Synergistic mechanism of well pattern adjustment and heterogeneous phase combined flooding on enhancing oil recovery in mature fault-block reservoirs

Abstract

With the maturity of fault-block reservoirs, the water percolation channels are formed after long-term waterflooding, which leads to large amounts remaining oil unrecovered and low recovery efficiency. Thus, it is imperative to seek for enhancing oil recovery methods to improve the development performance of mature fault-block reservoirs. Well pattern adjustment and heterogeneous phase combined flooding are both feasible technologies for enhancing oil recovery in mature fault-block reservoirs. Nevertheless, both technologies have their limitations. Thus, a hybrid approach combining WPA and HPCF was proposed. In this study, the large-scale plate sand-pack model flooding experiments were conducted to investigate whether hybrid strategy has better EOR ability than the single WPA or HPCF. Thereafter, on the basis of incremental oil recovery and distribution of remaining oil, the mechanism of the synergistic effect of WPA and HPCF was illustrated. Finally, the influence of reservoir inclination on development performance was proposed. The results show that EOR of hybrid strategy is the highest, followed by single HPCF, and single WPA is the least. The HPCF mainly recovers remaining oil on both sides of main streamline after water flooding, and it prolongs the period of EOR validity. WPA can change the fluid flow direction and force the subsequent liquid enters the un-swept non-main streamline areas in the water flooding stage. Furthermore, by combining WPA and HPCF, the HPCF can enter the non-main streamline areas to expand sweep volume and improve oil displacement efficiency under the induction of WPA. Besides, the reservoir inclination has an obvious influence on the development performance of fault-block reservoir. With the increase of reservoir inclination, the incremental oil recovery of the single strategy or hybrid strategy decreases. Thus, these findings of this study can help for better understanding the synergetic effect of HPCF and WPA, which can provide a hybrid strategy for enhancing oil recovery in mature fault-block reservoir.

Numerical Simulation on the Heat Recovery Law of Exploiting Geothermal Energy from a Closed-Loop Geothermal System Converted from an Abandoned Five-Spot Well Pattern

“…Deployment of the well pattern is an important step in oilfield development, which is crucial to improving oil and gas production efficiency. 12 Common well pattern deployment schemes include the four-spot, five-spot, and nine-spot methods as shown in Figure 1 . 13 …”

“…For the production technologies mentioned above, there are already relatively mature models for reference. However, in the production of oil fields, different well patterns are often deployed to improve the oil and gas recovery efficiency . There is still a lack of transforming a five-spot abandoned well pattern into a closed-loop geothermal system in the existing research.…”

“…However, in the production of oil fields, different well patterns are often deployed to improve the oil and gas recovery efficiency. 12 There is still a lack of transforming a five-spot abandoned well pattern into a closed-loop geothermal system in the existing research. Therefore, a novel production scheme based on the five-spot well pattern is proposed.…”

Numerical Simulation Study of Pressure-Driven Water Injection and Optimization Development Schemes for Low-Permeability Reservoirs in the G Block of Daqing Oilfield

“…Extensive water injection has left a considerable volume of untapped oil reserves and a lower-than-desired recovery rate. Researchers have been diligently exploring the optimal wellbore configuration and network design that can effectively boost water flooding recovery rates [3][4][5]. In the context of the study on the five-spot method, Xiao et al [6] proposed that the five-spot well pattern exhibits significant potential for enhancing methane recovery in coal bed methane reservoirs.…”

Mechanistic Insights into a Novel Controllable Phase-Transition Polymer for Enhanced Oil Recovery in Mature Waterflooding Reservoirs

“…Chemical flooding technology can significantly enhance oil recovery by expanding sweep efficiency and improving oil displacement efficiency. Chemical flooding technology can be categorized as follows: polymer flooding [4][5][6][7], surfactant flooding [8][9][10][11][12][13][14][15], nanoparticle flooding [16][17][18][19][20][21][22], surfactant-polymer combined flooding [23][24][25][26][27][28][29][30][31][32][33][34], and heterogeneous phase combined flooding [35][36][37][38][39][40].…”