Exploration Practice Technology and Enlightenment of Low Relief Structural-Thins and Oil Reservoirs: Taking K Area in Oriente Forel and Basin, South America as an Example

Abstract

The Oriente Foreland Basin in South America is one of the most important oil-producing basins in the piedmont of the Andes, the study area is located in the western slope belt of the foreland slope area, provenances come from the east, develops sea-land interaction facies thin sand, it is easy to develop low relief structural lithologic reservoirs with the mutual configuration of low relief structures on the western slope. In 1996, aiming at low relief structural-thin sand lithologic traps, 3 exploratory wells were drilled but 2 of them were failed. Because of the low relief structural trap, thin reservoirs, complex spatial distribution, and prediction-difficulty, the result difference between structure prediction and actual drilling is big, which once restricted the pace of rolling exploration and development. In 2020, in order to improve the identification precision of low relief structures and thin sand layer, integrated innovative compressive sensing seismic data expanding frequency, anisotropic velocity field modeling, wavelet transform low relief structure identification three technology. The high-resolution processing technology of compressed sensing is used to improve the vertical resolution under the condition of high amplitude preserving and high fidelity, and to improve the interpretation precision of the low relief structure of the reservoir in the time domain (4–10 ms). The anisotropic velocity field modeling technology is used to obtain high-precision time-depth relationship based on VTI correction, improve the precision of the velocity model and the identification of low relief structure. The wavelet transform low relief structure identification technology, using multi scale analysis of local signals to highlight low relief structural details at different scales. Based on the comprehensive use of effective seismic interpretation technology above, the drilling of Well K9 in 2019 was successful, the thickness of the effective oil layer was 9ft, and the stable oil production was 50 t/d. Under the guidance of these achievements, a large number of low relief structures with a closure 22–30ft (4–6ms) and thin sand reservoirs with a thickness 5–12ft (1–2ms) have been drilled, make important breakthroughs in low relief-thin reservoir traps rolling exploration in slope belts, reactivate the rolling development process of old oilfield, and also provides a reference for the subtle oil reservoirs exploration with the same geological genesis and type.

Copyright 2022, IFEDC Organizing Committee

This paper was prepared for presentation at the 2022 International Field Exploration and Development Conference in **’an, China, 16-18 November 2022.

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