emr-services

Petrophysics

 

Petrophysics

EMR provides a range of services in the area of Petrophysics. This starts from development of data acquisition programs for well proposals and drilling programs for exploration and development well campaigns. During drilling, EMR is able to provide onsite operations support and quick look evaluation of acquired data, reporting evaluation results real time. EMR also conducts interactive, multi-well petrophysical field reviews to support development planning and production management.

Integrating variety of data forms including logs, core, formation pressure and other ancillary data is a key strength of the EMR evaluation team. EMR has developed clear, consistent and repeatable workflows and evaluation protocols that ensure results, methods and assumptions are documented to the highest standard of quality.

Our petrophyscists are proficient in the use of variety of industry standard software. In addition, they’re able to develop bespoke user programs to solve unusual petrophysical problems. We are therefore not limited by some technical drawbacks inherent in available industry software.

At EMR, we work in integrated teams which bring all subsurface disciplines (geology, geophysics, petrophysics, reservoir engineering and production technology) together to create a powerful knowledge network that delivers high quality products to our clients.

Below is a sequenced list of Petrophysical services provided by EMR. The client’s need determines what portions are executed.
 

Operations Petrophysics

(Applicable before and during well drilling campaigns)
We do engage with our clients early on, starting from the planning stage of their logging campaign. Consequently we are able to

  • Ensure compliance with all Health Safety and Environment standards applicable to well construction.
  • Provide subsurface technical support to the drilling team during the planning stage of the well.
  • Provide data acquisition program input to well proposals.
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We are also on hand to;
  • Supervise Logging Operations on - and offshore.
  • Carry out cost estimation of operations.
We do also;
  • Prepare Open Hole and Cased Hole logging programs for both rig and rigless operations.
  • Work with service vendors to establish desired logging, coring, and testing procedures.

Log Analysis

(Applicable to single and multiwell field reviews to support development planning and production management)
Data Preparation (Data edit and depth matching)
• Depth matching of curves to primary log 
• SP baseline correction 
• Merging/Splicing 
• Filter or smooth log curves 
• Construction of Temp. curve and differential caliper
• Log reconstruction in badhole or intervals with missing data
Summation reports
• Input client defined formation tops and bottoms 
• Sensitivity analysis, select "cutoffs" for Vshale, PHIE, and Sw





Environmental corrections for standard log curves
• GR, NPHI, RHOB environmental correction 
• "Tornado chart" resistivity correction

Poro-Perm Relationship
• Rock typing and Electrofacies classification.
• Permeability modeling using wireline logs, core and pressure data.
• Porosity/permeability crossplot
Log normalization
• Well/Field histograms for GR, RHOB, NPHI, DT, and Resistivity 
• Well/Field cross-plots for available porosity and resistivity data 
• Cross-plot and curve fit for core "P&P" and core/log Phi data
Saturation height modeling
• Saturation height modeling from core capillary pressure measurements and log evaluation results



 
Derivation of petrophysical parameters and "Rw"
• Pickett plots for each zone to determine a, m, n, and Rw 
• Compute "Rwa" and Rw from Resistivity log or SP to verify Pickett plots

Special logging tool applications
• NMR applications
• Some cased hole log applications

 
Calculation of porosity and clay volume
• Calculate clay volume using appropriate model for each zone 
• Calculate lithology corrected porosity curves 
• Calculate cross-plot porosity and "PHIE
Multiwell field evaluations
• Petrophysics workflow



Core-Log Integration
• Matrix density determination
• Cross-plot and curve fit for core "P&P" and core/log Phi data
Production Log evaluation
•Carbon/Oxygen and pulsed neutron log interpretation
• Production log interpretation

Sw and other volumetric calculation
• Examine carbon fractions and gas ratios from mud log.
• With resistivity and porosity logs determine pay zones. 
• Select appropriate Sw model 
• Calculate gross, net, pay, N/G ratio, PHIE, average   PHIE, Sw, average 
• Sw, Phi-h, BVW, and HPV
Deliverables
• Color hard copy logs/pertinent cross-plots 
• Hard copy and digital summation spreadsheets 
• Original input and computed data on client specified media and format 
• Color hard copy or pertinent cross-plots and graphs 
• A written report summarizing methods, assumptions, parameters, and results

A log section showing results of Petrophysical Analysis

Log Analysis

  • Our formation evaluation team has an excellent approach to log analysis. In a typical multiwell study, analysis work flow starts from data preparation (data editing, depth matching, environmental corrections and log normalizations) to core-log integration (where core data is available) and consequent derivation of evaluation parameters including rw. These go into the computation of clay volume, porosity and water saturation. Quicklook and single well evaluations follow a slightly simplified version of the workflow.
  • When core data is unavailable, our rich regional knowledge of core data enables us to utilize appropriate evaluation parameters to deliver quality results to our clients.
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  • Ultimately, we deliver color hard copy logs and pertinent cross-plots
  • Hard copy and digital summation reports
  • Original input and computed data on client specified media and format
  • A report summarizing methods, assumptions, parameters, and results.


Core-Log Integration

At EMR, we are able to :

  • Integrate core analyses results (RCAL, SCAL) with log data to improve reservoir evaluation.
  • Predict permeability in non cored wells
  • Deduce Flow-Zone- Indicators and Reservoir Quality Index
  • Compute cap curves and saturation ht functions.

Poro-Perm Relationship

When core data is available in some wells, we’re able to derive a relationship between porosity and permeability that can be carried over to estimate perms in wells that don’t have core data.

When core data is not available within the field we’re able to use our experience to select appropriate Poro-Perm functions that characterize the permeability behavior of the clients formation.

Special logging tool applications

We add value to our clients with our experience in the application of special logging tools like

  • NMR (Cased-Hole and Open-hole applications)
    • MagTrak, CMR etc
  • Image logs
  • Stethoscope
  • Ecoscope etc.

Cased-Hole / Production Log evaluation

Our experience in cased hole and production log interpretation has helped our clients in the following areas:

  • Hydrocarbon Bypass detection
  • Develop inputs for workover operation
  • Casing integrity and cement log evaluation
  • Fluid contact analysis for producing wells
  • Produce more HC than water
  • Detect Thief Zones