The Technology And Application Of Rigid Wedge Mud Loss Control Under Pressure

Lost circulation,the most complex and most complicated type of loss during drilling engineering,has always hindered the development of drilling engineering and become one of the difficulties in the development of oil and gas fields.In this essay,through the analysis of causes related to lost circulation and plugging,the mechanism of “stress cage” plugging is used to propose a rigid wedge-into-pressure plugging technique.On the basis of the reasons for stratum bearing pressure capacity,the fundamental reason for the strata being fracturing or having low pressure bearing capacityis the result of mud column pressure exerting a hydraulic sharp point on various cracks and cracks in the stratum,or the pressure of the mud column is greater than the open pressure of the fracture to produce a hydraulic wedge effect.The principle study of improving the pressure bearing capacity of the formation is completed,and the reason for the low pressure bearing capacity of the formation is analyzed.To improve the pressure bearing capacity of the formation,it is necessary to enhance the borehole wall,and promptly and effectively block all kinds of cracks,in order to reduce or block the drilling fluid into the formation of cracks,preventing the occurrence of hydraulic fracturing,and the formation of induced cracks.Through the improvement of the JHB,a new high-temperature and high-pressure leak detector,the experimental evaluation method for the formation pressure capability was improved.Quartz sand is selected as a rigid wedge-increase pressure plugging agent.According to the relationship between crack and leakage velocity,the crack opening can be predicted by predicting the crack opening formula,and then the size of the rigid particles can be estimated according to the crack opening.The rigid wedging series of plugging agent was determined to have a particle size distribution;through the evaluation of the rigid wedging plugging agent pressure-bearing effect,it was concluded that the rigid wedge plugging agent can bridge thefracture and form a plugging section in a very short time.The more reasonable the rigid wedge plugging agent grading,the shorter the time for bridging to form a plugged section in the fracture,and the higher the pressure bearing capacity.Through calculations and experiments,leak-proof plugging formulas for different leak rates and different plugging methods were given,and “Technical Specifications for Rigid Wedging Leakage Plugging” was prepared.In the two wells tested,the success rate of plugging was 100%,and the effect of improving the pressure bearing capacity of the formation was significant in later construction.