Pressure and temperature dependence of acoustic wave speeds in bitumen-saturated carbonates: Implications for seismic monitoring of the Grosmont Formation

Geophysics ◽  
2017 ◽  
Vol 82 (5) ◽  
pp. MR133-MR151 ◽  
Author(s):  
Arif Rabbani ◽  
Douglas R. Schmitt ◽  
Jason Nycz ◽  
Ken Gray
Keyword(s):  
Oil Recovery ◽  
Oil Sands ◽  
Saturation Pressure ◽  
Time Lapse ◽  
S Wave ◽  
Heated Sample ◽  
Wave Speeds ◽  
Seismic Reflectivity ◽  
Water Saturated ◽  
Northern Alberta

Recent time-lapse seismic observations in carbonate reservoirs subject to steam-assisted enhanced oil recovery display substantial changes in seismic reflectivity due to the combined effects of saturation, pressure, and temperature. Understanding these field seismic observations requires knowledge of the effects on the seismic wave speeds in bitumen-saturated carbonates. We have conducted ultrasonic measurements of P- and S-wave velocities in bitumen-saturated dolomite taken from the Grosmont Formation in northern Alberta. Wave speeds are measured under a variety of conditions of constant pore pressure, constant effective pressure, and with varying temperature to map the various controlling factors. The temperature-dependent declines of 12% and 9% for the P- and S-wave speeds, respectively, with temperatures from 10°C to 102°C are most notable. Unlike oil sands, at times, the dolomite retains its structure upon removal of the bitumen allowing for measurement of the dry and water-saturated frame properties and their subsequent use in substitutional modeling. None of the standard bounding, inclusion, or Biot-Gassmann family models adequately describe the observations in the heated sample. The deviations may be in part due to the inability of these models to properly incorporate the complex bitumen non-Newtonian rheology including a bulk viscosity.

Time-Lapse Pulsed Neutron Well Logging in Oil Sands for Monitoring Steam Chamber Development

2021 ◽  
Author(s):  
Yonghwee Kim ◽  
Alexandr Kotov ◽  
David Chace
Keyword(s):  
Oil Recovery ◽  
Heavy Oil ◽  
Oil Sands ◽  
Extreme Temperature ◽  
Time Lapse ◽  
Well Logging ◽  
Life Cycles ◽  
Temperature Variations ◽  
Steam Chamber ◽  
Pulsed Neutron

Abstract Steam-assisted gravity drainage (SAGD) technology, although a relatively new oil recovery method, has already proved its value in economic development of heavy-oil sands in Western Canada. The SAGD process requires a lifetime monitoring of steam chamber growth to optimize reservoir development, improve oil recovery, and minimize environmental impact. Operators have widely used pulsed neutron well logs to monitor their life cycles of oil sand reservoirs. Time-lapse pulsed neutron logs acquired in observation wells enable operators to effectively track the growth of the steam chamber and identify the changes of formation fluid saturations. We present high-temperature pulsed neutron logging technology and an algorithm to quantify steam, heavy oil and water saturations in SAGD wells. One of the major challenges in well logging operation is to withstand the thermal shock from the steam chamber. Reservoir temperature often varies abruptly, by as much as 250 degrees C in a very short interval, so the logging tool must be stable in drastic temperature variations. Well logging conditions such as a steam-filled wellbore, extra completion hardware and bad cement quality are challenging factors as well. Furthermore, formation fluid saturation analysis in Canadian oil sands is typically complex because the formation water salinity is relatively fresh but varies, clay properties are not homogeneous, and SAGD operations create conditions in which three-phase fluids coexist in the formation. These environmental conditions make it difficult to rely only on commonly used thermal neutron capture cross-section measurements (formation sigma). In this paper, case study examples present the above-mentioned challenges and solutions to identify the multi-component formation fluids. The multi-detector pulsed neutron well logging instrument has been modified with a custom-designed heat flask to handle the extreme temperature variations in the SAGD environment. This heat-flask equipped instrument ensures a stable data acquisition in the presence of rapid and extreme temperature variation and enables a prolonged and time-efficient operation through effective heat management. For saturation analysis, we demonstrate an advanced algorithm to quantify three fluid components using a combination of gamma ray ratio and carbon/oxygen (C/O) measurements.

scholarly journals An Experimental and Modeling Study on the Response to Varying Pore Pressure and Reservoir Fluids in the Morrow A Sandstone

2012 ◽  
Vol 2012 ◽  
pp. 1-17 ◽  
Author(s):  
Aaron V. Wandler ◽  
Thomas L. Davis ◽  
Paritosh K. Singh
Keyword(s):  
Pore Pressure ◽  
Wave Velocity ◽  
Oil Recovery ◽  
Laboratory Experiments ◽  
Time Lapse ◽  
P Wave ◽  
Well Logs ◽  
S Wave ◽  
Core Samples ◽  
Fluid Saturation

In mature oil fields undergoing enhanced oil recovery methods, such as CO2injection, monitoring the reservoir changes becomes important. To understand how reservoir changes influence compressional wave (P) and shear wave (S) velocities, we conducted laboratory core experiments on five core samples taken from the Morrow A sandstone at Postle Field, Oklahoma. The laboratory experiments measured P- and S-wave velocities as a function of confining pressure, pore pressure, and fluid type (which included CO2in the gas and supercritical phase). P-wave velocity shows a response that is sensitive to both pore pressure and fluid saturation. However, S-wave velocity is primarily sensitive to changes in pore pressure. We use the fluid and pore pressure response measured from the core samples to modify velocity well logs through a log facies model correlation. The modified well logs simulate the brine- and CO2-saturated cases at minimum and maximum reservoir pressure and are inputs for full waveform seismic modeling. Modeling shows how P- and S-waves have a different time-lapse amplitude response with offset. The results from the laboratory experiments and modeling show the advantages of combining P- and S-wave attributes in recognizing the mechanism responsible for time-lapse changes due to CO2injection.

Remote monitoring of the steam‐flood enhanced oil recovery process

Geophysics ◽  
1987 ◽  
Vol 52 (11) ◽  
pp. 1457-1465 ◽  
Author(s):  
E. F. Laine
Keyword(s):  
Oil Recovery ◽  
Heavy Oil ◽  
High Frequency ◽  
Oil Sands ◽  
Seismic Velocity ◽  
Color Image ◽  
Vertical Plane ◽  
Recovery Process ◽  
Steam Flood ◽  
Borehole Seismic

Cross‐borehole seismic velocity and high‐frequency electromagnetic (EM) attenuation data were obtained to construct tomographic images of heavy oil sands in a steam‐flood environment. First‐arrival seismic data were used to construct a tomographic color image of a 10 m by 8 m vertical plane between the two boreholes. Two high‐frequency (17 and 15 MHz) EM transmission tomographs were constructed of a 20 m by 8 m vertical plane. The velocity tomograph clearly shows a shale layer with oil sands above it and below it. The EM tomographs show a more complex geology of oil sands with shale inclusions. The deepest EM tomograph shows the upper part of an active steam zone and suggests steam chanelling just below the shale layer. These results show the detailed structure of the entire plane between boreholes and may provide a better means to understand the process for in situ heavy oil recovery in a steam‐flood environment.

scholarly journals Breccia interlayer effects on steam-assisted gravity drainage performance: experimental and numerical study

2021 ◽  
Author(s):  
Qichen Zhang ◽  
Xiaodong Kang ◽  
Huiqing Liu ◽  
Xiaohu Dong ◽  
Jian Wang
Keyword(s):  
Numerical Simulation ◽  
Oil Recovery ◽  
Oil Sands ◽  
Numerical Study ◽  
Middle Part ◽  
Experimental Results ◽  
Production Performance ◽  
Peak Oil ◽  
Steam Chamber ◽  
The Impact

AbstractCurrently, the reservoir heterogeneity is a serious challenge for developing oil sands with SAGD method. Nexen’s Long Lake SAGD project reported that breccia interlayer was widely distributed in lower and middle part of reservoir, impeding the steam chamber expansion and heated oil drainage. In this paper, two physical experiments were conducted to study the impact of breccia interlayer on development of steam chamber and production performance. Then, a laboratory scale numerical simulation model was established and a history match was conducted based on the 3D experimental results. Finally, the sensitivity analysis of thickness and permeability of breccia layer was performed. The influence mechanism of breccia layer on SAGD performance was analyzed by comparing the temperature profile of steam chamber and production dynamics. The experimental results indicate that the existence of breccia interlayer causes a thinner steam chamber profile and longer time to reach the peak oil rate. And, the ultimate oil recovery reduced 15.8% due to much oil stuck in breccia interlayer areas. The numerical simulation results show that a lower permeability in breccia layer area has a serious adverse impact on oil recovery if the thickness of breccia layer is larger, whereas the effect of permeability on SAGD performance is limited when the breccia layer is thinner. Besides, a thicker breccia layer can increase the time required to reach the peak oil rate, but has a little impact on the ultimate oil recovery.

Numerical Simulation of Thermal Solvent Replacing Steam under Steam Assisted Gravity Drainage SAGD Process

2010 ◽  
Author(s):  
Weiqiang Li ◽  
Daulat D. Mamora
Keyword(s):  
High Temperature ◽  
Oil Recovery ◽  
Oil Sands ◽  
Steam Injection ◽  
Thermal Recovery ◽  
Production Performance ◽  
Gravity Drainage ◽  
Steam Assisted Gravity Drainage ◽  
Recovery Technique ◽  
Simulation Results

Abstract Steam Assisted Gravity Drainage (SAGD) is one successful thermal recovery technique applied in the Athabasca oil sands in Canada to produce the very viscous bitumen. Water for SAGD is limited in supply and expensive to treat and to generate steam. Consequently, we conducted a study into injecting high-temperature solvent instead of steam to recover Athabasca oil. In this study, hexane (C6) coinjection at condensing condition is simulated using CMG STARS to analyze the drainage mechanism inside the vapor-solvent chamber. The production performance is compared with an equivalent steam injection case based on the same Athabasca reservoir condition. Simulation results show that C6 is vaporized and transported into the vapor-solvent chamber. At the condensing condition, high temperature C6 reduces the viscosity of the bitumen more efficiently than steam and can displace out all the original oil. The oil production rate with C6 injection is about 1.5 to 2 times that of steam injection with oil recovery factor of about 100% oil initially-in-place. Most of the injected C6 can be recycled from the reservoir and from the produced oil, thus significantly reduce the solvent cost. Results of our study indicate that high-temperature solvent injection appears feasible although further technical and economic evaluation of the process is required.

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