Characterization Method of Tight Sandstone Reservoir Heterogeneity and Tight Gas Accumulation Mechanism, Jurassic Formation, Sichuan Basin, China

Abstract

Although significant progress has been made in tight gas exploration and development, there is still a limited understanding of the gas accumulation mechanism in tight formation. The description of heterogeneity in the tight reservoir is still an obstacle during tight gas exploration. In this work, we will develop a 3D gas accumulation facility that can reflect the high temperature and pressure under the geological condition to simulate the gas accumulation process in the tight formation of the Jurassic Formation, Sichuan Basin. Both the physical experiment simulation and numerical simulation methods will be combined to reveal the mechanism of gas accumulation. The results show that (1) the permeability ratio can characterize the heterogeneity of tight reservoirs. Based on this parameter, petroleum geologists can understand the interlayer heterogeneity during fluvial deposition and predict the sweet spots of tight gas; (2) the permeability ratio relationship between hydrocarbon accumulation of the tight sandstone reservoir mainly manifests as long as there is the existence of the differential permeability and there will be differences in natural gas migration dynamics, so that the natural gas accumulates in pores and depends on the extent of source rock; and (3) although the difference between capillary force curves is at the core of the influence of the permeability ratio on the gas-bearing capacity of the “sweet spot” sand body, the permeability ratio is a parameter of practical engineering significance. This work adds new methods to tight gas formation heterogeneity characterization and sheds light on the mechanisms of hydrocarbon accumulation in tight formation.

Analysis on the Difference of Micropore Structure Characteristics and Physical Properties of Mixed Rock Reservoir

“…The reservoir quality is affected by the micropore structure [5][6][7][8][9][10][11][12][13][14]. The complex pore structure of mixed reservoir leads to poor reservoir characterization based on mercury injection curve shape or pore throat distribution and other parameters.…”

Evaluation of Profile Control and Oil Displacement Effect of Starch Gel and Nano-MoS2 Combination System in High-Temperature Heterogeneous Reservoir

“…Meanwhile, significant residual oil remains in the lowpermeability layers, highlighting the contrast between layers. Intralayer heterogeneity refers to differences in reservoir properties within a single sand layer [9,10]. For instance, in rhythmically deposited reservoirs, the bottom high-permeability segments are prone to intralayer advancement, while the top low-permeability segments accumulate residual oil, emphasizing the intralayer contrast.…”

Hydrocarbon Geological Characteristics and Factors Controlling Hydrocarbon Accumulation of Jurassic Da’anzhai Continental Shale

“…This provides an important strategic replacement resource to increase the hydrocarbon reserves and production. In chronological order, Jurassic oil and gas exploration in the Sichuan Basin has undergone three stages: the conventional hydrocarbon stage, the tight reservoir stage, and the shale oil and gas stage [8][9][10]. Before 2010, the exploration targets were the Jurassic Lianggaoshan tight sandstone and Da'anzhai (J 1 dn) tight limestone reservoirs, and production was achieved using sand fracturing technology.…”