| As the oilfield waterflood development many oilfields in China have, high water cut stage in the development stage, comprehensive water cut oil field more than 80%. Due to the injected water along the high permeability layer channeling is serious, water drive recovery factor is low, water injection development contradictions increasingly obvious. We must use the new technology to enhance oil production rate.Be aimed at the problems of low amplitude stimulation and short useful life with conventional profile controlling and water shutoff, propose a technology of depth profile controlling and water shutoff, Which is filling profile controlling agent with intensity rom weak to strong in zone far from wellbore、interim zone of wellbore and immediate vicinity of wellbore. The purpose of deep adjusting will be sent to the deep formation with the constant migration of injecting water,so that the changing flow of injected water in the reservoir,the maximum increase the swept volume of the injected water,the blocking agent must meet theto block maintained,able to move Therefore,the use of flexible microgel as the optimal solution.The deep adjusting is able to improve the heterogeneity of formation,raise sweep efficiency of polymer driving,and then reach the aim of enhancing oil recovery. Field experiment also approved that the technology of depth profile controlling and water shutoff was a economic benefit means to controling water prod and steady oil yield,enhance oil recovery.lt is worth attention and popularization.The original study on the technology of polymer-controlling Which using the formation of Shuanghe Oilfield madeup and diluted with befouled water, from the geological data, laboratory experiment, and so.According to the requirements of the technology of depth profile controlling and water shutoff, select separately three kinds of formula:high-strength gel, immediate vicinity of wellbore, the gelling time is short; middle-strength gel, interim zone of wellbore, the gelling time is middle; low-strength gel, zone far from wellbore, the gelling time is length.The researches should be conducted in the following aspects when it comes to optimization of formula:the influence of concentration of primary agent to gel time and viscosity;the influence of concentration of crosslinking agent to gel time and viscosity;the influence of concentration of stabilizer to gel time and viscosity;the influence usage of dominating agent to gel time;the influence of PH value to gel time;the measurement of shearing resistance;the comparison between polymer viscosity and adjusting agent viscosity before geling following above aspects,we can ascertain formula,and than conduct properties evaluation of retardation crosslinking adjusting agent. By analyzing the temperature profile of the weak gel system, pH, salinity, mechanical shear and other factors, obtained in laboratory experiments profile crosslinking agent performance evaluation.In-depth profile modification on physical model experiments:in which high, medium and low permeability of sand filling tube, connected in parallel simulated formation heterogeneity. By injection of different concentration, the number of PV profile control agent, the record in the process of injection agent and subsequent water flooding injection point pressure data parallel model and the pipe out of the oil and water yield data, and finally improve the recovery rate for data analysis and trend along with the change of injection pressure. Single polymer profile control experiments, different slug size profile control experiment and the formula of profile control experiment.Conclusion:1. According to different formula results, three kinds of formula system:low intensity formula-polymer 1000～2500 mg/L, crosslinking agent,150～200 mg/L, gel strength of 108.4～529.5 mpa. S, gelling time 10 days; Strength formula-polymer in 1000～2500 mg/L, crosslinking agent,400 mg/L, gel strength,270.7～1133 mpa. S, gelling time 5 days; High strength formula～polymer 1000～2000 mg/L, crosslinking agent,600～1000 mg/L, gel strength,1100-2380.7 mpa. S, gelling time 4days;2. The formula of three kinds of weak gel system of temperature, pH, salinity, shear machinery, such as the analysis of the influence factors:three formula under the condition of 80℃ system of gelling performance will not affected by temperature limits, would be able to crosslinking, and the steady performance good; Oilfield water salinity had a little effects on the three kinds of formula system; Double hua river sewage and fresh water pH does not affect the gel; Three kinds of formula in the ambient temperature of 80℃ shear resistance is better.3. To study the effect of profile control switch slug size cutting, the influence of growth and FenLiuLv indicators, considering recovery degree in polymer injection formula for 2000 mg/L+crosslinking agent under the condition of 200 mg/L,0.125 PV is the most suitable for the formula of the reservoir.4. Cut profile control effect of the different formulation experiments, the results showed that the polymer 2000 mg/L+crosslinking agent 600 mg/L-0.125 PV formula can make note agent before and after the high permeability layer FenLiuLv reduced by more than 30%, and the influence is small, medium and low permeability layer permeability seal can be achieved the purpose of high permeability channel, start low and medium permeability, technical indexes meet the project requirement.5. A single polymer profile control experiment was carried out, at the same time and injection profile control agent experiment comparison and study, the results show that the single polymer plugging high permeable layer ability is poor, at the same time will increase by a single polymer injection recovery degree below the profile control agent. |
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