Oil well cement paste and horizontal well technical casing cementing process (2023)

[0002] At present, in the underground mining process of mine salt mines, horizontal well drilling construction is a very important link, especially the cementing quality of productive technical casing, which directly determines the brine concentration and production life of the well group; During the deposition process, there is often the possibility of water filling near the top of the salt layer, and this phenomenon is particularly prominent in old mining areas

When tapping the potential of an old mining area, the probability of well kick and lost circulation is very high when drilling near the top of the salt layer, because it is often associated with the adjacent mined rock salt solution cavity, and well killing or cementing is required; the existing In the casing cementing process of horizontal well technology, cement is usually mixed with clean w...

[0013] Embodiment one

[0014] A kind of oil well cement slurry of this embodiment comprises 1 part of G grade oil well cement, 1.2 parts of saturated brine, 0.02 part of oil well cement expansion agent and 0.002 part of coagulant, according to the ring between the casing and the well wall Empty size, the quality of 1 part of G grade oil well cement is 10 tons, the quality of corresponding 1.2 parts of saturated brine is 12 tons, the quality of 0.02 part of oil well cement expansion agent is 200 kg, and the quality of 0.002 part of coagulant is 20 kg, the oil well cement expansion agent uses montmorillonite, the coagulation accelerator uses calcium chloride, and mixes evenly.

[0015] Embodiment two

[0016] An oil well cement slurry of this embodiment includes 1 part of G grade oil well cement, 1.1 part of saturated brine, 0.018 part of oil well cement expansion agent and 0.0025 part of coagulant. Empty size, the quality of 1 part of G grade oil well cement is 8 tons, the quality of corresponding 1.1 parts of saturated brine is 8.8 tons, the quality of 0.018 part of oil well cement expansion agent is 144 kg, and the quality of 0.0025 part of coagulant is 20 kg, the oil well cement expansion agent uses montmorillonite, the coagulation accelerator uses calcium formate, and mixes evenly.

[0017] Embodiment three

[0018] A kind of oil well cement slurry of this embodiment comprises 1 part of G grade oil well cement, 1.35 parts of saturated brine, 0.03 part of oil well cement expansion agent and 0.003 part of coagulant, according to the ring between casing and well wall Empty size, the quality of 1 part of G grade oil well cement is 20 tons, the quality of corresponding 1.35 parts of saturated brine is 27 tons, the quality of 0.03 part of oil well cement expansion agent is 600 kg, and the quality of 0.003 part of coagulant is 60 kg, the oil well cement expansion agent uses montmorillonite, the coagulation accelerator uses calcium formate, and mixes evenly.

[0019] like figure 1 As shown, the horizontal well technical casing cementing process using any of the above three oil well cement slurries includes the following steps: A) establish a horizontal well 1, and run the technical casing 4 into the wellbore until the level of the horizontal well 1 Section 2, the horizontal section 2 is located below the salt layer roof 3 in the formation; B) inject the above-mentioned oil well cement slurry 6 through the technical casing 4 through the annular space between the technical casing 4 and the well wall 5, and then carry out the second A pumping displacement operation, so that the oil well cement slurry 6 enters the annulus between the salt layer roof 3 and the technical casing 4 and the annulus between the technical casing 4 and the well wall 5 below it, and at the same time, the technical casing 4 The remaining part of the oil well cement slurry 7 is about 3 cubic meters; when the thixotropy of the oil well cement slurry is enhanced before the initial setting, the second pumping displacement operation is performed, and a part of the remaining oil well cement slurry 7 in the technical casing 4 is pushed out, The produced oil well cement slurry accounts for 5% of the oil well cement slurry in the annular space between the technical casing 4 and the well wall 5 after the first displacement operation, and the volume is about 1 cubic meter; In three pumping displacement operations, part of the remaining oil well cement slurry 7 in the technical casing 4 is pushed out, and the ejected oil well cement slurry occupies the oil well in the annular space between the technical casing 4 and the well wall 5 after the first displacement operation. 5% of cement slurry, the volume is about 1 cubic meter, remaining about 1 cubic meter of cement slurry in technical casing 4;

[0020] Saturated salt water is used in the oil well cement slurry of the present invention. When the cement slurry is solidified, the precipitated salt water will not dilute and take away the solid salt in the salt layer, avoiding the increase of the gap with the salt layer, and adding an expansion agent to make the cement slurry The volume expansion rate is 10%, which can fill the gap between the cement slurry and the salt layer and the small gap inside. The saturated brine has a retarding effect. The addition of the coagulant will push out part of the oil well cement slurry during the three replacement operations each time, which can Various gaps are completed to maintain pressure and accelerate coagulation, avoiding the erosion of cement slurry by light brine, which can greatly reduce the gap between cement body and salt layer, and can effectively seal off the passage of light brine. The cementing quality is good, and the oil well cement slurry 6 enters the salt layer The annulus between the roof 3 and the technical casing 4 below it and the well wall 5 can prevent water penetration of the salt layer roof 3 and ensure the brine concentration and production life of the well group; G-grade oil well cement can resist high temperature and high pressure and is suitable for Relatively harsh working conditions; the second displacement operation and the third displacement operation eject the appropriate amount of cement slurry in the oil well each time, and at the same time retain a certain amount of cement slurry in the technical casing 4, which can ensure good pressure holding and coagulation acceleration Effect.