6 results about "Well cementing" patented technology

The invention provides an expansion-type rotatable tail pipe hanger and belongs to the field of oil gas well fixation. The expansion-type rotatable tail pipe hanger comprises a hanger body and a feeding tool system, wherein the hanger body is an expandable metal tubing, a group of triangle-shaped annular protrusions are formed on the outer surface of an expansion section of the hanger body, annular rubber sections are vulcanized between every two adjacent triangle-shaped annular protrusions, and the diameter of each annular rubber section is larger than the outer diameter of top portion of each triangle-shaped annular protrusion. Rotation of a tail pipe can be realized, tripping-in capability and cement slurry displacement efficiency of the tail pipe are improved, sit-hanging and seal-separating functions of the hanger are realized via a hydraulic expansion hanger body. By the aid of the expansion-type rotatable tail pipe hanger, construction requirements on tail pipe cementation of an oil gas well can be met, and the technical difficulties like complex structure, many potential construction safety hazards and hardness in guaranteeing well cementation quality of a slip-type hanger are overcome. Operation process is simplified, tail pipe cementation quality is improved, risk is reduced, and cost is saved.

The invention discloses an anti-gas-channeling simulation test apparatus in a later stage of well cementation. The apparatus comprises a bearing rod, a cement sheath inner tube, a cement sheath outer tube and a shell which are arranged in order from inside to outside, wherein a first sealing cavity is formed between the bearing rod and the cement sheath inner tube; the inner cavity of the bearing rod is communicated with the first sealing cavity; the inner cavity of the bearing rod is communicated with a first connecting hole for injecting a medium; a second sealing cavity is formed between the cement sheath inner tube and the cement sheath outer tube; the second sealing cavity is communicated with a second connecting hole for injecting the medium; a third sealing cavity is formed between the cement sheath outer tube and the shell; and the third sealing cavity is communicated with a third connecting hole for injecting the medium. The apparatus can simulate the size of hardened cement paste in full-scale, simulate loading conditions of the hardened cement paste in all directions and study sealing completeness of the hardened cement paste, is convenient for taking specific measures to improve a cement slurry system, and is helpful for increasing the anti-gas-channeling performance in the later stage of the hardened cement paste, thereby increasing the quality of the well cementation.

The invention discloses low-temperature early-strength toughening cement slurry and a method for preparing the same, relates to cement slurry used during well cementing and belongs to the technical field of oil and gas well cementing engineering. By the aid of the low-temperature early-strength toughening cement slurry and the method, inherent shortcomings of slow strength development and high brittleness of cement stone at low temperatures can be solved. The low-temperature early-strength toughening cement slurry comprises, by weight, 100 parts of oil well cement, 1-2 parts of low-temperature early-strength agents, 1-2 parts of cementing agents, 1-4 parts of low-temperature toughening agents, 0.8-1.2 parts of PVA (polyvinyl acetate) fluid loss agents, 0.8 part of acetone formaldehyde condensation compound drag reducing agents, 0.2 part of defoamers and the balance clear water. A mass ratio of the clear water to the oil well cement is 0.44:1, and the density of the cement slurry is 1.85g/cm<3>-1.90g/cm<3>. The low-temperature early-strength toughening cement slurry and the method have the advantages that the low-temperature early-strength toughening cement slurry is excellent in stability and low in fluid loss characteristics, and the compressive strength and the toughness of cement stone at low temperatures can be obviously improved.

The invention provides a weak gelling agent, a preparation method of the weak gelling agent, a cement paste suspension stabilizer and application of the cement paste suspension stabilizer. The weak gelling agent is obtained by initiating reaction of raw materials through an initiator, and the raw materials comprise sodium p-styrenesulfonate, itaconic acid, acrylic acid, N, N '-dimethylacrylamide, N-isopropylacrylamide or N-hydroxymethyl acrylamide and N-vinyl pyrrolidone. The weak gelling agent can relieve the phenomena of dilution and viscosity reduction generated in well cementation construction. The invention further provides a cement paste suspension stabilizer which comprises a tackifying and shear strength improving agent and the weak gelling agent. The invention further provides application of the cement paste suspension stabilizer in well cementation construction at the temperature of 200 DEG C or above. The cement paste suspension stabilizer can ensure the safety of cementing and well cementation construction under high-temperature and ultrahigh-temperature working conditions, and can improve the packing effect and well cementation quality of a deep stratum.