Abstract
Currently, conventional seismic inversions are mostly premised on well data, and there exist uncertainty in seismic inversions in areas with few fixed wells. After years of production practice, well-seismic cooperative inversion under the constraint of pseudo wells is a more effective method for reservoir prediction in areas with few fixed wells and complex phase spread changes. Nevertheless, the selection of locations of conventional pseudo wells only takes into account the spatial distribution of wells but seldom considers the changes of phase spreads; curves of pseudo wells are mostly derived from sparse pulse inversion with relatively low longitudinal resolution, which cannot accurately reflect the vertical and horizontal variation characteristics of the reservoir; there is no effective quality control method to prove the reliability of the curve after selecting the pseudo well. To solve the above-mentioned problems, this thesis acquires pseudo-wave impedance curves with high-frequency components by means of waveform difference inversion, controls quality and optimizes the location of pseudo wells under the guidance of geological results, and performs phase control inversion under the constraint of high-frequency pseudo-wave impedance curves, which greatly enhances the vertical and horizontal resolution of inversion, solves the problem of fine reservoir prediction in areas with few fixed wells, and offers strong support for high-speed and efficient development of oil and gas.
Highlights
Traditional reservoir seismic inversions are a special technology that predicts the lithology, morphology, physical properties and oil-gas bearing property of oil and gas reservoirs employing seismic information as the main basis and comprehensively regarding geological, logging, petrophysical and other information as constraints
Predecessors have solved this problem by participating pseudo wells, but the selection of locations of conventional pseudo wells usually only considers the spatial distribution of wells but is lack of geological rationality [2]
Waveform Difference Theory Waveform difference inversion is similar to geostatistical inversion, with intermediate frequency constrained by earthquake and high frequency derived from well data [4]
Summary
Traditional reservoir seismic inversions are a special technology that predicts the lithology, morphology, physical properties and oil-gas bearing property of oil and gas reservoirs employing seismic information as the main basis and comprehensively regarding geological, logging, petrophysical and other information as constraints. Most inversion techniques are premised on the information of fixed wells, using interwell interpolation or geostatistical methods for modeling, combined with the comprehensive constraint inversion technique characterized by intensive horizontal sampling of seismic data [1]. The dependence of this inversion method on the quantity and quality of well data leads to an increase in uncertainty of inversion results in areas with few wells. (3) Inversion is conducted under the constraint of high-frequency pseudo wave impedance curves with phase control characteristics
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