New Gel Aggregates To Improve Sweep Efficiency During Waterflooding

2011 ◽  
Vol 14 (01) ◽  
pp. 120-128 ◽  
Author(s):  
Guanglun Lei ◽  
Lingling Li ◽  
Hisham A. Nasr-El-Din
Keyword(s):  
Low Cost ◽  
Oil Production ◽  
High Water ◽  
Resistance Factor ◽  
Water Production ◽  
Sweep Efficiency ◽  
Low Viscosity ◽  
Productivity Decline ◽  
High Water Cut ◽  
Water Cut

Summary A common problem for oil production is excessive water production, which can lead to rapid productivity decline and significant increases in operating costs. The result is often a premature shut-in of wells because production has become uneconomical. In water injectors, the injection profiles are uneven and, as a result, large amounts of oil are left behind the water front. Many chemical systems have been used to control water production and improve recovery from reservoirs with high water cut. Inorganic gels have low viscosity and can be pumped using typical field mixing and injection equipment. Polymer or crosslinked gels, especially polyacrylamide-based systems, are mainly used because of their relatively low cost and their supposed selectivity. In this paper, microspheres (5–30 μm) were synthesized using acrylamide monomers crosslinked with an organic crosslinker. They can be suspended in water and can be pumped in sandstone formations. They can plug some of the pore throats and, thus, force injected water to change its direction and increase the sweep efficiency. A high-pressure/high-temperature (HP/HT) rheometer was used to measure G (elastic modulus) and G" (viscous modulus) of these aggregates. Experimental results indicate that these microspheres are stable in solutions with 20,000 ppm NaCl at 175°F. They can expand up to five times their original size in deionized water and show good elasticity. The results of sandpack tests show that the microspheres can flow through cores with permeability greater than 500 md and can increase the resistance factor by eight to 25 times and the residual resistance factor by nine times. The addition of microspheres to polymer solutions increased the resistance factor beyond that obtained with the polymer solution alone. Field data using microspheres showed significant improvements in the injection profile and enhancements in oil production.

Polymer Application in High-Water-Cut Wells Enhances Productivity in a Mature Field

2021 ◽  
Vol 73 (09) ◽  
pp. 60-61
Author(s):  
Chris Carpenter
Keyword(s):  
Trinidad And Tobago ◽  
Production Rate ◽  
Produced Water ◽  
Oil Production ◽  
High Water ◽  
Water Production ◽  
Oil Viscosity ◽  
High Stakes ◽  
High Water Cut ◽  
Water Cut

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 200957, “Application of Specially Designed Polymers in High-Water-Cut Wells: A Holistic Well-Intervention Technology Applied in Umm Gudair Field, Kuwait,” by Ali Abdullah Al-Azmi, SPE, Thanyan Ahmed Al-Yaqout, and Dalal Yousef Al-Jutaili, Kuwait Oil Company, et al., prepared for the 2020 SPE Trinidad and Tobago Section Energy Resources Conference, originally scheduled to be held in Port of Spain, Trinidad and Tobago, 29 June–1 July. The paper has not been peer reviewed. A significant challenge faced in the mature Umm Gudair (UG) field is assurance of hydrocarbon flow through highly water-prone intervals. The complete paper discusses the field implementation of a downhole chemical methodology that has positively affected overall productivity. The treatment was highly modified to address the challenges of electrical-submersible-pump (ESP)-driven well operations, technical difficulties posed by the formation, high-stakes economics, and high water potential from these formations. Field Background and Challenge The UG field is one of the major oil fields in Kuwait (Fig. 1). The Minagish oolite (MO) reservoir is the main oil producer, contributing more than 95% of current production in the UG field. However, water cut has been increasing (approximately 65% at the time of writing). The increasing water cut in the reservoir is posing a major challenge to maintaining the oil-production rate because of the higher mobility of water compared with that of oil. The natural water aquifer support in the reservoir that underlies the oil column extends across the reservoir and is rising continuously. This has led to a decline in the oil-production rate and has prevented oil-producing zones from contributing effectively. The reservoir experiences water-coning phenomena, especially in high-permeability zones. Oil viscosity ranges from 2 to 8 cp, and hydrogen sulfide and carbon dioxide levels are 1.5 and 4%, respectively. During recent years, water production has increased rapidly in wells because of highly conductive, thick, clean carbonate formations with low structural dip as well as some stratified formations. Field production may be constrained by the capacity of the surface facilities; therefore, increased water production has different effects on field operations. The average cost of handling produced water is estimated to be between $5 billion and $10 billion in the US and approximately $40 billion globally. These volumes often are so large that even incremental modifications can have major financial effects. For example, the lift-ing cost of one barrel of oil doubles when water cut reaches 50%, increases fivefold at 80% water cut, and increases twenty-fold at 95% water cut.

scholarly journals New Waterflooding Characteristic Curves Based on Cumulative Water Injection

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Zhiwang Yuan ◽  
Zhiping Li ◽  
Li Yang ◽  
Yingchun Zhang
Keyword(s):  
Characteristic Curve ◽  
Water Injection ◽  
Material Balance ◽  
Oil Production ◽  
High Water ◽  
Difficult Problem ◽  
Prediction Errors ◽  
High Water Cut Stage ◽  
High Water Cut ◽  
Water Cut

When a conventional waterflooding characteristic curve (WFCC) is used to predict cumulative oil production at a certain stage, the curve depends on the predicted water cut at the predicted cutoff point, but forecasting the water cut is very difficult. For the reservoirs whose pressure is maintained by water injection, based on the water-oil phase seepage theory and the principle of material balance, the equations relating the cumulative oil production and cumulative water injection at the moderately high water cut stage and the ultrahigh water cut stage are derived and termed the Yuan-A and Yuan-B curves, respectively. And then, we theoretically analyze the causes of the prediction errors of cumulative oil production by the Yuan-A curve and give suggestions. In addition, at the ultrahigh water cut stage, the Yuan-B water cut prediction formula is established, which can predict the water cut according to the cumulative water injection and solve the difficult problem of water cut prediction. The application results show Yuan-A and Yuan-B curves are applied to forecast oil production based on cumulative water injection data obtained by the balance of injection and production, avoiding reliance on the water cut forecast and solving the problems of predicting the cumulative oil production of producers or reservoirs that have not yet shown the decline rule. Furthermore, the formulas are simple and convenient, providing certain guiding significance for the prediction of cumulative oil production and water cut for the same reservoir types.

scholarly journals Effects of oil viscosity on waterflooding: A case study of high water-cut sandstone oilfield in Kazakhstan

2020 ◽  
Vol 12 (1) ◽  
pp. 1736-1749
Author(s):  
Jincai Wang ◽  
Zifei Fan ◽  
Lun Zhao ◽  
Li Chen ◽  
Jun Ni ◽  
...  
Keyword(s):  
High Water ◽  
High Viscosity ◽  
Oil Wells ◽  
Oil Reservoirs ◽  
Low Viscosity ◽  
Well Pattern ◽  
Remaining Oil ◽  
Oil Water ◽  
High Water Cut ◽  
Water Cut

Abstract After a sandstone oilfield enters the high water-cut period, the viscosity of crude oil has an important influence on remaining oil distribution and waterflooding characteristics under the same factors of, e.g., reservoir quality and development methods. Based on a comprehensive interpretation of the waterflooded layers in new oil wells, physical simulation experiments, and reservoir numerical simulations, we analyzed the waterflooding laws of a high water-cut sandstone reservoir with different oil viscosities in Kazakhstan under the same oil production speed, and we clarified the remaining oil potential of reservoirs with different viscosities and proposed corresponding development measures. The results show that low-viscosity oil reservoirs (1 mPa s) have uniform waterflooding, thick streamlines, small waterflooding areas, and low overall waterflooding degrees because of their homogeneous oil–water viscosities. However, within waterflooded areas, the reservoirs have high oil displacement efficiencies and high waterflooding degrees, and the remaining oil is mainly concentrated in the unwaterflooded areas; therefore, the initial production and water cut in new oil wells vary significantly. High-viscosity oil reservoirs (200 mPa s) have severe waterflooding fingering, large waterflooding areas, and high overall waterflooded degrees because of their high oil–water mobility ratios. However, within waterflooded areas, the reservoirs have low oil displacement efficiencies and low waterflooding degrees, and the remaining oil is mainly concentrated in both the waterflooded areas and the unwaterflooded areas; therefore, the differences in the initial production and water cut of new oil wells are small. Moderate-viscosity oil reservoirs (20 mPa s) are characterized by remaining oil distributions that are somewhere in between those of the former two reservoirs. Therefore, in the high water-cut period, as the viscosity of crude oil increases, the efficiency of waterflooding gradually deteriorates and the remaining oil potential increases. In the later development, it is suggested to implement the local well pattern thickening in the remaining oil enrichment area for reservoirs with low viscosity, whereas a gradual overall well pattern thickening strategy is recommended for whole reservoirs with moderate and high viscosity. The findings of this study can aid better understanding of waterflooding law and the remaining oil potential of reservoirs with different viscosities and proposed corresponding development measures. The research results have important guidance and reference significance for the secondary development of high water-cut sandstone oilfields.

scholarly journals Experimental study on waterflooding development of low-amplitude reservoir with big bottom water

2021 ◽  
Author(s):  
Yanlai Li ◽  
Jie Tan ◽  
Songru Mou ◽  
Chunyan Liu ◽  
Dongdong Yang
Keyword(s):  
Bottom Water ◽  
Water Injection ◽  
Water Reservoir ◽  
High Water ◽  
Recovery Factor ◽  
Low Viscosity ◽  
Well Spacing ◽  
High Water Cut Stage ◽  
High Water Cut ◽  
Water Cut

AbstractFor offshore reservoirs with a big bottom water range, the water cut rises quickly and soon enters the ultra-high water cut stage. After entering the ultra-high water cut stage, due to the influence of offshore production facilities, there are few potential tapping measures, so it is urgent to explore the feasibility study of artificial water injection development. The quasi-three-dimensional and two-dimensional displacement experiments are designed using the experimental similarity criteria according to the actual reservoir parameters. Several experimental schemes are designed, fluid physical properties, interlayer distribution, and development mode according to the actual reservoir physical properties. Through the visualization of experimental equipment, the bottom water reservoir is visually stimulated. The displacement and sweep law of natural water drive and artificial water injection in bottom water reservoir with or without an interlayer, different viscosity, and different well spacing is analyzed. The following conclusions are obtained: (1) For reservoirs with a viscosity of 150 cp. The recovery factor after water injection is slightly higher than before water injection. However, the recovery factor is lower than that without injection production. The reason is that the increment of injection conversion is limited to reduce one production well after injection conversion. (2) For reservoirs with a viscosity of 30 cp. The recovery factor after injection is 39.8%, which is slightly higher than 38.9% without injection. (3) For reservoirs with a viscosity of 150 cp. In the case of the interlayer. The recovery factor after injection is 30.7%, which is significantly higher than 24.8% without injection. (4) After the well spacing of the low-viscosity reservoir is reduced, the recovery factor reaches 46.1%, which is higher than 38.9% of the non-infill scheme. After the infill well in a low-viscosity reservoir is transferred to injection, the recovery factor is 45.6%, which has little change compared with non-injection, and most of the cumulative production fluid is water. The feasibility and effect of water flooding in a strong bottom water reservoir are demonstrated. This study provides the basis for the proposal of production well injection conversion and the adjustment of production parameters in the highest water cut stage of a big bottom water reservoir.

Fieldwide Application of Autonomous Inflow Control Valve in Increasing the Field Recovery in One of the Matured Fields in the Sultanate of Oman: Case Study

2021 ◽  
Author(s):  
Salim Buwauqi ◽  
Ali Al Jumah ◽  
Abdulhameed Shabini ◽  
Ameera Harrasi ◽  
Tejas Kalyani ◽  
...  
Keyword(s):  
Control Valve ◽  
Oil Production ◽  
Horizontal Wells ◽  
High Water ◽  
Lessons Learned ◽  
Water Production ◽  
Sultanate Of Oman ◽  
Well Performance ◽  
Reservoir Conditions ◽  
Water Cut

Abstract One of the largest operators in the Sultanate of Oman discovered a clastic reservoir field in 1980 and put it on production in 1985. The field produces viscous oil, ranging from 200 - 2000+ cP at reservoir conditions. Over 75% of the wells drilled are horizontal wells and the field is one of the largest producers in the Sultanate of Oman. The field challenges include strong aquifer, high permeability zones/faults and large fluid mobility contrast have resulted that most of the wells started with very high-water cuts. The current field water cut is over 94%. This paper details operator's meticulous journey in qualification, field trials followed by field-wide implementation and performance evaluation of Autonomous Inflow Control Valve (AICV) technology in reducing water production and increasing oil production significantly. AICV can precisely identify the fluid flowing through it and shutting-off the high water or gas saturated zones autonomously while stimulating oil production from healthy oil-saturated zones. Like other AICDs (Autonomous Inflow Control Device) AICV can differentiate the fluid flowing through it via fluid properties such as viscosity and density at reservoir conditions. However, AICVs performance is superior due to its advanced design based on Hagen-Poiseuille and Bernoulli's principles. This paper describes an AICV completion design workflow involving a multi-disciplinary team as well as some of the field evaluation criteria to evaluate AICV well performance in the existing and in the new wells. The operator has completed several dozens of production wells with AICV technology in the field since 2018-19. Based on the field performance review, it has shown the benefit of accelerating oil production as well as reduction of unwanted water which not only reduces the OPEX of these wells but at the same time enormous positive impact on the environment. Many AICV wells started with just 25-40 % water cut and are still producing with low water cut and higher oil production. Based on the initial field-wide assessment, it is also envisaged that AICV wells will assist in achieving higher field recovery. Also, AICV helped in mitigating the facility constraints of handling produced water which will allow the operator continued to drill in-fill horizontal wells. Finally, the paper also discusses in detail the long-term performance results of some of the wells and their impact on cumulative field recovery as well as lessons learned to further optimise the well performance. The technology has a profound impact on improved sweep efficiency and as well plays an instrumental role in reducing the carbon footprint by reducing the significant water production at the surface. It is concluded that AICV technology has extended the field and wells life and proved to be the most cost-effective field-proven technology for the water shut-off application.

Fracture Treatment Design in the Lower Miocene Reservoir, Offshore Viet Nam

2021 ◽  
Author(s):  
Truong Nguyen Huu
Keyword(s):  
Production Rate ◽  
Oil Production ◽  
High Water ◽  
Oil Field ◽  
Base Case ◽  
Fracture Conductivity ◽  
Lower Miocene ◽  
High Water Cut ◽  
Water Cut ◽  
Fractured Well

Abstract In the past decades, most oil explotation in the White Tiger oil field was produced from the basement reservoir. However, in recent years, these pay zones consist of basement reservoirs, Oligocene reservoirs, and Miocene reservoirs of which oil field s have been declined in oil production rate due to several issues such as complex fracture network, high heterogeneity formation, high water cut, and the reduction of reservoir pressure. The huge issues in the most production wells at basement reservoir were high water cut and it has been significantly increasing during oil production yearly. Therefore, the total amount of oil production in all pay zones sharply decreased with time. At present, the lower Miocene reservoir is one of the best tight oil reservoirs to produce oil extractrion. The lower Miocene reservoir has been faced some issues such as high heterogeneity, complex structure, catastrophic clay swelling, low connectivity among the fractures, low effective wellbore radius and the reservoir that is hig h temperature up to 120°C, the closure pressure up to 6680psi, reservoir pressure up to 4500 psi, reservoir depth up to 3000m. Another reason low conductivity consists of both low reservoir porosity ranging from 1% of the hard shale to 10% of the sandstone formation, and the low permeability raining from 1md to 10md. By considering the various recovery methods, the integrated hydraulic fracturing stimulation is the best tool to successfully stimulate this reservoir, which method allows an increase in oil production rate. In the post fractured well has been shown an increase in productivity over 3 folds in comparison with the base case with fracture half-length nearly 75m, and fracture conductivity about 5400md.ft, which production rate is higher than the production rate of the base case. In addition, the proppant mass is used of 133,067 lbs of which the first main stage is to pump sinter lite bauxite proppant type of 20/40 into the fractures and the next big stage is to pump sintered ball bauxite proppant size of 16/30 into the fractures, which not only isolate proppant flow back but also increase fracture conductivity at the near wellbore as wel as high productivity rate after fractured well. To improve proppant transport, fract uring fluid systems consist of Guar polymer concentration of 11.2 pptg with these additives to form a total leak-off coefficient of 0.00227 ft/min0.5.

scholarly journals The method of the spatial locating of macroscopic throats based-on the inversion of dynamic interwell connectivity

Open Physics ◽  
2017 ◽  
Vol 15 (1) ◽  
pp. 313-322
Author(s):  
Aimin Lv ◽  
Xuyan Li ◽  
Miao Yu ◽  
Gangzhu Li ◽  
Shoulong Wang ◽  
...  
Keyword(s):  
Sedimentary Facies ◽  
High Water ◽  
Tracer Test ◽  
Sweep Efficiency ◽  
Interwell Connectivity ◽  
Multiple Materials ◽  
High Water Cut Stage ◽  
High Water Cut ◽  
Water Cut ◽  
Accuracy Of Results

AbstractThis paper presents a practical technique to quantitatively locate macroscopic throats between injector/producer pairs in a reservoir, considering the problems of extensively developed macroscopic throats and the low sweep efficiency of waterflooding on high water cut stage. The method combines dynamic and static data, based on the results of geological research and the inversion of dynamic interwell connectivity. This technique has implemented the spatial locating of macroscopic throats, using the data of injection/production profiles and tracer test over the years, considering the sedimentary facies of each small layer and the permeability of each sand body. The results of this work show that this method is more convenient and less expensive than previous ones. It is able to locate macroscopic throats in a reservoir accurately and quantitatively. Multiple materials ensure the accuracy of results, and this method is convenient to be applied in the oilfield.

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