Research On Calculation Method Of Fracture Displacement Of Casing Leap Well

As injection time grows, injected water communication into the parting clay causes formation creepage and faulting recurrence in waterflood development reservoir. The number of wells with casing faulted increases in time. Faulted well seriously damaged has sanding problem.Casing leap pattern was researched in this paper based on the resent analysis of casing leap. The main reason of casing leap is wetted claystone creep to cut casing.Mechanical property of wetted claystone was researched on casing leap mechanics in Sanan area Daqing Oilfield. Curve of cohesion and angle of internal friction varied to water cut was obtained. Process of claystone wetted was stimulated by finite element software. Relation curve of claystone volume expansion ratio, immersed volume, mass fraction of water and casing equivalent stress was found.According to the research of this paper, we come to the conclusion that the inherent condition of slip is rock mass destabilizing, and external condition is high pressure water injection. Computational formula of stratigraphic gap was deduced in accordance with the theory of rock mass forced vibration on differential effect. The relationship among time, pressure difference distance and stratigraphic gap was got through case.Mechanical model under the influence of claystone creep and formation slip was built on the condition of casing leap. By combined action of formation deformation, slip mechanics, axial tensile load and interlayer pressure; we got computational formula of horizontal and vertical displacement. Take a casing leap well in field as a calculation example, comparison calculated values only vary 5.60% and 9.96% to the actual horizontal and vertical displacement.