Flow towards a guarded sampling probe: Modelling of a 2D flow cell

Sherwood, J.D.

doi:10.1016/j.petrol.2009.02.002

Cited by 2 publications

(1 citation statement)

References 13 publications

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“…Filtrate continues to arrive at the probe, from near-well bore regions increasingly far from the probe, but this filtrate enters the guard annulus and is discarded. Analysis of idealised axisymmetric and plane geometries (Sherwood 2005;Tarvin et al 2008;Sherwood 2009) has been confirmed by laboratory experiment (Tarvin et al 2008) and by field tests (Weinheber and Vasques 2006;O'Keefe et al 2006). We consider flow towards a guarded probe in a well bore and assume that a fixed fraction λ of the flow Q goes into the central sampling probe, with the remaining fraction 1 − λ going into the guard probe.…”

Section: Guarded Probesmentioning

confidence: 96%

Fluid Sampling From Porous Rock to Determine Filtrate Contamination Profiles Around a Well Bore

Sherwood

2009

Transp Porous Med

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Drilling fluid filtrate invades the pores of rock surrounding a well bore during drilling of the well, and contaminates the pore fluid originally within the rock pores. Models for the flow of contaminated pore fluid towards a sampling tool within the well bore are investigated, assuming that the filtrate has the same viscosity as the original pore fluid and that the wellbore radius is small compared to the depth of filtrate invasion. If the filtrate contamination in the fluid withdrawn from the rock is monitored as a function of the volume withdrawn, then it is shown that results can be inverted to give the radial distribution of filtrate around the well bore. A new generation of guarded sampling probes is then considered, and it is shown that the radial distribution of filtrate can be obtained by means of such a probe if the fraction of flow entering the central sampling region of the probe is small compared to that entering the concentric annular guard probe. The effects of dispersion, non-zero wellbore radius and anisotropic hydraulic permeability of the rock are also studied, and numerical simulations are used to give some indication of the effect of the ratio of the filtrate viscosity to that of the original pore fluid.

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Section: Guarded Probesmentioning

confidence: 96%

Fluid Sampling From Porous Rock to Determine Filtrate Contamination Profiles Around a Well Bore

Sherwood

2009

Transp Porous Med

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Numerical Simulation of Formation Fluid Sampling with Three Different Probe-Type Wireline Formation Testers

Yu,

2024

Energies

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Wireline formation fluid sampling is extensively utilized to acquire downhole fluid samples. Due to mud filtrate invasion, enough time is required to pump out the formation fluid so that an acceptable level of contaminant is reached. Excessive cleanup time would increase costs and the risk of the testing tool becoming stuck within the drilling mud. The challenge lies in deciding what type of formation-tester probe should be used to ensure minimally contaminated measurements for a specific tool configuration and when the withdrawal sample is sufficiently purged of contaminants. A numerical simulator to simulate the virgin formation fluid sampling was developed, and the accuracy of the simulator was validated based on the spherical flow theory. Through running 2515 simulation cases, the effects of various operational and formation conditions on the breakthrough and pumpout times with three different probes (i.e., the standard probe, the elliptical probe, the elongated probe, and their corresponding 3D radial probes) were compared and analyzed quantitatively. We numerically investigated the key factors influencing the breakthrough and pumpout times and delved into the impact of the formation anisotropy. This study reveals the parameters that encompass the first-order effect on the breakthrough and pumpout times, enabling the determination of the probe-type selection and the early predictions of pumpout time. By leveraging these insights, sampling operations can be optimized to enhance sample quality, reduce operational time, and mitigate the risks associated with tool entrapment.

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Flow towards a guarded sampling probe: Modelling of a 2D flow cell

Cited by 2 publications

References 13 publications

Fluid Sampling From Porous Rock to Determine Filtrate Contamination Profiles Around a Well Bore

Fluid Sampling From Porous Rock to Determine Filtrate Contamination Profiles Around a Well Bore

Numerical Simulation of Formation Fluid Sampling with Three Different Probe-Type Wireline Formation Testers

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