Geomechanical mechanisms involving faults and fractures for observed correlations between fluctuations in flowrates at wells in North Sea oilfields

Heffer, Kes

doi:10.1144/sp374.2

Cited by 6 publications

(3 citation statements)

References 36 publications

(38 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Barton et al, 1995;Heffer et al, 1995;Tamagawa and Pollard, 2008;Hennings et al, 2012;Heffer, 2012). Fractures under high resolved shear stress are more easily perturbed than fractures under lower resolved shear stress.…”

mentioning

confidence: 99%

Comment on Davies et al., 2012 – Hydraulic fractures: How far can they go?

Lacazette¹,

Geiser²

2013

Marine and Petroleum Geology

View full text Add to dashboard Cite

mentioning

confidence: 99%

Comment on Davies et al., 2012 – Hydraulic fractures: How far can they go?

Lacazette¹,

Geiser²

2013

Marine and Petroleum Geology

View full text Add to dashboard Cite

“… An extensive, 18 year old body of work demonstrates that in many/most cases resolved shear stress on a fracture is correlated positively with its hydraulic transmissivity (e.g. Barton et al, 1995;Heffer et al, 1995;Morris et al, 1996;Ferrill et al, 1999;Sibson , 2000;Takatoshi and Kazuo, 2003;Tamagawa and Pollard, 2008;Heffer, 2012;Hennings et al, 2012). Higher resolved shear stress is positively correlated with seismic activity so that more microseismically active fractures are generally expected to be more hydraulically transmissive.…”

Section: Methodsmentioning

confidence: 99%

Ambient Fracture Imaging: A New Passive Seismic Method

Lacazette¹,

Vermilye²,

Fereja³

et al. 2013

Unconventional Resources Technology Conference, Denver, Colorado, 12-14 August 2013

View full text Add to dashboard Cite

Knowledge of discrete transmissive features such as faults or fracture zones prior to drilling offers substantial benefits for all phases of operations from exploration to development planning and hydraulic fracture design. We describe a new application of a relatively new passive-seismic method. The product is images of seismic activity produced by discrete features such as faults and fractures in the reservoir prior to drilling. We will present data acquired with passive seismic listening arrays in two unconventional reservoirs and a fractured carbonate reservoir.An extensive body of literature shows that fracture/fault zones with high resolved shear stress correlate positively with fracture transmissivity. In many cases, discontinuities with high resolved shear stress will be the most microseismically active. This method therefore allows mapping of many hydraulically transmissive zones prior to drilling or any other activity.The passive seismic method (Tomographic Fracture Imaging™ or TFI) directly images seismically active hydraulic fractures and natural fractures as complex surfaces and networks. Until recently, TFI has been used primarily to image hydraulic fracture treatments. We report a new application: imaging ambient seismic activity both prior to frac monitoring and by quiet-time monitoring using 3D reflection grids, i.e. by recording on a reflection grid or dedicated passive seismic grid when shooting or vibrating is not in progress. The resulting images reveal seismically active fracture and fault zones that correlate well with features illuminated by fracing or that are imaged by 3D reflection seismic attributes. The presence and hydraulic transmissivity of some of these features have been validated by independent measures including chemical tracers and pressure monitoring.This work also considers drivers of ambient seismic activity including earth tides and epeirogenic movements. Earth stress studies have established that the brittle crust is a self-organizing critical system in a state of frictional equilibrium and hence is constantly on the verge of movement. The earth's brittle crust is continually loaded by a variety of forces although tectonic movements, isostacy and isostacy-related flexure appear to dominate. It has been shown that stress or pressure changes of less than 0.01 atmospheres can stimulate seismicity. We present our work to date on quantitative correlations between earth tides and ambient seismic activity imaged on large grids. The results suggest that earth tides help stimulate release of stored elastic strain energy in the brittle crust.

show abstract

“…Understanding the orientation distribution and spatial configuration of natural fractures is important because these structural discontinuities significantly influence the behavior of many oil and gas reservoirs. As such, they impact fluid flow (e.g., Wilson et al, 2011b) and geomechanical state of the reservoirs (e.g., Heffer, 2012;Couples, 2013). Therefore, it is a common practice to include the contribution of fractures into static and dynamic reservoir models and simulations (e.g., Wilson et al, 2011aWilson et al, , 2011bBisdom et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Quantitative characterization of a naturally fractured reservoir analog using a hybrid lidar-gigapixel imaging approach

et al. 2018

View full text Add to dashboard Cite

The inability to accurately resolve subseismic-scale structural discontinuities such as natural fractures represents a significant source of uncertainty for subsurface modeling practices. Fracture statistics collected from outcrop analogs are commonly used to fill the knowledge gap to reduce the uncertainty related to fracture-induced permeability anisotropy. The conventional methods of data collection from outcrops are tedious, time consuming, and often biased due to accessibility constraints. Recent advances in virtual outcrop-based methods in fracture characterization enhance conventional methods by streamlining data collection and analysis. However, certain limitations and challenges exist in virtually obtained fracture data sets. The ability to identify fractures that are both exposed as lineations and as planes from a digital outcrop model depends heavily upon the fidelity and resolution of its surface display of RGB color, reducing the capacity of light detection and ranging (lidar) to the resolution of the scanner-attached camera. In the present study, we adopted a hybrid approach, combining lidar-based digital outcrop models and georeferenced high-quality photomosaics, providing improved texture maps in terms of pixel density compared to maps generated from on-scanner camera images. With this approach, the effects of truncation on digital outcrop models were limited, giving the ability to detect fractures that would otherwise be aliased from on-scanner camera imagery. The fracture system developed within the exposures of the Mississippian Boone Formation, an outcrop analog for age-equivalent reservoir objectives in Mississippi Lime hydrocarbon play, was characterized using conventional and virtual outcrop-based techniques. To test the fidelity of the virtual fracture extraction approach, fracture orientation statistics generated from lidar are compared with equivalent data sets collected using traditional surveys. The results suggest that terrestrial lidar, coupled with referenced gigapixel photomosaics, provide an effective medium for fracture identification with the capacity of resolving fracture characteristics with sufficient fidelity to potentially act as conditioning data for discrete fracture network models, making it an attractive alternative tool for fracture modeling workflows.

show abstract

Geomechanical mechanisms involving faults and fractures for observed correlations between fluctuations in flowrates at wells in North Sea oilfields

Cited by 6 publications

References 36 publications

Comment on Davies et al., 2012 – Hydraulic fractures: How far can they go?

Comment on Davies et al., 2012 – Hydraulic fractures: How far can they go?

Ambient Fracture Imaging: A New Passive Seismic Method

Quantitative characterization of a naturally fractured reservoir analog using a hybrid lidar-gigapixel imaging approach

Contact Info

Product

Resources

About