Decline curve analysis of oil production in low permeability reservoirs with great heterogeneity

2008 ◽  
Author(s):  
Da Huo ◽  
Li Li ◽  
Xiaodong Fan ◽  
Yanmin Yu ◽  
Kewen Li
Keyword(s):  
Oil Production ◽  
Curve Analysis ◽  
Low Permeability ◽  
Decline Curve Analysis ◽  
Decline Curve ◽  
Great Heterogeneity ◽  
Low Permeability Reservoirs

A Decline Curve Analysis Model Based on Fluid Flow Mechanisms

2005 ◽  
Vol 8 (03) ◽  
pp. 197-204 ◽  
Author(s):  
Kewen Li ◽  
Roland N. Horne
Keyword(s):  
Fluid Flow ◽  
Linear Relationship ◽  
Relative Permeability ◽  
Oil Recovery ◽  
Single Phase ◽  
Oil Production ◽  
Curve Analysis ◽  
Production Data ◽  
Decline Curve Analysis ◽  
Decline Curve

Summary Decline-curve-analysis models are used frequently but still have many limitations. Approaches of decline-curve analysis used for naturally fractured reservoirs developed by waterflooding have been few. To this end, a decline-analysis model derived on the basis of fluid-flow mechanisms was proposed and used to analyze the oil-production data from naturally fractured reservoirs developed by waterflooding. Relative permeability and capillary pressure were included in this model. The model reveals a linear relationship between the oil-production rate and the reciprocal of the oil recovery or the accumulated oil production. We applied the model to the oil-production data from different types of reservoirs and found a linear relationship between the production rate and the reciprocal of the oil recovery as foreseen by the model, especially at the late period of production. The values of maximum oil recovery for the example reservoirs were evaluated with the parameters determined from the linear relationship. An analytical oil-recovery model was also proposed. The results showed that the analytical model could match the oil-production data satisfactorily. We also demonstrated that the frequently used nonlinear type curves could be transformed to linear relationships in a log-log plot. This may facilitate the production-decline analysis. Finally, the analytical model was compared with conventional models. Introduction Estimating reserves and predicting production in reservoirs has been a challenge for many years. Many methods have been developed in the last several decades. One frequently used technique is the decline-curve-analysis approach. There have been a great number of papers on this subject. Most of the existing decline-curve-analysis techniques are based on the empirical Arps equations: exponential, hyperbolic, and harmonic. It is difficult to foresee which equation the reservoir will follow. On the other hand, each approach has some disadvantages. For example, the exponential decline curve tends to underestimate reserves and production rates; the harmonic decline curve has a tendency to overpredict the reservoir performance. In some cases, production-decline data do not follow any model but cross over the entire set of curves. Fetkovich combined the transient rate and the pseudosteady-state decline curves in a single graph. He also related the empirical equations of Arps to the single-phase-flow solutions and attempted to provide a theoretical basis for the Arps equations. This was realized by developing the connection between the material balance and the flow-rate equations on the basis of his previous papers. Many derivations were based on the assumption of single-phase oil flow in closed-boundary systems. These solutions were suitable only for undersaturated(single-phase) oil flow. However, many oil fields are developed by waterflooding. Therefore, two-phase fluid flow (rather than single-phase flow)occurs. In this case, Lefkovits and Matthews derived the exponential decline form for gravity-drainage reservoirs with a free surface by neglecting capillary pressure. Fetkovich et al. included gas/oil relative permeability effects on oil production for solution-gas drive through the pressure-ratio term. This assumes that the oil relative permeability is a function of pressure. It is known that gas/oil relative permeability is a function of fluid saturation, which depends on fluid/rock properties.

scholarly journals PENGARUH SCALE TERHADAP PRODUKTIVITAS PADA SUMUR BN-52, BN-104, DAN BN-110 DI LAPANGAN “X”

PETRO ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 14
Author(s):  
Abhikama Pradipta ◽  
Lestari Lestari ◽  
Samsol Samsol
Keyword(s):  
Flow Rate ◽  
Oil Production ◽  
Maximum Flow ◽  
Stability Index ◽  
Curve Analysis ◽  
Maximum Flow Rate ◽  
Well Production ◽  
Decline Curve Analysis ◽  
Decline Curve ◽  
Index Value

<p><em>BN-52, BN-104, and BN-110 wells are located on the X field, PT. PERTAMINA FIELD RAMBA ASSET 1, South Sumatra. The three wells are oil-producing wells in field X. Using the Vogel equation, the IPR curve and maximum flow rate of each well are obtained, which are 152.14 BOPD, 57.2 BOPD, and 53.76 BOPD respectively. By using the exponential Decline Curve Analysis calculation method, it can be seen the rate of decline in production, as well as the time of well production to economic limit. The results of the Decline Curve Analysis show that the BN-52 well will still be in production until March 2022, and the BN-110 well can produce until March 2020. In the analysis with the Stiff &amp; Davis Method, carbonate deposits are proven, with each Stability Index value  +1.19, +1.60, and +1.35, whereas with the Skillman, Mcdonald &amp; Stiff method there was no scale sulfate, with S values of each well at 57,272 meq / l, 54,416 meq / l, and 55,147 meq / l. The scale causes oil production to decrease, consequently the IPR curve shifts to the left. The decreasing production of the three wells is due to a scale that inhibits the flow rate. Maximum flow rate was obtained by using the Standing correlation in each well of 100.06 BOPD, 54.53 BOPD, and 28.72 BOPD. The decline in oil production caused by scales must be handled appropriately.</em></p>

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