Light-weight temporary-sealing cement for medium temperature geothermal wells by using polyvinyl alcohol fibers and fly ash cenospheres

Tan, Huijing; Shen, Lan; Zuo, Yu; Fan, Lisheng; Zhang, Gengchao; Qiu, Delong; Xie, Lijuan; Zheng, Xiuhua; He, Wei

doi:10.1016/j.petrol.2022.110704

Cited by 5 publications

(2 citation statements)

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“…The polymer plugging material can form a versatile viscoelastic gel that can conform to different types of cracks. However, the compressive or tensile strength of the gel needs to be improved, which may flow out during the recovery drilling process, resulting in drilling fluid loss. , Inorganic crosslinked LCM (e.g., cement) is the main treatment method for major losses. , The success rate is relatively high, but the cost is also high. The cement waiting time is long and the acid solubility of the cement is low, which will cause significant damage to the reservoir.…”

Section: Introductionmentioning

confidence: 99%

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Magnesium Oxychloride and Magnesium Oxysulfate Cements as Temporary Plugging Agents in Geothermal Drilling

Yan,

Pang,

Dong

et al. 2023

ACS Omega

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The development and utilization of geothermal resources are effective ways to alleviate the current haze situation, adjust the energy structure, and achieve energy conservation and emission reduction. Geothermal formations typically contain extensive fracture networks, with fracture openings. These fracture networks can result in substantial losses of the drilling fluid and increased costs for geothermal drilling. Temporary plugging cements are used to solve the problem of lost circulation due to their high strength and high acid solubility. In this paper, two types of temporary plugging materials, magnesium oxysulfate (MOS) cement and magnesium oxychloride (MOC) cement, were prepared. The influence of the plugging agent on the flow field and the force exerted on the solid under the action of the fluid was analyzed using fluid−solid coupling software. The simulation results show that when subjected to a flow rate of 10 m/s, the edge of the cement experiences a significant force, while the stress is not widely transmitted to the middle and rear of the cement. This indicates that the cement has a strong resistance to the fluid flow. The fundamental characteristics of MOC cement and MOS cement, such as compressive strength and setting time, were investigated. The test results show that adjusting the molar ratio of the two types of cements can shorten the setting time by 60% and increase the compressive strength to up to 23 MPa. In addition, the acid solubility of the cement with different ratios of raw materials is above 95%. The plugging performance of these two cements as loss circulation materials was evaluated by using a physical simulation device. The pressure bearing capacity of the MOC cement with different MgO/MgCl 2 •6H 2 O/H 2 O molar ratios ranged between 13.4 and 23.6 MPa. The maximum bearing capacity of the MOS cement can reach up to 18.6 MPa. The results showed that both cements possess excellent plugging and pressure bearing capacity.

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Section: Introductionmentioning

confidence: 99%

“… 19 , 20 Inorganic crosslinked LCM (e.g., cement) is the main treatment method for major losses. 21 , 22 The success rate is relatively high, but the cost is also high. The cement waiting time is long and the acid solubility of the cement is low, which will cause significant damage to the reservoir.…”

Section: Introductionmentioning

confidence: 99%