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Open AccessArticle

A Polymer Plugging Gel for the Fractured Strata and Its Application

1
College of Petroleum Engineering, Southwest Petroleum University, Chengdu 610500, China
2
State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, China
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Department of Civil, Geological and Mining Engineering, École Polytechnique de Montréal, Montreal, QC H3T 1J4, Canada
4
Sinopec Nanjing Chemical Research Co., Ltd., Nanjing 210000, China
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Drilling Engineering Research Institute of Sinopec Southwest Petroleum Engineering Co., Ltd., Deyang 618000, China
*
Author to whom correspondence should be addressed.
Materials 2018, 11(5), 856; https://doi.org/10.3390/ma11050856
Received: 3 April 2018 / Revised: 8 May 2018 / Accepted: 15 May 2018 / Published: 21 May 2018
(This article belongs to the Section Advanced Composites)
Well leakage of fractured strata is a tricky problem while drilling. This unwieldy problem is usually caused by the poor formation of the cementing degree, the staggered-mesh of the fracture, and the low bearing capacity of the formation, which can also lead to a narrow and even unsafe window of drilling fluid density. For fractured strata, the normal plugging material has the disadvantages of unsuitable size and low strength, resulting in unsuccessful first time plugging and an increase in cost. Therefore, we developed a polymer plugging gel for the fractured strata, named XNGJ-3. XNGJ-3 is mainly made of an acrylamide monomer and is accompanied by the reactive monomers of carboxyl and hydroxyl as ingredients. XNGJ-3 has a low viscosity before gelling. At 80 °C it becomes gelled, and the gelling time was controlled within the required time of the practical application. These conditions are beneficial for making the plugging material enter the crossing fracture smoothly and occlude the fracture. XNGJ-3 also has a good deformability and can avoid being damaged during the process of fracture closure. The well leakage simulated experiment revealed that the bearing capacity of this material can reach 21 MPa and the inverse bearing capacity can reach 20 MPa. These strengths are more than twice that of common polymer plugging gels. Finally, three leaked wells in the fractured strata of the Sichuan Basin were used to verify the plugging effect of XNGJ-3. Compared with other common plugging materials, XNGJ-3 has the advantages of having a higher success rate of first time plugging, a lower economic cost, a shorter work time, and so forth, which indicate that this plugging material has a good engineering application value in dealing with well leakage of fractured strata. View Full-Text
Keywords: drilling engineering; well leakage; fractured strata; polymer gel; plugging material drilling engineering; well leakage; fractured strata; polymer gel; plugging material
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MDPI and ACS Style

Fan, X.; Zhao, P.; Zhang, Q.; Zhang, T.; Zhu, K.; Zhou, C. A Polymer Plugging Gel for the Fractured Strata and Its Application. Materials 2018, 11, 856.

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