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Visualization and Quantification of Deeply Buried Paleokarst Reservoirs in Tahe Oilfield, Tarim Basin, Previous HitChinaNext Hit

Abstract

Mapping and quantify Previous Hit3-DNext Hit construction of the paleokarst reservoirs is a challenge in deeply buried (>5500m) heterogeneous carbonate system, as their irregular geometry and complex filling materials. Well-logging constrained acoustic impedance Previous HitseismicNext Hit dataset and Previous HitseismicNext Hit attribute analysis combined with Previous Hit3-DNext Hit visualization technology provide a significant amount of visible information about paleokarst reservoirs’ features in Tahe oilfield, Tarim basin. This paper describes an integrated approach to visualize and quantify the paleokarst reservoirs. First, caves’ recognize equation is developed using conventional well-logging Previous HitdataNext Hit, which is demarcated Previous HitfromNext Hit core and image logs with a cave resolution of approximately 0.5 m. Second, time-depth conversions for 97 wells are identified one by one, and the recognition results in the signal wells are tied to Previous HitseismicNext Hit dataset. Third, after determining the cutoff values of the host rocks and the caves in acoustic impedance, the impedance Previous HitinversionNext Hit volume can recognize the spatial construction of the paleokarst reservoirs effectively. Forth, the Previous Hit3-DNext Hit mapping and visualization of the paleokarst reservoirs are achieved by tracing the distribution of caves. Fifth, based on the Previous Hit3-DNext Hit ‘geobody’ and karst genetic theory, comparing with spatial geometry of the Mammoth Cave, the Tahe paleokarst reservoirs are divided into epikarst, vadose and runoff zones. Additionally, the genetic types of them are identified, i.e. chamber caves, main channel, branch channel etc. Using Previous Hit3-DNext Hit visualized geobody, the length, width, area, volume of different genetic types are calculated, and the chamber caves and main channels are pointed out as prior targets for hydrocarbon exploration. Using Previous Hit3-DNext Hit visualization technology, the spatial construction of paleokarst reservoirs is delineated; combined with the karst hydrodynamics theory, vertical zones and genetic types of the reservoir are divided; the entrances, exits, collapses and relative high points of the cave systems are identified; the quantification of each genetic type is calculated Previous HitfromNext Hit line, area to volume. All achievements above provide detailed information of the reservoir for Previous HitstructuralNext Hit model, geological model, hydrocarbon exploration and can be Previous HitappliedTop to other similar paleokarst oilfields.