The quality of cementing operations and cementing equipment is related to the successful completion of oil and gas exploration. And affects the life of oil and gas wells and the production of oil and gas wells. The cost of cementing operations accounts for a large proportion in drilling engineering. This paper introduces the current cementing operations. Existing problems and new technologies and technologies for cementing technology development. To Clarify the importance of cementing in drilling engineering and even the entire oil and gas exploration process.
Key words: cementing technology; drilling project; importance
In the drilling process, oil wells are often encountered in the case of blowout prevention, leakage, collapse, etc.
That is not only affects normal drilling, but also causes the wellbore to be scrapped. In response to these conditions,
First, the packer should be set up to form a composite and then continue drilling. Until a stable oil and gas channel is established. Therefore, to achieve high-quality drilling operations and ensure oil and gas production efficiency, cementing technology must be adopted.
Purpose of cementing operation
1. 1 to Ensure oil separation of gas and water Effective.
When the pressure of the water layer is less than the pressure of the oil and gas layer, the oil and gas will break into the aquifer.
which will not only cause water pollution, but also affect the production of oil and gas. Once the water layer pressure is higher than the oil and gas layer pressure. The oil and gas layer will break into the water, leading to water quality in the early stage of oilfield development and quality destruction of the entire oil and gas field. So, how to ensure the quality of solidification, it is necessary to cement the different types of fluids in the formation.
1.2. Supporting the weight of the wellhead device and casing
Drilling and completion technology requires cementing operation. After cementing, the cement quality must not only support the weight of the casing, but also bear the weight of the wellhead installed in the casing. and establish the oil and gas passage.
Prepare for the next drilling or completion.
1. 3 Protect fresh water resources and prepare for acid fracturing
It can effectively protect fresh water in the upper sand layer and not be oiled in the lower rock layer. Gas, salt water, etc. are polluted. After the oil well is put into operation, it has created certain favorable conditions for the next acid fracturing operation.
The main problem of cementing operations
2. 1 The cement that does not meet the design requirements is high. Cannot block the formation
The decrease in the annuls flow velocity affects the displacement effect, resulting in poor cementation. Consequences include a lost circulation when the casing is lowered, causing a casing accident and the casing cannot be lowered to a predetermined depth. The cement ring is not well cemented. It is easy to see a layer of polluted strata between oil and gas water layers, and the leakage is serious. It may also cause pollution to oil and gas production layers and affect the production of oil and gas wells.
In the middle and late stages of development. Cementing leakage is caused by artificial cracks caused by fracturing. Most of the leakage will affect the cementing quality and even lead to failure of consolidation and uncontrollable oil and gas wells.
2.2 cement slurry application efficiency is not high
The reason why the application efficiency of cement slurry in deep water cementing is not high is probably. Summarized as the following points:
1.) The loose form of the surface layer of the deep seabed is not conducive to the cementation of the cement slurry. In addition, it is the influence of the “window” phenomenon, that is, the fracture pressure is too close to the formation void pressure, and it is difficult to achieve turbulence or hierarchical gradient displacement.
2.) The soft formation has a great influence on the structure of the wellbore, and the resistance is affected by the friction during drilling. The influence of the flow of the sand layer is also difficult to meet the conditions of turbulent displacement.
3.) The complicated casing structure causes the gap between the casing and the joint to increase the vacant space under the well,. It is not conducive to turbulent displacement.
4.) Under the field conditions, the unreasonable well structure also poses a challenge to achieve casing centering.
Cementing is a systematic project. the influencing factors are complex and diverse, with its particularity. After continuous scientific research and technical accumulation in solving practical problems in the field, cementing technology has made great progress. A large number of advanced Shichuan’s on-site cementing branches have been formed.
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