Merge branch 'next-major-release' of https://github.com/OPM/ResInsigh…

…t-UserDocumentation into next-major-release

content/getting-started/download-and-install/build-instructions-ubuntu.md

@@ -61,7 +61,7 @@ Open a command prompt for Visual Studio x64
     cmake \
     -DRESINSIGHT_ENABLE_GRPC=true \
     -DVCPKG_TARGET_TRIPLET=x64-linux \
-    -DCMAKE_TOOLCHAIN_FILE=..ThirdParty/vcpkg/scripts/buildsystems/vcpkg.cmake \
+    -DCMAKE_TOOLCHAIN_FILE=../ThirdParty/vcpkg/scripts/buildsystems/vcpkg.cmake \
     -DRESINSIGHT_GRPC_PYTHON_EXECUTABLE=python \
     ..
 

content/plot-window/DeclineCurveAnalysis.md

@@ -0,0 +1,96 @@
++++
+title = "Decline Curve Analysis"
+published = true
+weight = 80
++++
+
+
+
+## Create Decline Curves
+
+Decline curves can be created from the right-click menu for a curve in the **Plot Project Tree**.
+
+
+
+## Origins
+
+J.J. Arps [[1]](#1) concluded that the decline in oil production rate ($q_i$) over time can be described by these equations:
+
+$$\frac{ 1 }{ q_0 }  \frac{\partial q_0}{ \partial t}  = -D$$
+
+where the decline rate, $D$ is a time-dependent function:
+
+$$D = \frac{D_i}{1+bD_i t}$$
+
+where:
+
+- $q_0$ is the production rate (e.g. oil production) in a unit of choice (e.g STB/day)
+- $t$ is the time
+- $D$ is the time dependent decline rate
+- $D_i$ is the initial decline rate (constant)
+- $b$ is a dimensionless constant (typically used as a tuning parameter to match actual field data) and is in the range of $ 0 <= b <= 1 $.
+
+The equations can be used to forecast future reservoir and well production.
+
+Based on the value of $b$ in the function, Arps classified the decline curves into three types:
+ - The exponential decline has $b = 0$.
+ - The harmonic decline has $b = 1$.
+ - The hyperbolic decline has $b$ ranges between 0 and 1.
+
+## Rate-Time Decline Curves
+
+
+### Exponential Decline
+
+Exponential decline is the production decline when $ b = 0 $. This gives a constant decline  ($D_i = D$).
+
+$$q_0 = q_i e^{-Dt }$$
+
+### Hyperbolic Decline
+
+$$q_0 = \frac{q_i}{ (1+bD_i t )^\frac{1}{b} }$$
+
+### Harmonic Decline
+
+Harmonic decline is the production decline when $b = 1$:
+
+$$q_0 = \frac{q_i}{ (1+D_i t ) }$$
+
+
+
+## Rate-Cumulative Production Decline Curves
+
+
+### Exponential Decline
+
+Exponential decline is the production decline when $b = 0$. This gives a constant decline  ($D_i = D$).
+
+$$N_p = \frac{q_i - q_0}{D}$$
+
+### Hyperbolic Decline
+
+$$N_p = \frac{q_i^b}{D_i(1-b)} [q_i^{(1-b)} - q_0^{(1-b)}]$$
+
+### Harmonic Decline
+
+Harmonic decline is the production decline when $ b = 1 $:
+
+$$N_p = \frac{q_i}{ D_i } * \ln(\frac{q_i}{ q_0} )$$
+
+
+## Decline Rate
+
+The continuous decline rate ($D_i$) can be determined from production history data. Using production rate and time data the value is the slope of the straight line on a semi-log plot. Taking two points on from the data $(t_1, q_1)$ and $(t_2, q_2)$:
+
+$$D_i = \frac{1}{t_2 - t_1} \ln(\frac{q_1}{q_2})$$
+
+where:
+- $t_1$ is the time of the first point.
+- $q_1$ is the production rate in the first point.
+- $t_2$ is the time of the second point.
+- $q_2$ is the production rate in the second point.
+
+
+## References
+<a id="1">[1]</a>
+Arps, J. J.: “Analysis of Decline Curves,” SPE-945228-G, Trans. of the AIME (1945)