Enhanced Oil Recovery Study of a New Mobility Control System on the Dynamic Imbibition in a Tight Oil Fracture Network Model

Abstract

Aiming at increasing the recovery in tight oil reservoir with fractures, a new kind of mobility control system with function of imbibition (MCSI) was prepared with dispersed particle gel (DPG) and surfactant. The dynamic imbibition can effectively control the mobility ratio in a tight oil fracture network and increase oil recovery. Based on the characteristics of tight oil reservoir fractures, the preparation method of a multiple fracture network model was established. The prepared fracture network model has the characteristics of controllable fracture length, width, and height. The MCSI system can reduce the oil–water interfacial tension to 10–2 mN/m. It features low viscosity, strengthening water wet, thus promoting the imbibition effect. Dynamic imbibition tests of the multiple fracture network model show that the MCSI system has higher oil recovery than each single component. At the same time, the subsequent water flooding after soaking also has the function of enhancing oil recovery. The effects of fluid type, flow rate, fracture width, and matrix fracture network model type on oil recovery of MCSI are clarified.

New Method Based on CO2-Switchable Wormlike Micelles for Controlling CO2 Breakthrough in a Tight Fractured Oil Reservoir

“…This study was operated to investigate the plugging performance of the dispersion; a single-tube sand pack model and an artificial fracture core were employed. , The basic parameters of the models are shown in Table .…”

“…Over the past few decades, CO 2 flooding technology has been widely applied in oil and gas field production and recognized as the most promising application approach in a tight reservoir as a result of its favorable injectivity. − In recent years, tight reservoirs have an increasing proportion of oil development and account for about 40% of the recoverable oil resources in China. , To increase the initial oil production, hydraulic fracturing technology is mainly adopted, which forces the induced fractures and natural fractures to form a complex network in tight reservoirs. − However, this fracture network tends to become a gas channel during CO 2 flooding, which causes the injected CO 2 breakthrough and bypasses crude oil, seriously affecting the CO 2 sweeping volume and the ultimate oil recovery. − …”

Differences in Imbibition Efficiency Between Bedding and Tectonic Fractures in the Lucaogou Formation in the Jimusar Sag: Evidence From Simulation Experiments

“…On the other hand, due to the strong heterogeneity between the matrix and fracture network, the fractures are likely to become flow channels for water and oil (Kathel et al, 2013). Therefore, the high permeability channel formed by fractures leads to poor water flooding efficiency in lowpermeability reservoirs (Zhao et al, 2018). The permeability of a tight reservoir matrix is low, generally less than 0.1 mD in the subsurface, and conventional water flooding is difficult for improved oil production, and spontaneous imbibition is an alternative method for tight oil reservoir development (Schechter et al, 1994).…”

Study on the Reducing Injection Pressure Regulation of Hydrophobic Carbon Nanoparticles

“…With the deepening of research, the research focus is gradually transferring from new technology field to the traditional petrochemical energy research field. Because of their volume effect, surface effect, and quantum size effect, nanomaterials have shown wide application potentials in oilfield. − Facing the problem of “high injection pressure” greatly restricting the exploitation of tight reservoirs, it is of great significance to seek suitable nanofluid to realize the pressure-reducing of tight reservoirs. The research on the application of nanomaterials in oilfield is early carried out.…”