Difference between revisions of "Reciprocal Rate Method"

From wiki.pengtools.com
Jump to: navigation, search
(→‎Workflow)
(→‎Discussion)
Line 47: Line 47:
 
*single [[Well]] [[EUR]]
 
*single [[Well]] [[EUR]]
 
*single [[Reservoirs| Reservoir]] [[EUR]].
 
*single [[Reservoirs| Reservoir]] [[EUR]].
 +
 +
[[Reciprocal Rate Method]] can be used for fracture and refracture analysis, sidetrack analysis etc.
  
 
==Case Study==
 
==Case Study==

Revision as of 21:07, 28 May 2018

Brief

Reciprocal Rate Method - is the method to estimate oil Wells and Reservoirs EUR using only rate-time production data[1] published in 2007 by Thomas Blasingame et al.

The methodology does presume that flowing well bottomhole pressures are approximately constant[1].

The interpretation technique is fitting the data points with the straight line to estimate the slope which gives EUR.

ReciprocalRateMethod.png

Reciprocal Rate Method in the E&P Portal

Math & Physics

The total pressure drop at the wellbore is:

\Delta P =P_i - P_{wf} = (P_i - \bar{P}) + (\bar{P}-P_{wf})

Where:

P_i - \bar{P} = m_{mb} N_p, is pressure drop due to depletion defined by the Oil Material Balance for black oil at P>Pb,
\bar{P}-P_{wf} = b_{pss} q_o, is pressure drop due to Darcy's law

Where:

m_{mb} = \frac{B_o}{N c_t B_{oi}}
b_{pss} = \frac{141.2 \mu_o B_o}{k_o h J_D}

The total pressure drop at the wellbore now can be rewritten as:

\Delta P =P_i - P_{wf} = m_{mb} N_p + b_{pss} q_o

Dividing both sides by the assumed constant: \Delta P =P_i - P_{wf} = P_{con} = constant [1]:

1 = m_{mb}^' N_p + b_{pss}^' q_o

As the flowrate decreases to zero (i.e., qo → 0)[1]:

\lim_{q_{o}\rightarrow 0} N_p=\frac{1}{m_{mb}^'}= EUR

Therefore a plot of 1/qo versus Np/qo yields a straight-line trend where the slope of the line is inversely proportional to the EUR[1].

Discussion

Reciprocal Rate Method can be applied to estimate:

Reciprocal Rate Method can be used for fracture and refracture analysis, sidetrack analysis etc.

Case Study

This Case Study demonstrates the application of the Oil Flowing Material Balance engineering technique using the E&P Portal.

The Study is based on the oil well from a field in West Siberia, Russia.

It is shown how to:

  • Input the data to the E&P Portal;
  • Apply the Oil FMB to estimate the well's STOIIP and JD;
  • Save and export the analysis results.

All the input data is attached to the Case Study for the reference.

OilFMB Case Study.png

Download Case Study (pdf)

Download the input well production data (csv)

Workflow

  1. Upload the data required
  2. Open the Reciprocal Rate Method tool here
  3. Fit data with the red trend line
  4. Calculate the slope of the line and EUR
  5. Save the Reciprocal Rate Method model
  6. Move to the next well

Data required

In case you need to calculate the flowing bottomhole pressure from the wellhead pressure:

In case you want to add the static reservoir pressures on the FMB Plot:

Nomenclature

B_{o} = oil formation volume factor, bbl/stb
B_{oi} = initial oil formation volume factor, bbl/stb
b_{pss} = reservoir constant, inverse to productivity index, psia/stb/d
b_{pss}^' = \frac{b_{pss}}{P_{con}} = reservoir constant, inverse to productivity index, 1/stb/d
c_t = total compressibility, psia-1
J_D = dimensionless productivity index, dimensionless
k_oh = oil permeability times thickness, md*ft
m_{mb} = slope term, psia/stb
m_{mb}^' = \frac{m_{mb}}{P_{con}} = slope term, 1/stb
N = stock tank oil initially in place, stb
N_p = cumulative oil production, stb
\bar{P} = average reservoir pressure, psia
P_{i} = initial pressure, psia
P_{con} = constant, psia
P_{wf} = well flowing pressure, psia
q_o = oil rate, stb/d

Greek symbols

\mu_o = oil viscosity , cp

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 Blasingame, Thomas Alwin; Ilk, Dilhan; Reese, Parker D. (2007). "Estimation of Reserves Using the Reciprocal Rate Method"Free registration required (SPE-107981-MS). Society of Petroleum Engineers. 
Retrieved from "https://wiki.pengtools.com/index.php?title=Reciprocal_Rate_Method&oldid=3889"