动态复杂压力下的水泥浆体系及性能评价

为了提高渤海油田动态复杂压力体系下的调整井固井质量，满足注水泥期间周边注水井不停注的要求，针对压力体系紊乱复杂、储层段固井质量差、层间封隔不良等固井难题，利用自主设计研发的抗动态水分散性能评价装置、界面胶结防窜性能测试装置和塑性体体积测试装置，形成了适用于动态复杂压力下的水泥浆防窜性能综合评价方法。通过抗动态水分散剂、膨胀剂、增韧剂以及缓凝剂等外加剂材料的评价与优选，开发出一套适用于渤海油田动态压力体系固井的新型防窜水泥浆体系，该水泥浆较目标区块原始体系抗压强度提高18.6%、胶结强度提高28.7%、抗水窜压力提高60.8%。在蓬莱油田完成了4口井的现场应用，固井质量较邻井提高22.3%～37.5%。应用表明，新型防窜水泥浆体系具有优良的防窜性能，可大幅提高复杂压力体系下的调整井固井质量，满足注水泥期间注水井不停注的要求，推广应用前景广阔。 

Study and Application of Evaluating the Performance of Cement Slurries Under Dynamic Complex Pressures

A comprehensive method for evaluating the anti-channeling performance of cement slurries under dynamic complex pressures was developed for the purpose of improving the job quality of cementing adjustment wells under dynamic complex pressures and satisfying the requirements of performing well cementing without interrupting water injection job nearby in the Bohai oilfield. This evaluation method involves three devices, which are a self-developed device for evaluating the performance of resisting dynamic water dispersion, a device for evaluating the anti-channeling performance of interfaces between cement sheath and casing string/borehole wall, and a device for measuring the volume of plastic materials. This method can be used to evaluate the performance of a cement slurry aimed at dealing with difficulties such as disordered and complicated pressure system, low quality of pay zone cementing job and poor isolation between different pay zones. A new anti-channeling cement slurry was developed based on the evaluation and optimization of anti-dynamic water dispersion agents, expanding agents, toughness enhancers and cement retarders etc. The development of this new cement slurry was aimed at dealing with problems encountered in cementing wells affected by the dynamic pressure system in the Bohai oilfield. Compared with the cement slurries used in this oilfield, the set cement of the new cement slurry had compressive strength that was increased by 18.6%, bonding strength increased by 28.7%, pressure to resist water channeling increased by 60.8%. This new cement slurry has also been used in four wells in the Penglai oilfield, and the well cementing job quality was enhanced by 22.3%-37.5% over the job quality of cementing performed previously. Field application of the new anti-channeling cement slurry has indicated that it has excellent anti-channeling capacity, and is able to greatly improve the well cementing job quality of adjustment wells drilled in formations with complex pressure system. This new cement slurry helps realize well cementing without interrupting water injection operation, and has broad prospects of application in the future.