Laboratory Experimental Study On The Blocking Law Of Complex Fracture Channeling In Oil Wells

With the extension of oilfield development time and the implementation of secondary and tertiary infill mining schemes,the underground situation of the oilfield is becoming more and more complicated,and the channeling phenomenon is becoming more and more serious.Due to the existence of channeling wells,the development stratum is disrupted,causing interlayer interference,affecting the normal production of oil and water wells,greatly increasing production costs,and rapidly decreasing oil well output.Blocking the effluent horizon and channeling outside the pipe is currently the conventional method of controlling the effluent,mainly by injecting channeling agent into the channeling channel to block the channel,but due to the complexity of the channeling of the oil well,the existing technology and process methods have defects This has led to problems such as low oil well sealing channeling rate and short validity period of most well sealing channels,which restricts the large-scale promotion of sealing channeling technology and cannot meet the demand for sealing channeling in oilfield field production.For the channeling of some old oil wells outside the pipe,not only the first channel,the second interface and other interface channels are affected,but the interlayer fracture is also an important factor causing channeling.Due to the existence and complexity of interlayer cracks,it directly increases the difficulty of plugging,resulting in a short period of effective plugging of channeling.So,increasing the blocking rate of interlayer fracture channeling in oil wells not only improves the blocking rate of interlayer channel channeling,but it is difficult to directly discuss the situation of on-site channeling channel channeling.Therefore,in order to solve the above problems,different types of crack channeling were simulated in the laboratory,and different injection methods were changed to block the crack channeling,the plugging effect was studied,and then two rounds of double slug were determined.The method of injecting the plugging agent to block the fracture channeling greatly improves the oil recovery rate.A plugging agent was prepared with modified polymer as the main agent,ammonium persulfate as the initiator,bisacrylamide as the reinforcing agent,and cement as the additive,and the ratio of each additive was optimized by orthogonal test to investigate the plugging agent Viscosity performance,temperature resistance,pollution to the formation and other indicators,and by comparison with oil well cement,ultra-fine cement and other commonly used oil channeling agent proved that it has a very good plugging effect.An oil well channeling simulation plugging model was made in the laboratory.The oil channeling channel crack channeling and interface channeling were artificially produced.Through the channeling channel blocking laboratory experiment,the oil well channeling channel model was blocked to study the blocking effect.The continuous injection method of plugging agent can effectively block the first and second interface channeling,but it is less effective in blocking channeling of cracks.Build a model of crack channeling with different widths.For single crack channeling with different widths,when using a single plug to continuously inject plugging agent,the smaller the width of the crack,the greater the breakthrough pressure after plugging,and the better the plugging effect;When the plugging agent is injected in rounds,the breakthrough pressure values of cracks of different widths after plugging are almost the same,and they all have a good plugging effect.Cracks of different widths are connected in parallel to form a complex crack.When a single plug is used to continuously inject a plugging agent,cracks with a larger width form an effective plug,while cracks with a smaller width fail to form an effective plug.When two plugs are used for two rounds of injection of plugging agent,cracks with large widths and small widths can form effective plugging;when three plugs are used for three rounds of injection of plugging agent,the plugging effect of parallel crack groups of different widths is slightly better The injection effect of the plugging agent in two rounds of double-segment plugging is not significant.