Investigating the effects of polymer plugging mechanism of liquid production decrease and improvement by the cross-linked gel performance

Polymer flooding, as the most successful and well-known chemical EOR method was broadly applied around the world. Mostly, contrasted with Waterflooding, the production rate decrease during polymer flooding is smaller based on field application. Nevertheless, the production liquid rate decreased critically in the middle phase to late phase due to plugging, which could lead the way to poor flooding performance and fewer cumulative oil. In this work, first, we approached the affecting polymer plugging mechanism model on liquid production decrease to investigate the parameters such as; solid-phase concentration (SOLIDMIN), reacting frequency factor (FREQFAC) and others affecting components are all investigated consecutively. Secondly the model approached by cross-linked gel for the improvement of production liquid rate. The physical work was designed by a physical model, and then the polymer adsorption that generating blockage emerging in permeability diminish assessed by a mathematical model. The outcomes specify that the existence of this debris, excessive assemblage of solid-phase and the excessive reactant frequency factor has major mechanical and physical parameters effects on the reservoir throughout polymer flooding. Polymer flood model base case liquid ratio loss is 11.15 m3/day between the years 2014-08-01 to 2020-03-04. Comparing with the polymer flood model case 1, liquid ratio loss ranging to 1.97 m3/day between the years 2014-08-02 to 2020-03-03. While the oil ratio loss of the polymer flood base case model between the years 2015-07-08 to 2020-03-04 attained 12.4 m3/day contrasting with the polymer flood model case 1 oil ratio increase to 0.37 m3/day between the years 2014-08-04 to 2019-04-02. The cross-linked gel model base case liquid ratio loss is 2.09 m3/day between the years 2015-01-02 to 2020-02-03, while the oil ratio lost reached 9.15 m3/day between the years 2015-09-01 to 2020-02-03. Contrasting with the cross-linked gel model case 2 liquid ratio recovered from the loss and attained 25.43 m3/day in the year 2020-12-01, while the oil ratio is reached 15.22 m3/day in the year 2020-12-01. Polymer flood model examined through cross-linked gel model performed reliable outcomes by taking out the plugging, which also occasioned the reservoir production rate to decrease. With the application of cross-linked gel the affected parameters and the production rate have achieved an improvement.

www.nature.com/scientificreports/ This is kind of permeability diminution is calculated alongside a permeability diminution factor (Rk) who defined to a proportion with effective permeability toward brine as well as polymer solution. This outcome of permeability diminution remains undertaken to be irreparable also carry on afterwards polymer flooding as well as is named residual resistance factor (RRF). The RRF interpreted like the proportion of this mobility with a brine solution ahead also afterwards this polymer injection. The diminution of the permeability factor is likely considerable despite many polymers like Xanthan gum, or during this establishment, permeability occur higher 56 .
The injectivity reduces because of the permeability diminution element terminate; meanwhile, polymer retention achieves to the greatest extent.
Throughout this activity of water plugging, mostly this frequent non-success circumstance alike polymer gel simply is infiltrated by the ensuing water passage because of this failure of the polymer substance. Consequently, recently developed water passage established is also the extension about this swept away capacity happened to be restricted 57 . These, due to plugging the fracture, need a polymer gel alongside a steady scheme along with an inflated mechanical solidity, who can entirely bung this water passage also preserve an acceptable achievement under the prolonged cleaning of the injected water.
In conformance with the numbers of Changqing oilfield and Yanchang oilfield, these mostly used polymer gels are the gel fragments with the in-situ cross-linking polymer gel. Gel particles have a concentrated threedimensional mesh shape alongside a vigorous energy storage size, an elevated solidity, also a high viscoelasticity 58 .
The objective of this research is to investigate the main parameters causing the plugging mechanism on the reservoir production rate. Along with applying cross-linked gel for improving the affected parameters and boosting the production rate.
The affecting parameters were assessed through CMG STARS software. The indicated analysis introduces a clear method for the forthcoming study.
The higher proceeding simulators STARS is entirely presented thermal compositional model (Rubin and Buchanan, Oballa et al.) such utilized earlier within a wide variety of primary recovery besides secondary recovery simulation to many years. Additionally, as typical reservoir gridding capacities, entirely integrated well models, together with forward numerical solution approach plus adjustable implied algorithms, its adaptability in explaining many fluid flow methods with structure is especially significant. Such last level capabilities comprise the outcomes of proceeding supplements as follow; polymer, gels, surfactants, including foams 59 .
Therefore, this frequent multi-element non-equilibrium originally build for in-situ combustion modeling used in order to illustrate supplementary non-equilibrium combining in addition to condition substituting operation like foamy oils 60 . The usefulness of this sort of capability in the modeling of sand migration besides production will be enlarged in this work.

Methods
This research work was formed on a five spot-pattern model of 21 × 21 × 5 grid blocks in total 2205 are active was been modelled to accomplish this analysis. X, Y with a mesh size of 40 ft. It was partitioned toward five layers in distinction to uppermost orientate toward the base. Such explain the median thickness of the primary layer is 5 ft. Water Oil Contact (WOC) about 4050 m moreover the Gas Oil Contact (GOC) about 4000 m. This permeability differs through primary toward the 5th layer (X, Y, as well as Z), orientation like presented in Table 1, and (see Fig. 1) 61,62 .
The reservoir water injection well is specified upon restraint STW surface water ratio of 100 m 3 /day, alongside a BHP controlled at 17,000 kPa on utmost. The producer wells are specified to function on BHP (bottom hole pressure) of 16,000 kPa. The liquid phase viscosity table, and a lower range of 25 °C to an ultimate range of 100 °C.
The non-equilibrium blockage mechanism operated with the SOLIDMIN and the FREQFACT with differing ranges for the base cases (polymer flood model and cross-linked gel model) beside the sensitivity cases in Table 2.
For the achievement of this work, CMG STARS software was used 63  During the application of polymer flooding model, the sand migration along with movement treatment were approached as follow in this work: 'N_MOVING': Sand composition which appear in solid-phase which remains non-moving or stagnant (Solid). Stagnant sand possibly causes permeability decrease (blockage) in particular to equilibrium mass transfer to the rock (Adsorption).
SAND: A sand composition which is available toward oil stage (oleic), who brought within oil moreover liberated whereas the entrance of the operating formation. The presence of this element possibly varies oil viscosity within material affecting the migration of sand about the producer well surrounding.
('N_MOVING'): The Initial solid concentration which is fixed with a concentration of 0.052 along with the oil mole fraction (sand) of 0.0025 determined; each one is evaluated by the software.
(STOREACT): The influence of reaction frequency activation energy that appear toward the reaction constituent of CMG STARS (STARS USER GUIDE), shows the frequency factor of the reacting portion. Such contributes a crucial part to the outcome, additionally the plugging influences. Through model ingredient, it was recognized such chemical element positioned through the stoichiometric proportion, every accumulation specified about, it is mass throughout the sand plug model (polymer, Sand, 'N_MOVING') reaction outcome in sand-solid consistency.
By specifying the foremost polymer molecular mass of the polymer, it is advantageous for appraising reservoir permeability as well oil viscosity.
This gel is predominantly utilized throughout this worldwide due to its adherence, alongside injecting the concentration of gel, lessen the permeability of elevated areas which occur obstructed or plugged regardless of www.nature.com/scientificreports/ influencing this little permeable area. It explains that additional oil were recuperated out of the non-swept fewer permeable areas. This fundamental modeling method goes along with 64 . The fluid input model was detailed alongside six chemical elements as follows: water, polymer (polyacrylamide), cross-linker (phenol-formaldehyde) also gel established into the aqueous phase while dead oil, as well as solution gas were determined into the oleic phase, the polymer, along with gel elements as well adsorbed through the rock.
Polymers will be classified as biopolymers (natural polymers) and synthetic (plastic) polymers. Natural polymers were produced by microscopic organisms such as bacteria, fungus whereas synthetic polymers were synthesized by scientists (or humans) 65 .
By injecting polymer toward the formation, encircled within the inactive proportion. Beneath a number of the succeeding circumstances: high temperature, and high pressure, the plugging alongside complicated mechanisms remains initiated.   www.nature.com/scientificreports/ In order to barrage or plugging issue eradication, a model input constituted of the subsequent chemical elements: Water, polymer, cross-linker, and gel altogether set into the aqueous phase, xanthan into (solid-phase) as well as dead oil into (Oleic phase).
Polymer, gel as well as xanthan elements altogether soaked up within this rock. Polymer, xanthan, as well as cross-linked gel are entirely used for: porosity, permeability, water viscosity, polymer deterioration, inaccessible pore volume, the elevated accumulation of solid-phase also the elevated reactant frequency factor.
Xanthan can resist to mechanical degradation (shear), and is thermally steady between the temperature limit of 70-90 °C 66 .
However, these composite is especially sensitive to bacterial deterioration once injected toward this field consisting of lower temperature areas in the reservoir. In addition, it has already been outlined that xanthan can transport a number of cellular junk that result in plug 67 .
In this current research work, some of the following polymers were considered; Hydrolyzed Polyacrylamide (HPAM), biopolymers (xanthan) and synthetic polymer as a gel.
HPAM is a polyelectrolyte that interconnect firmly alongside ions in solution. The adaptability of HPAM polymeric interconnected structure form further interactive to the ionic solidity of aqueous solutions and therefore additional sensible to salt/hardness contrasted to additional polymers like xanthan gum 68 .
Xanthan gum is a biopolymer liberated alongside the microorganism Xanthomonas campestris as well is produced economically at the fermentation operation. Aqueous solutions of xanthan gum are extremely viscous overdue to the existing dual with triple helix structure of the polymer chain accompanied by enormous polar side bonds that forward considerable hydrogen bonds 69 .
Gel injection is one of the most efficient techniques of EOR to increase oil recovery. Water management can be a better option than increasing oil production 70,71 . Especially in heterogeneous reservoirs, gel injection, could be selected instead of polymer injection 72 .
The purpose of applying gels for oil recuperation has begun during the 1990s. Biopolymers and synthetic polymers which form gelation, thickening or emulsification/stabilizing agents have been used successfully in the oil reservoirs 48 . With the commercially available biopolymers and synthetic polymers in aqueous solutions, this mixture produces gels as a result of the thickening in water 73 . The movable gels have high viscosity that leads increase of oil mobility. Gels have been used in highly permeable reservoirs to reduce permeability. Hydrogels or water-based gels decrease the permeability of water rather than oil permeability 74 .
Similarly, oil-based gels reduce the permeability of oil compared to water permeability. Resistance factor increases due to high viscosity of water and low permeability that shows an increment of recovered oil 75 .
Microgels, performed particle gel (PPG), pH-sensitive cross-linked polymers are the commercially available gels to use in the petroleum reservoirs 76 .
The interaction between gels and water can make the gels shrink, swell or stay in the same size based on the gel type, the salinity of water, temperature and shear rate 77 . PPG are strength and size-controlled, environment friendly, and their stability is not sensitive to reservoirs minerals and formation water salinity. The size of PPG can be controlled based on the pore sizes to decrease permeability. Gels have been applied to heterogeneous reservoirs to form the reservoirs homogenous 78 . Therefore, gels injection may also be preferred for the reason of its enhancement of sweep efficiency prior to injecting a costly polymer.
The blockage mechanism is used for the distinct cases of the polymer model and the gel cross-linked are investigated under the identical model. www.nature.com/scientificreports/ The permeability reduction is on account of mechanical entrapment beside it demonstrated as phase permeability decrease 79 .
The permeability influencing or varying while polymer flooding and cross-linked gel model cannot be observed in the three-dimensional model outcome.
The permeability decrease is relying on the adsorption, input elements alongside ADSCOMP. The rock depending on adsorption is detailed as shown: These replacements prior to polymer flooding also afterwards polymer flooding possibly evaluated through the Eq. (1) below; The adsorption element is determined like the adsorption element, residual resistance factor, and desorption proportion depends upon this permeability of the formation.
Reservoir heterogeneities generate those properties to vary significantly throughout the bounds of a reservoir. Appropriately, equilibrium adsorption remains a justification of position in addition to component concentration as well as temperature.
The adsorption can generate the clog up who is the reduced amount in the effective permeability. Such is considered as for ascending the adsorption acquired out of delimited concentration along with temperature circumstances alongside the factor 80 .
While the amount of adsorption degree rise through time variation, R k vary starting with 1.0 to a very higher RRF 81 . Ahead of the utilization of polymer flooding, the RRF alongside mobility differentiation can be formulated like specified by; Polymer flooding lessens the permeability to a particular layer, predominantly provided this solid accumulation stage of the polymer adsorption, who in consideration of reducing the permeability of all layers.
A linear fluid flow by Darcy law intended to remain used in that manner; because of non-variant flow rate and entire pressure reduce is p the entire of the diminish of every single layer.
Displacing the pressure decrease by Darcy equation for each of the five (5) layers as well as permeability; Concluding the equivalent designation then defining the equation will appear as: where; AK determined as usual grid block permeability for water as AK w (i, j, k) an issue and for oil as AK o (i, j, k) . The relative mobility of the phase carrying an absorbing component was certainly influenced by the viscosity and blockage. Where; (i, j, k) indicate the grid block permeability flow in a different directions. The permeability reduction influences the permeability of water and oil were presented as listed below; AK w (i, j, k), AK o (i, j, k) as; Polymer adsorption who cause in permeability decrease evaluated alongside the factor as shown; (2) www.nature.com/scientificreports/ The non-accessible pore volume (IPV) primary was recommended by (Daws on and Lauthz 1972), a certain number of pore were not attained while the polymer flooding process moreover it was in the end acknowledged by (Pancharoen Thiele and Kovscek 2010), this effective polymer porosity was no more compared to the realistic. The below pore volume method will be fulfilled toward the aqueous polymer solutions by;

Results and discussion
Test cases and justification. Base case: polymer sand plug model. Sand plugging arising examined pointing to the production well; 1D model in addition differentiated along with the graph figures while was introduced in the outcomes.
A few years ago, a blockage took place that was depicted in one-dimensional (1D) model numbers in such a way that it affected the fluid rate and amount of oil rate in the reservoir while taking production into account.
Sand plugs arise from the investigation of production points in a 1D model, in addition to the differentiation of graph numbers and the introduction of results. Figure 5 indicates the presence of a concentration of sand during production, in the range of 0.0520077, and the solids concentration decrease with the injector well from 0.0520031 to 0.000031. Sand plug model and distinct color scale indicate the occurrence of sand in the production direction, which reaches a considerate extent over time from a small area. Figure 6 shows the porosity reduction through the polymer sand plug model; the yellow porosity diminishes sighted at the location of producer well in the range of 0.22743. Nevertheless, in the midway, model nearby the injector well porosity lessen with a lower range of 0.22647. That is due to the presence of mechanical entrapment, debris provoking porosity to decrease. Figure 7 shows the polymer adsorption throughout the polymer sand plug model, we can remark the appearance of high adsorption of polymer bordering the injector well alongside a portion of 0.50, whereas a range of 0.01-0.00 surrounding the producer well. Figure 8 shows the water viscosity through the polymer sand plug model, in addition to the polymer deterioration, this viscosity decreased to it is lowest throughout the injection of polymer flooding. The viscosity ratio diminution reached to a high rise of 0.981.
The steady rate lessens because of the high-level existence of sand-solid concentration component reaction of non-moving ('N_MOVING') including the moving SAND whichever existing in the oil affecting through the polymer flooding. Such a high-level reduction in addition on account of high sand-solid concentration portion of (0.052), together with the FREQFACT range of 0.031 influence the liquid including the oil rate to decline endlessly.
Based on our outcomes, we find that the variables influencing the liquid ratio and oil ratio to decrease on account of the existence of sand fragments and scrap resulting from the clogging of polymer floods. As shown:  www.nature.com/scientificreports/ polymer adsorption, polymer degradation, diminution of permeability, decreased porosity, inaccessible pore volume, water viscosity volume, the elevated solid-phase accumulation plus a high reactant frequency factor, accompanying by an elevated proportion of impact on the liquid rate and oil rate, which reduce the derived parameters of reactant frequency factor as well solid-phase accumulation and additionally cause low production. Figure 9 shows the polymer sand plug model liquid ratio attained to it is elevated ratio of 25 m 3 /day within 2014-08-01 steadily declining up to it has outreached a ratio about 14.68 m 3 /day in 2019-05-02, then this ratio continued decreasing before it has attained to this a lower rate of 13.85 m 3 /day in the middle of 2020-03-1.
During continuous production, the liquid ratio declined, in the following years (2014-09-02 and 2015-07-09) in relation to 1.410 m 3 /day, which could not be regenerated. Over time, the oil production ratio decreased from 2015-07-09 and 2016-06-02, the production rate fell rather than increased, with only a portion of 3.2 m 3 /day not recovered. In contrast, in the three of the four years from 2016-06-02 to 2020-03-04, the drop is remarkable, a complete ratio of 10.4 m 3 /day lost. At the same time, the production oil ratio decreased from year 2017-02-02 to 2018-03-04, with a decrease proportion of 4.66 m 3 /day. Eventually, in the year 2018-03-04 as to 2020-03-04, the loss is smaller than earlier years alongside oil ratio non-recoverable about 2.37 m 3 day. Figure 10 shows the polymer sand plug model oil ratio, the ratio is continuously increasing attained 20.1 m 3 / day in 2015-07-08 but started decreasing from 2016-02-02 up to it has outreached toward a beneath ratio of 12.56 m 3 /day within 2020-03-04.
Base case: cross-linked gel model. Since sand plugging circumstance taking place while the polymer flooding is influencing the liquid ratio together with the oil ratio to decrease endlessly, exploring for an obstructive treatment to remove polymer plugging and ameliorating the liquid ratio as well as the oil ratio is extremely vital.
The polymer sand plug model alongside these corresponding variables examined throughout cross-linked gel accomplishment for this purpose of diminishing necessarily plugging impact. Accompanied by the implementation of a cross-linked gel method, those affected variables such as; cross-linked gel adsorption, permeability, porosity, water viscosity, the accumulation of solid-phase decreased, and this liquid production rate has been improved after the removal of plugging.
Gao-Qian-Bei block located within Ji-Dong field, Shengli encountered an active edge aquifer water, a crosslinked polymer used to increase the oil recuperation 82 .
Gel conformance treatment is widely used around the world for the reason of its effectiveness. Reviewed by Seright, this initial deliberation in order to identify the foremost variation uniting a gel applied for reservoir conformance control in addition to a polymer flood. Conventional gels utilized in "conformance constraint" www.nature.com/scientificreports/ are considered to obstruct instead decrease the circulation volume of elevated permeability conduits with no sabotaging the fewer permeable hydrocarbon profitable section. It is consequently mandatory to reduce the inflow of gelants toward this not so much as permeable 83 . Figure 11 Indicates the Cross-linked gel solid-phase concentration in the direction of the production well; throughout last year, we can observe that the accumulation of solid-phase varies from 0.000120 to 0.00 compare to Fig. 5 Indicates risen accumulation of sand nearby the production well, this solid-phase concentration was highly gathered surrounding the model. With the application of cross-linked gel, the solid debris concentration will be reduced.  www.nature.com/scientificreports/ Figure 12 indicates the porosity rise of the cross-linked gel performance model, the porosity at the place of an injection well alongside an increasing portion of 0.2277800. However, at the position of the producer well decreased to a range of 0.227782. Comparing to Fig. 6 shows the porosity reduction during the polymer sand plug model, the porosity was improved. Figure 13 gel adsorption of the cross-linked gel achievement model, we can notice from the previous year that cross-linked gel is exceedingly soaked up alongside a range of 0.022601 within the complete model comparing to Fig. 7 shows the polymer adsorption throughout polymer sand plug model, this absorption is hugely concentrated toward the injector well. Figure 14 shows the water viscosity of the cross-linked gel achievement model, the viscosity of the water has augmented alongside an extent of 0.994 nearby the injector well along with a scope of 0.991 until 2020-11-03. Comparing to Fig. 8 shows the water viscosity during the polymer sand plug model is 0.981 because of the plugging effect taking place throughout polymer flooding process, an accumulation of solid sand or a piece of movable sand toward the production well influencing the liquid rate together with the oil ratio to lessen based on the time that the sand-solid accumulate in the direction of the production well.
We can observe the results after the usage of cross-linked gel treatment, plugging impact has been decreased and results have been ameliorated. Established on the chart outcome of; Fig. 15 indicates the liquid rate afterwards the cross-linked gel treatment graph including Fig. 16 shows the oil ratio afterwards the cross-linked gel treatment graph, cross-linked gel accomplished satisfactory outcomes; the blockage has crucially reduced on the liquid ratio and the oil rate can be observed on the graphs curve. This signifies, with the application of crosslinked gel achievement the affected variables can also be ameliorated. The implementation of cross-linked gel give shear solidity, warrant thermal solidity, erosion privilege for considering it is a strong gel interconnection. Figure 15 shows the liquid ratio afterwards the cross-linked gel treatment graph, we can notice on the outcome that the liquid ratio commenced raising through the year; 2014-02-01 prior to it has outreached the higher ratio of 21.609 m 3 /day in 2015-01-02, then declined to the smallest range of 19.52 m 3 /day in 2020-02-03, without attaining 1 month the ratio started to rise again however it did not reached to 20 m 3 /day. Figure 16 shows the oil ratio afterwards the cross-linked gel treatment graph commenced rising it has outreached a ratio about 14.  We can notice with the decrease of solid-phase accumulation, the element reaction frequency factor reduces, and some of the affected parameters due to plugging have also improved. That improvement can be observed on the following figures; Fig. 17 indicates the accumulation of sand neighbouring the production well, Fig. 18 shows the porosity decrease through the polymer sand plug model, Fig. 19 indicates the polymer adsorption throughout the polymer sand plug model, Fig. 20 shows the water viscosity of the polymer sand plug model. We can notice on the base case model graph curves (see Fig. 9 shows the polymer sand plug model liquid ratio, Fig. 10 shows the polymer sand plug model oil ratio) the rate has experienced a continuous decrease. The liquid ratio and the oil ratio were afflicted before the lessening caused by the corking influence as we can notice on the curve graphs of; Fig. 21 shows the polymer sand plug model liquid ratio, Fig. 22 shows the polymer sand plug model oil ratio. Figure 17 indicates the solid-phase accumulation pointing to the production well. We can view that the accumulation of solid-phase at the primary layer were accompanied with the scope of 0.049, whereas the remaining layers ranged to 0.046. Figure 18 shows the porosity diminish throughout the polymer sand plug model, the porosity scope toward the injector well is 0.22563, while surrounding the producer well ranges to 0.22780. Figure 19 indicates the polymer adsorption through polymer sand plug model, polymer adsorption is tremendously soaked up throughout the injector well with a range of 0.90, whereas nearby the producer well is nearly negligible. Figure 20 shows the water viscosity of the polymer sand plug model, the viscosity of water nearby the injector well ranges 0.9853, while surrounding the producing well ranging to 0.9809. Figure 21 shows the polymer sand plug model liquid ratio, the liquid ratio has attained a higher ratio of 25.810 m 3 /day in 2014-08-02, the rate commenced slowly decreasing and increasing from time to time, in the year 2018-03-03 reached a ratio of 23.452 m 3 /day. Afterwards, the liquid ratio steadily commenced rising has outreached a ratio of 24.74 m 3 /day in 2019-04-02, steadily the ratio commenced descending has outreached to  www.nature.com/scientificreports/ a lower rate in the year 2020-03-03 to 23.853 m 3 /day. Furthermore, we can notice upon the graph that the ratio commenced rising and stable until the year 2020-12-1. Figure 22 shows the polymer sand plug model oil ratio, whereas the oil ratio attained on it is foremost to 12.23 m 3 /day in 2014-08-04 also declined to 11.972 m 3 /day in the year 2014-12-01, we can see that in the year 2014 the oil ratio does not outreach to an elevated rate for the reason of the rapid increase along with sharp drop. The augmented ratio of 12.43 m 3 /day in 2017-04-02, throughout two months the oil ratio commenced lessening attained a ratio of 11.863 m 3 /day in the year 2018-03-02. Out of the diminish, the oil ratio begun recuperating till    Figure 23 indicates the porosity increased during the cross-linked gel performance 2020-11-03, the increment of porosity surrounding the injection well ranging to 0.227799, while the porosity ranges to 0.227784 in the direction of the rest of the model. Figure 24 shows the gel adsorption of the cross-linked achievement model 2020-11-03, gel cross-linked is thoroughly soaked up pointing to the whole model ranges to 0.0178, whereas nearby the injector well the adsorption ranging to 0.013. Figure 25 shows the water viscosity of the cross-linked gel achievement 2020-11-03, we can remark on the figure that the viscosity ranges to 0.987 surrounding the injector well, whereas the rest of the model ranges 0.982.
We can notice based on the outcome evaluation that, with the reduction of solid-phase accumulation, frequency reaction factor diminution has lessened ratio contrasted to the prior Fig. 15 indicates the liquid rate afterwards the cross-linked gel treatment graph, while the ongoing Fig. 26 indicates the liquid ratio succeeding the cross-linked gel treatment graph, achieved away preferable outcomes with nearly no presence of plugging impacts, alongside a more significant liquid ratio differentiating to Fig. 15, however the present graph, Fig. 27 shows the oil ratio following the cross-linked gel treatment graph, displays the plugging effect did not occurred at all upon the graph, except the oil ratio is smaller compare to Fig. 16 shows the oil ratio afterwards the crosslinked gel treatment graph. Figure 26 indicates the liquid ratio afterwards the cross-linked gel treatment graph, with the decrease of solidphase accumulation, along with the frequency reaction factor diminish we could remark through this graph that the liquid rate importantly improving without encountering any liquid ratio reduction. With a commencing ratio of 23.52 m 3 /day in the year 2014-03-02 toward 2015-10-03, ceaselessly rising free from ratio decline attained a rate of 24.54 m 3 /day in 2017-01-02. Progressively the liquid ratio rising, within the year 2019-01-03 attained the elevated ratio of 25.43 m 3 /day, the liquid ratio steady up to 2020-12-02. Figure 27 shows the oil ratio afterwards the cross-linked gel treatment graph, along with bottommost solidphase accumulation and frequency reaction factor, oil ratio initiated rising unceasingly free from encountering somewhat a decline through the year 2014-01-01 up to it has outreached it is elevated ratio 15.22 m 3 /day in 2020-12-02.     www.nature.com/scientificreports/ Another finding mentioned that; solid-phase invasion, fines migration, scale formation, as well as water sensitivity can occasion pollution and plugging nearby the wellbore; therefore has an unfavourable impact on oil production. This researcher proposed a acidizing treatment is one of the extremely crucial techniques that used in aiming to bring out the pollution and recover formation permeability.
An insight was generated through our research study results on the base cases (polymer flood model, crosslinked gel model) furthermore on sensitivity cases (polymer flood model, cross-linked gel model) that the liquid ratio, oil ratio of polymer model diminishes faster furthermore unsteady apart from the cross-linked gel model indicate stability.
The bigger the SOLIDMIN and the FREQFAC, the more terrible the liquid ratio, oil ratio were remarked on the base case (polymer flood model).
The foremost parameters of the plugging mechanism who was engendering production liquid decrease investigated plus ameliorated as shown: 1. Solid-phase concentration toward the wells and FREQFACT are the dominant influences originating plugging also directing the production rate to diminish. 2. Throughout polymer flooding, the liquid rate, oil rate lessened because of the plugging mechanism, the application of cross-linked gel boosted reservoir production rate. 3. Along with the approach of polymer flooding, the viscosity has enlarged accompanied by the plugging effect, however, water viscosity diminished, enhanced the displacement and, also the application of the cross-linked gel. 4. Comparing with polymer flood model based case and polymer flood model case 1, the cross-linked gel model of Case 2 performed a far better result with no plugging occurring and production rate increased, followed by the base case cross-linked gel model the plugging impact is decreased. 5. For a better understanding of the adsorption of polymer, it was highly recommended to study and investigate the adsorption of polymer on the surface of the core or sandstone powder (reservoir rock) for further research.

Conclusion
Based upon the outcomes, it can be concluded that the parameters affecting the reservoir were stated as below:  www.nature.com/scientificreports/ 1. The parameters influencing the liquid rate, oil rate to decline given the existence of sand fragments, junks who were generating plugging throughout polymer flooding as shown: Polymer adsorption, polymer deterioration whichever influences the permeability to diminish, porosity reduction, inaccessible pore volume, water viscosity, the elevated accumulation of solid-phase along with the elevated reactant frequency factor along with an elevated ratio could impact poorly the liquid ratio, oil ratio to diminish speedily on the other hand steadily derived from the specification of the parameters (reactant frequency factor along with the accumulation of solid-phase) as well as will direct to production deficit. 2. As result of the sand plugging circumstance taking place throughout the polymer flooding influencing the liquid ratio also oil ratio to diminish unceasingly, exploring for preventive treatment to lessen polymer plugging moreover ameliorating the liquid with oil ratio was exceptionally demanded. 3. We could remark on the outcome after the implementation of cross-linked gel treatment on the polymer sand plugged model impact were decreased and the outcome was enhanced. 4. Cross-linked gel soaking up, permeability, porosity, water viscosity, the accumulation of solid-phase were boosted also the production rate were improved. 5. With the application of cross-linked gel treatment fulfilled a satisfactory outcomes; the solid-phase concentration volume and the plugging have been remarkably diminished on the liquid ratio as well as oil ratio though we can observe some decline. 6. As the solid-phase concentration volume and the reactant frequency factor rate decreased in the polymer plug model Case 1 achieved better results compare to polymer plug model base case with less concentration of solid-phase, plugging and better production rate. 7. Comparing with polymer flood model based case and polymer flood model case 1, the cross-linked gel model of Case 2 performed a far better result with no plugging occurring and production rate increased, followed by the base case cross-linked gel model the plugging impact is decreased. 8. Comparing with polymer flood model based case and polymer flood model case 1, the cross-linked gel model of Case 2 performed a far better result with no plugging occurring and production rate increased, followed by the base case cross-linked gel model the plugging impact has been decreased. 9. The implementation of cross-linked gel affords shear solidity, promising thermal reliability, erosion release due to it is a robust gel mesh. 10. Our research results found the main parameters which are causing the productivity losses and decreased the plugging effects by the cross-linked gel treatment. 11. Future work has to be concentrated more on understanding and improving the parameters of (SOLIDMIN) and (FREQFAC) in order to enhance the reservoir performance.

Data availability
The data initiated throughout or examined through the ongoing study are available from the corresponding author upon request. www.nature.com/scientificreports/