Abstract:

A cosine transform technique has been developed to calculate the complete gravity gradient tensor from pre-existing vertical gravity data which provides an alternative determination of the gravity gradient tensor components. Gravity gradient tensor components are computed for different thickness of three dimensional oil spherecoronal models. The characteristics of gradient tensor are similar to homogenized three dimensional spherecoronal model when the thickness of oil is low, and the components of V_xx and V_yy show the symmetric characteristics of “one low value between two high values”. V_xy reduced gradually and reached minimum in center, there are four higher values in the center of four boundaries and show symmetric characteristic.  V_zz component shows high in the middle and low on all sides; V_zx and V_zy are lower in west and south, and higher in east and north, respectively. However, when the thickness of oil is great, V_xx and V_yy show the symmetric characteristics of “one high value between two low values”. V_xy accreted gradually and reached maximum in center. V_zz is lower in the middle and higher on all sides , and changed more acute. V_zx and V_zy are higher in west and south and lower in east and north, respectively. The studies on gravity gradient tensor of three dimensional oil sphere-coronal models could provide a theory basis for finding storage anticline tectonic.

Key words: cosine transform, three dimensional sphere-coronal, gradient tensor, thickness of oil