Abstract

The Delaware Basin and surrounding area has been the object of intense study over the past decade; with renewed interest gravity and aeromagnetic data sets are being studied with new computing tools. The use of current computing technology (processor speed and memory size) larger data sets are being used in combination with advanced modeling software to produce results that that may offer renewed interest in geophysical prospecting with potential field methods. Our goal in this study was to offer an unbiased 3-D differential density model for the Delaware Basin and adjoining Central Basin Platform region covering 31 - 34 degrees north latitude; -102 - -105 degrees east longitude. Tikhonov regularization inverse techniques were applied to solve for the unknown density distribution of a model space described by rectangular blocks of dimension 16 x 16 x 3 (x, y, z). The Tikhonov regularization technique is the most widely used technique for regularizing discrete ill-posed problems. Because of the size of the model space (768) and the data space (1700) the system matrix, which relates the data to the unknown model parameters is considered slightly ill posed. Tikhonov regularization provides a way of performing the inversion in a quick and stable manner, for a low cost.

This method and current computing capability allowed this approach to be implemented on large gravity data sets with a sizable model space. Other advantages of the method include 1) existing geologic information can be used to constrain the solution by using a starting model 2) minimizes subjective user input 3) doesn’t encounter problems related to wave number domain transforms (as in the upward/downward continuation problem).

Applying this method to a gravity data set covering southeast New Mexico and west Texas show geologically believable results when compared to previous geologic work describing the basement structure.