A new water flooding characteristic curve at ultra-high water cut stage

Abstract

A large number of field practices show that the water flooding characteristic curve will appear up-warping phenomenon in ultra-high water cut stage, and the conventional water flooding characteristic curve is difficult to accurately characterize. In this work, a new expression of oil–water relative permeability ratio (Kro/Krw) and water saturation (Sw) is proposed based on the statistical analysis of experimental data of oil–water relative permeability at high displacement multiples. The new expression has a simpler form and fewer unknown parameters. The results show that the expression can accurately fit the later section of the conventional relative permeability ratio curve, and the correlation coefficient is above 0.996. On this basis, a new type of water flooding characteristic curve suitable for the whole process of water flooding reservoir development is established by combining the reservoir engineering method. Numerical simulation and field application show that the new curve has higher accuracy and wider applicability than conventional curve. The prediction error of recoverable reserves calculated by the new curve is only 0.22%, and the error of geological reserves is less than 5%. According to the comparison between the actual data and the predicted data, the actual cumulative oil production is 2.579 × 106 t, the predicted by the new curve is 2.569 × 106 t, the actual ultimate oil recovery is 50.235%, and the predicted is 50.04%. The predicted value is consistent with the actual one. It provides a more reliable method to accurately predict reservoir development indexes and guides the oilfield’s subsequent decision-making.

The Influence of Micro-Heterogeneity on Water Injection Development in Low-Permeability Sandstone Oil Reservoirs

“…The relative permeability curve of the investigated area exhibited a concave upward type in the water phase, aligning with the standard shape for oil-water relative permeability curves (Figure 11) [57,58]. Initially, a rapid decline was observed in the oil phase permeability curve, which gradually decelerated as water saturation increased.…”

Sedimentary characteristics, formation conditions, and distribution mechanisms of beach bar sand bodies of Chang 82 submember, southwest Ordos Basin

“…Moreover, a Dutch PANalytical (Panaco) Empyrean (Sharpening) was used to perform XRD to obtain the mineralogy of the samples. 21,22 Samples were pretreated, for the purpose of observing ultraviolet reflection of the samples to ensure that the oil content of the sample is less than allowed levels, otherwise it should have been cleaned by organic solvents. The ball mill was then used to grind the rock piece to about a 380 mesh, and after that about 2 g was selected for scanning.…”

“…For grain-supported sandstone and mudstone, the empirical formula K = b-alnh is used (K is the compression coefficient, h is the present burial depth, a and b are the constants of shale a = 0.1, b = 1.46; and for sandstone, a = 0.08, b = 1.37) for compaction correction. 21,36 In the sandstone segments of the study area, the sample points of the grain-supported structure account for about 50%. The high precision compaction correction for this part of sandstone also improves the accuracy of formation compaction correction in the entire study area.…”

“…Especially in the Dongying Depression, a large area of a beach bar sandstone reservoir has been explored, proving a large hydrocarbon exploration prospect. [19][20][21] All and all, considering the importance of such geological systems to the petroleum industry, their sedimentary characteristics, distribution mechanisms, and factors impacting their petrophysical properties are subjects of research in petroleum geology.…”