Analysis of low permeability reservoir development technology

: As an important energy source for social production and development, oil is non-renewable. In the process of development and utilization, attention should be paid to continuously improve the exploitation technology, enhance the ability of oil exploration, and strengthen the development of low permeability reservoir resources, so as to provide sufficient oil resources for social production and development. However, low permeability reservoir resources have their own characteristics and are limited by multiple factors in the process of exploitation. It is difficult to improve the exploitation efficiency of low permeability reservoir resources without adopting corresponding exploitation technology. This it is scientific and reasonable exploitation of low permeability oil reservoir resources technology are analyzed and discussed, in the comprehensive analysis based on the characteristics of low permeability oil reservoirs, mining characteristics, puts forward the well pattern optimization, waterflood recovery, fracturing technology and mining method, working for the effective implementation of the low permeability reservoir development provides the technical support, also need to continue well technology application in the construction process in the future.


Low permeability oil field analysis 1.1 Low permeability oil field type
Low permeability oilfield is mainly refers to the reservoir permeability reservoir level and low level of abundance oil field of single well production capacity is relatively low, in carries on the classification, mainly according to the classification of low permeability reservoir in lower limit, it can usually be divided into the following three kinds: general low permeable oil fields, especially low permeability oilfield, and ultra low permeable oil fields.Each field has its own characteristics, which can be described as follows: The first is a general lowpermeability field, where oil flow standards meet industrial production standards and fracturing measures can be used to increase productivity.The second is the ultra-low permeability oil field, the whole reservoir bound water saturation is relatively high, oil flow standards can not meet industrial standards, which requires large-scale fracturing methods to complete development.Finally, ultra-low permeability oil field, which has high oil layer density and comprehensive bound water saturation, is not of high development value due to its relatively low production capacity.However, due to its advantages of high oil quality and thick oil layer, it can be used as backup energy for development.The author sorted out the permeability of the three, and the specific values are shown in Table 1 below: The production level of oil field will decrease gradually with the development time.For low permeability oil field, the comprehensive production may decrease, the water content of oil well gradually increases, the aging of mining equipment is obvious, and it is difficult to adapt to the more difficult mining work, and the comprehensive efficiency will decrease, which will lead to the comprehensive economic benefit of bottom hole oil field.Because low permeability oilfield is still an important object of petroleum development.It has the characteristics of rich reserves, diverse types and relatively wide distribution.In terms of the current proven oil reserves, the proportion of low permeability oil fields is more than two-thirds, which has good development potential.Therefore, in the future oil exploitation process, we should pay attention to the research and development of a variety of exploitation technologies, and give full play to the performance of low permeability oil fields.

Reservoir characteristics analysis of low
permeability reservoir Has significant characteristics of low permeability reservoir, first of all, the relatively poor reservoir physical property of low permeability reservoir, with more sandstone grain size, and distribution range is relatively wide, sandstone particles has obvious characteristic, such as poor sorting, clutter, and cement is more, it can cause internal structure presents obvious heterogeneity.Second, the pore channel radius is smaller than that of a normal reservoir, the pores are somewhat curved, and the entire outer surface is rough.Again, when the fluid in the reservoir is in contact with the demo, physical and chemical interactions occur, resulting in thinning and narrowing of the original pore channels within the rock structure.Over time, serious blockage occurs throughout the pores, and the reservoir permeability naturally decreases.Finally, the bound water saturation of oil layer is much higher than that of low permeability reservoir, that is, the maximum water saturation of low permeability reservoir can reach about 60%.In the process of exploiting low permeability reservoirs, the production staff should do a good job of characteristic analysis to improve the production efficiency [1].

Development characteristics of low permeability reservoir in oilfield
Low permeability reservoirs have the following characteristics: First, there is a direct proportional relationship between recovery and permeability, that is, when permeability increases, recovery increases, and vice versa.Second, there is an inverse relationship between start-up pressure and permeability, that is, the higher the permeability, the lower the start-up pressure, and vice versa.Thirdly, the comprehensive permeability level of reservoir is not high, and the abundance is relatively low, and the overall rate is relatively slow in the process of oil recovery.Fourth, the inner layer structure has natural cracks, and the cracks show irregular characteristics.When affected by external factors, the formation heterogeneity is significant, which affects the subsequent mining work.Fifth, the reservoir water shows poor hydrodynamic connectivity, which increases the difficulty of drainage work.Combined with the above characteristics, in the process of oil exploitation, we should adopt specific exploitation methods based on the characteristics of low permeability reservoir, so as to improve the production efficiency.

Current situation of low permeability reservoir development technology 2.1 Well pattern optimization technology
The use of well pattern can affect the development quality of low permeability reservoirs and requires accurate understanding of well location, which is determined by field conditions, oil fluid properties, and current development of the field.However, in the same layer, crude oil has a large drainage radius, which will exceed the normal radius range, making it relatively difficult for crude oil to return to the oil well.Therefore, it is necessary to pay attention to accurate measurement of the radius value and improve the efficiency of well pattern layout.
Based on the analysis of previous experience, the current production capacity of oil Wells should be considered comprehensively when determining the location of well points.The following aspects can be considered: First, in the process of supplementing oil Wells, it is necessary to select oil Wells with high production and high potential to supplement formation capacity.Second, in the process of water injection, the advantage of geological conditions should be fully utilized to minimize the amount of loss at the production well point.Third, the production team needs to maximize the use of low-yield Wells to increase production at production points.

Advanced waterflooding technique
Water injection technology can effectively solve the problem of poor pressure conduction performance and low natural energy reservoir, improve the use value, so this technology is mainly used in the early development, so as to effectively ensure formation pressure, reduce the influence of reservoir permeability formation.When the reservoir has a certain distance between, you need to use the layered water injection form, increase the rate of crude oil in the reservoir, and in the process of water injection, water injection work along the oil analysis, so the choice of injection Wells location should be close to crack location, and injection Wells location to do a good job in uniform distribution to ensure the water flooding efficiency.

Water injection method
Through many years of experience in water injection, it is concluded that high pressure water injection, periodic water injection and cross pulse water injection have good water injection effects.However, the low pressure water injection is not ideal, and the comprehensive output of oil well does not reach the expected goal.Since fractures are not obvious in low permeability oil fields, it is more appropriate to use high pressure water injection, which can effectively remedy the problem of loss and form a water wall to ensure water flooding efficiency.Periodic water injection can be used when the well is multi-zone, but it can also be used when the combined water content of the well is not very high.

To ensure the water quality
Low permeable oil fields in the process of mining, should ensure that use water comprehensive water quality, which requires the staff before the formal water injection well water purification, disinfection, sterilization and anticorrosive processing, because if not for the corresponding processing, has been the problem of pollution of water quality of the oil would be caused by the bad influence.Therefore, attention should be paid to water treatment before water injection [2].

Acidizing technology
Acidizing technology is the most critical technical means to improve the productivity of low permeability reservoirs.It can effectively improve the production efficiency of oil Wells when it is applied to special well locations.Generally in the application of acidification process, the common ways include conventional acid acidification, acidification and fracturing and acidification in application technology, the main principle is to give play to the role of acid itself with the chemical, applied to the mining work, can have certain dissolution, blockage can be used for mining in the corrosion dissolution, Gradually restore the original permeability of the formation to ensure the effect of crude oil exploitation.Acidizing can reduce the combined pressure of the fluid, helping to increase the flow efficiency at the bottom of the hole.

Pressure system optimization technology
Pressure system optimization technology is the key technical means to ensure the production of low permeability oil fields.In the formal development of oil Wells, the production capacity of oil Wells should be comprehensively analyzed according to the production target starting pressure and oil production situation, and development plans should be made to monitor the net flow pressure of reservoir, so that the production efficiency of oil fields is gradually improved.In the application of this technology, the flow pressure is accurately calculated, the fluidity of the oil is reduced, and the overall viscosity of the oil is improved, which increases the sensitivity to pressure, improves the ease of extraction, and improves the utilization efficiency.

Microbial oil recovery technology
Microbial oil recovery technology mainly uses the degradation function of microorganisms to enhance the light components in crude oil.Because link of microorganisms in the degradation of crude oil, usually form some metabolic substances, which contains a large number of surface active agent, surfactant, interaction between crude oil and comprehensive annual can effectively control the oil, to improve the original crude oil flow state adverse situation, so as to gradually raise the overall production of crude oil Wells.

Fracturing and development technology
Generally speaking, the natural productivity of low permeability reservoirs is relatively low, which cannot meet the industrial oil production standards.In this case, fracturing can be adopted to improve the comprehensive development intensity, which is the main way to improve the development of low permeability reservoirs.Ongoing efforts to develop the technology have improved extraction efficiency.Fracturing technology includes many forms, including limited flow fracturing technology, carbon dioxide fracturing technology and composite fracturing technology.When applying the fracturing truck technology, the main principle is that the fracturing technology can effectively improve the existing fractures in the bottom hole reservoir, so that the irregular state of crude oil can be transformed into regular length fractures with sand filling fracture characteristics [3].The reservoir also changes its permeability properties, allowing the direction of reservoir fluid flow and pressure changes to improve the overall well layout.

Stimulation technique
In the whole process of crude oil exploitation, due to various factors, improper mining operation seriously polluted the shallow crude oil, so that it is difficult to use the shallow crude oil efficiently.Especially in ultra-low permeability fields, the combined permeability level near the well is lower, which makes it difficult for oil to flow into the wellbore.These factors can seriously affect the improvement of oil production efficiency of the well.If this problem is not solved, it is difficult to improve the efficiency of crude oil recovery.In this regard, the author believes that physical stimulation can be adopted to realize gravity separation between crude oil, water and rock strata, so as to improve the comprehensive flow level of crude oil, enhance the fluidity of crude oil and expand the comprehensive oil production efficiency of oil Wells [4].

Horizontal well development technology
The main form of traditional Wells is vertical well development mode, which is relatively low in the exploitation of low permeability oil fields.Therefore, the author believes that horizontal well development can be fully utilized in the future exploitation.Horizontal Wells can increase the fracturing gradient during oil production, so that the pressure around the well gradually decreases, and water injection operations can improve the efficiency of water injection by applying the necessary pressure.Compared with vertical Wells, the combined pressure level is relatively small and can reduce the energy consumption in the process of crude oil extraction [5].

Conclusion
In v, this article around the oil field of low permeability reservoir development technology is analyzed and discussed, it can be seen that the number of low permeability reservoirs is relatively abundant, but due to the complexity of this resource has certain, in the process of mining, using traditional mining technology, then nature will be affected by many factors, reduce overall production efficiency, such as congestion, pollution and other problems, It is not good for the performance of low permeability reservoir.In order to effectively solve such problems, combining with the existing types of low permeability reservoir development technology of oilfield, put forward the targeted the development of technology, into the exploitation in the future work, need to do a good job, well pattern arrangement to ensure scientific and reasonable distribution, guarantee the production efficiency, but also can take a variety of other forms of mining technology, multi-pronged, Only in this way can we deal with various technical problems that may occur in the mining process and improve the mining efficiency.

Table 1
Permeability values