A Simulation Study of Novel Thermal Recovery Methods in the Ugnu Tar Sand Reservoir, North Slope, Alaska

Sharma, Bakul C.; Khataniar, Santanu; Patil, Shirish; Kamath, V.A.; Dandekar, Abhijit

doi:10.2118/76729-ms

Cited by 8 publications

(5 citation statements)

References 6 publications

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“…They showed that anisotropy influences SAGD oil rate, and their plots reveal a definite time component to this phenomenon i.e., not only is the rate reduced for decreasing v h k k ratios, but the shape of the plots, though similar, appear shifted in time as v h k k varies. Sharma et al (2002) also observed that when the vertical permeability was increased beyond 200md for the specific reservoir they considered, the anisotropy ratio had no influence on cumulative oil recovery. 9 in their paper) is presented here for clarity in Fig.…”

Section: Introductionmentioning

confidence: 89%

“…Yet it is unclear what the role of anisotropy would be because the orientation of the fluid flow streamlines with respect to the principal axis of anisotropy during a typical SAGD process will change with time. Sharma et al (2002) used a thermal simulator to perform a study of several thermal recovery techniques including the SAGD process. Alali et al (2009) used a geometric average of the vertical and horizontal permeability for developing their semi-analytical SAGD model.…”

Section: Introductionmentioning

confidence: 99%

“…Sharma et al (2002) used a thermal simulator to perform a study of several thermal recovery techniques including the SAGD process. They commented on the non-intuitive nature of their results especially when compared with the results in Sharma et al (2002). One of these plots ( Fig.…”

Section: Introductionmentioning

confidence: 99%

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Modeling the Effect of Permeability Anisotropy on the Steam-Assisted Gravity Drainage (SAGD) Process in Multi-Layered Reservoirs

Azom

Srinivasan

2013

All Days

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The performance of the SAGD process is significantly impacted by permeability anisotropy both during the initial rise of the steam chamber as well as during the lateral spreading of the steam chamber. Previous models for SAGD performance take into account the effective permeability of the medium but don't explicitly account for the anisotropy. We extend our earlier development of a semi-analytical model that accounts for permeability anisotropy during the SAGD process to multi-layered reservoirs. We explicitly account for permeability anisotropy by resolving the resultant oil drainage and resultant gravity head vectors on to the principal axes of the reservoir's permeability ellipsoid. The extension to multi-layered systems recognizes that the entire reservoir may not be characterized by a single anisotropy ratio and in fact the ratio may vary from one reservoir layer to the next. We model oil recovery in such situations taking into account the unique quasi-steady state flow characteristics of the SAGD process.Our method involves using the quasi-steady assumption to derive the appropriate SAGD slope drainage equations for both the resultant gravity head (RGH) and the resultant oil discharge (ROD) vector orientations. These vectors are later mapped to the principal anisotropy axes of the permeability field. The entire modeling is done in dimensionless space making the model suitable for use as predictive type-curves.Our results show that just like for the single layer case, both the RGH and ROD models give different results especially at low equivalent anisotropy ratios. We also show that there is a limitanisotropy ratio beyond which the anisotropy ceases to affect the production characteristics. Moreover, our results show that static averaging techniques like arithmetic, harmonic averaging that yield effective permeability used in traditional models for the SAGD process fail to capture the effect of anisotropy on SAGD flow rates for multi-layered reservoirs. The resulting production expression can be used as a fast proxy to model the SAGD process in more complex reservoirs for the purposes of history matching and/or in a predictive modeling framework.

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Section: Introductionmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Modeling the Effect of Permeability Anisotropy on the Steam-Assisted Gravity Drainage (SAGD) Process in Multi-Layered Reservoirs

Azom

Srinivasan

2013

All Days

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“…We assume: (a) steady state is reached for each measurement, (b) there is no radial heat flux due to the thermal resistance of the guard zone of insulation and a guard heater that opposes radial heat flux, (c) in view of the previous assumption, the heat flux is one-dimensional, (d) the contact resistance between the heat flux sensor (HFS) and the sample is negligible, and (e) the thermal conductivity of the sample is a linear function of the temperature, b aT + = λ ( 2 ) where λ is the thermal conductivity of the sample, T is the temperature of the sample and a and b are two constant coefficients. We comment that the assumption of no contact resistances is reasonable because the samples have low thermal conductivities.…”

Section: Theorymentioning

confidence: 99%

“…The original oil in place is estimated at 6 billion bbl 1 . Various studies 1,2 showed that thermal processes with steam injection, and more particularly SAGD and its variants, allow good recovery from relatively deep oil-sand deposits.…”

Section: Introductionmentioning

confidence: 99%

Thaw Front Dynamics and Super Insulated Well for Thermal Recovery in Cold Environments

Marques

Castanier

Kovscek³

2009

SPE Western Regional Meeting

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Thermal recovery methods such as steam injection or in-situ combustion are preferred for heavy oil. In cold environments, wellbore heat losses are significant and limit the applicability of thermal recovery. Therefore, it is essential to insulate the well effectively and economically.Our study focuses primarily on the problem of wells penetrating thick layers of frozen earth (i.e., permafrost). The experimental component determines thermal conductivity versus temperature of nanomaterials fashioned into insulation (socalled black and white silica aerogels that are 90-99.8% air), fiberglass, thermolastic insulation, and carbon fibers. A comparator thermal conductivity apparatus as well as direct measurements using heat flux sensors were developed. A simplistic experimental simulation explored the role of mechanical stress due to thermal cycling.Semianalytical and numerical models were also developed to design a superinsulated well. The models incorporate various composite insulations. Computations include wellbore heat losses, wellbore temperature and the permafrost temperature. Different processes were simulated including an injector well with constant fluid temperature. Well failure/stability is inferred from the rate of thaw front propagation. A key parameter is the insulation thermal conductivity versus temperature that is measured directly.Results show agreement of conductivity with literature values at ambient temperature. Aerogels (0.012-0.025 W/m K) are half as conductive as fiberglass (0.03-0.045 W/m K) and three to four times less conductive than thermolastic insulation and carbon fibers (0.04-0.067 W/m K) for temperatures between 40 and 140 °C. Moreover, aerogels and carbon fibers have good mechanical resistance in comparison to fiberglass. The wellbore heat loss and thaw front propagation model indicates that aerogels alone or aerogels in a composite with more conductive insulation may meet the requirements to avoid well failure, even for very high temperature fluids and over long periods.Thus, alone or in combination with active subcooling of the permafrost, aerogel insulations appear to provide effective thermal isolation to insure well integrity. Although aerogel insulations alone are not as effective as active refrigeration, their moderate cost and their ease of use encourage further investigation.

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Heavy Oil Displacement by Thermal Recovery Using Different Horizontal/Vertical Wells Configurations

2006

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The use of horizontal wells in oil industry has increased rapidly during the last decade. The main reason for this upsurge is that wells provide large contact area with the reservoir and therefore enhance the well productivity or injectivity better than conventional vertical wells. The high productivity coupled with the recent advances in drilling technology for horizontal wells has made their application to be an economically viable option. The study will investigate by numerical simulation technique the performance of horizontal injection wells with production vertical wells in thermal recovery processes. A high resolution numerical simulator (ECLIPSE) will be used during the course of this research. Extensive three-dimensional, fine-mesh simulation runs will be performed to determine the oil recovery under different operating/reservoir conditions. The purpose will be to study the functional relationship between several design parameters and the oil recovery from horizontal/vertical wells configurations during thermal flooding. These parameters will include:configurations of horizontal and vertical wells,flood patterns,Horizontal well length,Mobility ratio. Introduction The use of horizontal wells in oil industry has increased rapidly during the last decades. The employment of horizontal wells instead of vertical wells is thought to improve the oil production, reduces gas and water coning problems, and increases the sweep efficiency. Therefore, the utilization of horizontal wells, instead of vertical ones, in enhanced oil recovery processes became attractive for the oil industry. Algharaib and Gharbi1 studied the advantages of Horizontal/Multilateral wells over the conventional vertical wells. They compared the performance of four Horizontal/Multilateral well configurations to that of the vertical wells in waterflooding operations. Their study shows that the pattern used has a significant effect on the displacement performance. Thermal Recovery is one of the common EOR recovery methods. Thermal recovery methods are used worldwide to recover heavy oil and bitumen. The basic process concept involved in thermal recovery processes is to generate hot fluid on the surface or in situ and inject it through an injection well into an oil bearing formation.

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A Simulation Study of Novel Thermal Recovery Methods in the Ugnu Tar Sand Reservoir, North Slope, Alaska

Cited by 8 publications

References 6 publications

Modeling the Effect of Permeability Anisotropy on the Steam-Assisted Gravity Drainage (SAGD) Process in Multi-Layered Reservoirs

Modeling the Effect of Permeability Anisotropy on the Steam-Assisted Gravity Drainage (SAGD) Process in Multi-Layered Reservoirs

Thaw Front Dynamics and Super Insulated Well for Thermal Recovery in Cold Environments

Heavy Oil Displacement by Thermal Recovery Using Different Horizontal/Vertical Wells Configurations

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