Abstract
One of the difficulties in high temperature and high pressure wells and deepwater well cementation in China South Sea is that the pressure range is very narrow. In the drilling or cementation process, the formation is easy to form sharp crack leakage. In general, the traditional simulation of bottom-hole mud or cement slurry leakage is to use the mesh plate or fixed width at a certain temperature and pressure difference. However, when there are wedge cracks in the formation, it will cause repeated "huff and puff" dynamic leakage of fluids. Dynamic leakage puts forward higher requirements for evaluation methods and plugging materials. In view of the problems, a new dynamic fracture plugging evaluation instrument was developed, and the new hydraulic wedge plugging material and matching cementing technology were optimized, which solved the problem of cement slurry leakage and return in China South Sea. The results of this paper have been successfully applied in cementing operations of high temperature and pressure wells and deepwater wells in the China South Sea, effectively solving the problem of hydraulic wedge leakage in sandstone formation cementing with narrow safety pressure window.
Highlights
There is rich in oil and gas resources in China South Sea, and Yingqiong basin in the China South Sea is one of the three major high-temperature and high-pressure zones
Formula: sea water + G class cement + 25% reinforcer + 20% lightening agent+ 0.5% defoamer + 5% water loss agent + 1.5% dispersant + 1.3% retarder + plugging material. It can be seen from the experimental results in table 1 that the cement slurry system mixed with B62 and B69 can effectively block the dynamic fractures below 1.0mm and increase the wellbore pressure by more than 6.5MPa
This is because the B62 fiber material is similar to the "steel bar" in concrete, which is evenly distributed into the cement slurry and has a good supporting and framing effect
Summary
There is rich in oil and gas resources in China South Sea, and Yingqiong basin in the China South Sea is one of the three major high-temperature and high-pressure zones. Jianglin Zhu et al.: A New Dynamic Fracture Plugging Evaluation Method and Its Application in Cementation for Mudstone and Sandstone Formation with Narrow Pressure Range in China South Sea annulus gap; large particle composites attached to the crack near the mouth, in the crack "one and one" of the "huff and puff" effect is easy to spit out, pointed crack plug reliability is poor. The research results have been successfully applied in well A in the west of the China South Sea, and have been widely applied in cementation operations of high-temperature and high-pressure wells in the China South Sea and ultra-deep wells in the China East Sea with narrow pressure range, effectively solving the problem of hydraulic wedge leakage in mudstone and sandstone formation
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
