# A Novel Application of New High-Strength Plugging Agent in Baikouquan Oilfield
###### Abstract  
The Baikouquan Oilfield is entering middle and later periods of development. Casing failure, caused by the quality of cementing and casing corrosion, affects the normal production of the well. The number of wells in this situation has been increasing in recent years. Some wells with a high aquifer have no way to achieve effective plugging. The conventional measures have short validity periods and low plugging strengths. They cannot meet the requirements of subsequent fracturing operations and long-term production. Therefore, a new type of plugging agent with high strength, temperature resistance, salt resistance and micro-expansion features was designed and developed. The field test was carried out on four wells in the Baikouquan block, including three wells with a strong water-flooded layer and one well with an upper casing leakage point. A field test showed that the leakage formation was successfully plugged under the condition that the oilfield pressure test value was 30 MPa, with a 100% success rate. The average fluid volume decreases by 51.4%, and the average oil volume increases by 270.8%. The average daily oil volume per well increases by 3.2 t/d. The new plugging agent has the characteristics of no regurgitation, fast cementing speed with the new interface, high cementing strength and construction safety. The above advantages are of great significance in reducing the operation cost of oil and water well production and enhancing oil recovery. casing failure; water channeling; leakage formation; plugging strength; field test +
Footnote †: journal: Applied Sciences  
azimuth angle and operational requirements for the bending section of the casing and rough/poor construction quality of well cementation, which leads to casing failure [12; 13]. Fifth, the span of the oil layer is large, and it is difficult to reconstruct the lower formation, for which reason the lower formation cannot be effectively used. Therefore, in order to meet the requirements of long-term production and subsequent fracturing, it is necessary to plug wells with casing damage, such as corrosion perforation, casing deformation and casing faults, and wells with outside casing channeling and interlayer channeling [14; 15; 16; 17; 18] as shown in Figure 2. How to effectively and successfully plug a well with damaged casing and leakage formation to increase single well production is still an urgent problem to be solved in the process of oilfield development. The existing casing leakage repair measures, including the casing subsidy method, suspending packer and installing new casing to replace the previously damaged casing, can not only dissatisfy the requirements of subsequent fracturing and water injection measures but also has the problems of low success rates of plugging, high construction cost and long construction times [19; 20]. The cost of conventional cement plugging is low, but the amount of cement used in plugging operations is large. The solidified body has relatively poor strength and cementation after plugging. In addition, the volume of cement plugging agent is susceptible to shrinkage and can crack at high temperatures, which reduces the structural compactness of the cement solidified body, resulting in plugging failure [21; 22; 23]. Based upon the conditions described above, chemical plugging agents have been developed. At present, there are many kinds of chemical plugging agents. For example, [PERSON] et al. [24] developed a polymer plugging gel for fractured strata, named XNGJ-3. In the study by [PERSON] et al. [25], a temporary plugging agent composed of two different types of guest molecules for thermally induced phase change fracturing was constructed. In addition to gel plugging agents, researchers have also performed a lot of research on resin plugging agents. For instance, [PERSON] et al. [26] developed a composite plugging agent with water-absorbent swelling resin for drilling plugging. Nowadays, inorganic gel plugging agents and thermosetting resin plugging agents are mainly used.