Impact of Polymer Rheology on Gel Treatment Performance of Horizontal Wells with Severe Channeling

Abstract

Summary Gel treatment has been a cost-effective method to control the conformance of a reservoir with severe heterogeneity problems. The water channels in such reservoirs can be classified as open fractures or high permeability porous media with pore-throat network. Many simulation studies have been conducted to discuss gel treatment performance for conformance control. However, nobody considered the polymer rheology difference in open fractures and porous media in simulation. Previous simulation studies also ignored the residual resistance factor as a function of rock permeability rather than a constant parameter. In this study, a conceptual simulation model was established to simulate the linear flow system for the reservoir with horizontal wells considering the two factors mentioned above. The results demonstrate that the gel treatment always provides the better placement results in the open fracture type channel than pore-throat network type channel. Moreover, it is very necessary to consider residual resistance factor as a function of permeability, which is based on the experimental results and can provide much greater plugging efficiency in the higher permeable channels than constant residual resistance factor. Sensitivity analysis studies and multifactor analysis indicate that increasing oil viscosity and permeability ratio has a strong positive influence on conformance control results, which indicate in-situ gel treatment can be better applied in heavy or viscous oil reservoirs with fracture-like channels. Besides, the results also indicate that in reservoirs with severe channeling problem where channel velocity was high, the differences of gelant placement and profile improvement in models with two different types of channels could be enlarged greatly.

A Novel Numerical Model of Gelant Inaccessible Pore Volume for In Situ Gel Treatment

“…Gel treatment is commonly applied in severe heterogenous reservoir that contains fractures. At a high flow velocity, the gelant can have different rheology responses in the matrix and in fractures [ 14 ].…”

“…Many factors that benefit the gelant placement of gelant have been previously studied [ 13 , 14 , 15 , 16 ]. Inaccessible pore volume (IAPV) is one of the beneficial factors.…”

Preparation and Study of Polyvinyl Alcohol Gel Structures with Acrylamide and 2-Acrylamido-2-methyl-1-propanesulfonic Acid for Application in Saline Oil Reservoirs for Profile Modification

“…There are appreciable difficulties in applying many EOR operations owing to conformance problems. , Meanwhile, harsh environmental factors such as high temperatures and ultrahigh salinity restricted EOR. For example, the Tahe oilfield (Tarim Basin, NW China) is an Ordovician fracture-cavity carbonate reservoir, wherein under high temperature (130 °C) and salinity (>20 × 10 4 mg/L), the application of the polymer gel system has been one of the most effective methods to plug the absorbent layer and improve oil recovery. − …”

Influence of the Injection Scheme on the Enhanced Oil Recovery Ability of Heterogeneous Phase Combination Flooding in Mature Waterflooded Reservoirs

“…In situ polymer gels with a three-dimensional network structure are formed by the crosslinking reaction of a polymer and a crosslinking agent. Nevertheless, there are many factors that affect the crosslinking reaction and gelation performance, leading to the uncertainty of gelation and uncontrollable gelation time. , Therefore, to overcome the problem of the uncertainty of gelation, preformed particle gels have been developed and attracted extensive attention in recent years. PPGs can absorb water and swell to form soft solid particles .…”