Abstract
In order to analyze the factors influencing sandstone mechanical compaction and its physical property evolution during compaction processes, simulation experiments on sandstone mechanical compaction were carried out with a self-designed diagenetic simulation system. The experimental materials were modern sediments from different sources, and the experiments were conducted under high temperature and high pressure. Results of the experiments show a binary function relation between primary porosity and mean size as well as sorting. With increasing overburden pressure during mechanical compaction, the evolution of porosity and permeability can be divided into rapid compaction at an early stage and slow compaction at a late stage, and the dividing pressure value of the two stages is about 12 MPa and the corresponding depth is about 600 m. In the slow compaction stage, there is a good exponential relationship between porosity and overburden pressure, while a good power function relationship exists between permeability and overburden pressure. There is also a good exponential relationship between porosity and permeability. The influence of particle size on sandstone mechanical compaction is mainly reflected in the slow compaction stage, and the influence of sorting is mainly reflected in the rapid compaction stage. Abnormally high pressure effectively inhibits sandstone mechanical compaction, and its control on sandstone mechanical compaction is stronger than that of particle size and sorting. The influence of burial time on sandstone mechanical compaction is mainly in the slow compaction stage, and the porosity reduction caused by compaction is mainly controlled by average particle size.
Highlights
The analysis shows that the evolution of porosity and permeability has a segmentation characteristic with the increasing overburden pressure and depth during mechanical compaction, and the evolution trend line can be divided into two stages
Regression analysis results show that there is an exponential relationship between porosity and overburden pressure, and the relationship can be expressed as y = AeBx; while a power function relationship exists between permeability and overburden pressure, that is y = CxD
There is a logarithmic relationship between primary porosity and particle size as well as sorting, and the binary function relation between primary porosity and the two factors is U0 = -3.0413So - 3.4907 M ? 47.828123, which can provide reference for the calculation of primary porosity of sandstone reservoir
Summary
With increasing oil and gas exploration and the growing demand for oil and gas reserves, the oil and gas exploration targets of clastic rocks have turned to low porosity and permeability reservoirs, even to tight sandstone reservoirs, and they have gradually become the main source of increasing reserves and production of oil and gas (Wang and Tian 2003; Dai et al 2012; Hart 2006; Zou et al 2013; Tobin et al 2010; Jia et al 2012; Worden et al 2000; Bloch et al 2002; Wang et al 2010; Zhang et al 2011). Current studies about various factors influencing compaction mainly focus on simple and qualitative description, and little work has been done on quantitative analysis based on simulation experiments, leading to the vague understanding of the evolution of physical properties and influencing mechanisms of various factors during mechanical compaction processes. This directly restricts the accurate characterization of the formation of low porosity and permeability sandstone reservoirs and their densification processes. The automatic control system is used for measuring and recording sandstone permeability in real time
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
