环氧渣油凝胶套外窜流治理剂研制与应用

Development and application of epoxy residual oil gel casing channeling treatment agent

摘要:

针对现有套漏治理堵剂存在固化胶结强度低、堵后易脆裂不易降解等问题,本文以环氧植物渣油和甲基六氢苯酐为原料制备了可降解高强度堵剂(VOR)。利用理论分析、微观结构表征和室内实验评价等方法,考察了堵剂的流变性能、稳定性能、力学性能、封堵性能及其固化机理和降解机理。研究结果表明,VOR的制备机制为聚酯交联聚合作用；堵剂注入性能较好,固化时间可控；堵剂的抗压强度大于40MPa,热降解温度为257.87℃,在高温高矿化度条件下(固化温度为100℃,矿化度≥8×10₄^mg/L)老化90天,堵剂质量保留率大于93%,堵剂稳定性能优异；堵剂分子类球状颗粒分布形式赋予了堵剂的高强度性能和高粘附特性,由此使得堵剂具有优异的封堵性能,当温度为100℃,水驱突破压力大于20MPa。在80~140℃时,VOR凝胶在270h内可被完全降解,且反应温度越高,降解速率越快,红外光谱证实了堵剂降解机理为交联结构中的酯键分解。该堵剂的研制既实现了植物渣油的资源化利用,又可满足套漏治理、水平井管外封窜、堵压一体化等作业对高强度堵剂的需求。

Abstract:

Aiming at those problems that plugging water agents are lower bonding strength, easily cracked in the progress of water plugging and difficultly degraded when agent has been cured, this paper offers a way to prepare a degradable and high-strength resin water plugging agent by using vegetable oil residue with epoxidation modification and methylhexahydrophthalic anhydride. Based on a combination of microstructure characterization, laboratory test and theoretical analysis, this paper evaluates thermal stability, compressive strength and water plugging performance of VOR, respectively, as well as explains curing mechanism and degradation mechanism of VOR. The rheological properties, stability, mechanical properties, plugging performance, curing mechanism and degradation mechanism of the plugging agent were investigated by means of theoretical analysis, microstructure characterization and indoor experimental evaluation. The results showed that the preparation mechanism of VOR gel was polyester crosslinking polymerization.The plugging agent has good injection performance and controllable curing time. The compressive strength of the plugging agent is more than 40 MPa, the thermal degradation temperature is 257.87 °C, and the mass retention rate of the plugging agent is more than 93 % under the condition of high temperature and high salinity ( curing temperature is 100 °C, salinity ≥ 8 × 10_⁴ mg / L ) for 90 days. The plugging agent has excellent stability. The distribution of spherical particles of plugging agent molecules endows the plugging agent with high strength and high adhesion characteristics, which makes the plugging agent have excellent plugging performance. When the temperature is 100 °C, the breakthrough pressure of water flooding is greater than 20 MPa. At 80 ~ 140 °C, the VOR gel can be completely degraded within 270 h, and the higher the reaction temperature, the faster the degradation rate. The infrared spectrum confirmed that the degradation mechanism of the plugging agent was the decomposition of the ester bond in the cross-linked structure. The development of this plugging agent not only realizes the resource utilization of plant residue, but also meets the needs of high-strength plugging agent for plugging and pressure integration, casing leakage treatment, horizontal well pipe external channeling and other operations.