Fault fractures usually have large openings and considerable extension. Accordingly, cross-linked gel materials aregenerally considered more suitable plugging agents than water-based gels because the latter often unde...Fault fractures usually have large openings and considerable extension. Accordingly, cross-linked gel materials aregenerally considered more suitable plugging agents than water-based gels because the latter often undergo contaminationvia formation water, which prevents them from being effective over long times. Hence, in this study, aset of oil-based composite gels based on waste grease and epoxy resin has been developed. These materials havebeen observed to possess high compressive strength and resistance to the aforementioned contamination, therebyleading to notable increase in plugging success rate. The compressive strength, thickening time, and resistance toformation water pollution of these gels have been evaluated indoors. The results show that the compressivestrength of the gel can reach 11 MPa;additionally, the related gelation time can be controlled to be more than3 h, thereby providing a safe construction time;Invasion of formation water has a small effect on the gel strengthand does not shorten the thickening time. All considered performance indicators of the oil-based gel confirm itssuitability as a plugging agent for fault fractures.展开更多
In view of the shortcomings of poor temperature resistance, poor pumpability and poor pressure-bearing capacity of commonly used gel plugging materials, polyacrylamide (HPAM) and N,N-methylene bisacrylamide (BIS) were...In view of the shortcomings of poor temperature resistance, poor pumpability and poor pressure-bearing capacity of commonly used gel plugging materials, polyacrylamide (HPAM) and N,N-methylene bisacrylamide (BIS) were selected for crosslinking and compounding to make a new type of gel plugging material with high temperature and pressure resistance. The compressive strength and yield stress were measured by inverted observation method to evaluate the gel strength. The anti-temperature, anti-pressure, anti-dilution and gel-breaking properties of the gel were evaluated. Finally, 71 type high temperature and high pressure water loss instrument and high temperature and high pressure filter with slit plate were used to evaluate the plugging capacity of gel plugging agent. The experimental results show that the new gel plugging system between 100°C - 120°C, gelation time can be controlled at about 5 h;it has strong temperature resistance, compression resistance, dilution resistance and gel breaking performance. In the face of permeability and fracture leakage simulation experiments, when the ambient temperature below 120°C, pressure within 5 MPa, the filter loss of gel plugging agent is far less than the market two conventional plugging agent, has excellent plugging performance.展开更多
At present, in the workover operations of old gas wells in the Changqing Gas Field, due to years of exploitation in the production layer, pressure deficits, and general leakage during the well killing, the well must b...At present, in the workover operations of old gas wells in the Changqing Gas Field, due to years of exploitation in the production layer, pressure deficits, and general leakage during the well killing, the well must be plugged before the well can be killed. In particular, the fracture-cavity type fractures of the lower paleocarbonate reservoirs have serious leakage. Traditional plugging materials and traditional plugging materials and methods have some limitations in dealing with leakage problems. Therefore, a composite plugging system using polymer solution as the base carrier fluid, multi-particle size rigid particles, expandable particles and modified fibers is developed. Its formula is: water + 2% polyacrylamide + 0.1% N, N-methylene bisacrylamide polymer gel is the base carrier fluid;the formulation of the particle plugging agent was continuously optimized through the CDL-II high temperature and high pressure dynamic and static plugging ability to plug the core. The final formulation of the plugging agent is: 1) 20% rigid particles (5 mm, 1 mm, 0.5 mm CCP-3 ratio 4:2:1) + 1% 3 mm expanded particles SMK-1 + 1% 1 ~ 2 mm fiber SRXW-10;2) 20% rigid particles (3 mm, 0.1 mm, 0.05 mm CCP-3 ratio 3:2:1) + 1% 3 mm expanded particles SMK-1 + 1% 1 ~ 2 mm fiber SRXW-10. The water swelling multiples of the granular plugging agent in salt water are all above 7 times, which meets the requirements of leak-proof plugging operations under high salinity;3% HCl is selected as the gel breaker, and the plugging system has a gel breaking rate of 95%;through the water plugging and profile control experimental system, the sand-filled pipe is used to simulate the plugging effect under high temperature and high pressure, and the plugging system can be sealed for 5 days at a high temperature of 110°C and a high pressure of 20 MPa to achieve a good plugging of the formation. It is expected that the developed plugging system has a good application prospect in future workover operations.展开更多
基金“Research and Application of Key Techniques for Drilling and Completion of Bozhong 19-6 Condensate Gas Field Development-Phase I”sub topic 4“Research on Leakage Prevention and Plugging Techniques for Fault and Buried Hill Reservoirs”,a Project of China National Offshore Oil (China)Co.,Ltd. (Project No.YXKY-2020-TJ-03).
文摘Fault fractures usually have large openings and considerable extension. Accordingly, cross-linked gel materials aregenerally considered more suitable plugging agents than water-based gels because the latter often undergo contaminationvia formation water, which prevents them from being effective over long times. Hence, in this study, aset of oil-based composite gels based on waste grease and epoxy resin has been developed. These materials havebeen observed to possess high compressive strength and resistance to the aforementioned contamination, therebyleading to notable increase in plugging success rate. The compressive strength, thickening time, and resistance toformation water pollution of these gels have been evaluated indoors. The results show that the compressivestrength of the gel can reach 11 MPa;additionally, the related gelation time can be controlled to be more than3 h, thereby providing a safe construction time;Invasion of formation water has a small effect on the gel strengthand does not shorten the thickening time. All considered performance indicators of the oil-based gel confirm itssuitability as a plugging agent for fault fractures.
文摘In view of the shortcomings of poor temperature resistance, poor pumpability and poor pressure-bearing capacity of commonly used gel plugging materials, polyacrylamide (HPAM) and N,N-methylene bisacrylamide (BIS) were selected for crosslinking and compounding to make a new type of gel plugging material with high temperature and pressure resistance. The compressive strength and yield stress were measured by inverted observation method to evaluate the gel strength. The anti-temperature, anti-pressure, anti-dilution and gel-breaking properties of the gel were evaluated. Finally, 71 type high temperature and high pressure water loss instrument and high temperature and high pressure filter with slit plate were used to evaluate the plugging capacity of gel plugging agent. The experimental results show that the new gel plugging system between 100°C - 120°C, gelation time can be controlled at about 5 h;it has strong temperature resistance, compression resistance, dilution resistance and gel breaking performance. In the face of permeability and fracture leakage simulation experiments, when the ambient temperature below 120°C, pressure within 5 MPa, the filter loss of gel plugging agent is far less than the market two conventional plugging agent, has excellent plugging performance.
文摘At present, in the workover operations of old gas wells in the Changqing Gas Field, due to years of exploitation in the production layer, pressure deficits, and general leakage during the well killing, the well must be plugged before the well can be killed. In particular, the fracture-cavity type fractures of the lower paleocarbonate reservoirs have serious leakage. Traditional plugging materials and traditional plugging materials and methods have some limitations in dealing with leakage problems. Therefore, a composite plugging system using polymer solution as the base carrier fluid, multi-particle size rigid particles, expandable particles and modified fibers is developed. Its formula is: water + 2% polyacrylamide + 0.1% N, N-methylene bisacrylamide polymer gel is the base carrier fluid;the formulation of the particle plugging agent was continuously optimized through the CDL-II high temperature and high pressure dynamic and static plugging ability to plug the core. The final formulation of the plugging agent is: 1) 20% rigid particles (5 mm, 1 mm, 0.5 mm CCP-3 ratio 4:2:1) + 1% 3 mm expanded particles SMK-1 + 1% 1 ~ 2 mm fiber SRXW-10;2) 20% rigid particles (3 mm, 0.1 mm, 0.05 mm CCP-3 ratio 3:2:1) + 1% 3 mm expanded particles SMK-1 + 1% 1 ~ 2 mm fiber SRXW-10. The water swelling multiples of the granular plugging agent in salt water are all above 7 times, which meets the requirements of leak-proof plugging operations under high salinity;3% HCl is selected as the gel breaker, and the plugging system has a gel breaking rate of 95%;through the water plugging and profile control experimental system, the sand-filled pipe is used to simulate the plugging effect under high temperature and high pressure, and the plugging system can be sealed for 5 days at a high temperature of 110°C and a high pressure of 20 MPa to achieve a good plugging of the formation. It is expected that the developed plugging system has a good application prospect in future workover operations.
