From dbee5f3f69edb7143f0fd797cc88407dbfcf1533 Mon Sep 17 00:00:00 2001
From: Even Solbraa <41290109+EvenSol@users.noreply.github.com>
Date: Thu, 11 Sep 2025 17:12:50 +0200
Subject: [PATCH] Add CVD simulation page for reservoir fluids

---
 README.md       |  6 ++++
 pages/80_CVD.py | 93 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 99 insertions(+)
 create mode 100644 pages/80_CVD.py

diff --git a/README.md b/README.md
index b818a7c..3dc5a9a 100644
--- a/README.md
+++ b/README.md
@@ -6,3 +6,9 @@ The NeqSim Web project is a web user interface for the [neqsim process simulator
 The application is in initial development and is using the [streamlit framework](https://streamlit.io/).
 
 The application is hosted by streamlit and can be tested at [neqsim web app link](https://neqsim.streamlit.app/).
+
+## Features
+
+- Thermodynamic calculations such as TP flashes and phase envelopes.
+- LNG ageing and property generation utilities.
+- **Constant Volume Depletion (CVD)** simulation page for reservoir fluids.
diff --git a/pages/80_CVD.py b/pages/80_CVD.py
new file mode 100644
index 0000000..485bbd5
--- /dev/null
+++ b/pages/80_CVD.py
@@ -0,0 +1,93 @@
+import streamlit as st
+import pandas as pd
+from neqsim.thermo.thermoTools import fluid_df
+from neqsim.thermo import CVD
+from fluids import detailedHC_data
+
+st.title('Constant Volume Depletion (CVD)')
+"""
+Perform a constant volume depletion simulation for a reservoir fluid. The NeqSim
+library will automatically select an appropriate thermodynamic model based on the
+input composition.
+"""
+
+st.divider()
+st.text("Set reservoir fluid composition:")
+
+hidecomponents = st.checkbox('Show active components')
+if hidecomponents:
+    st.edited_df['MolarComposition[-]'] = st.edited_df['MolarComposition[-]']
+    st.session_state.activefluid_df = st.edited_df[st.edited_df['MolarComposition[-]'] > 0]
+
+if 'uploaded_file' in st.session_state and hidecomponents == False:
+    try:
+        st.session_state.activefluid_df = pd.read_csv(st.session_state.uploaded_file)
+        numeric_columns = ['MolarComposition[-]']
+        st.session_state.activefluid_df[numeric_columns] = st.session_state.activefluid_df[numeric_columns].astype(float)
+    except:
+        st.session_state.activefluid_df = pd.DataFrame(detailedHC_data)
+
+if 'activefluid_df' not in st.session_state or st.session_state.get('activefluid_name') != 'detailedHC_data':
+    st.session_state.activefluid_df = pd.DataFrame(detailedHC_data)
+    st.session_state.activefluid_name = 'detailedHC_data'
+
+st.edited_df = st.data_editor(
+    st.session_state.activefluid_df,
+    column_config={
+        "ComponentName": "Component Name",
+        "MolarComposition[-]": st.column_config.NumberColumn("Molar Composition [-]", min_value=0, max_value=10000, format="%f"),
+        "MolarMass[kg/mol]": st.column_config.NumberColumn("Molar Mass [kg/mol]", min_value=0, max_value=10000, format="%f kg/mol"),
+        "RelativeDensity[-]": st.column_config.NumberColumn("Density [gr/cm3]", min_value=1e-10, max_value=10.0, format="%f gr/cm3"),
+    },
+    num_rows='dynamic'
+)
+
+isplusfluid = st.checkbox('Plus Fluid')
+
+st.text("Fluid composition will be normalized before simulation")
+st.divider()
+
+if 'cvd_pressure_data' not in st.session_state:
+    st.session_state['cvd_pressure_data'] = pd.DataFrame({'Pressure (bara)': [400.0, 350.0, 300.0]})
+
+st.text("Input Pressures (bara)")
+st.edited_pressure = st.data_editor(
+    st.session_state.cvd_pressure_data,
+    num_rows='dynamic',
+    column_config={
+        'Pressure (bara)': st.column_config.NumberColumn(
+            label="Pressure (bara)",
+            min_value=0.0,
+            max_value=1000.0,
+            format='%f',
+            help='Enter pressure in bar absolute.'
+        )
+    }
+)
+
+temperature = st.number_input('Temperature (C)', value=50.0)
+
+if st.button('Run CVD Simulation'):
+    if st.edited_df['MolarComposition[-]'].sum() > 0:
+        pressures = st.edited_pressure['Pressure (bara)'].dropna().tolist()
+        neqsim_fluid = fluid_df(st.edited_df, lastIsPlusFraction=isplusfluid, add_all_components=False).autoSelectModel()
+        rel_vol = []
+        liq_rel_vol = []
+        zgas = []
+        zmix = []
+        cum_depl = []
+        CVD(neqsim_fluid, pressures, temperature, rel_vol, liq_rel_vol, zgas, zmix, cum_depl)
+        results = pd.DataFrame({
+            'Pressure (bara)': pressures,
+            'Relative Volume [-]': rel_vol,
+            'Liquid Relative Volume [-]': liq_rel_vol,
+            'Zgas [-]': zgas,
+            'Zmix [-]': zmix,
+            'Cum Mole% Depleted': cum_depl,
+        })
+        st.subheader("CVD Results")
+        st.data_editor(results)
+    else:
+        st.error('The sum of Molar Composition must be greater than 0. Please adjust your inputs.')
+
+st.sidebar.file_uploader("Import Fluid", key='uploaded_file', help='Fluids can be saved by hovering over the fluid window and clicking the "Download as CSV" button in the upper-right corner.')