In Situ Stress Field, Fault Reactivation and Seal Integrity in the Bight Basin, South Australia

Reynolds, Scott; Hillis, Richard R.; Paraschivoiu, Evelina

doi:10.1071/aseg2003ab141

Cited by 4 publications

(6 citation statements)

References 6 publications

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“…Important considerations relevant to exploration and the utilisation of subsurface reservoirs include the integrity of reservoir sealing related to fracturing of cap-rocks and pressure-induced fault reactivation (Finkbeiner et al 2001;Reynolds et al 2003;Streit & Hillis 2004).…”

Section: Introductionmentioning

confidence: 99%

In-situ stress orientations in the UK Southern North Sea: Regional trends, deviations and detachment of the post-Zechstein stress field

Williams

Fellgett

Kingdon

et al. 2015

Marine and Petroleum Geology

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The orientation of the maximum horizontal compressive stress (S Hmax ) in the UK Southern North Sea has been determined using data derived from borehole breakout analysis of four-arm caliper logs.The results agree with existing stress models for NW Europe, confirming that horizontal stresses in the region have an approximately NW-SE orientation of S Hmax . This is interpreted as being a result of plate boundary convergence. Local deviations in the horizontal stress orientations are observed spatially and also vertically within some wells. Some of these deviations are attributed to rotations of the stress field adjacent to faults or between different fault blocks. The data also suggest detachment of the stress regime in the post-Permian cover rocks, caused by the presence of a thick underlying Permian-aged evaporite sequence and associated halokinesis. Despite the generally low scoring of the stress measurements when compared with the quality ranking scheme proposed by the World Stress Map project, the consistent orientation of the stress trajectories suggests that these data are reliably indicative of regional stress orientations. Analyses of borehole resistivity image logs have been used to verify the calculated stress orientations in some wells. These image logs validate some measurements whilst highlighting a number of deficiencies in the use of four-arm caliper data to characterise borehole breakouts. From the available data it is difficult to unambiguously define the nature of variations from the mean stress orientations observed. Further analysis of image log data over greater depth intervals is therefore required in order to investigate more fully the effects of stress rotations near faults and apparent stress detachment above saltcored anticlinal structures.

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Section: Introductionmentioning

confidence: 99%

In-situ stress orientations in the UK Southern North Sea: Regional trends, deviations and detachment of the post-Zechstein stress field

Williams

Fellgett

Kingdon

et al. 2015

Marine and Petroleum Geology

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“…This however requires accurate knowledge of the pore pressure and temperature during drilling, and of the tensile and compressive strength of the rock at the specific depths where the breakouts or drilling-induced tensile fractures are observed. In the absence of such data, broad limits can be placed on the magnitude of SHmax based on frictional limits to stress, beyond which faulting would be expected to occur (Reynolds et al 2003).…”

Section: Methodsmentioning

confidence: 99%

“…The methods above have been used to determine a regionally applicable in situ stress model which is used to assess the potential for fault reactivation in the EISB. When the full stress tensor is known, the potential of faults with any given orientation to become reactivated, as well as the pore pressure increase required to induce failure can be calculated (Ferrill et al 1999;Reynolds et al 2003). Such an increase in pore pressure can be induced by the continued accumulation of a hydrocarbon column asserting buoyancy pressure on the fault (Finkbeiner et al 2001), or from the injection of fluids such as natural gas for short-term storage or disposal of waste products such as CO2 (Chadwick et al 2009;Meng et al 2017).…”

Section: Methodsmentioning

confidence: 99%

“…Accurate determination of the effective in situ stress conditions is critical for effectively managing subsurface resources, particularly in mature hydrocarbon provinces such as the East Irish Sea Basin (EISB). Characterisation of the in situ stress state is essential for a range of subsurface engineering and energy applications (Bell 1996;Hillis & Nelson 2005;Tingay et al 2005), including seal integrity studies relating to exploration and storage of hydrocarbons (Wiprut & Zoback 2000;Finkbeiner et al 2001;Reynolds et al 2003;Meng et al 2017), and carbon capture and storage (Lucier et al 2006;Chiaramonte et al 2008;Williams et al 2016). Detailed stress field information is also commonly applied to the study of fluid flow through or along faults, as faults can constitute a risk to hydrocarbon exploration and subsurface fluid storage while also contributing positively to flow in tight, unconventional or geothermal reservoirs (Barton et al 1995;Bjørlykke et al 2005;Mildren et al 2005;Bretan et al 2011;Hennings et al 2012).…”

Section: Introductionmentioning

confidence: 99%

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Impact of in situ stress and fault reactivation on seal integrity in the East Irish Sea Basin, UK

Williams

Gent

Fellgett

et al. 2018

Marine and Petroleum Geology

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Despite having been affected by several stages of exhumation during the Cretaceous and Cenozoic, the contemporary stress state of the East Irish Sea (EISB) is poorly characterised. As the basin is mature in terms of exploitation of hydrocarbons, future exploration beyond the conventional Sherwood Sandstone Group reservoir (Triassic) necessitates a greater understanding of the in situ stress field, while proposed natural gas storage and carbon sequestration schemes also require detailed stress field information. Using petroleum well data, the in situ stress field of the EISB has been characterised to assess the mechanical seal integrity. A strike-slip stress regime most-likely prevails in the basin, meaning the Maximum Horizontal Stress (SHmax) is the greatest of the principal stresses. Interpretation of stress orientation data suggests that SHmax is oriented 152˚ ± 12˚, consistent with mean stress orientations across the wider region associated with plate boundary forces. Some degree of structural control appears to influence the orientation of SHmax, with orientations locally aligned sub-parallel to major Permo-Triassic basin-bounding faults. Fault reactivation risk is evaluated through modelling the pore pressure increase required to induce failure on pre-existing faults. Vertical faults striking 30˚ from SHmax are optimally-oriented to become reactivated under elevated pore pressure conditions. For any project relying on an element of fault seal for the containment of buoyant fluids at the average reservoir depth of 800 m, pore pressure increase should be less than 3.3 MPa to avoid reactivating pre-existing optimally-oriented faults. Higher pressure increases would be required to initiate reactivation of faults with other orientations. Vertical faults striking perpendicular to SHmax are least likely to become reactivated, and in the absence of halite, seal integrity would instead be limited by caprock strength and capillary-entry pressure. Major faults affecting the basin have been analysed for their slip tendency (ratio of shear to normal stress), which provides an indication of their susceptibility to become reactivated. Although the analysis is limited due to lack of an accurate 3D representation of the fault network, the results suggest that many of the fault orientations observed in the EISB exhibit high slip tendencies, including N-S striking faults to the north and west of the East Deemster Fault, where the SHmax orientation is NW-SE. Faults striking perpendicular to SHmax, such as the Lagman Fault, are least likely to become reactivated due to higher normal stresses that inhibit frictional sliding, while faults striking parallel or very close to SHmax also exhibit low slip tendency as they are not subjected to significant shear stresses.

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“…In addition, drilling horizontal well is the other important and critical technique for shale gas production. Commonly, a newly generated hydraulic fracture generally propagates along the path that requires the minimum force [30,34]. Therefore, in the Longmaxi 9 Geofluids shale reservoir of Haiba Block, horizontal wells are better drilled parallel to the S hmin direction as shown in Figure 5.…”

Section: Effects Of Stresses On Hydraulic Fracturing and Horizontalmentioning

confidence: 99%

Present-Day In Situ Stress Analysis in Shale Reservoir of Haiba Block, Southern Sichuan Basin, South China

Guo

Zheng

et al. 2023

Geofluids

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Natural gas from shale gas reservoirs has been an important contributor for reserve growth, deliverability construction, and profits growth in natural gas industry in the world. Hydraulic fracturing is commonly required in the shale gas commercial development, and thus understanding the present-day in situ stress field is greatly significant for the hydraulic fracturing and efficient development in shale gas reservoirs. However, there are no systematic investigations on the present-day in situ stress field in the Haiba Block from the Sichuan Basin, South China. In this study, the present-day in situ stress orientations and magnitudes in shale reservoir of Haiba Block are investigated based on the well interpretations from borehole image log and geomechanical modeling. Then, the effects of stresses on hydraulic fracturing, horizontal wells, and natural fracture reactivation were discussed. The results indicate that the horizontal maximum principal stress (SHmax) orientation is mainly in the NE-SW-trending, NW-SE-trending, and WNW-ESE-trending in the Haiba Block. The magnitudes of horizontal maximum and minimum principal stresses are 13.5 MPa~85.5 MPa and 2.8 MPa~31.6 MPa, respectively. In the Haiba Block, the differential stress is generally low in the northern part, which indicates that complex hydraulic fracture networks may be produced. While the natural fractures are generally stable under the present-day in situ stress field. When the increase of pore pressure gradient is about 30 KPa/m, nearly all natural fractures in the Longmaxi Formation may be reactivated. The results can provide the insights into a better understanding of the present-day in situ stress distribution so as to optimize perforation orientation, hydraulic fracturing design, and enhance gas production in shale gas reservoirs.

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In Situ Stress Field, Fault Reactivation and Seal Integrity in the Bight Basin, South Australia

Cited by 4 publications

References 6 publications

In-situ stress orientations in the UK Southern North Sea: Regional trends, deviations and detachment of the post-Zechstein stress field

In-situ stress orientations in the UK Southern North Sea: Regional trends, deviations and detachment of the post-Zechstein stress field

Impact of in situ stress and fault reactivation on seal integrity in the East Irish Sea Basin, UK

Present-Day In Situ Stress Analysis in Shale Reservoir of Haiba Block, Southern Sichuan Basin, South China

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