Formulation Development of High Strength Gel System and Evaluation on Profile Control Performance for High Salinity and Low Permeability Fractured Reservoir

Abstract

For the large pores and cracks of reservoirs with low temperatures, high salinity, and low permeability, a new type of high strength gel ABP system is developed in this paper. The defects of conventional gels such as weak gel strength, no gelling, and easy dehydration are overcome under the conditions of low temperature and high salinity. The temperature and salt resistance, plugging characteristics, and EOR of the gel system are studied. Under the condition of 32°C and 29500 mg/L salinity, the ABP system formulation is for 0.3% crosslinking agent A + 0.09% coagulant B + 3500 mg/L polymer solution P. The results show that when the temperature was increased, the delayed crosslinking time of the system was shortened and the gel strength was increased. The good plugging characteristics of the ABP system were reached, and the plugging rate was greater than 99% in cores with different permeability. A good profile control performance was achieved, and the recovery rate was improved by 19.27% on the basis of water flooding. In the practical application of the gel system, the salinity of formation water and the permeability of fractures are necessary to determine the appropriate formulation.

Microbial enhanced oil recovery through deep profile control using a conditional bacterial cellulose-producing strain derived from Enterobacter sp. FY-07

“…Unlike FY-07, pressure when using FY-0701 did not show an obvious change during the cell injection process, but it increased by approximately 3.29-fold in the subsequent water flooding process (Fig. 6a, b), which conforms to the general trait of profile control [10,16,26]. The schematic diagram of FY-07 and FY-0701 in oil displacement processes are shown in Fig.…”

“…Flooding water is then redirected into low permeability zones, thereby enlarging sweeping volume [16,34]. The deeper the plugging position, the larger is the volume between the plugging position and entrance, and the higher is the sweep volume [25,26]. This implies that the sweep volume of flooding water in deep profile control was higher in comparison to non-deep profile control.…”

“…Deep profile control is essential because in extensively developed reservoirs, residual oil is still present in zones far from the injection well [7]. The sweep volume and enhanced oil recovery (EOR) are positively correlated with profile control depth [25,26]. BC is a primary metabolite of FY-07; FY-07 growth is accompanied by BC production, which, however, is not beneficial for FY-07 migration.…”

Investigation on Plugging and Profile Control of Polymer Microspheres as a Displacement Fluid in Enhanced Oil Recovery

“…Then, in combination with the size of the PMs, the matching pattern can be determined. As shown in Figure 8, the pore throat size of the core varies widely, rather than the value calculated by Equation (1). Further, the size of the PMs is not a constant value but varies within a certain range.…”

“…Once the oil field is in the high water-cut stage, oil-water distribution in the reservoir becomes complicated, and reservoir heterogeneity becomes severe, causing water to bypass small pores and low-permeability layers, flowing along the large pores and high-permeability layers. As a result, the remaining oil in the small pores and the low-permeability strips cannot be displaced, forming an ineffective water circulation [1,2]. In order to further enhance oil recovery (EOR), it is possible to increase the sweep factor and oil displacement efficiency of the injected fluid.…”