RU93029487A - METHOD OF MOUNTING WELLS - Google Patents

Claims (1)

The method relates to the mounting of wells in the interval of occurrence of rocks prone to significant plastic deformation. The purpose of the invention is to improve the reliability of the mounting wells in the presence of plastic rocks in the section by ensuring uniform lining strength in relation to hydrostatic and uneven pressure. To do this, in the method of attaching wells, including the descent into the well, passing plastic rocks, casing strings and pumping cement mortar into the annular and annular space, cement mortar is pumped into the annular space from the bottom of the well to the sole of ductile rocks and from the roof of ductile rocks to the wellhead and in the interval from the bottom to the roof of plastic rocks, a viscoelastic fluid is injected. In this case, the viscoelastic fluid is chosen with a compressibility factor

where ΔV is the change in the volume of the annular space during deformation of the casing, V _о is the initial volume of the annular space, q is the pressure in the annular space. The strength characteristics of the casing is chosen from the condition P _{n and p} > W _y , P _{in n .} > P _{g e o s t .} where P _{n and p .} - the critical pressure of rupture of the outer column, P _{in n .} - removing critical pressure inside the column, W _y - rock contact pressure to the outer plastic casing, R _{f g C m.} - geostatic pressure at the bottom of the plastic rock. The use of the method increases the reliability of the mounting wells, improves the conditions of fluidity of rocks without additional costs to increase the thickness of the walls of casing and their strength categories.