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