OTHER TOOLS

4D ANALYSIS

This is a simple tool but with a very practical property: user don't need to pre-balance 3D and 4D data. The algorithm perform an autobalance and gridding in input 3D and 4D data. The final result is good. We have used this tool in some 3D-4D data and the result allow interpreters to evaluate the dinamic oil/water repositioning and pressure changes after production. The program generates statistics in 3D data, 4D data and 3D/4D differences. The input data must be the seismic 3D and 4D amplitudes, not necessarily in the same grid reference. If it is the case, the algorithm performs re-gridding to adjust amplitude geographycal information.

NetPay computations

Again a very simple tool, but efficient. Its results were compared to refined commercial tools and the differences became minimal. Based on well logs GR, DT, RHOB, NPHI the user defines acceptable cuttof that culminates in reservoir pay definition. After, by adding ILD information and resistivity cuttof the netpay is configured. See figure bellow.

3D well velocity building from TxD curves (VELPOÇO)

This is also a unique tool, designed for high density drilled areas (oil fields?) with many sonic profiles available. Based on sonic, accurate TxD tables are obtained with shift/drift methodology. By using these tables, a complete 3D velocity cube is built at user defined cell size. Interpolation and extrapolation is available. The user must select the wells to be interpolated, what implies kriging. Since it is a 3D velocity cube, any horizon inside cube limits may be depth converted with no need using seismic velocities. See SBGf paper (green box) and figure below.

Well based 3D velocity cube

Velocities derived from RHOB profile (VELDEDEN)

Computing velocities from densities is the inverse direction of Gardner-Willie methodology. Taken into account same premises, velocities are computed from density profiles. It is possible to do well to seismic correlations based only in the RHOB profile: RHOB data were used to build the time-depth curve and the synthetic seismogram. This is quite important once many production wells have RHOB profiles but don't have sonic profile. Se in figure bellow one example extracting velocities from density

Computing erosion from sonic profile

IF no erosion, sonic profile must show a complete set of DT readings that carry information about porosity or compaction. When gaps are observed, the chance for erosion interpretation is possible. In Heasler and Karitonova (AAPG Bulletin, V80, no 5) there is a detailed study relating erosion and sonic readings. Bellow one figure that shows an erosion computation based on sonic data.

Structural Evolution - MOVIE2D

Do You want to use Your mind to try to understand the structural evolution of a Geological area? It is not an easy task to implement the idea in this tool, but it is possible. Major difficulty is to code the input data to the program: one must build some layer snapshots representing what was the structural situation at one specific age. Each imagined snapshot must be transported to a spreadsheet, where you code the grid position of each layer. Trained, one must spend 1 or 2 days mounting the snapshots in the gridded spreadsheet. The tool simply transpose dynamically the position of each layer, from one snapshot to the following. Bellow there is a figure showing the final snapshot in a structural imagined evolution. Other figure is the spreadsheet to code the layer nodes of each snapshot.

more tools are available ...