The fractured-vuggy carbonate reservoir is one of the main types of oil and gas reservoirs in Tarim Basin, which has great potential and broad prospect. In recent years, Sinopec Northwest Oilfield Company has continued the exploration and development for them, and has made many breakthroughs in the researches of basic geological theory of carbonate rock, seismic identification technology of fracture cavity body, and high-efficiency development engineering technology. And it has established a series of relatively perfect geological and reservoir engineering methods and technologies for carbonate reservoirs. It has realized the continuous increase of storage and production and efficient development of carbonate reservoir in Tahe oilfield, showing a good prospect of exploration and development, and also providing reference for the exploration and development of similar reservoirs at home and abroad. However, how to develop carbonate fracture-cavity reservoir sustainably also faces the problems and challenges such as theoretical innovation and technological breakthrough. It is urgent to tackle the key problems and make breakthroughs in fracture-cavity structure description, quantitative characterization of remaining oil, utilization of reserves around wells, and heavy oil recovery, so as to continuously promote high-efficiency and high-quality development of carbonate fracture-cavity reservoirs.

Carbonate fractured-vuggy reservoir is the most complex reservoir type in the world because of its complex controlled factors, strong heterogeneity and diverse reservoir rock types. There are many reservoir types such as caves, holes and fractures in the whole reservoir unit. The traditional description of single parameter system restricts the detailed description of underground geological bodies. According to the standards of SEC proved reserves, how to establish a scientific geological model, determine the parameters such as proved area, proved effective thickness and recovery rate, estimate various levels of geological reserves and technical recoverable reserves, confirm the number of undeveloped wells, and predict the reasonable proved reserves in the future is facing a great challenge. Therefore, the SEC reserve evaluation of a typical fault zone in Shunbei Oilfield is taken as an example, and the Ordovician reservoir in this well area is subdivided into three types, namely cavern reservoir, hole reservoir and fracture reservoir, to calculate the geological reserves respectively by using the mature reservoir prediction technology in this area. When confirming reserve evaluation, by combining a variety of the evaluation methods, such as static proved reserves evaluation method, analogy method and dynamic method, on the one hand, evaluating the dynamic rules of the developed wells to contrast its actual diminishing and forecast for verifying its rationality; on the other hand, confirming the reliability of the position of undeveloped wells by the judgment of distribution rule of fault-karst reservoir, and verifying the reliability of the forecast by the actual production changes after putting on production. Finally, a set of techniques and methods for SEC reserve evaluation of such reservoirs is formed, which has guiding and reference significance for ensuring the rationality of evaluation.

The main and secondary fault zones in Shunbei and Tuoputai areas are the main fields of exploration and development evaluation. The faults play an important role in controlling reservoir, reservoir and wealth. It is of great significance to carry out research on the internal structural characteristics of the faults for the optimization of exploration targets and the evaluation of development potential. The reservoir types and physical characteristics of different internal structure of the fracture units are different from those of the original rocks, so there must be a corresponding reflection on the logging data. This makes it feasible to describe the internal structure of the fracture with various well logging data. Further exploration of the information contained in the logging data will be a “key” to understanding the internal structure of the fracture. By combining outcrop profile with seismic data, the internal structure of the fracture was qualitatively analyzed by making full use of conventional and imaging logging data in shunbei and Tuofutai blocks. It can be divided into four types of fracture structural units: fault core, crushed zone, fracture zone and dispersed fracture. And then the logging response characteristics of each structural unit in the fracture are summarized, and the identification standard of the structural unit in the fracture is established.

Matrix acidification is one of the important measures for the stimulation of carbonate reservoirs. The studies on its formation regularity and influencing factors of acid wormhole are the basic theories of carbonate matrix acidification. An orthogonal experimental scheme considering three factors of acid injection rate, acid concentration and reaction temperature was designed. Acid displacement experiments were carried out on the cores taken from a carbonate reservoir in oilfield A. The influence of the factors on wormhole shape was studied by fractal dimension and multi-fractal spectrum width used as the target parameters. The optimization goal is to try to ensure the minimum width of multifractal spectrum while obtaining the maximum fractal dimension. The results showed that in the range of factor values, the optimal combination of experimental parameters for wormhole shape was when the acid concentration was 20 %, the temperature was 50~70 °C, and the acid injection rate was 2 cm ³/min. The factors affecting the fractal dimension and multi-fractal spectrum width were in a descending order as: acid injection rate, acid concentration and reaction temperature. Therefore, the optimization of the acid injection displacement should be emphasized in the design of the construction parameters of carbonate matrix acidification.

Reservoir effectiveness is a key factor restricting the efficient development and also one of the difficulties in reservoir evaluation. Formation C and J of the T oilfield in Syria are carbonate fractured reservoirs. The diversified storing space, complex lithology, pore structure and other reservoir characteristics lead to high porosity and low permeability of matrix pore. Although fractures formed by tectonic action have improved reservoir’s seepage capacity significantly, there still have great ambiguity in fracture effectiveness well logging interpretation. It is urgent to establish a criterion for the effectiveness of matrix-fracture complex carbonate reservoirs. According to the above problem, geology and rock physics analysis such as core observation, scanning electron microscopy（SEM） and mercury injection data are used to calibrate well logging. In combination with multivariate statistical method, the comprehensive evaluation standard of reservoir effectiveness, including the lithology, physical properties, pore structure characteristics, logging response and reservoir parameters like reservoir quality factor and flow index of different reservoir storing space, has been established. This study provides technical support for comprehensive evaluation and efficient development of such complex carbonate reservoirs.

In the fractured-vuggy reservoir unit, the water injection mainly affects the oil well unidirectionally and is easy to advance rapidly along the main channel, leading to the problems of difficult to effective control the water drive reserves and low efficient production. By the methods of physical model and numerical simulation, the relation between the structure of fracture/cave and the development effect of water flooding in different karst background is analyzed, and the differential injection-production relation based on the spatial distribution of fracture/cave is formed. The results show that: in the crust karst reservoirs, the mode of water injection in the low part and oil production in the high part of the structure, and water injection in the undeveloped area and oil production in the developed area is adopted to establish the injection-production relation of one injection well to multiple production wells. In the fracture-controlled reservoirs, the mode of water injection in the secondary fault and oil production in the main fault, and water injection in the deep fracture area and shallow for oil production in the longitudinal direction is adopted to form the stereoscopic injection-production relation. In the ancient underground river reservoirs, the water injection in the main section and oil production in the branch are implemented in the main dark section, and the water injection in deep and oil production in shallow are implemented in multiple dark rivers, so as to establish the layered injection-production relation. The establishment of injection-production relation in different karst backgrounds of fractured-vuggy reservoirs lay an important foundation for maximizing water drive controlled reserves of spatial well pattern.

Carbonate palaeo-subterranean river reservoirs are fractured-vuggy reservoirs composed of deep main rivers, shallow branch and high-angle fractures, with large-scale karst caves as the storage space, belonging to the three main reservoir types in Tahe oilfield. Taking the knowledge of remaining oil and tapping potential in TK440 well area as an example, through the fine characterization of the fracture-cave structure, comprehensive analysis of production dynamics, and systematic analysis of water flooding characteristics, four patterns of remaining oil distribution and feasible potential tapping methods are summarized..The results show that: using large pump for the well drainage and changing the distribution of pressure field, can excavated the remaining oil in shallow underground river. Water flooding in reverse direction, with the advantage of the height difference, can effectively excavate the remaining oil in deep underground river. Based on the difference of oil and gas density, the vertical displacement of artificial gas cap formed of the principle of gravity differentiation can effectively recovery the attic oil around single well and the remaining oil in the blind side of underground rivers. Feasible means of potential tapping under different distribution patterns of remaining oil has been found, and good results have been achieved in the field implementation, which further validates the reliability of remaining oil distribution patterns and the effectiveness of tapping the potential of the reservoir, and provides technical support for the effectively potential tapping of remaining oil in the similar reservoir.

The fractured-vuggy carbonate reservoirs with low porosity and low permeability basically have no oil and gas storage capacity. Fractures and caves are the main storage and permeability spaces, but fractures and caves have complex developed space and poor connectivity. Due to the limited sizes of fractures and caves during drilling in single well, and the failure of conventional water injection and acid fracturing reforms to achieve efficient expansion in remote well areas, single well production has high initial production, rapid decline, and low production. Therefore, a field test of the high-pressure water injection volume expansion process was carried out, that is, using high-pressure water injection as an energy carrier to break through the barrier of an isolated fractured-vuggy system and achieve effective expansion. This process was tested in the well-S1 of Tahe Oilfield, and the effect was significant. The well was subjected to conventional water injection and oil replacement for 3 rounds in the early stage, and the effect gradually became worse. The production is characterized by constant volume. The seismic data show large-scale of the fractured-vuggy system around the well. Two rounds of high-pressure water expansion test are carried out, with the cumulative water injection of 2.98×10 ⁴ m ³ and maximum injection pressure of 23 MPa. The water injection curves show that the high-pressure water injection make two fractured-vuggy systems around one well communicate with each other, improving the production status of this well. The cycle water content is reduced from 45 % to 4 %, and the production pressure drop is reduced from 29 MPa to 26 MPa. The production volume per unit pressure drop increased from 201 m ³/MPa to 547 m ³/MPa. So far, the cumulative oil increase has been 14 721 t. The tests show that the high-pressure water injection expansion technology can achieve the effective expansion of fractured-cavity carbonate wells with constant-volume, increase single-well production and reserves, and at the same time, create space for reducing the oil-water interface near the well, so as to extend the dry oil recovery period.

Fault-karst carbonate reservoir is a new object for oil and gas exploration in carbonate fractured-vuggy reservoirs. Based on the further study of development dynamics and water flooding mechanism, and in order to solve three typical problems in the development of Tahe oilfield, which are the poor matching of well storage relation, the water-like coning formed by conventional water injection, and the combination of multiple fractures and caves, an injection method by imitating bottom-water is proposed, which is more suitable for the well-reservoir relation, different distribution patterns and complex internal structure of the fracture and vug. In this way, the water flooding sweep rate is increased, and efficiency of water injected increased from 60% of conventional water flooding to 75% of simulated bottom water flooding. Three problems of poor water injection channel between borehole and fracture-vug are common, that is, there is an offset between the fracture and vug, no effective channels are established for the borehole and fracture-vug, and the reserve recovery degree of well-controlled fracture-vug is high but the untapped fracture-vug exist in far wells. A low-cost water injection method by imitating fracturing for establishing effectively fracture network producing system is proposed, which can effectively expand well controlled producing reserves, and the average productivity per well increase by 22 t/d. Practices show that these two technologies can increase the total water injection volume and water injection pressure, make the water injection efficiency improved greatly, so as to improve the effect of water injection and stimulation obviously.

Carbonate fractured-vuggy reservoirs in Tahe oilfield have complex geological characteristics, which is mainly reflected in the various forms such as pore, fracture and cave developed in the reservoir, poor continuity of spatial distribution, complex combination mode, and the residual fracture-vuggy storage space formed in surface karst system by weathering. During the development, it is easy to form the bottom water coning along the high angle crack. The remaining oil between the wells outside the water channels and the “attic oil” stored by the residual fault are enriched in large quantities. In the earlier stage, the macroscopic mechanism of gravity displacement by using density difference in N₂ injection of seam-hole reservoir is clarified by means of physical simulation. However, the displacement mechanism of the “attic oil” and the residual oil between wells is not clear. Through the simulation experiments of the effects of the injected N₂ on the physical properties of crude oil under the conditions of 55 MPa and 130 ℃, the micro mechanism such as the effects of N₂ on dissolution, expansion, capacity increase, extraction and dissolution of crude oil under the condition of high temperature and high pressure reservoir. Based on the fractured-vuggy geological characterization, visual physical model is made to observe the displacement mechanism of gravity displacement and water coning suppression during N₂ injection. After field application, the feasibility and popularization potential of the technology are further proved.

The strong bottom water condensate gas cap reservoirs in Tahe Oilfield is the sandstone reservoir composed of gas cap, oil reservoir and large scale of bottom water. In the process of development, gas channeling or oil channeling exists due to the uneven production of gas cap and bottom oil, and the development effect is poor. According to the actual production situation of gas cap reservoirs with massive bottom water in block T of Tahe oilfield, and considering the gas-oil ratio and density changes in the production process, a new method to split gas cap and reservoir ground production, integrated splitting method for single-well production stage, is explored. By this method, recovery rates of crude oil, condensate, condensate gas and dissolved gas in gas cap reservoirs are calculated, which are 12.28 %, 22.96 %, 29.75 % and 12.05 %, respectively. The calculated results are compared to that of the similar reservoirs at home and abroad, and it is found that they are matching the development characteristics of such reservoirs, and the field operation is relatively simple. Through the calculation of the oil recovery for the gas cap reservoirs, the development status is understood, and the problems existing in the development and the development potential of the block are timely discovered, so as to develop gas cap oil reservoir more reasonably.

As Tahe fractured-vuggy carbonate reservoir has many fractured-vuggy units, pressure systems and seepage units, its oil-water relation is complex and the water body energy distribution is unbalanced. Therefore, studies on the water intrusion process before water seepage is conducted for the elastic drive unit oil wells in single fracture and single hole reservoir with closed bottom water. There exists a connected water body. The fluid expands elastically in the dissolved hole. As time goes on, the water intrusion is inevitable due to the pressure decay of the reservoir during the mining process and begins at some point. Based on the characteristics of the fracture-cavity reservoir, the intrusion water is considered as the bottom water, and the elastic water flooding continues to supply the insufficient of the formation energy. According to the Poiseuille’s equation, the pressure of the karst cave before water breakthrough and the incremental rate of the cumulative oil production in the dissolved pores both decrease exponentially with time, following the rules of rapid in the early stage and slow down in the later stage. Meanwhile, combining the improved material balance method of reservoir engineering to calculate the water influx during the elastic driving period before water breakthrough. Taking well-TH12523 as an example, water intrusion occurs during its elastic mining stage, and the elasticity and the water body drive together. The actual measured incremental rate of the measured oil production and the karst pressure varied with in the whole mining process are consistent with the dynamic prediction results of the reservoir .

Natural micro-fractures in carbonate reservoirs are generally developed and have little effect on porosity, but has a great influence on the simulation results. In previous studies, the effect of micro-fractures on the growth of wormholes has not been studied in detail. Based on the double-scale wormhole propagation model, and the natural fracture model with a certain statistical distribution law produced by coupling of the Monte Carlo method, the acid wormhole propagation mathematical model considering the existing of natural fractures is established. By adjusting the parameters such as azimuth, density, length and connectivity of micro-fractures, the effects of its spatial distribution on wormhole propagation is studied. It is found that the existence of natural micro-fractures will reduce the pore volume of acid invasion into the cores, which greatly affects the optimal injection speed and acid-liquid dosage. Natural micro-fractures with high density can form complex dispersion fracture networks, increasing the permeability and production obviously. Increasing the length of micro-fractures can reduce the pore volume of acid invasion, and penetrate the damage zone rapidly. In the cores contain micro-fractures with better conductivity, the wormhole will connect the adjacent micro-fractures in the process of propagation, so as to increase the core's conductivity.

The energy of fluid in oil reservoir determines the direction of fluid flow. In order to study the energy distribution of fluid in fractured-vuggy reservoirs, a theoretical model of fluid potential is established, and the 3D fluid potential characterization method is determined. The mechanism models of four typical fractured-vuggy structures, single hole with bottom water, single hole with side water, double hole with bottom water and double hole with side water, are use to study the change rules of flow potential, and five main control factors affecting the flow potential adjustment effect are determined, finally, the research on potential tapping of residual oil was carried out in combination with flow potential analysis. The results show that the adjustment of flow potential for the model of single hole with bottom water make the production wells work best. The model’s water multiple is the decisive factor, and the flow potential regulation effect is better when the water multiple is less than 10 times. The greater the discharge, the better the effect of water control for production wells. The proposed fluid potential solving model of fractured and cavern reservoir can truly reflect the changing rules of fluid energy distribution in the actual formation.

Due to the lack of dilute oil and the poor economical benefit in the dilution process of heavy oil in ultra-deep wells of Tahe Oilfield, the mixed oil is treated by dilute oil recycling combined with high-temperature thermal cracking process. For one thing, the experiment of dilute oil recycling after heavy oil distillation is carried out to determine the feasibility of cycling of light component oil. For another thing, the viscosity of the heavy components is reduced to meet the requirement of external transportation. The results show that when in the dilute oil recycling experiment, the light component yield obtained by distillation at 350 ℃ is stable at about 27 %, and the dilution ratio is stable at 0.39∶1, which indicates that dilute oil recycling is feasible. While in the modification experiment by thermal cracking, after the heavy components obtained by distillation reacting at 380 ℃ for 60 minutes, the oil viscosity can be reduced from 398 800 mPa·s to 1 704 mPa·s, which means it has met the requirement of long-distance transportation, and the density can be reduced from 1.001 8 g/cm ³ to 0.991 1 g/cm ³. Therefore, the lightening of heavy oil is realized. This method not only greatly reduces the amount of dilute oil by the recycling utilization of light oil, but also improves the quality and utilization efficiency of heavy oil. It provides a new idea for the efficient development of heavy oil in ultra-deep wells.

The super heavy oil of Tahe Oilfield has high geological reserves, deep burial, and fluidity in the reservoir. During lifting, as the temperature decreases, the viscosity increases and the flow capacity decreases, leading to the impossible production. Therefore, recovery mainly adopts dilute oil to reduce adhesion. With the continuous drop in oil prices, the influence by the sales price difference between the added dilute oil and the produced heavy oil, and the energy consumption caused by the repeated work of dilute oil, lead to the decrease of the benefit. In order to improve the production efficiency of super heavy oil reservoir, the technology exploration, technical tackling and pilot test are carried out from three aspects of stratum, wellbore and surface. The application of mineral-insulated copper-clad cable heating and nano thermal insulation tubing has achieved remarkable results, saving 98 600 tons of dilute oil. It can be popularized in such super heavy oil reservoirs. The breakthrough of temperature-resistant and salt-resistant water-soluble viscosity reducer and the progress of the sulfur-resistant screw pump lift technology provide sufficient conditions for the efficiency recovery of super heavy oil reservoirs. The principle of efficient ground gathering and transportation is simple, but involves the network transformation and equipment upgrade, with high cost and complex implementation. Now the test equipments are in preparation. As the technology of formation viscosity reduction is very difficult, it is in the stage of technical demonstration. The development and integrated application of low-cost recovery technology for super heavy oil improve the development benefit. And after general consideration, the bottleneck is found out according to the specific well conditions, and the matching technology in the technical system is select, so as to achieve the goal of efficiency recovery for super heavy oil, and improve the ability of oilfields to cope with low oil prices.

After a long time of depletion production and bottom water coning, the YT1 Fault Block in Tahe Oilfield has generally entered the high water cut stage. Conventional measures such as gas lifting, drainage and gas production have failed in some case, and water plugging has become the main replacement in the later stage. Based on the water plugging experience of Tahe Oilfield, the relative permeability adjusting agent is took as the main research and development direction, and forms the emulsified oil plugging agent is formed based on the medium dilute oil and the “anion+non-ion” compound emulsified system of Tahe Oilfield. Under the formation condition, the viscosity reaches 50~60 mPa·s, causing low damage to the reservoir. Through the single and double sand filling tube displacement experiments, it is found that the water-phase plugging rate of the emulsified oil system is 83.4 %, and that for oil-phase is only 11.9 %. Therefore, it has better erosion resistance, oil-water phase selectivity and formation permeability adjustment ability. The slug of water plugging process by emulsified oil is designed as "dilute oil acted as isolation fluid+emulsified oil system+dilute oil acted as isolation fluid+clear water displacement fluid", without moving the string, and with 1~2 days’ soaking, to implement 1~2 rounds. The field application has a good water plugging effect, providing an important guiding for the similar condensate oil and gas reservoirs in water plugging

In Tahe ultra-heavy oil block, the rod pump cannot meet the requirements of heavy oil pumping. Through the application of deep pumping electric pump for heavy oil and its coordination with tail pipe suspension, the development of ultra-heavy oil has achieved good results. Up to now, this technology has been used in wells for 187 times. However, due to the limitation of the small casing size, 56 electric pump wells are still not equipped with tail pipe. The average operation life in production is only 337 d, which is far lower than that of wells equipped with tail pipe electric pump, 542 d. Based on the investigation of the casing used in China, the casing with high strength, anti-corrosion and suitable for the development of Tahe oilfield is selected. A kind of aluminum magnesium alloy tail pipe and 139.7 mm casing with 147 mm pitch collar are designed. It can be suspended in both 193.675 mm and 177.8 mm cased wells and has been successfully applied in wells for 13 times in the field. Finally, the mature and reliable suspension technology of tail pipe equiped by electric submersible pump for ultra-heavy oil is formed, and has certain guiding significance for the development of Tahe ultra-heavy oil block

Tahe Oilfield is an ultra-deep and ultra-heavy carbonate oil reservoir, which needs to mix with dilute oil to decreasing viscosity The mechanical lifting method is mainly hydraulic feedback heavy-oil pump and heavy oil electric pump. As the development of heavy oil enters the middle-high water cut period, the existing processes are facing the problems of water-cut emulsification, corrosion and scaling, high abnormal rate and poor economic benefit. It is urgent to seek more efficient and economical recovery technology. According to the lifting characteristics of heavy oil wells with water cut, the solution is found from the thought of process optimization and technology substitution. The screw pump is optimized to replace the old pumps, and the water-soluble viscosity reducer is used to replace the dilute oil. Therefore the heavy oil recovery technology by the combination of ground driven by screw pump and water soluble viscosity reducer is formed. Through the application of 6 wells, the average lean ratio decreased by 0.3, for single well per day in average, 4.9 tons of dilute oil are saved, and 3.8 tons of oil are increased. The success of the field application proves that this technology has the advantages of strong adaptability, good application effect and outstanding economic benefit for water-bearing heavy oil wells, and further widen and improve the technical system of high efficiency development of heavy oil.

Nitrogen injection in Tahe oilfield is one of the important measures to enhance oil recovery in carbonate reservoirs, and has achieved good effect of reducing the gradual decrease and increasing oil production. However, the purity of nitrogen produced by membrane separation and carbon molecular sieve separation is 97 % and 99 %, respectively. And the injected gas contains a certain amount of oxygen. With the increase of gas injection cycle rounds, borehole corrosion becomes more and more serious. In order to solve the problem of wellbore corrosion in nitrogen injection wells, dynamic corrosion simulator of high temperature and high pressure was used to study the corrosion mechanism of nitrogen injection wellbore, and the effects of oxygen content of gas injection, temperature, injection pressure and injection rate on corrosion rate were measured. Experiments show that the corrosion rate of pipe in simulated downhole environment increases by 1.3~2.0 times from 70 ℃ to 110 ℃, reaching 4.23 mm/a; the oxygen content increases from 0.7 % to 1.5 %, and the corrosion rate of pipe in simulated downhole environment increases by 0.7~1.0 times, reaching 2.91 mm/a. Thus, the main controlling factors of wellbore corrosion are oxygen content and temperature. Meanwhile, corrosion countermeasures of nitrogen injection wellbore are discussed, and the idea of improving purity of nitrogen production, reducing oxygen content, matching liner and corrosion inhibitor is put forward. It can effectively control corrosion of nitrogen injection wellbore.

Hydraulic fracturing is an important technical means for stimulation and transformation of oil and gas reservoirs, and has been widely used in the production of major oil fields at home and abroad. After studying a large number of literature research on the fracturing fluid system, it is found that various improvements of the current fracturing fluid system are mainly around “carrying sand”. However, in this paper, a new type of self-supporting fracturing fluid system is innovatively put forward, which completely gets rid of the concept of "carrying sand". In the process of fracturing fluid pumping, there is no solid proppant at all, but the fracturing fluid is combined with the proppant as a whole. When the fluid reaches the target layer, it is affected by the formation temperature and transformed from liquid phase to solid-state to prop up the fracturing fractures. The obtained self-supporting fracturing fluid system can form supporting solids with certain sphericity and strength at 85 ℃ and in 30 minutes. The upper limit of liquid system viscosity is 45.58 mPa·s, bringing the system good injectivity and stability. The density of the solid-state proppant is 1.07 g/cm³, the separation coefficient is 1.41, the main particle size range is 20~40 and 40~70 mesh, and the crushing rate is 4.7 % and 8.75 %, respectively.

The early polymer injection technology can further improve the polymer flooding effect, and the method to judge the time of polymer transfer by laboratory experiment and numerical simulation is relatively complex and limited in application. Based on the mechanism of oil-water relative permeability, an application method for quickly determining the time of injection and accumulation is established by using reservoir engineering method. The characteristics of the relative permeability curves of four reservoirs are obtained through laboratory experiments, and the influence of the water cut change rule, water cut rise rate, dimensionless production fluid（oil） index, oil-water mobility ratio and other characteristic parameters on the injection timing of polymer flooding under different reservoir conditions is analyzed by the reservoir engineering method. The results show that the above characteristic parameters are obviously different under different reservoir conditions. The injection time of polymer flooding should be determined by sorting the characteristic parameters according to the actual demand. Taking production as an example, the dimensionless production index, dimensionless production index, water cut rising rate and oil-water flow rate ratio determine that the water cut of the injection time for four reservoirs（BZ, JZ, QHD and SZ） is above 80 %, 79.9 %, 86 % and 34 %, respectively. According to the actual situation of the field, the time of polymer injection time can be determined quickly by analyzing the relative permeability curve with reservoir engineering method.