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Specific type of Production Analysis (PA) workflow based on correlation between multi-well production/injection history and bottomhole pressure history from permanent downhole gauges (PDG) data records.
The key simulation engine of MRT is Pressure Convolution which is based on Unit-rate Transient Responses (UTR) retrieved from Production rates / PDG data history by means of Pressure Deconvolution.
It does not require new data acquisition at well site and makes use of historical dynamic data records, usually few months or longer.
Motivation
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Production rate in producing well depends on its productivity index
, current formation pressure LaTeX Math Inline body J
and current BHP LaTeX Math Inline body p_e
: LaTeX Math Inline body --uriencoded--p_%7Bwf%7D
LaTeX Math Block | ||||
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q_1^{\uparrow}(t)=J \cdot \left( p_e(t) - p_{wf}(t) \right) |
and as such depends on completion/lift settings (defining
) and how formation pressure is maintained LaTeX Math Inline body --uriencoded--p_%7Bwf%7D(t)
over time. LaTeX Math Inline body p_e = p_e(t)
It keeps declining due to the offtakes:
LaTeX Math Block | ||||
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p_e(t) = p_e[q_1^{\uparrow}(t), q_2^{\uparrow}(t), q_3^{\uparrow}(t), \dots] |
and maintained by either aquifer or Fluid Injection and in the latter case depends on injection rates:
LaTeX Math Block | ||||
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p_e(t) = p_e[q_1^{\downarrow}(t),q_2^{\downarrow}(t),q_3^{\downarrow}(t),\dots ] |
The combination of
, LaTeX Math Block Reference anchor qup
and LaTeX Math Block Reference anchor peup
lead to the correlation between production rates, injection rates and bottomhole pressure variation. LaTeX Math Block Reference anchor pedown
The ultimate purpose of MRT is to extract maximum information from correlation between the long-term (few months or longer) flowrate history and BHP history (recorded by PDG).
It is essentially based on the fact that BHP in a given well (whether producing or injecting) responds to flowrate variation in the same well and may (or may not) respond to flowrate variation in offset wells.
This information is further related to well flow performance and cross-well connectivity.
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- Create short-term prediction model on production response to various multi-well production regimes
- Compare the well dynamics and and cross-well connectivity with expectations and identify the candidates for drilling, workover or additional well surveillance
- Assess dynamic reservoir properties
Inputs
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Outputs
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Production History | |||||
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Simulated total subsurface flowrate history,
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Simulated BHP history,
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Simulated formation pressure history,
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Simulated Productivity Index history,
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Simulated Cross-well interference history,
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Production Forecast | |||||
Rate forecast under Pressure Control regime,
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BHP forecast under Liquid Control regime,
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Formation pressure forecast under Liquid Control regime,
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Diagnostic Metrics | |||||
Cross-well interference map | |||||
Unit-rate Transient Response Matrix (UTRM) | |||||
Unit-rate Transient Response Spider (UTRS) | |||||
Material Balance Pressure Plot | |||||
Inflow Performance Relationship (IPR) | |||||
Cumulative Productivity Plot (Hall Plot) | |||||
J-plots | |||||
WOR diagnostics | |||||
GOR diagnostics | |||||
Primary Well & Reservoir properties | |||||
Potential drainage volume | |||||
Current dynamic drainage volume | |||||
Secondary Well & Reservoir properties | |||||
Apparent transmissibility | |||||
Apparent skin-factor | |||||
Fracture half-length | |||||
Dynamic fracture pressure threshold |
Inputs
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Primary Inputs | |
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PVT model | |
Production/injection history for all wells in a test | |
Bottom-hole pressure (BHP) history for at least one well | |
Additional Inputs | |
Well locations map | |
Well schematic | |
Surface Well Tests | |
Production Logging Reports | |
Cased-Hole Pressure Transient Test Reports | |
SGS – Static Gradient Survey Reports | |
Well Intervention History |
Applications
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Production forecasts | |
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Predict formation pressure without shutting wells down and avoiding production deferment | |
Short-term production forecasts for different multi-well production scenarios | |
Selecting well-intervention candidates | |
Identify well-intervention candidates with possible thief production/injection | |
Identify well-intervention candidates with possibly inefficient reservoir flow profile | |
Identifywell-intervention candidates for Rate Optimization | |
Identifywell-intervention candidates for producer ↔ injector conversion | |
Dynamic Model Calibration | |
Adjusting historical production allocation | |
Adjusting the potential reservoir volume extension at different directions | |
Adjusting faults / channels / compartmentalization | |
Adjusting fracture model |
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[ MRT @sample ] [ MRT @workflow ]
[ permanent Permanent downhole gauges (PDG) ] [ Pressure Convolution ] [ Pressure Deconvolution ] [ Multiwell Deconvolution (MDCV) ]
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