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Definition


Primary Production Analysis is the specific workflow and report template on Primary Well & Reservoir Performance Indicators.


Application


  • assess current production distribution

  • assess current distribution of recovery against expectations

  • assess current status and trends of recovery against expectations

  • assess current status and trends of reservoir depletion against expectations
     
  • assess current status and trends of water flood efficiency against expectations

  • quantitatively compare performance of different wells or different groups of wells 

  • identify and prioritize redevelopment opportunities


Technology


Primary Production Analysis is built around production data against material balance and require current FDP volumetrics, PVT and SCAL models. 


It includes well-by-well diagnostics and gross field diagnostics, but may be extended to sector-by-sector diagnostics.


Metrics


Primary Production Analysis includes the following metrics:


Metric nameDiagnostic plotsObjectives
1Production History Map

Background = STOIIP & Structure

Bubbles = qo, qg , qw, qinj

Number = VRR, Pe

Production Distribution Overview
2Recovery Map

Background = STOIIP & Structure

Bubbles = Qo, Qg , Qw, Qinj

Number = VRR, Pe

Recovery Distribution Overview
3Production History Graphs

Left Axis = qo, qg , qw, qinj,

Rigth Axis = Yw, GOR, Pe , Np, Ninj

Hor Axis = Elapsed Time

Production History Overview
4

Decline Curve Analysis

Left Axis = qo1, qliq1, qinj1,

Rigth Axis = Yw, GOR, VRR, Pe

Hor Axis = Elapsed Time

Production Forecast
5Recovery Diagnostic

Left Axis = qo1, qliq1, qinj1

Rigth Axis =Yw, GOR, VRR, Pe, Pem

Hor Axis = RF

Estimate recovery efficiency and pressure decline
6Watercut Diagnostic

Left Axis = Yw, Ywm

Hor Axis = qliq

Check for water balance and thief water production
7GOR Diagnostic

Left Axis = GOR, GORgm

Hor Axis =qo

Check for gas balance and thief gas production
8

Injection Efficiency Diagnostics

Left Axis = PIR , PIRm

Hor Axis = Yw

Evaluate WI efficiency
9Well Performance Analysis

Left Axis = Pwf_IPR , Pwf_VLP

Hor Axis = qo

Check for the optimal production/injection target
10

Productivity Index Diagnostic

Left Axis = JPI, JPIm

Hor Axis = dP = Pwf - Pe

Check for PI dynamics




Below is the list of the production properties  involved on the above metrics.


Property AbbrevyProperty NameFormula
VRRcum

Cumulative Voidage Replacement Ratio

LaTeX Math Block
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{\rm VRR_{cum}} = \frac{B_w \, Q_{WI}}{B_w \, Q_W + B_o \, Q_O + B_g Q_G - B_g R_s Q_O}
VRRinstInstantaneous Voidage Replacement Ratio
LaTeX Math Block
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{\rm VRR_{inst}} = \frac{B_w \, q_{WI}}{B_w \, q_W + B_o \, q_O + B_g (q_G - R_s Q_O)}
RF

Recovery Factor


LaTeX Math Block
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{\rm RF} = \frac{Q_o}{V_{STOIIP}}
Yw

Watercut

LaTeX Math Block
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{\rm Y_w} = \frac{q_w}{q_{lis}}




GORGas-Oil Ratio
LaTeX Math Block
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{\rm GOR} = \frac{q_g}{q_o}
qliqLiquid rate
LaTeX Math Block
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q_{liq} = q_o + q_w
Ywm

Watercut model


LaTeX Math Block
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{\rm Y_wm} = \frac{1}{1 + \frac{K_{ro}}{K_{rw}} \cdot \frac{\mu_w}{\mu_o} \cdot \frac{B_w}{B_o}}

PIR

Production Injection Ratio


LaTeX Math Block
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{\rm PIR} = \frac{Q_o}{Q_i}



PIRmProduction Injection Ratio Model
LaTeX Math Block
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{\rm PIR_m} = { \frac{1}{VRR} }*{ \frac{1-Y_w}{ Y_w + (1-Y_w) [ \frac{B_o}{B_w} - \frac{B_g}{B_w}(Y_g - R_s) ] } }
JPIoOil Productivity Index
LaTeX Math Block
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P_{wf} = P_e - \frac{1}{J_{PIo}} q_o

JPI

Total Productivity Index


LaTeX Math Block
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{\rm J_{PI}} = \frac{Q}{P_e - P_{wf}} {\quad \Rightarrow \quad} P_{wf}=P_e - \frac{1}{PI}Q



JPImTotal Productivity Index Model
LaTeX Math Block
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{\rm J_{PIm} } = \frac{q_o}{P_e - P_{wf}}





Expand
titlePIR equation deduction
LaTeX Math Block
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Y_w=\frac{q_q}{q_w + q_o} \rightarrow \frac{q_o}{q_w} = \frac{1-Y_w}{Y_w}
LaTeX Math Block
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PIR=\frac{q_o}{q_i}
LaTeX Math Block
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PIR = \frac{q_o}{q_i}={ \frac{1}{VRR} }*{ \frac{1-\gamma}{ \gamma +  [ \frac{B_o}{B_w} - \frac{B_g}{B_w}(GOR - R_s) ] } }


Diagnostic


Expand
titleExpand
Show If
groupsofoil

Введение

История добычи



Рис. 1. График общей добычи и пластового давления в добывающих и нагнетательных рядах




Рис. 2. История фонда скважин




Рис. 3. График среднескважинных дебитов и пластового давления в добывающих и нагнетательных рядах


Карты разработки




Рис. 2.1. Карта текущих отборовРис. 2.2. Карта кумулятивных отборов



Падающая добыча

Стационарная добыча


Стационарная добыча это режим в котором давление на линии отбора поддерживается постоянным за счет газовой шапки, аквифера или закачки в нагнетательные скважины.

Растущая добыча


Динамика пластового давления


Снижение пластового давления приводит к потере депрессии и следовательно дебита случае если забойное давление достигло технологического минимума.

Снижение пластового давления приводит к снижению пористости и проницаемости коллектора, что приводит к потере продуктивности и снижению дебита сквжаины.

Снижение пластового давления ниже давления насыщения приводит к выделению газа в призабойной зоне и потере продуктивности скважин по жидкости за счет более высокой мобильности газа и за счет дроссельного охлаждения, что в итоге приводит к снижению дебита скважины.



Диагностические графики анализа добычи NDR


q1o vs RF




Рис. 1. График среднескважинного дебита нефти и пластового давления от КИН



LaTeX Math Block
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q_{1o} = \frac{\sum Q_o }{ \sum {t_o}}
LaTeX Math Block
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RF = \frac{\sum_t Q_o }{V_{STOIIP}}

Yw vs RF 





Рис. 1. График обводненности от КИН


Pe vs RF 


Диагностические графики анализа заводнения WIR









Sample Case





Fig. 1. Production History Map

Fig. 2. Recovery Map
Fig. 3. Pressure Diagnostic





Fig. 4. Decline Curve AnalysisFig. 5. Recovery DiagnosticFig. 6. Watercut Diagnostic






Fig. 7. GOR DiagnosticFig. 8. Injection Efficiency DiagnosticsFig. 9. Well Performance Analysis




Fig. 10. Productivity Index Diagnostic