A New Modeling Method for the Sandbody Architecture of Braided River Reservoirs: A Case Study from HG Formation, N Gas Field

Abstract

A new modeling method is proposed to address the shortcomings of conventional geological modeling methods in simultaneously characterizing the geometry, stacking patterns, and well data of the channel bar in braided river. The channel bar model is reconstructed based on the target body, which is defined by the channel bar’s geometric parameters points, lines, and surfaces. In the simulation process, the distributions of sandstone and mudstone are simulated first. Then, the channel bars at the well are simulated based on the channel bars identified on the well and the thickness of the sandstone, the priori geometries, and sizes of the channel bars. It is judged whether the proportion of the simulated channel bars has reached the global proportion. If not, a randomly selected point between wells is used as a virtual well, and the sandstone thickness is used to determine whether it is a single or composite channel bar. The process is repeated until the proportion of channel bars reaches the set proportion. Take the N gas field as an example. The analysis of the geometry, variance function, thickness distribution histogram, and volume distribution histogram of the simulation results shows that the new method can better characterize the channel bar’s geometry, sizes, and stacking patterns than the multipoint geostatistical modeling method Snesim.

Quantitative Scale Analysis of the Channel Bar in a Braided River and Its Internal Architecture

“…After the determination of the inclination angle of the architecture interface of the accretion, as well as the width and length of the accretion, this study establishes the architecture model of the vertical deposited sand in PI3 sublayer in the dense well pattern area in the Nanwu area [39]. The cross-paleocurrent direction is nearly horizontal, while the paleocurrent direction is slightly inclined to the downstream direction (Figure 11).…”