Design and Implementation of Field Tests in Unconventional Reservoirs: Practical Perspectives

McClure, Mark; Albrecht, Maggie; Cipolla, Craig L.; Molina, Claudia

doi:10.2118/210477-ms

Cited by 3 publications

(2 citation statements)

References 48 publications

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“…However, it is not easy to measure the size and shape of the drainage volume around a well. Proppant settling and localized screenout prevent proppant from being placed along the full length of hydraulic fractures (Almasoodi et al, 2020;Cipolla et al, 2022;McClure et al, 2022b). Diagnostics such as microseismic and offset fiber can measure the full wetted length of fractures, but diagnostics to measure propped length are not readily available.…”

Section: Introductionmentioning

confidence: 99%

A new method for interpreting well-to-well interference tests and quantifying the magnitude of production impact: Theory and applications in a multi-basin case study

Almasoodi

Andrews

Johnston

et al. 2023

Preprint

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Interference tests are used in shale reservoirs to evaluate the strength of connectivity between wells. The results inform engineering decisions about well spacing. In this paper, we propose a new procedure for interpreting interference tests. We fit the initial interference response with the solution to the 1D diffusivity equation at an offset observation point. It is advantageous to use the initial interference response, rather than the subsequent trend, because the initial response is less affected by nonlinearities, time-varying boundary conditions, and uncertainties about flow geometry and flow regime. From the curve fit, we estimate the hydraulic diffusivity and the conductivity of the fractures connecting the wells. For engineering purposes, it would be useful to quantify the impact of interference on well production. Thus, we seek a relationship between the ‘degree of production interference’ (DPI) and an appropriate dimensionless quantity that can be derived from the estimate of fracture conductivity. Using simulations run under a wide range of conditions, we find that the classical definition for dimensionless fracture conductivity does not achieve a consistent prediction of DPI. This occurs because the dimensionless fracture conductivity was derived assuming radial flow geometry, but the dominant flow geometry during shale production is linear. We also find that the CPG (Chow Pressure Group) metric does not yield consistently accurate predictions of DPI. As an alternative, we derive a dimensionless quantity similar to the classical ‘dimensionless fracture conductivity,’ but which is derived for linear, not radial, flow geometry. Using this approach, we calculate a ‘dimensionless interference length’ that collapses all cases onto a single curve that predicts DPI as a function of fracture conductivity, well spacing, and formation properties. We conclude by applying the new method to field cases from the Anadarko and Delaware Basins.

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Section: Introductionmentioning

confidence: 99%

A new method for interpreting well-to-well interference tests and quantifying the magnitude of production impact: Theory and applications in a multi-basin case study

Almasoodi

Andrews

Johnston

et al. 2023

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…However, it is not easy to measure the size and shape of the drainage volume around a well. Proppant settling and fracture roughness prevent proppant from being placed along the full length of hydraulic fractures (Almasoodi et al 2020;Cipolla et al 2022;McClure et al 2022b). Diagnostics such as microseismic and offset fiber can measure the full wetted length of fractures, but diagnostics to measure propped length are not readily available.…”

Section: Introductionmentioning

confidence: 99%

A new method for interpreting well-to-well interference tests and quantifying the magnitude of production impact: theory and applications in a multi-basin case study

Almasoodi

Andrews

Johnston

et al. 2023

Geomech. Geophys. Geo-energ. Geo-resour.

Self Cite

View full text Add to dashboard Cite

Interference tests are used in shale reservoirs to evaluate the strength of connectivity between wells. The results inform engineering decisions about well spacing. In this paper, we propose a new procedure for interpreting interference tests. We fit the initial interference response with the solution to the 1D diffusivity equation at an offset observation point. It is advantageous to use the initial interference response, rather than the subsequent trend, because the initial response is less affected by nonlinearities, time-varying boundary conditions, and uncertainties about flow geometry and flow regime. From the curve fit, we estimate the hydraulic diffusivity and the conductivity of the fractures connecting the wells. For engineering purposes, it would be useful to quantify the impact of interference on well production. Thus, we seek a relationship between the ‘degree of production interference’ (DPI) and an appropriate dimensionless quantity that can be derived from the estimate of fracture conductivity. Using simulations run under a wide range of conditions, we find that the classical definition for dimensionless fracture conductivity does not achieve a consistent prediction of DPI. This occurs because the dimensionless fracture conductivity was derived assuming radial flow geometry, but the dominant flow geometry during shale production is linear. We also find that the Chow Pressure Group metric does not yield consistently accurate predictions of DPI. As an alternative, we derive a dimensionless quantity similar to the classical ‘dimensionless fracture conductivity,’ but which is derived for linear, not radial, flow geometry. Using this approach, we calculate a ‘dimensionless interference length’ that collapses all cases onto a single curve that predicts DPI as a function of fracture conductivity, well spacing, and formation properties. We conclude by applying the new method to field cases from the Anadarko and Delaware Basins.

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Low-frequency distributed acoustic sensing shape factors for fracture front detection

Leggett

2023

Interpretation

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Accurate knowledge of fracture extents generated in multistage unconventional completions remains elusive. Crosswell low-frequency distributed acoustic sensing (LF-DAS) measurements can determine the time and location of a frac hit. Knowing where and when a frac hit occurs constrains the fracture extent but does not estimate it quantitatively. A recent study on crosswell LF-DAS demonstrated a simple method to rapidly determine the instantaneous fracture propagation rate when a frac hit occurs. This method, the zero strain rate location method (ZSRLM), is based on laboratory experiments and numerical modeling assuming a radial fracture geometry. An estimated fracture propagation velocity can be used to extrapolate a final fracture extent. The propagation rate is calculated based on dynamic estimates of the nearest distance from the fiber to the front of a propagating fracture.In this work, the ZSRLM is adapted to estimate the distance to the fracture front based on rectangular fracture geometries. A three-dimensional displacement discontinuity method program generates crosswell LF-DAS strain rate waterfall plots considering a single, rectangular fracture of constant height. Over thirty different simulations were conducted varying formation mechanical properties, fracture height, and the vertical and horizontal offset between the treatment and monitor well. For each simulated case, the ZSRLM is used to estimate the distance to the fracture front based on the simulated waterfall plots. The difference between the estimated and actual distance to the front is minimized by a shape factor. The relationship between the shape factor, fracture height ratio, and vertical offset ratio is determined. Using a shape factor improves the performance of the ZSRLM by up to a factor of two for rectangular fractures. The updated ZSRLM is applied to extrapolate final fracture extents in two field cases: a single cluster stage in the Montney formation and a multi-cluster stage of an Austin Chalk completion.

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Design and Implementation of Field Tests in Unconventional Reservoirs: Practical Perspectives

Cited by 3 publications

References 48 publications

A new method for interpreting well-to-well interference tests and quantifying the magnitude of production impact: Theory and applications in a multi-basin case study

A new method for interpreting well-to-well interference tests and quantifying the magnitude of production impact: Theory and applications in a multi-basin case study

A new method for interpreting well-to-well interference tests and quantifying the magnitude of production impact: theory and applications in a multi-basin case study

Low-frequency distributed acoustic sensing shape factors for fracture front detection

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