Cementing technology for mud loss well at Pu7 block in Zhongyuan Oilfield

Loss circulation and well kick coexist on the drilled wells in Pu7 block of Zhongyuan Oilfield. Cementing operation faces difficulties of dispersive oil and gas layers, developed water contained layers, many injection wells, severe water production, and scattered and long distributed salt bed. According to the area features mentioned above, a series of technology measures are strengthened: in wiper trip process adjustment drilling mud performance after finish drilling, as far as possible to reduce the viscosity, shear force and water loss of the mud, to guarantee the stability of oil and gas layer. Fully clean well by 1.2 times delivery rate of drilling to improve the bonding ability and displacement efficiency of cement slurry; select reasonable balance liquid to prevent loss circulation; use centralizer to enhance the centralization degree of casing; apply open hole packer to resolve the problem of water channeling between the layers; optimizing cement slurry design, displacing under plug flow, pumping back pressure piecewise and other effective measures have been done, that not only stop the oil-gas-water channeling, but also ensure the quality of cementing operation. By application of 8 wells such as Pu7-9 sidetracked hole, achieved good results of 100% fine/excellent rate of cementing quality.