InverTrace^Plus

Constrained Sparse Spike Inversion

InverTrace^Plus™ transforms seismic data to an acoustic impedance log at every trace. Acoustic impedance is a property of the rock layer itself, unlike seismic amplitude, which is a property of the interface between two acoustic layers.

The asset team uses acoustic impedance to produce more accurate and detailed structural and stratigraphic interpretations than can be obtained from seismic (or seismic attribute) interpretation. In many geological environments acoustic impedance has a strong relationship to petrophysical properties such as porosity, lithology, and fluid saturation. Moreover, the acoustic impedance models are more readily understood (versus seismic attributes) by all members of the asset team, and can enable better overall communication within the team.

The Constrained Sparse Spike Inversion (CSSI) algorithm is the centerpiece of InverTrace^Plus and is the state of the art implementation of non-linear sparse spike technology. InverTrace^Plus produces high quality acoustic impedance volumes from full or post-stack seismic data. The four output volumes are:

• Full Bandwidth Impedance
• Band-Limited Impedance
• Reflectivity model
• Low frequency component

These volumes are used in unique workflows to design better drilling programs, resulting in higher productivity well.

A key test of any seismic inversion algorithm is its ability to solve the wedge model. InverTracePlus clearly is able to solve the wedge model as shown in these images.

Benefits

Inversion of seismic data to impedance improves exploration and reservoir management success, producing more hydrocarbons with fewer, more highly productive wells. Among the improvements are:

• Higher resolution through reduction of the wavelet effects, tuning and side lobes.

• Incorporation of low frequencies not contained in the seismic data.

• Increase asset team interaction through the use of layer based (versus interface) acoustic impedance models that are readily understood by all asset team members.

• Accurate rock property modeling, as impedance can be related to several key rock/petrophysical properties such as porosity, lithology, and water saturation.

• Better understanding of the accuracy of seismic processing and acquisition, well log data and quality, and quality of input interpretations. Through rigorous tying of the wells to the seismic and estimation of the waveform that is in the earth and the seismic inversion of the data back to well control, the asset team can better understand accuracy and consistency of their input data.

Since drilling costs account for the majority of the total E&P costs, reducing the number of wells required to exploit a field will have a significant impact on profitability.