Research of phenolic crosslinker gel for profile control and oil displacement in high temperature and high salinity reservoirs

Abstract

To further enhance oil recovery of high temperature and high salinity reservoir at Tahe Oilfield, field test results from profile control and oil displacement of gel were carried out in this article. Static and dynamic evaluations were performed through gel strength code method, environment scanning electron microscope, and physical simulation experiment devices. The field test results show that, under the conditions of high temperature (100.8 8C) and salinity (19.8 3 10 4 mg/L), the stable gel system was formed with gelling time range from 26 to 45 h, gel strength ranging from E to H, and dehydrating amount lower than 3.0% after ageing 60 days. Meanwhile, the microstructure is very stable. When the permeability and gel strength ranges from 0.212 to 0.970 lm 2 and E to H, respectively, the plugging ratio is larger than 85%, and the plugging performance becomes better with the increase of permeability or gel strength. Due to the profile improvement rate of 99.8% and the oil recovery up to 28.5%, profile control and oil displacement technology of gel can effectively promote fluid diverting. The water cut reduced from 95.2% to 89.0% during field test carried out in Tahe Oilfield, which means that profile control and oil displacement technology of gel could stabilize oil production by water control effectively. Also, this technology has a wide application prospective that provides with strong technical support for further enhanced oil recovery in high temperature and high salinity reservoirs.

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

“…Increased global energy demand has substantially increased oil production. , Oil recovery processes are categorized into three stages: primary, secondary, and tertiary oil recovery [known as enhanced oil recovery (EOR)]. However, only ∼55% of the original light oil (30–50° API) and ∼10% of the original heavy oil (<15° API) can be recovered in the primary and secondary recovery operations of the original oil in place. , In secondary oil recovery, most oilfields are developed using the water injection technology, which aggravates the heterogeneity and anisotropy of the reservoir environment, gradually forming fractures and dominant channels. , The exploitation processes of unconventional oilfields have led to the development of more significant hydraulic fractures, and the natural fractures have deteriorated further. − Excessive water production has become a serious issue in petroleum reservoir development, adding to the production cost as the disposal of excess water should be considered and much oil from the reservoir remains unswept. − Conformance control is essential for reducing water production for successfully applying water injection and enhancing oil recovery operations in petroleum development. − Nevertheless, EOR contribution to the global oil supply is ∼2% . 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.…”

“…However, only ∼55% of the original light oil (30−50°API) and ∼10% of the original heavy oil (<15°API) can be recovered in the primary and secondary recovery operations of the original oil in place. 3,4 In secondary oil recovery, most oilfields are developed using the water injection technology, 5 which aggravates the heterogeneity and anisotropy of the reservoir environment, gradually forming fractures and dominant channels. 6,7 The exploitation processes of unconventional oilfields have led to the development of more significant hydraulic fractures, and the natural fractures have deteriorated further.…”

Investigation of Polyvinyl Alcohol–Phenolic Aldehyde–Polyacrylamide Gel for the Application in Saline Oil Reservoirs for Profile Modification

“…Due to the special reservoir environment (high temperature and high salinity), the stability of conventional profile control plugging agents is weakened, − and the high permeability layer seriously affects the water flooding operation, which limits the recovery rate. , As one of the most effective methods in the process of reservoir profile control and water plugging and enhanced oil recovery, the polymer gel profile control system is mainly composed of polyacrylamide (PAM), hydrolyzed polyacrylamide (HPAM), acrylamide (AM), and the organic or inorganic cross-linking system; − furthermore, the carboxylic acid groups of PAM hydrolysis are also coordinated with the multivalent cation. − However, the field application of conventional gel profile control agents in Tahe oilfield still has limitations. , In the research process of gel profile control agents with high-temperature resistance and high salt, phenol-formaldehyde gel has been widely used, ,− but the toxicity of formaldehyde limits its application . In addition, EOR technology using profile control agents or oil displacement agents accounts for two-thirds of the initial oil production .…”

Preparation Method and Performance Evaluation of a Gel Based on AM/AMPS Copolymer

“…In the process of EOR research, physical simulation experiments are required to complete the oil displacement mechanism, formulation, and injection mode optimization performance evaluation of oil displacement agent and its effect verification. At present, the plugging performance evaluation of gels is mostly carried out in the sand pack [ 19 ]. In this paper, the plate model is used for reservoir simulation for the first time.…”