An Interpretation Method with “Well-Cave-Crack” Model of Dissolves Reservoir Considering Gravity Factors

doi:10.19596/j.cnki.1001-246x.8032

Abstract

Abstract: Shunbei oilfield belongs to fault reservoir formed by movement of large fracture structures. Longitudinal fracture system and vertical distribution of caves are main storage collective spaces. It is proposed that the pressure change in a cavern is caused by flow and fluctuation. According to this, energy conservation equation is combined with well test theory, and a method is established to explain well test of dissolvable reservoir considering gravity factors. With dimensionless quantity and Laplace transformation of dimensionless equation, bottom pressure on Laplace space is obtained. Plate curve for well test analysis is obtained with Stehfest numerical inversion algorithm. Sensitivity analysis of gravity factors shows that gravity factors affect end of the double logarithmic curve. As gravity factors are obvious, curve characteristics are similar to fixed pressure boundary. A well in Xinjiang oilfield is analyzed, in which the reason why it fell down in the later stage of the curve is explained and the valume of karst cave and other related parameters are given. The results are consistent with actual production situation.

Key words: Shunbei oilfield, dissolution reservoir, gravity, crack cave

CLC Number:

TE371

XU Yandong. An Interpretation Method with “Well-Cave-Crack” Model of Dissolves Reservoir Considering Gravity Factors[J]. CHINESE JOURNAL OF COMPUTATIONAL PHYSICS, 2020, 37(2): 189-197.

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