Evaluation of Residual Oil Saturation With Use of Single Well Chemical Tracer Test Swctt For Estimation of Eor Efficiency. From Theory to Experiment

2021 ◽  
Author(s):  
Fedor Andreevich Koryakin ◽  
Nikolay Yuryevich Tretyakov ◽  
Vladimir Evgenyevich Vershinin ◽  
Roman Yuryevich Ponomarev
Keyword(s):  
Analytical Methods ◽  
Tracer Test ◽  
Hydrodynamic Modeling ◽  
Residual Oil ◽  
Tracer Studies ◽  
Oil Saturation ◽  
Residual Oil Saturation ◽  
Chemical Tracer ◽  
Single Well

Abstract This article provides a brief overview of the theory of tracer studies, describes approaches to the interpretation of tracer studies using both analytical methods and hydrodynamic modeling, compares the results of analytical and numerical interpretation. The article also describes the problems that arise during the interpretation of real case study.

scholarly journals MUSCL scheme for Single Well Chemical Tracer Test simulation, design and interpretation

2019 ◽  
Vol 74 ◽  
pp. 10 ◽  
Author(s):  
Benjamin Braconnier ◽  
Christophe Preux ◽  
Frédéric Douarche ◽  
Bernard Bourbiaux
Keyword(s):  
Numerical Scheme ◽  
Tracer Test ◽  
Time Shift ◽  
Residual Oil ◽  
Oil Saturation ◽  
Residual Oil Saturation ◽  
Chemical Tracers ◽  
Chemical Tracer ◽  
Single Well ◽  
Order Scheme

Our paper presents an improved numerical scheme to simulate Single Well Chemical Tracer Test (SWCTT) method. SWCTT is mainly applied to determine the residual oil saturation of reservoirs. It consists in injecting an aqueous slug of a primary tracer into the reservoir formation and displacing it at a certain distance from the well. This tracer is partly miscible with oil on the one hand, and generates in situ a secondary tracer on the other hand. As a consequence, a shift is observed between the primary and the secondary tracers arrival times when production is resumed. This time shift is used to evaluate the residual oil saturation. In our paper, we propose a numerical scheme based on a fractional time stepping technique to decouple the resolution of the phases mass conservation equations and the chemical tracers mole conservation equations. For the phases resolution, we use an implicit scheme to ensure stability and robustness. For the chemical tracers, we propose an explicit second-order scheme in time and in space via MUSCL technique to improve the tracers time-shift calculation. The proposed numerical method is implemented on a realistic simulation model consisting of a vertical well crossing a reservoir consisting of a stack of homogeneous layers. By reducing the numerical dispersion, the proposed scheme improves the accuracy of predicted concentration profiles, without significantly increasing the computation time. Finally, the advantages of using a second-order scheme for residual oil saturation assessment are discussed on the basis of a radial 1D mesh convergence study.

Analysis of a Single-Well Chemical Tracer Test To Measure the Residual Oil Saturation to a Hydrocarbon Miscible Gas Flood at Prudhoe Bay

2000 ◽  
Vol 3 (06) ◽  
pp. 544-551 ◽  
Author(s):  
A.P. Cockin ◽  
L.T. Malcolm ◽  
P.L. McGuire ◽  
R.M. Giordano ◽  
C.D. Sitz
Keyword(s):  
Small Sample ◽  
Oil Field ◽  
North Coast ◽  
Residual Oil ◽  
Compositional Simulation ◽  
Oil Saturation ◽  
Residual Oil Saturation ◽  
Chemical Tracer ◽  
Single Well ◽  
Prudhoe Bay

Summary In 1990, a single-well chemical tracer (SWCT) test was performed in Prudhoe Bay to measure the effective waterflood and miscible gasflood residuals over a 12 ft reservoir interval. This is believed to be the first such use of this technology for a hydrocarbon miscible gas. This paper describes how the usual SWCT design was modified to accommodate the miscible gas, the results of the SWCT, which indicate significantly higher residual oil saturation for miscible gasflood than expected from coreflood experiments, and the subsequent simulation of the test which has provided good agreement with the observed results. The paper shows, with compositional simulation support, that the high apparent residual oil saturation was a consequence of incomplete volumetric sweep by the miscible gas and draws on the experiences of this test to make recommendations for the design of future SWCT tests measuring residuals to gasflooding. Introduction The Prudhoe Bay Miscible Gas Project (PBMGP) is the world's largest miscible flood. Prior to startup in 1987, numerous slim tube, coreflood, and phase behavior experiments were carried out to confirm the recovery potential of the process. Since the startup of the PBMGP a fibreglass observation well has been used to observe the flood progress and a sidetrack cored to observe the extent of the gas sweep. In 1990, a single-well chemical tracer (SWCT) test was carried out on a producing well which first measured the effective residual to waterflood and then to miscible gasflood. The attraction of the SWCT was that it investigated a much larger volume of rock than a coreflood and native wettability, away from the wellbore, should be assured. However, it should be recognized that this still only represents a small sample which may not represent the average performance on a broader scale. The tests were successfully carried out although production problems resulted in four tests, instead of the originally planned two, finally being performed. The subsequent analysis suggested an effective residual oil saturation to the miscible flood (Sorm) of 8%±2%. This was somewhat higher than the coreflood observed values of around 2%. Compositional simulation work has since been carried out to model the full suite of tests, including the aborted ones, to ascertain whether this higher value really conflicted with the coreflood results. Throughout the paper the remaining oil saturation following a water- or gasflood is referred to as the effective residual oil saturation since the paper demonstrates that the apparent high residual oil saturation after a miscible gasflood was a consequence of incomplete volumetric sweep. Hence, the measured remaining, or effective, residual saturation could have been lowered further if complete sweep had occurred. The theory behind a SWCT test is described in detail in Ref. 1 and recovery methods in Ref. 2. Background The Prudhoe Bay oil field on the north coast of Alaska is the largest oil field in the USA. The major producing sand is the Sadlerochit, which can be over 400-ft thick in some locations. It is mostly comprised of high-permeability fluvial sands with interbedded shales. Some of these shales are continuous over large areas while the majority are discontinuous over interwell distances. The structural and hydrocarbon histories are documented in Ref. 3, while Ref. 4 covers the reservoir description. Prudhoe Bay is overlain by a large gas cap. All produced gas components not used for fuel or spiked into the export oil line are reinjected either as a lean gas back into the gas cap or as a rich gas into the PBMGP or other projects. Lean gas injection into the gas cap recovers additional relict oil by vaporization. The expansion of the gas cap downwards recovers oil by gravity drainage. Around the periphery of the field there are approximately 200 inverted nine-spot patterns undergoing waterflood or water-alternating miscible gasflood. The general history of the development of Prudhoe Bay is described in more detail in Ref. 5. The PBMGP was preceded by a pilot at Drill Site 13 in 1982 prior to the startup of the central gas facility (CGF) in 1987. The CGF has since been expanded several times and now produces up to 550 mmscf/d of miscible gas. To date, 1.6 trillion scf of miscible gas have been injected. The development of the PBMGP is documented by Refs. 6 and 7. The optimization of the flood is achieved by directing the miscible gas to the most efficient patterns, as described in Ref. 8, and the use of predictive tools described in Refs. 9 and 10. During 1993, the need to sidetrack Injector DS 13-18 provided an opportunity to acquire additional information on the vertical sweep of the injected gas and the extent to which the miscible gas was reducing the oil saturations in this immature pattern (see Ref. 11). Prior to the start of the PBMGP, continuous and water-alternating miscible gas (WAG) floods were carried out on 16 plugs taken from a total of 4 preserved cores. These cores were injected with different miscible gas compositions and varying quantities of between 0.88 and 3.74 stock tank pore volumes. They exhibited residual to miscible gas saturation values between 1.0% and 4.5% (see Ref. 12), with an average of S orm. In 1990, the magnitude of the reserves being booked to the PBMGP warranted the investment in a SWCT test to provide additional confidence that miscible flooding in the field could achieve the low residuals suggested by the preserved state corefloods.

Single-Well Chemical Tracer Test for Residual Oil Measurement: Field Trial and Case Study

2016 ◽  
Author(s):  
Mohammed AlAbbad ◽  
Senthilmurugan Balasubramanian ◽  
Modiu Sanni ◽  
Sunil Kokal ◽  
Ibrahim Zefzafy ◽  
...  
Keyword(s):  
Field Trial ◽  
Tracer Test ◽  
Residual Oil ◽  
Chemical Tracer ◽  
Single Well

Hydrocarbon saturation determination with the single-well-chemical-tracer-test under laboratory conditions

2021 ◽  
pp. 131-143
Author(s):  
F. A. Koryakin ◽  
N. Yu. Tretyakov ◽  
O. B. Abdulla ◽  
V. G. Filippov
Keyword(s):  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Production Efficiency ◽  
Oil Production ◽  
Tracer Test ◽  
Core Sample ◽  
Oil Saturation ◽  
Chemical Tracer ◽  
Single Well ◽  
Efficiency Estimation

Nowadays the share of hard-to-recover reserves is growing, and to maintain oil production on necessarily level, we need to involve hard-to-recover reserves or to increase oil production efficiency on a brownfields due to enhanced oil recovery. The efficiency of enhanced oil recovery can be estimated by oil saturation reduction. Single-well-chemical-tracer-test (SWCTT) is increasingly used to estimate oil saturation before and after enhanced oil recovery application. To interpret results of SWCTT, reservoir simulation is recommended. Oil saturation has been calculated by SWCTT interpretation with use of reservoir simulator (CMG STARS). Distribution constants has been corrected due to results of real core sample model, and core tests has been successfully simulated. Obtained values of oil saturation corresponds with real oil saturation of samples. Thus, SWCTT as a method of oil saturation estimation shows good results. This method is promising for enhanced oil recovery efficiency estimation.

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