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BEAVER CREEK-MADISON FORMATION RESERVOIR STUDY
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An Engineering Report submitted to the Faculty and the Board of Trustees of the Colorado School of Mines in partial fulfillment for the requirements for the degree of Master of Engineering. Signed f Marco T. Castro Golden, Colorado Date: io » 1973 t Approved: ^_/" 4$ïesis Advisor/ Head of Department Golden, Colorado Pete s ,/P > 1973
ARTffUH LAKES LIBRARY
:,v v ;._)OL OF MI^BS
COLORADO
ABSTRACT
A reservoir engineering study was made with the m i s cible displacement method to determine the feasibility of tertiary recovery at the Beaver Creek-Madison Formation
( W y o m i n g ) . The original oil-in-place was calculated volu- metrically and was found to be 68.2 MMSTB. The primary recovery was determined to be 5.9 MMSTB. The secondary recovery performance by water-flooding until August 1972 was determined to be 24.6 MMSTB. The calculations i ndi cated no increase in oil recovery by miscible displacement.
In conclusion, a miscible displacement project will not be feasible at the Beaver Creek-Madison Formation.
ER 1567 CONTENTS Page A B S T R A C T ... iii INTRODUCTION ... 1 GEOLOGY AND H I S T O R Y ... 2 Geology of F i e l d ... 2 History of F i e l d ... 3 RESERVOIR PARAMETERS ... 5
Effective Pay Thickness ... 5
Water S a t u r a t i o n ... 5
P o r o s i t y ... 6
P e r m e a b i l i t y ... 6
RESERVOIR FLUID S T U D Y ... 8
RELATIVE PERMEABILITY DATA ... 9
D E T E R MINATION OF OIL-IN-PLACE. ... 10
PRIMARY AND SECONDARY RECOVERY ... 11
MISCIBLE D I S P L A C E M E N T ... 13
R EVIEW OF THE L I T E R A T U R E ... 15
L ABORATORY STUDIES ... 18
Miscible Fluid T e s t s ... 18
TERTIARY R E C O V E R Y ... 19
Displacement Fluid Injection. . . ... 21
Oil Recovery F a c t o r ... 21
Mobility R a t i o ... 23
Permeability V a r i a t i o n ... 24
Oil R e c o v e r y ... 24
Oil Production Rate . ... 25
Gas Production R a t e ... * ... 26
Page
CONCLUSIONS AND RECOMMENDATIONS. . . . ... 28
BIBLIOGRAPHY . •... 29 T A B L E S ... 31 F I G U R E S ... 44 APPENDIX A ... 62 APPENDIX B ... 70 v
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FIGURES
Figure Page
1. Location Map of the Beaver Creek F i e l d ... 44 2. Beaver Creek-Madison Structure Map, Top
M a i n P a y ... In pocket 3. Beaver Creek-Madison Oil-Effective
Isopach M a p ... In pocket 4.. Beaver Creek-Madison Composite Production
History (19 5 9 - 6 2 ) ... 45 5• Beaver Creek-Madison Composite Production
History ( 1 9 63-72)... 46 6. Typical Beaver Creek-Madison
Spontaneous-Potential and Resistivity L o g ... 47 7. Porosity H i s togram for Samples of Beaver
Creek-Madison F o r m a t i o n ... 48 8. Beaver Creek-Madison Differential Gas
L i b e r a t i o n ... 49 9• Beaver Creek-Madison Oil P ressure-Volume
Relationship ... 50 10. Beaver Creek-Madison Viscosity D a t a ... 51 11. Beaver Creek-Madison Gas Formation Volume
F a c t o r s ... ... 52 12. Beaver Creek-Madison Water-Oil Relative
Permeability C u r v e s ... 53 13. Beaver Creek-Madison Determination of
Water S a t u r a t i o n ... 54 14. Oil Recovery F a c t o r ... 55 15. Beaver Creek-Madison Permeability Variation. . . 56 16. Projected Oil Production Rate vs T i m e ... 57 17• Projected Total Gas Production Rate vs Time. . . 58
Figure Page 18. Cumulative Oil vs T i m e ... 59 19. Costs Expended for Solvent and Generated
from Oil vs T i m e ...
20. Prediction of Secondary and Tertiary Recovery. . 6l
ER 156? Table I. II. III. IV. V. VI. VII. VIII. IX. X. XI. XII. TABLES Page Stratigraphie Section of the Beaver Creek
Field ... 31.
W eighted Average Water Saturation Based
on Log A n a l y s e s ... 32 Classification of Porosity Data ... 33 Geometric Mean Permeability of the Beaver
Creek-Madison ... 34 Beaver Creek-Madison P V T D a t a ... 35 Calculation of Net Volume of Reservoir
from Isopachous M a p ... 36 Fluid C o m p o s i t i o n ... 37 Minimum Propane Requirements for Miscibility. . 38 Displacement Fluid C o m p o s i t i o n ... 39 Vertical Distribution of Permeability ... 40 Line Drive Recovery Factors ... 4l Calculation of Tertiary Recovery from
Miscible Displacement ... ... 42
ACKNOWLEDGMENTS
The author expresses his gratitude to Professor J . R . Bergeson, thesis advisor. Professor W. R. Astle, chairman of oral d e f e n s e , and Professor H. K. van Poollen for their time and help in this s t u d y .
Appreciation is also extended to Professor W. J . Chapitis for editorial suggestions on the manuscript.
The author thanks the Amoco Oil Company for supply ing data, and also Mr. C. B. Pollock of Amoco for all his cooperation during the present study.
Thanks are also due to Professor D . M. Bass, Head of Petroleum Engineering Department, for council and guid ance that made this study possible.
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1
INTRODUCTION
A reservoir engineering study was made with the miscible displacement method to determine the feasibility of tertiary recovery at the Beaver Creek-Madison F o r m a t i o n . The data for this study were obtained from fluid and core analyses made by commercial laboratories, well logs, and production h i s t o r y . This study was based on production data from December 1953 to August 1972.
A structural map was prepared from the top of the Madison Formation. An effective-oil isopach was prepared from individual well logs. The oil-in-place was calculated v o l u m e t r i c a l l y .
Primary recovery above the bubble-point pressure was calculated by considering fluid and rock expansion.
Secondary oil recovery by w aterflooding was obtained directly from p roduction history, and the prediction of future waterflood recovery was supplied by Amoco. Pre d i c tion of tertiary oil recovery was obtained using the Doepel and Sibley procedure (1962, p. 73).
An approximated calculation of the cost for injecting the miscible fluid at the Beaver Creek-Madison Formation is i n c l u d e d .
GEOLOGY AND HISTORY
The Beaver Creek field is located in Fremont County, Wyoming, approximately 14 miles southeast of Riverton.
Fig. 1 shows the location of the field. The following is a d iscussion of the geology, history, and well designation of the Bea v e r Creek field.
Geology of Field
An examination of the structural map (Fig. 2) of the Beaver Creek structure indicates that it is a dome with a plunging nose to the north. The structure dips quite sharply to the east and south, with gentler dips to the north and west. Some faulting, present along the east flank, has had a major influence upon the accumulation of the oil in the deeper Tensleep and Madison reservoirs. The dip of the fault shown in the structural map is about 3 0 ° W . , and the strike is The formation of interest is the Beaver Creek Madison, which consists of g r a y , cherty, vugular limestone with o c c a
sional interbeds of dolomites. The entire interval shows scattered oil staining. H o w e v e r , the pay is contained in three main zones. The Madison reservoir has a m aximum oil production closure of 790 ft. The oil-effective isopach map is shown in Fig. 2a.
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History of Field
The Beaver Creek field was discovered in 1938 when Unit 1 found gas and condensate in the Cretaceous Frontier, Muddy,and Lakota horizons. The depth of these formations ranges from 6,000 to 8,000 ft. Subsequent development, after a gas market was obtained in 19^4, resulted in the discovery of oil in the Pennsylvanian Tensleep at 10,600 ft in 1949, the Cretaceous Mesaverde at 3,900 ft in 1951, and the M i s s issippian Madison at 11,200 ft in December 1953.
The Madison reservoir is at an average depth of 11,200 ft and is approximately 2 miles long and 1.5 miles wide. It is an oil-wet reservoir. This statement is based on core data plus field tests on crushed core samples (Pollock, 1973 personal c o m m u n i c a t i o n ) .
Although many Madison reservoirs in the Rocky M o untain region have a very active natural water drive, early p e r formance at Beaver Creek indicated that the natural water drive would be inadequate to maintain p r o d ucing rates and that costly artificial lift equipment would be required. T h e r e f o r e , a supplemental water injection program was chosen as the most logical method of secondary recovery. At p r e s ent, the Madison reservoir is being w a t e r f l o o d e d . Initially two wells along the edge of the reservoir were chosen for water injection. Currently there are ten injectors which form a peripheral p a ttern around the reservoir as shown on
the structure map of the field. To August 1972, 68,336,901 bbl of water has been i n j e c t e d .
The composite production curves for the field are shown in Figure 4 from 1954 to 1962, and Figure 5 from 1963 to 1972.
The stratigraphie column for the Beaver Creek Field is shown in Table I.
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RESERVOIR PARAMETERS
An accurate knowledge of reservoir parameters such as effective pay thicknesses, permeability, porosity and water saturation is invaluable to the reservoir engineer who studies the reservoir behavior. The following is the way effective pay thickness, porosity, water saturation,
and permeability were determined for the Beaver Creek-Madison.
Effective Pay Thickness
The pay thickness for each well was determined from laterojlog, sonic log-gamma ray, and electrical and micrologs. The net pay was found to vary from 20 ft at well 39 to 300 ft at well 8l. The arithmetic average pay thickness from
the different wells for the Madison Formation was determined to be 148 ft. The net pay thickness and top of the M a dison F o r m ation were obtained by using electrical and micrologs as indicated in Figure 6.
Water Saturation
For the calculation of the weighted average water sat uration, log analyses from wells No. 45, 42, 34, and 30 were made as shown in Table II. The weighted average water sat uration weighted on formation thickness for the Beaver Creek- Madison Formation was found to be 14%.
Porosity
The porosity of the m a i n pay was obtained from statis tical analysis of cores taken in wells No. 22, 31, and 32.
The arithmetic mean porosity was determined from the equation:
0 =
I
0, F
a
1=1 1 1
where 0 o = arithmetic m ean porosity, fractional 0^ = value of porosity at mid-point of i-th
interval or range
n = number of class intervals
= frequency for i-th class interval, fractional. Table III shows the calculation using the above equation. The arithmetic mean porosity and the unweighted arithmetic average porosity were calculated to be 10.59# and 10.50%, respectively. A porosity histogram for samples of Beaver Creek-Madison formation is shown in Figure 7. However, since few wells were cored and both sonic and density logs were not available on the above w e l l s , log and core p o r o s i ties were not compared.
Permeability
The arithmetic average permeability and geometric m ean permeability were obtained from a statistical analysis of the same cores used for evaluating porosity.
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The geometric mean permeability was calculated from the following equation :
log Kg = P j log(Ka )j
w h ere = geometric m e a n permeability, millidarcies Fj = frequency of j interval, fractional
(K ). = arithmetic average permeability of logarithm! a j
class interval j , millidarcies n = total number of class intervals.
Table IV shows the calculation of geometric m e a n p e r m e a b i l i t y for Beaver Creek-Madison, which was found to be
7.44 md. The unweighted arithmetic average permeability was found to be 7.2 md.
RESERVOIR FLUID STUDY
Reservoir fluid data were obtained from bottom-hole fluid s a m p l e . Table V presents the results of the PVT analysis of one sample.
The saturation pressure was determined to be 673 psig at the reservoir temperature of 232°F. This indicates that the fluid in the reservoir was highly undersaturated since the initial reservoir pressure was 5,200 psig. The solution gas-oil ratio was found to be 288 standard cubic feet of gas per barrel of stock tank oil ( F i g . 8). The formation
volume factor at the bubble point pressure was 1.3250
barrels of saturated fluid per barrel of stock tank oil (Fig. 9). The oil viscosity varied from 0.640 at initial r e s e r voir pressure to 0.470 centipoise at the saturation p r e s sure, and the oil viscosity at atmospheric pressure and reservoir temperature was found to be 0.770 centipoise. The gas viscosity varied from 0.014] centipoise at the saturation pressure to 0.0107 centipoise at atmospheric pressure (Fig. 10). The gas formation volume factor was 0.0048 reservoir bbl per standard cubic feet of gas at 673 psig.
Figure 11 shows a plot of gas formation volume factor as a function of pressure.
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RELATIVE PERMEABILITY DATA
Representative relative permeability curves (Kr Q , K ^ ) were obtained for the Beaver Creek Madison formation by means of a model, matching production h i s t o r y .
The first step in the history match was to calculate reservoir performance by using the best data available. The results were compared with the field-recorded histories of the wells. The agreement was satisfactory, following proper adjustment of the relative permeability data. The final relative permeability curves used in the match are presented in Pig. 12.
The two-dimensional sophisticated m od e l was done by Amoco (Pollock, 1973, personal communication).
DETERMINATION OF OIL IN PLACE
The oil-in-place was obtained volumetrically with the use of the following equation:
N = 77580Ah(l-Sw l )/Boi
where N = initial oil-in-place, stock-tank barrels
0
- average arithmetic mean porosity, fractional A = surface area, acresh = effective pay thickness, feet
= average initial water saturation, fractional B q ^ = oil formation volume factor at initial p r e s s u r e ,
reservoir bbl per stock-tank bbl.
7758 barrels is the equivalent of one a c r e - f o o t . The initial oil-in-place was determined to be 68,200 MSTB based on the reservoir volume of 122,727 acre ft or
556 STB per acre ft.
Table 6 shows the calculation of the net volume of the reservoir from isopachous map.
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PRIMARY AND SECONDARY RECOVERY
From December 1953 through January 1959, cumulative p r o duction was 5,998,000 bbl of oil and 582,000 bbl of water.
Pressure decreased from 5,200 psl to 4,000 psl. During this time there were 13 p r o d u c e r s . The original oil in place as calculated by volumetric method was 68,200,000 stock tank b a r r e l s .
The possibility of reducing reservoir pressure below the bubble point in an attempt to produce oil from the
tighter sections of the reservoir were considered in the laboratory. However, well capacity, lift-equipment limita tions, and the magnitude of the natural water influx were such that it would not be feasible to attempt this program.
Based on the above statement, during early development of the reservoir, it was decided to commence a supplemental wa t e r - i njection program as the most adequate method of sec ondary recovery. This program was started in 1959 by inject ing 2,000 BWPD in 2 wells. An ample supply of water for injecting is available in the field from a shallow water well (Pollock, i 9 6 0 , p. 4l).
Cumulative production by secondary recovery was 24.6 MM barrels of oil, 26,348 M barrels of water, and 7,430 MCF of gas by August 1972. During this time there were 14
pro-d u c e r s .
The prediction of oil recovery by waterflooding pro vided by Amoco is shown at the end of this s t u d y . Calcula tions indicated that the economic limit of 200 BOPD will b reached by 1996.
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MISCIBLE DISPLACEMENT
It is well known that generally more than 50 percent of the oil in place is unrecoverable by primary and second ary recovery t e c h n i q u e s . It is also known that the demand for petroleum exceeds the supply, and the gap is i ncreas ing. Most of the e a r t h ’s major oil bearing zones have already been defined, and new oil reservoirs are becoming harder to find. For this reason the reservoir engineer must try to improve the recovery efficiency of the existing oil f i e l d s .
Currently about 25 to 30 percent of U.S. oil produc t i o n is obtained by means of secondary recovery techniques.
Water flooding is the most commonly used technique for this p u r p o s e . However, due to high-water mobilities, recovery efficiencies are low and billions of barrels of oil are left within the r e s e r v o i r s .
The idea of using miscible-phase displacement to
increase recovery of crude oil has been under active study for more than 20 years. Most of this work has been carried out in the research laboratories of industry and in u n i v e r sities. In such studies a great deal of attention has been directed toward determining the amount of miscible material required to recover the m a x i m u m amount of oil from a porous
medium.
Miscible displacement is a technique which offers the possibility of recovering a sizeable amount of the oil remaining in the reservoir. Due to the miscibility of the displacing and displaced phases, the interfacial tension and the capillary forces are eliminated. As a r e s u l t , essentially all of the oil contacted by the displacing phase is r e c o v e r a b l e .
When miscible fluids are used for a tertiary recovery project, it is not necessarily true that all capillary
pressure and surface forces are reduced to zero. These forces are only reduced to zero w h e n the initial water sat uration remains immobile.
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REVIEW OF THE LITERATURE
Miscible fluid systems for the recovery of oil have been studied In the laboratory, and some field tests have been I n i t i a t e d . Whorton and Kleschnick (1950) have p r e sented experimental w ork on a dynamic system in which r e s e r voir fluid was displaced from a porous medi u m with gases at pressure above 3,000 psl. The recovery was improved by the higher mutual solubility of the phases at the higher p r e s sures with the attendant effect of reduction in the differ ence in viscosity between the displaced and displacing p h a s e s .
Brownscomble (195*0 applied the high-pressure process in West Texas and compared the estimated recoveries by lab oratory runs of this system with water flooding and natural depletion at the Block 31 Field. He concluded that increased recovery is obtained through the use of high-pressure m i s cible displacement. During the same year Offeringa and van der Poel studied the recovery of viscous crudes by miscible liquids and the subsequent recovery of the solvents by water flooding. Because of the large quantities of solvent
required, the * introduction of a circulation process reduced the amount of solvent required. Nevertheless the process is not yet e c o n o m i c .
Koch and Slobod (1956) made a laboratory study of p r o pane slug p r o c e s s . The propane displaced oil completely at one front because it was miscible with the oil, and gas d i s places the propane completely at a second front because it was miscible with the propane ; the result is a high recovery
from the area of the reservoir contacted. Blackwell and others (1958) have presented an experimental investigation in both microscopic and macroscopic levels of factors that control the efficiency with which oil is displaced from porous media by a miscible fluid. It was found that m o l e c u lar diffusion is the dominant dispersion m e c h a n i s m for r e s e r voir conditions of rate, length, and pore sizes.
Doepel and Sibley (1962) presented a comprehensive
treatment for predicting a miscible displacement performance for either monolayer of multilayer s y s t e m s . This method is more fully explained in the calculation procedure of tertiary recovery of the Beaver Creek Madison Formation. Mahaffey and Matthews (1966) outlined results of an experimental study of the sweep efficiency by miscible displacement for a five s p o t . The experiments show that very early b r eak through may be expected in miscible floods because of the unfavorable viscosity r a t i o . Thompson and Mungan (1 9 6 9 ) examined the influence of the displacement rate, fracture density, fracture orientation, fracture permeability, cross- flow, core length, and.connate water on the oil recovery in
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fracture systems under miscible conditions. It was found that displacement rate, matrix permeability and the sub vertical fractures affected oil recovery most.
Lantz (1970) shows how a method by which two- and three-phase reservoir simulators can be made to calculate miscible displacement rigorously. The above method is not necessarily correct for the reservoir. The only r e q u i r e ment of the method is that relative permeability and capil lary pressure be special functions of saturation. Chaudhari
(1971) presented a numerical technique for solving m u l t i dimensional miscible equations. The procedure was developed for one- and two-dimensional systems. He also shows that this method can be extended to a three-dimensional system. In summary, miscible displacement techniques have developed to the point at which it does not appear u n r e a s o n able to think that in the near future they will be more generally accepted. However, not much data are available to show that this technique is practical or economical at this time.
A collection of abstracts of references in a l p h a b e t ical order by various authors is described in Appendix B.
LABORATORY STUDIES
Miscible Fluid Tests
Miscible displacement studies were carried out for the Beaver C r e e k - M a d i s o n .
Results of laboratory tests by Amoco indicated that the injection fluid (75% propane and 25% methane) and the oil in place would reach miscibility at a pressure of 2689 psia at the reservoir temperature of 232°F. Fluid com p o s i tions are shown in Table VII. Table VIII shows the d i s p l a c e ment fluid composition, and Table IX shows the results of the t e s t .
E R 1 5 6 7
19
TERTIARY RECOVERY
In this study it is assumed that the water saturation at the beginning of injection remains immobile and will not be displaced by injected f l u i d s . With this assumption, it should be noted that the calculated recoveries would be
optimistic. However, a displacement efficiency suggested by Jones (1973a personal communication) was included in part to account for the effect of the movable water on the dis p l a c e ment efficiency of the injected fluids. The displacement efficiency can be expressed as:
E _ Soi t ” Sor D "
where E^ = displacement efficiency, fractional
= oil saturation at the start of tertiary recovery, f r a c t i o n a l , 0.47
SQr = residual oil saturation, from relative p e r m e a b i l ity c u r v e , fractional, 0.094.
. The oil saturation at the start of tertiary recovery was found as an average of the oil saturation in the different areas of the reservoir as shown in Figure 3. These values were 43% in the areas inside and outside of the patterns with w a ter cuts greater than 9 0 %, 48% in the area b etween 90-80% water cut, 53% in the area between 80-70% water cut, and 82% in the area less than 70% water cut. The saturation in the
k Q
averaging of saturations determined as function of
r—
, Sw Kwand fw as shown in Figure 13 based on production data as of August 1972.
Since below - 6 s 200 ft datum no oil will be recovered by any kind of injection p rogram because the oil in place is too small to support the cost of a well, C.B. Pollock (1973, personal communication) the above portion of the reservoir was not considered in this study.
From existing wells the patterns were 3 five spot and 2 direct line drive. Figure 3 shows the different patterns and the portion of the reservoir which will be covered by the tertiary flood.
The tertiary performance from miscible displacement for the Beaver Creek-Madison Formation was calculated considering 12,473 MSTB of oil in place, and an oil saturation of 47% and a reservoir pressure of 2,000 psig.
The oil in place at the beginning of tertiary recovery was calculated adding the oil volume contained in the d i f f e r ent regions according with the patterns.
No attempt was made to calculate performance as explained by Davis and Jones (1968, p. 1415), upon personal r e c o m m e n d a tion of Jones, due to the following main reasons :
a) They 'assume perfect homogeneous media.
b ) Their technique was developed mainly for the cases in which a polymer is used as a displacement f l u i d . Jones considered that the use of this method when
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21
Injecting propane, would result In very optimistic and unrealistic a n s w e r s .
c) Their equations require the use of parameters which can be determined only by means of sophisticated laboratory techniques. Without these d a t a , Jones considered that answers could be given based on assumed guesses. He suggested that the Doepel and Sibley meth o d with the inclusion of the correction factor discussed previously, would give a more r eal istic answer for the Beaver Creek-Madison Formation.
Displacement Fluid Injection
The reservoir study was made by continuous miscible
injection until 3 hydrocarbon pore volumes plus 27^,428 bbls of the displacement fluid were injected.
The amount of displacement fluid injected in reservoir barrels was calculated from the equation:
v d = V P x * 1
where = displacing fluid injected, reservoir barrels Vp = hydrocarbon pore volume, reservoir barrels q^ = displacement phase injection, fraction of
hydrocarbon pore volume.
Oil Recovery Factor
Total recovery factor were found for the Beaver Creek- Madison Formation using a five spot and line drive p a t t e r n s , since these arrangements can be obtained utilizing the p r e s ent well configuration. Recovery is a function of mobility
volume of displacing fluid as explained by Doepel and Sibley (1966, p. 77). Figure 14 is a plot from which values of
recovery were read for the five spot pattern and then applied to the following equation:
R !c = R ee x ( 4 ^
where R * c = recovery factor for the five spot p attern for each pore volume of solvent injected
R ec = recovery read from figure 14 S . , — S
(_2i--- — ) = displacement efficiency, 0.8 oit
Oil recovery factor for the line drive pattern were obtained as follows :
R ec.L.D. = CA.L.D. X Cv x ED
where R^ T n = line drive recovery, fractional
S C ft Li • JJ •
Ca l d " areal coverage corrected line drive = average areal coverage five spot x
/Single layer line drive c o v e r a g e ^ single layer five spot coverage Cy = vertical coverage, fractional
Ep = displacement efficiency, 0.8
Table XI shows the figures used in the calculation of oil recovery factors used in Table XII.
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Mobility Ratio
The mobility ratio of the Beaver Creek-Madison is defined with the use of the equation :
„ . ' V ' * >
where M = mobility ratio
= permeability to displacing phase, md Kq = permeability to oil, md
= permeability to water, m d
= viscosity of the displacing fluid, centipoise yo = viscosity of the oil, centipoise
u = viscosity of the water, centipoise
Assuming immobile water, the above equation was simplified as follows :
The oil viscosity was found by Amoco to be 0.558 c e nti poise at reservoir temperature of 232°F and miscibility pressure of 2,689 p s i g . The displacing fluid viscosity was determined to be 0.036 centipoise at 232°F and miscibility pressure of 2,689 psig from graphs prepared by Craft and Hawkins (19 5 9 » p . 265). With the use of these p a r a m e t e r s , the mobility ratio was determined to be 15.5 for oil-solvent p h a s e .
The permeability variation was determined as follows (Law, Standing, Dykstra and P a r s o n s ).
a) Permeabilities were tabulated in descending order with their corresponding cumulative frequencies
(Table X ) .
b) Permeabilities and cumulative frequencies were plotted on log-probability graph paper (Figure 16). c) The best straight line was drawn through the
central points.
d) The following equation was used to determine the permeability variation :
v = |K 50 ~ * 8 4 . 1 1 K 50
where V = permeability variation, fractional
Kj-q = permeability at 50% of cumulative frequency, md. (on straight line)
Kgij ^ = permeability at 84.1% of cumulative frequency, md. (read from the straight line).
According to the above equation, the permeability variation for the Beaver Creek-Madison Formation was found to be 0.80.
Oil Recovery
Oil recovery from miscible displacement of the Beaver Creek-Madison Formation was determined by calculating oil in place at the moment of initiating the tertiary recovery p r o ject in each one of the patterns, and the application of the
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values found In the equation :
\
= NF.S. X ^R , F *^F.S. + NL.D. X fR -P ->L.D. where = oil r e c o v e r y 3 barrelsNp g = oil In place at the initiation of tertiary
project in the five spot pattern, 8.651 MM STB (R.F.)p g = recovery factor of the five spot pattern,
fractional
p = oil in place at the initiation of tertiary
project in the line drive pattern, 3.822 M M STB (R.F.)^ p = recovery factor of the line drive pattern,
f r a c t i o n a l .
Oil Production Rate
The average oil production rate was calculated with the following equation:
^q o ^ a v g = q F. S . x ^R e e V . S . + q L . D . x ^ e c ^ L . D .
where (qo )aVg = average oil production, STB/dayqp S = total pro d u c t i o n rate from five spot, STB/day (R eC )F
s
= °^-1-Production
from five spot for each porevolume injected, fractional
qL D = total p roduction rate from line drive, STB/day ^R ec^L D ” production from line drive for each pore
The gas production rate was calculated assuming an
injection and production rate of 16,000 res bbl/day with the use of the following equation:
^ g ^ S C F / d a y = t:L6’0 0 0 " (qo )avg x B o^
* ' Ç ] 5 61 * ‘’o ' * -where CQg)SCF/day = gas Production, SCF/day
16,000 = production rate, res bbls/day
Bq = oil formation volume factor, res. b b l s/STB 0.75 = composition of propane in the injection
fluid, moles
0.25 = composition of methane in the injection fluid, moles
R g = solution gas-oil ratio, SCF/STB
Bgp = propane formation volume factor, r e s . bbls/STB
Bgm = methane formation volume factor, r e s • bbls/STB
5 . 6l = cubic feet per bbl.
Column 12 of Table XII shows the gas production rate calculations. The remaining columns of Table XII are self- explanatory.
The performance plots for the Beaver Creek-Madison F o r m a t i o n consist of average oil production rate (Figure 16), gas p roduction rate (Figure 17), cumulative oil production
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27
(Figure 18), dollars generated from the oil recovery, and dollars expended for solvent (Figure 19) as a function of t i m e .
A production rate comparison of A m o c o 's forecast by w a t e rflooding and the prediction computed in this study by miscible displacement is shown in Figure 19. These fore casts indicate that continued waterflooding will result in the additional recovery of 8.5 MM STB in 24 years. If water- flooding were stopped and miscible injection initiated, it would result in a recovery of 4.2 M M STB in 8.27 years.
Figure 19 illustrates that the injection of 274,428 bbls of solvent to establish miscibility prevents the project from ever generating more money than is expended.
It is evident from the above results and from Figure 19 » dollars generated from the oil recovery and dollars expended for solvent, that a miscible displacement project is not feasible for the Beaver Creek-Madison Formation.
Appendix A is an approximated calculation of the cost for injecting the miscible fluid at the Beaver Creek-Madison Formation.
CONCLUSIONS AND RECOMMENDATIONS
The purpose of this study was to determine the adv i s a bility of tertiary recovery at the Beaver Creek-Madison Formation. Calculations indicated that a miscible dis placement project is not feasible.
In conclusion, because of the initial investment for the tertiary miscible project without increase in oil recovery this project is not feasible, and it is r e c o m mended to continue with the present waterflooding project at the Beaver Creek-Madison Formation.
ER 1567 29
BIBLIOGRAPHY
Amyx, J. W . , B a s s , D. M . , and Whiting, R . , I960, Petroleum reservoir engineering : New York, McGraw-Hill, 610 p. Blackwell, J. R . , and Rayne, J. R . , 1953, Factors influencing
the efficiency of miscible displacement : Pet. Trans, series, no. 8, p. 196-204.
B r o w n s c o m b l e , E. R . , 1954, A t l a n t i c ’s high-pressure gas p r o cess being used in West Texas block 31 field: Oil and Gas J o u r . , v. 5 2 - 5 3 » p. 133, 135•
C h a u d h a r i , N. M . , 1971, A n improved numerical technique for solving multidimensional miscible displacement equations: T r a n s . AIME, v. 251, p. 277-284.
Craft, B. C ., and Hawkins, M. F . , 1959, Applied p e t r oleum reservoir engineering : Englewood Cliffs, Prentice-Hall, 437 p.
Doepel, G. W . , and S i b l e y , W. P., 1962, Miscible displacement - a m u ltilayer technique for p redicting reservoir p e r formance : Jour. P e t . Tech., p. 73-30.
Dykstra, Herman, and P a r s o n s , R. L . , 1950, The secondary recovery of oil in the United States : Am. Petroleum I n s t ., p. 160-173*
H u r s t , W . , and V a n Everdingen, A., 1946, Performance of distillate reservoirs in gas cycling : T r a n s . AIME, v. 165, p. 36-50.
Koch, H. A., and S l o b o d , R. L . , 1956, Miscible slug process : Pet. T r a n s . Reprint, no. 8, p. 143-150.
Lantz, R. B . , 1970, Rigorous calculation of miscible d i s p l a c e ment using immiscible reservoir simulation: Trans.
AIME, v. 249, P* 192-202.
Mahaffey, J. L . , and Matthews, C. S., 1966, Sweep efficiency by miscible displacement in a five-spot: T r a n s . AIME, v. 237, P* 73-80.
Offeringa, J., and van der Poel, C.j 1954, Displacement of oil from porous media by miscible liquids: P e t . T r a n s . Reprint no. 8, p. 227-237*
Pollock, C. B . , i 9 6 0 , Beaver Creek Madison, W y o m i n g ’s d e e p est water injection project: Jour, -et. Tech., p. 39-41.
S c h l u m b e r g e r , 1962, Log interpretation chart book: Houston, Schlumberger Well Surveying Corporation.
Smith, C. R . , 1966, Mechanics of secondary oil recovery : New York, Reinhold, 504 p.
Thompson, J. L . , and M u n g a n , N . , 1 9 6 9 , A laboratory study of gravity drainage in fracture systems under miscible conditions : T r a n s . AIME, v. 246, p. 247-254.
Whorton, L. P., and Kieschnick, W. P., 1950, A preliminary report on oil recovery by high-pressure gas injection: Drilling and Production Practice, API, p. 247-257•
ER 1567 31
T a b l e I - Stratigraphie Section of the B e a v e r Creek Field
Time Period F o r m ation
ME E T E E T S E M E S A VERDE CODY FR O N T I E R CRETACEOUS M O WRY MUDDY THERMO P O L I S 8 CLOVERLY-MORRISON 8 Es JUR A S S I C SUNDANCE GYPSUM SPRINGS TRIASSIC NUGGET C H U G W A T E R DINWOODY PERMIAN P H O S P H O R I A T E N S L E E P PENNSYLVANIAN AMSDEN 8 D A R W I N 8 S MISSI S S I P P I A N M ADISON
T a b l e II - W e i g h t e d A v e r a g e W a t e r S a t u r a t i o n B a s e d on L o g A n a l y s e s . W e l l 4 2 . in . > CM OO •=r no CM CO 1—1 1—1 t—1 rH 1—1 0 1—1 CM X P 1—1 CM 1—1 H 1—1 P: P^ •• • Ph VO in -=r CO OX CO * -=r -=3" no no no P-l pH 1 1 1 1 1 VO co CM no • . . . ■=r 1—1 r—l 1—1 rH rH 0 t>- no ox •Hi E 0 1—l ox no 1—1 K 1PC CM CM 1—1 CM CM PL, CO in CO ox CO co CM CM CM CM CM PH 1 1 1 1 1 O 0 O 0 O -P vo 0 O 0 in tr; ■=d_ 1—1 H™ vo vo in 1—1 0 . . X 1—1 CM in CM 0 Pd in CM rH vo ol 0 0 in t— 0 0 X E t-- t— 1—1 -=r 0 p^ 1PC 1—1 CM 00 CO co co CO vo no vo I 0 • » . CXJ E CM o\ 1^ CO CM K ll2T 1—1 1—1 I 0 vo no H Ë O . vo • O Ph Ic1C H vo vo rH CO co 1—1 -=r CO CM • . • . . CO CM CM CM no CO OX rH • . K no CM 1—1 1—1 no no -=r t-- t— no —1 vo vo OO 1—1 -=r cti I l 1 1 1 > -=r * vo in O 0 P in in vo O no A Q) 1— 1 CM CM no no <U P ** * * « Q c rH 1—1 H 1—l H H H rH H 1—1 1—1 co CO Il II
I
Q)U
Q)
0) O <d o, to <u n o E E Cu É É p to XI e XI O <U 0 1 0 XI E • P Ü ». XI > » C PI >1 0 S >1 Q •H p p O rH •H ». > >1 rH > b b <D •H p (d •H 0 0 rH P •H •H P P Û4 0 to > P to ü XI *H •H e •H id » to P QJ to p PI <D O to p <D O x: SH •H 0 b pi •H p to a 0 P <U 0) <D •H id p c b to PI P b 0 0 0 O O 3 N ti 0 N Q) P b O <D b id <u •y •H c 13 b to p (U P fd 0 0 V XI rd p 13 U b e w Ë pi id 0 cd 5 b 0 > P •H rH 0 04 c II id *0 P P to •H 5 b II II II 11 II 0 II P 0 PW O X P tn ■H id 5 13 P5 PH P3 inER 1567 33
Table III - Classification of Porosity Data
Porosity Range N u m b e r of Samples Mid-value of Range, % 0i Frequency Fraction Fi 0i L e s s t han 4 18 3 0.1500 0.4500 4 - 6 1 2 5 0.1000 0.5000 6 - 8 1 5 7 0.1083 0.7581 8 - 1 0 20 9 0.1666 1.4994 10 - 1 2 17 11 0.1416 1.5576 12 - 14 8 1 3 0.0666 0.8658 14 - 16 7 15 0.05 8 3 0.8745 16 - 1 8 6 17 0.0500 0.8500 18 - 20 9 19 0.0750 1.4250 20 - 22 6 21 0.0500 1.0500 22 - 24 4 23 0.0333 0.7659 A r i t h m e t i c mea n porosity ” 2 i * i ~ 1 0 . 59
.Table I V - Geometric M ean Permeability of the B e a v e r Creek Madison P e r m eability Average Range Permeability (Millidarcies) (Ka ) j Numb e r of Samples Frequency Fraction Fd Cumulative Frequency F j l o g U a 1.31 - 2.5 1.90 11 0.2391 0.2391 0.0667 2.6 - 5.0 3.80 11 0.2391 0.47 8 2 0.1386 5.1 - 10.0 7.5 8 0.1739 0.6521 0.1522 1 0 . 1 - 20.0 15.0 6 0 .1304 0.7825 0.1534 20.1- 40.0 30.0 4 0.0869 0.8694 0.1234 40.1- 80.0 60.0 6 0 .1304 0.9 9 9 8 0 .2319
Ta
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ER 1567 35 d 5 0 ■P H 60 CO ^ - g rH «H •H tQ O <D œ O OII
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en cv cv cv cv rH rH H 0• 0 O 0 0 O O O O O • • e 0 e O 0 O 0 O O O O O O r~i§
m m cn O inm 8 H8
t> t> to O' O rH cv CV cv CV en cn e e # 0 e rH H rH H H H a OH HO HO OH rHO in in in in m m cn» cn O cn cn cn e e •6
0 O O O 0 O & S cnE' g « O en to cv vO 0 E' in9
0 t> cv en rH rH O • • e • 0 O 0 O O O cv to m rH r- cn E' cn Q VJD rH \D en rH H p O cn r- E" E^ sO e • • • e e O O O 0 O O O O O 0 O O O O O 0 O O O in O m O m *» «* #» en cn cv CV rH O O 0 cn m Q H cv rH en cn cn ^ ♦ e H rH rH O O O H H rH in in m cn cn cn • 0 0 0 03
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o o O O in in O O O Q m 0 in m in O -<t cn O to E- in cn rH to E-- 0 c- in NO NO NO in m m in m -j- <!• -<r in in NO • • e e * # • e • e O O O O O O O O 0 O O O O O to C- O E- to 1> cn H m in cn mO £> O NO m to 0 8 O O NO cn E--in en cn 0 cn -Sf en to NO cn -<t E'- to cn rH cn cn O to in 0 • • • # • » e to O O O 0 rH rH rH cn -<r in to rH -N§
o \D in H g în o g gI
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14 .7 0 .7 5 2 3 0 .0 0 2 7 5 0 .9 5 1 0 1 .0 9 5 0 9 9 9 9 .0 0 .7 7 0 0 .0 1 0 7Table VI - Calculation of Net Volume of the Reservoir from Isopachous Map.
Productive Planimeter Area Ratio of Interval Equation V
Area Reading* Acres Areas ft Acre-ft
0 3.639 793 50 2.889 630 0.79 50 TRAP. 35,575 100 2.498 545 0.86 50 TRAP. 29,375 150 1.951 425 0.77 50 TRAP. 24,250 200 1.495 324 0.76 50 TRAP. 18,725 250 0.576 126 0.38 50 PYR. 10,866 300 0.182 39.6 0.31 50 PYR. 3,936 122,727
* For a map scale of one inch = 1, 000 ft;
ER 1567
T a b l e H I - Fluid Compositions
S eparator Oil A v a i l a b l e .Field Gas (35 psia & 90 °F)
Component Mol P e r Cent Component Mol P e r Cent
C1 0.05 n2 0.51 ° 2 0.57 0 0 no 0.33 C j 1.91 Cl 92.55 i C4 1 . 0 0 c 2 5 . 1 0 1104 2.92 C 3 1.41 n C 5 1.97 i C 4 0 . 0 2 C 6 6.57 n C 4 Tr. C7+ 82.54 C 7 + Mol. Wt. C 7 + Sp. Gr. C 5 + Mol. Wt. 1 8 3 0.8379, API 37.4 171
T a b l e VIII - Displacement F l uid Composition
Component Mol P e r Cent
N2
0.013
CO g
0 .0 0 8
C l
0 .2 3 5
c
2
0 .0 1 3
C
3
0 .7 5
iC
4
0 .0 0 0 0 5
nC4
0 .0 0 0 2
ER 1567 39
T a b l e IX - M i n i m u m Propane Requirements for Mi s c i b i l i t y Pre s s u r e P s i a M a x i m u m Mole fo Ci + Ng Propane Requirements Moles/Moles Inj. Gas 2,500 0.508 0.8 3 8 2,689 0.519 0.75 3,000 0.579 0 . 6 1 3 3,500 0.650 0.448 4,000 0.710 0.317 4,500 0.718 0.198 R e s e r v o i r T e m p e r a t u r e - 232 °F
T a b l e X » Vertical Distribution of Permeability
A verage Thickness Frequency Cumulative
P e r meability Feet Fraction Frequency
O f Range M i l l idarcies 60 6 0.130 0.130 30 4 0.087 0.217 15 6 0.130 0.347 7.5 8 0.17 3 0 . 5 2 0 3.8 11 0.240 0 . 7 6 0 1.9 11 0.240 1.00
T a b l e X I . * L i n e D r i v e O i l R e c o v e r y F a c t o r ER 1567 41 >»
u
<D > 0 • t' t^- in CXJ VO o x LfX -=3- rH 1—1 t" - CM 0 0 en t - On CM •=r t— rH m CO OX 1—1 on vo 0 cd 0 0 O 1—1 1—1 iH CM CM CM CM on on PS b • . • • • • • • • • PL 0 0 O O 0 O O O O O 0 0 <D h0| (ti <D >O
O in <d w >) cd 0 1—1 bO C •H 00 0 0 > •H U * 1-^0* 0 -P > o * •H CL* Ph CO 1—I -P cd O 0 CL SL CO < 0 > •H 0 bO-^ cd on > ^ bD O c\j > o ^<
1—I 0 cd bO 0 O > o 0 0 O 0 0 O LfX CO on t — CO o x 1—l CM on -=r LfX VO t— CO o x o x o x o x 0 O 0 0 O O O O 0 0 0 0 t — LfX O t— LfX OX t — CM 0- 0 -=3" CO 1—1 CM -=r •=r LfX LfX vo t~ - t— CO CO CO 0 O 0 0 O 0 0 0 0 0 0 0 LfX t— LfX o x CM on LfX on LfX VO t-. o x CO ■=r .=3- LfX LfX VO VO VO VO VO VO VO VO VO 0 O O O 0 O 0 0 0 0 0 0 • CL 0 cd t — CM h - OX CM -=3- CO O -=r LfX OX -=3" •H in rH CM CM CM o n o n on -=T -=3* ■=T -=d" LfX on p 0 * • • • • . • a • • a a a u > O O O O 0 0 O O 0 O O O CO CXJ o >> Ph 0 > P O O O CL 0 CO PS 0 > •H rH •H O CO CM VO CO 0 CM -=3" vo OX O -=3" c^-0 1—1 1—1 1—1 CM CM CM CM CM on on o n 0 O 0 0 O O O O O 0 0 0 Ah H <H i—I cd o Ci rH c rH CM on -=r LfX VO CO O CM LfX O O 0 • > O O O 0 0 O O O H rH rH CM on * F r o m D o e p e l a n d S i b l e y ( 1 9 6 2 , p . 7 7 * * F r o m D o e p e l a n d S i b l e y ( 1 9 6 2 , p . 7 4 * * F r o m H u r s t a n d V a n E v e r d i n g e n ( 1 9 4 6T a b l e X I I - C a l c u l a t i o n of T e r t i a r y R e c o v e r y f r o m M i s c i b l e D i s p l a c e m e n t >a z-n U 0 in 0 > CXJ. 1—1 1—1 in 1—1 -=r rH E— ■=r OX in CXJ t> *H •=T LfX vo E' CXJ ox OX CO ox rH CXJ in O U X on H en H CXJ OO VO vo •=J- CO rH ^ o f t f t n rx •> •X •* Cl •X •X «> Cl Cl VO 0 E-I 1—1 ^r on vo OO 0 1—1 in in CXJ vo OX v - z f t 0 CO f t ■=r OX vo vo in 0 CXJ in on rH -=r vo £ rH CXJ on -=r in vo CO ox 0 rH rH cxj H iH f t •H f t % O 1—1 1—1 1—1 1—1 <D H >a > Cd *H C 0 ^ 0 1—1 t> Q »H in 1-1 o -p ^ 0 0 0 0 <u S cd « i-t Jh t' E~- in CXJ vo CO in -=r 1—1 1—1 0 CXJ en E"— ox ou -=r t- rH in 0 - ox 0 on 0 O 0 1—1 rH 1—1 CXJ CXI CXI CXI on on
0 O 0 0 O 0 O 0 0 0 0 0 1 > PQ O (D Eh m o > co ^ \ 0i-| X -=r pd ^ v_^ -p co H >a O • •H Ph ft fe O 0 CO S >a O Cd 0 CO on «h 0 iH 00
