The Controls of Pore-Throat Structure on Fluid Performance in Tight Clastic Rock Reservoir: A Case from the Upper Triassic of Chang 7 Member, Ordos Basin, China

Yunlong Zhang,Fei Yang,Zhidong Bao,Li Jiang,Jian Song,Shuwei Mao

doi:10.1155/2018/3403026

Yunlong Zhang, Fei Yang + Show 4 more

Open Access

https://doi.org/10.1155/2018/3403026

Copy DOI

Abstract

The characteristics of porosity and permeability in tight clastic rock reservoir have significant difference from those in conventional reservoir. The increased exploitation of tight gas and oil requests further understanding of fluid performance in the nanoscale pore-throat network of the tight reservoir. Typical tight sandstone and siltstone samples from Ordos Basin were investigated, and rate-controlled mercury injection capillary pressure (RMICP) and nuclear magnetic resonance (NMR) were employed in this paper, combined with helium porosity and air permeability data, to analyze the impact of pore-throat structure on the storage and seepage capacity of these tight oil reservoirs, revealing the control factors of economic petroleum production. The researches indicate that, in the tight clastic rock reservoir, largest throat is the key control on the permeability and potentially dominates the movable water saturation in the reservoir. The storage capacity of the reservoir consists of effective throat and pore space. Although it has a relatively steady and significant proportion that resulted from the throats, its variation is still dominated by the effective pores. A combination parameter (ε) that was established to be as an integrated characteristic of pore-throat structure shows effectively prediction of physical capability for hydrocarbon resource of the tight clastic rock reservoir.

Highlights

Hydraulic properties of rock formations are critical to evaluate the economic viability of petroleum, gas, and geothermal and groundwater reservoirs [1, 2]
The pores and suborder throats are filled up; this process is, named subison, continued until the pressure returns back to the first pressure drop-down point, and it increases again to the process of rison and subison. This technique resolves the space of the reservoir into pore bodies and throats; each of them is characterized by entry pressure and mercury volume curve [58]
The weak relationship between core analysis porosity and permeability indicated that the porosity of these tight reservoirs inappreciably impacts on permeability, implying that the permeability of tight reservoir was controlled by the other factors (Figure 3)

Summary

Introduction

Hydraulic properties of rock formations are critical to evaluate the economic viability of petroleum, gas, and geothermal and groundwater reservoirs [1, 2]. Capillary flow, which was proposed by Washburn [9], as a kind of non-Darcy flow, dominated the seepage mechanism in the reservoir sophisticatedly and received more and more attention in researches of reservoir quality and petroleum and gas recovery [10,11,12,13,14,15]. The pore-throat structures are various significantly in tight clastic rock reservoir and the fluid flow inside needs to be concerned [25,26,27,28,29]

Methods

Findings

Discussion

Conclusion