The Environmental Corrections wizard processes Gamma Ray, Density, Neutron and Resistivity logs using correction models. It writes new calculated curves and leaves the source curves unchanged.

Open it from the Petrophysics ribbon tab, in the Logs group. The button caption is Env. corr.; its location is shown in Petrophysics.

Set up a run

On Data, choose a Well. Leave the interval selector off to process the whole log, or set an MD, TVD, TVDSS or marker interval. For several wells, select Batch calculation over wells and choose the well group. Under Log families to correct, check each family to process and select its source curve. Gamma Ray is checked initially; the Density, Neutron and Resistivity tabs become usable when you enable those families.

Set each family's Processing state to Raw / requires correction, Already environmentally corrected or Unknown. An unknown state is reported during the run and requires confirmation when saving. A correction that would act on an already corrected source is blocked by default. Use Allow re-correction of an already corrected source only when a second correction is intended.

Enter a Run name (LAS set) for the output group. If the curve exists offers Overwrite, Version and Prompt; Version is selected initially. Under Acquisition (recorded in provenance), optionally enter Service company / vendor and Tool family / run. Each From header button offers a LAS header value for you to confirm.

Resolve borehole inputs

On Borehole Environment, only inputs declared by the selected models are enabled. The Input rows cover Bit size and Caliper / hole diameter for hole geometry; Mud density / weight and Mud resistivity for borehole fluid; Density correction, DRHO for density compensation; and Borehole salinity, Formation water salinity, Borehole temperature and Borehole pressure for neutron conditions.

For each active row, choose Curve or Constant under Source. A curve is offered when its type matches the input. For a constant, choose its Unit, then select Use or type a value to confirm the proposed number. Status shows whether the input is resolved. From header offers a LAS header value for confirmation where available. Set Tool position to Centered, Eccentered or Unknown.

For the shipped Gamma Ray model, a caliper or hole diameter and mud density are required. If a required input remains unresolved, that family's correction is skipped and the wizard names the missing input; other enabled families can still run.

Choose a model

Each enabled family tab has a Model selector. Id / version identifies the selected model, and Source gives its reference. The Inputs used table lists each Input, whether it is Required, what it is Resolved from, and its Status. In Constants, Name, Unit and Description explain each parameter; edit its Value when the model needs calibration. Scroll either table to see additional rows. Output suffix changes the output names previewed under Will produce.

The Model library controls let you Import models... or Import folder.... Imported models are marked [user] and kept separate from installed models. Use Reload correction models after changing model files outside the wizard. Shipped models are marked as generic.

Gamma Ray

The Gamma Ray model uses the selected Gamma Ray curve, caliper or hole diameter, and mud density; bit size is optional. Its k constant is the attenuation coefficient, d_tool is the tool outer diameter, and k_max is the factor above which a computed correction receives a warning. Tool position is set on Borehole Environment.

Density

Density initially uses Density - QC only, no correction applied. It reviews the selected density curve without changing its values; DRHO, caliper and bit size are optional QC inputs. Its drho_max flags large density compensation and washout_max flags a caliper reading that exceeds bit size by too much.

Other Density models are selected explicitly. The DRHO model requires the density and DRHO curves; delta_max sets its warning threshold. Use it only when the source density has not already been compensated. The standoff model requires density, caliper and bit size; so_max is tolerated standoff, rho_mc is mudcake density, c_so is its calibration coefficient, and delta_max is the warning threshold.

Neutron

The Neutron model requires the selected neutron curve, caliper, mud density, borehole and formation-water salinity, temperature and pressure. Its k_bh, k_mw, k_sal, k_t and k_p constants control those environmental terms. d_ref, rho_ref, t_ref and p_ref give the reference conditions; delta_max sets the correction warning threshold, while phi_min and phi_max bound the output porosity. Lithology basis is read-only: the output keeps the source curve's basis and the wizard does not convert between bases.

Resistivity

Choose Induction or Laterolog as the Measurement family before choosing a Model; only models for that family appear. The pictured Induction model requires the selected resistivity curve and mud resistivity; caliper is optional. Its g_borehole is the borehole geometrical factor and k_max is the warning threshold.

The installed Laterolog chart is a demonstration model, not a quantitative correction for real data. It requires resistivity, caliper and mud density; its k_max sets the factor warning threshold. The chart produces no value outside its limits.

Review and save

Select Run to preview the selected well on Results. Review Borehole, raw and corrected, the QC messages, and the Outputs to commit table. Its Commit choices select the previewed well's output Curve and Unit rows to save; a batch save commits all model outputs for the other wells. The pictured preview shows a Density QC-only run.

Select Save to calculate and store the selected well or batch. The results are grouped in the named LAS set. Each model supplies a processed or QC-reviewed curve and a QC flag curve, and may supply a diagnostic curve. A processed curve retains its source log type for later type-based selection. Null required samples are skipped rather than replaced with zero. The QC report identifies warnings and skipped samples; chart models produce no value beyond their chart limits.

Use Save to workflow to store the setup as a task for a later run.

Inspect a saved run

To inspect a saved result, use Show correction settings on its curve in the Data manager. The wizard restores the settings and adds a read-only Recorded run tab. It lists the source and output curves, processing state, model and reference, acquisition details, resolved inputs, constants, units, interval and QC counts. Changing a restored setting starts a new run; the recorded details remain the record of the saved curve. If the recorded model is no longer installed, the tab warns that the current model selector cannot reproduce that run.