Staroxa Technology

Before we start the Petrophysics eLectures properly let take a look at:

Typical Outline for a Petrophysics Field Study

Introduction

The needs of clients differ for each Petrophysics field study but most projects follow the general outline given below.

The Petrophysics field study is often part of a larger reservoir description project such as a reservoir simulation model or a geostatistical study. All of the project technical team members must be kept fully informed of the progress of the Petrophysical analysis. Any reservoir anomalies, including heterogeneity features, must be promply discussed and documented.

The reservoir surveillance activities will likely out-live the Petrophysics Field Study, so it is vital that the final study report and all material used in the study be carefully archived.

Suggested Outline for a Petrophysics Field Study

(1) Review previous studies.

(2) Conduct a literature search for work done on analagous fields

(3) Data collection phase;

    Digital wireline log data,
    Wireline log paper prints,
    Mud logs including digital data if available,
    Cuttings sample descriptions,
    Sidewall core descriptions,
    Core descriptions,
    Core analysis results including any SCAL reports,
    Petrographic reports,
    Well test results,
    Formation pressure data (MDT, RFT, DST etc.)
    Fluid analysis (gas, oil, water) reports,
    Geological correlation sections,
    Depositional environment reports,
    Well survey data.

(4) Database development:

    Data entry;

        Digital wireline log data from a service company, log vendor or client,
        Digitized log data: either as the original data or as supplemental or remedial data,
        Log header information - usually entered manually,
        Core analysis results - usually entered manually,
        Formation pressure data,
        Well survey data. Be aware of order of validity (single-shot, multi-shot,Gyro)

    Verify the validity of digital log data with hard copies of the original data.

    Identify and document fluid contacts in all wells. Use Mud log data, well test results, formation pressure data, cores, mudlogs and well log response. Create color-coded "stick" plots (Subsea depth) to show the distribution of fluids in all reservoirs.

(5) Edit the log data;

    Splice logs,
    Normalize log curves, if necessary, after examination of regional trends,
    Baseline SP curves,
    Delete or edit invalid log data intervals (for example cycle-skipped sonic).

(6) Create hole size and "washout" curves.

(7) Create "bad hole" logic to identify zones with invalid log data,

(8) Create a set of TVD and/or subsea log curves for each well,

(9) Apply environmental corrections to log data, where appropriate.

(10) Develop and test an interpretation model using the available data (logs, core analysis, petrography, etc). The model will typically include;

    A method to predict formation temperature,
    Formation water resistivity (Rw) curves calculated using salinity data and formation temperature,
    Shale fraction determination (often using multiple logs),
    Shale properties algorithms (Qv, Rhoma, Rwb, etc.),
    Reservoir parameters (matrix and fluid density, a, m, n, etc.),
    Porosity algorithms. Porosity is often calculated using several logs and logic is developed to select the most appropriate value,
    Water saturation models, and,
    Permeability prediction algorithms.

(11) Working with other members of the study team develop facies identification models, if possible.

(12) Develop permeability transforms for each depositional facies, if possible. Calculate permeability-thickness for each well/zone.

(13) Compare the log interpretation results with available core data.

(14) Refine the interpretation with zoned analysis parameters. It may be necessary to use more than one interpretation model.

(15) Review the analysis model and reservoir zonation parameters with the project technical team (Geologists, Geophysicists, Reservoir engineers).

(16) Apply the refined interpretation model to all of the wells using the zoned analysis parameters.

(17) Review all analysis results prior to writing a final written report.

(18) Prepare a summary report for the Petrophysics field study, containing;

    An executive summary of the project and the analysis results,
    A detailed description of the techniques applied,
    Implications of the results of all computations
    Analysis results in tabular and graphical forms.
    Petrophysics composite logs ("Answer" plots) with;

        Raw logs, core analysis data, interpreted lithology and,
        Log analysis results curves.

(19) Prepare presentation materials;

    Slides or overhead projections,
    Posters,
    Cross sections showing petrophysical properties.

(20) Archive all hard copy and digital data. A very useful technique is to write a CD containing the project directory structure.  The directory structure should contain the raw data, results curves, interpretation programs, report files and plot files.


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Henderson Petrophysics

Drilling Engineering
As an entry-level drilling engineer, your career begins as a drill site manager — an on-site representative for drilling, completion, workover, and intervention operations.
Drill site managers work a rotational schedule, typically 14 days on/14 days off. Your typical responsibilities will include:
• Directing day-to-day drilling and completions operations to ensure the safety of all personnel on location  and compliance with all applicable environmental regulations
• Managing day-to-day activities of rig contractor personnel and third-party contractors
• Managing logistics for personnel and equipment to and from location
• Providing accurate daily drilling reports and maintaining accurate cost control After two to five years of  experience, entry-level drilling engineers have the opportunity to move into the office and work as a drilling or completions engineer.
Examples of project work for drilling or completions engineers are:
• Fit-for-purpose well or completion designs
• Bit and drill string design
• Casing and cement design
• Risk assessments and probabilistic cost estimating

Production Engineering
Production engineers are involved in the full lifecycle of field development — from conceptual design through  the production phase and eventually abandonment.
Production engineers specialize in reservoir surveillance and production system optimization, evolving development concepts, and contributing to well completions.
Your typical responsibilities willinclude:
• Production monitoring and evaluation
• Asset management planning
• Workover design and execution
• Production equipment design
• Cost estimating and budgeting
• Interfacing with working: interest partners, service companies, and regulatory agencies