Building Geostatistical Models Constrained by Dynamic Data - A Posteriori Constraints

Blanc, G.; Guerillot, D.; Rahon, D.; Roggero, F.

doi:10.2523/35478-ms

Cited by 11 publications

(8 citation statements)

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“…Here I have summarized the attempts by my group to understand well behavior over the past 10 years. Researchers at L'Institut Francais du Pétrole at Rueil Malmaison in France have made significant contributions in this regard [ Blanc et al , 1995; Rahon et al , 1996; Hu et al , 1996; Blanc et al , 1997, 1999].…”

Section: Discussionmentioning

confidence: 99%

A review of applications to constrain pumping test responses to improve on geological description and uncertainty

Raghavan

2004

Reviews of Geophysics

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[1] This review examines the single-phase flow of fluids to wells in heterogeneous porous media and explores procedures to evaluate pumping test or pressure-response curves. This paper examines how these curves may be used to improve descriptions of reservoir properties obtained from geology, geophysics, core analysis, outcrop measurements, and rock physics. We begin our discussion with a summary of the classical attempts to handle the issue of heterogeneity in well test analysis. We then review more recent advances concerning the evaluation of conductivity or permeability in terms of statistical variables and touch on perturbation techniques. Our current view to address the issue of heterogeneity by pumping tests may be simply summarized as follows. We assume a three-dimensional array (ordered set) of values for the properties of the porous medium as a function of the coordinates that is obtained as a result of measurements and interpretations. We presume that this array of values contains all relevant information available from prior geological and geophysical interpretations, core and outcrop measurements, and rock physics. These arrays consist of several million values of properties, and the information available is usually on a very fine scale (often <0.5 m in the vertical direction); for convenience, we refer to these as cell values. The properties are assumed to be constant over the volume of each of these cells; that is, the support volume is the cell volume, and the cell volumes define the geologic scale. In this view it is implicit that small-scale permeability affects the movement of fluids. Although more information than porosity is available, we refer to this system as a ''porosity cube.'' Because it is not economically possible to carry out computations on a finescale model with modern resources on a routine basis, we discuss matters relating to the aggregation and scale-up of the fine-scale model from the perspective of testing and show that specific details need to be addressed. The focus is on single-phase flow. Addressing the issue of scale-up also permits us to comment on the application of the classical or analytical solutions to heterogeneous systems. The final part of the discussion outlines the inversion process and the adjustment of cell values to match observed performance. Because the computational scale and the scale of the porosity cube are different, we recommend that the inversion process incorporate adjustments at the fine scale. In this view the scale-up process becomes a part of the inversion algorithm.

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Section: Discussionmentioning

confidence: 99%

A review of applications to constrain pumping test responses to improve on geological description and uncertainty

Raghavan

2004

Reviews of Geophysics

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“…Fine-grid simulation models [22][23][24] with different geostatistical realizations have been used to match pressure data for single-phase flow. If our goal was to find the most likely realization, we could have taken the fine-grid approach, ending up with a model with hundreds of thousand cells.…”

Section: Discussionmentioning

confidence: 99%

Analytic-Numeric Hybrid Modeling Approach for Interpreting Transient Tests in Horizontal Wells

Kabir

Dismuke

2000

Proceedings of SPE Annual Technical Conference and Exhibition

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractUncertainties arise while interpreting transient tests in horizontal wells. This study presents a hybrid approach in that both analytic and numeric models are used to circumvent most of the problems associated with the conventional analytic interpretation.This novel approach entails multiple steps. Initially, reservoir parameters are estimated by identifying as many flow regimes as possible using the analytic method. Thereafter, a numeric simulation model is built using a coupled wellbore-reservoir simulator. Herein, we seek to match the wellbore flow profile data, collected by production logs (PL), by adjusting local permeability and skin. This PLmatched model then allows rate calculation during the transient-test periods, using measured bottomhole pressure as the inner-boundary condition. Finally, the computed rate is convolved with pressure to interpret the drawdown data for seeking reconciliation with buildup interpretation.We present two field examples to illustrate the application of the notion presented here. Complications arise while interpreting flow and buildup tests using conventional tools, because of complex well trajectories penetrating this heterogeneous carbonate reservoir. Results show that reservoir anisotropy (k v /k h ) is a very sensitive parameter and is therefore well determined. The history-matched model was quite successful in predicting the water cut behavior over 18 months in one of the wells.

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“…For producers, the fluid rate in the well increases upward due to the influx from the formation. The fluid influx Q f (z) at location z is calculated as: (2) in which p e is the pressure at a radius r e from the center of the well, p w and r w are the well pressure and -radius, µ is the fluid viscosity, S is the skin, and k re is the end-point relative permeability to the flowing fluid. Note that Eq.…”

Section: Spe 65122mentioning

confidence: 99%

“…The approach is often based on the use of a numerical flow simulator. An example is the numerical inversion of well test data to improve the permeability description in a geostatistical model [2,3].…”

Section: Introductionmentioning

confidence: 99%

Conditioning Geostatistical Models to Flow Meter Logs

Mezghani¹,

Lingen²,

Cosentino

et al. 2000

All Days

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThis paper describes a method to condition facies (rock-type) permeabilities in geostatistical models to dynamic reservoir data: the flow meter log and the well test KH value. The proposed approach consists of two steps. In the first step, the flow meter logs are transformed into (reference) permeability profiles by use of the well test permeability-thickness (KH). This transformation is analytical, meaning that a geostatistical reservoir realization and numerical flow simulation are not required. In the second step, synthetic permeability profiles are computed for the known rock-type classification at the well locations. An optimization procedure is applied to improve the match of these synthetic permeability profiles with the reference (flow meter) profiles. In this process the initial (core based) rock-type permeability model is modified. The optimization procedure simultaneously takes into account all the wells, and is subject to geological constraints imposed by the user (ranking, permeability bounds). Although a number of assumptions must be verified, this fully analytical approach leads to a fast, flexible, and practical optimization routine that is relatively easy to implement. The up-front integration of dynamic data into the modeling process leads to a more representative permeability description than is obtained using only plug values. Because of the global nature of the optimization method, a satisfactory match can be extrapolated throughout the reservoir with a reasonable degree of confidence. The paper presents a successful application of the procedure to a Middle East reservoir.

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Building Geostatistical Models Constrained by Dynamic Data - A Posteriori Constraints

Cited by 11 publications

References 0 publications

A review of applications to constrain pumping test responses to improve on geological description and uncertainty

A review of applications to constrain pumping test responses to improve on geological description and uncertainty

Analytic-Numeric Hybrid Modeling Approach for Interpreting Transient Tests in Horizontal Wells

Conditioning Geostatistical Models to Flow Meter Logs

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