Hydraulic Fracturing in High Permeability Wells

Al-Haddad, S.; Arbaugh, R.; McKnight, D.

doi:10.2118/40008-ms

Cited by 6 publications

(1 citation statement)

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“…9,19,20,21,22 In most cases reported, production was substantially improved and the treatments were an economic success. However, we must conclude that extreme formation damage is occurring, or the propped fracture is not extending beyond near-wellbore damage.…”

Section: Issues Related To Fracturing High Permeability Gas Reservoirsmentioning

confidence: 99%

Fracture Fluid Damage to High-Permeability Gas Reservoirs: It Can Make A Difference

Robinson

Diyashev

Rahim

et al. 2000

SPE Annual Technical Conference and Exhibition

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractA new study has been performed that focuses on the reduction in gas flow rates and production that can occur due to damage from fracture fluid leakoff in high permeability gas reservoirs. We found, in some cases, fluid damage to the formation during fracturing operations (i.e., Frac Packs) may be more severe than what has been previously assumed in prior studies. As a result, gas flow rates can be significantly reduced, especially in gas reservoirs with moderate levels of permeability; e.g., 10 -50 md. The results of the study also showed that some fracture treatments are not achieving sufficient propped lengths to overcome near wellbore damage, thus compounding the problem and further reducing gas flow rates

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Section: Issues Related To Fracturing High Permeability Gas Reservoirsmentioning

confidence: 99%

Fracture Fluid Damage to High-Permeability Gas Reservoirs: It Can Make A Difference

Robinson

Diyashev

Rahim

et al. 2000

SPE Annual Technical Conference and Exhibition

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Optimizing Fracture Geometry and Productivity in High Permeability Reservoirs

et al. 2011

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In the Llanos basin of Colombia, there are shallow, highly permeable, poorly consolidated sandstone reservoirs close to oil-water contacts. The Carbonera formation is typical—several small, highly permeable (600 to 3000 mD) producing sands, with poorly defined barriers. High production rates and low bottom hole flowing pressures (BHFP) result in water coning and sand production. One solution is a stacked frac-pack completion. In these applications, conventional cross-linked fracturing fluids have limitations. High polymer concentrations and viscosity are required to control fluid leak-off and create a sufficiently wide hydraulic fracture to admit proppant. High fluid viscosity has led to uncontrolled fracture growth into oil-water contacts, while the high polymer concentration decreases fracture conductivity and effective half-length. A linear fluid comprised of polyacrylamide and polysaccharide polymers has proved an effective solution. The polyacrylamide greatly enhances fluid efficiency and elasticity, while reducing friction pressures and horsepower requirements. Fluid elasticity ensures adequate proppant transport. Fluid efficiency is determined by the polyacrylamide concentration and adjusted to achieve the required fracture geometry. The use of this fluid along with a geomechanical model and pseudo 3D fracturing simulator ensures that the propped fracture remains within the producing sand, with increased effective fracture half-length and conductivity. The polyacrylamide reduces the effective permeability to water and limits potential conning, when the well is produced. Wells completed with frac-packs using the linear fluid produce an average of 1420 bbl/day of fluid with 20% water-cut. The fluid efficiency during the treatments varies between 30% and 15% as a function of permeability. Offset conventionally gravel packed wells with a lower bottom hole flowing pressure (BHFP) average 980 bbl/day of fluid with 60% water-cut. Frac-packs, using an efficient linear fluid together with a geomechanical model and a pseudo 3D fracturing simulator have greatly improved the economics of producing these highly permeable reservoirs—maximizing production and recoverable reserves, while minimizing water production.

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Well Test Analysis of Infrequent Behavior of Fractured Wells in Oil and Gas Reservoirs

Amin

2012

All Days

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The purpose of hydraulic fracturing is to increase the contact area of the wellbore in the reservoir to maximise production rates. For modelling purposes, the induced fracture is assumed to be of infinite or finite conductivity. The modelled fracture tends to show either features of infinite conductivity with half slope or finite conductivity with quarter slope at early time. These flow behaviours are clear indications of a stimulated well. However, observations in some post-frac well tests report a single unit slope in early time, which indicates non-fractured well response. The objective of this study is to investigate the unusual flow behaviour associated with the testing of fractured wells following a proppant frac job and address reasons for this behaviour assuming the frac job has targeted the reservoir interval of interest. This infrequent behaviour is referred to briefly in a limited number of publications but with no clear explanation. Study suggests that the controlling factors are fracture length, fracture conductivity, non-Darcy flow in the case of gas wells and the damage caused by the fracture operation including choked fracture effect and less importantly fracture face skin. This study utilizes 3-D numerical black oil and compositional simulation in single and multi-layered reservoirs containing different fluid types. A range of factors are examined that may impact the introduced fracture flow behaviour based on actual fractured well flow features found in the literature. The main fracture and reservoir parameters investigated include: fracture half-length (x f), fracture conductivity (k f w f), fracture damage including fracture choke (S fc) and fracture face skin (S ff), non-Darcy effect, formation permeability and many others. The study also examines fractured well behaviour in naturally fractured reservoirs and gas-condensate (lean and rich) reservoirs to investigate liquid drop out effect on the induced fracture flow behaviour. It is concluded that the investigated fracture behaviour is likely to be associated with damaged fractures of short lengths and low fracture conductivity values, which often result from poorly executed frac job on the well. Knowledge obtained from the study is applied to the analysis of well tests from actual fractured wells. Understanding the flow behaviour of fractured wells is crucial to operators and service companies in evaluating the effectiveness of stimulation work performed on the well.

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Hydraulic Fracturing in High Permeability Wells

Cited by 6 publications

References 0 publications

Fracture Fluid Damage to High-Permeability Gas Reservoirs: It Can Make A Difference

Fracture Fluid Damage to High-Permeability Gas Reservoirs: It Can Make A Difference

Optimizing Fracture Geometry and Productivity in High Permeability Reservoirs

Well Test Analysis of Infrequent Behavior of Fractured Wells in Oil and Gas Reservoirs

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