Study On New Integrated Working Fluid Technology For Drilling And Cementing

Starting with activation hydration mechanism characteristics of potential active materials, using method incorporates lab experiments, field simulation test, numerical comparative analysis and interface micro-analysis, the paper conducts a systematic study to the characteristics of active materials, formula of working fluid, mud cake solidification and field operational technology, forms drilling-cementing integrated working fluid technique and matched drilling cementing operating measures. The research result has been popularized in the field.Firstly, complex active cement ASCP and plasticizer ZSJ used in integrated working fluid were developed based on the theories of ultrahigh strength cement and other composite material. ASCP contains high active metastable state multiphase composite material, can adhere to the end of clay subindividual, jam the gap among clay strata, restrain the clay hydration effectively and improve interfacial tension of shale. ZSJ is better than single fibre flexibilizer used in common cement, can enhance the toughness of condensate and increase shock resistant toughness and rupture strength by 20%. The integrated working fluid for drilling and cementing was obtained by adding developed and selected potential active cement, flow pattern regulator, activator and activity regulator to common water based drilling fluid. The working fluid has advantages of good rheological property and stability, little filtration, good compatibility and short static gel strength transient time. Condensate from which have strong-points of strong anticorrosion to salt and acid and small corrosion to casing pipes. The focus of controlling activity should be on temperature, aging time and pH value according to results of investigating the effect of solution pH, salt water, compound salt water and aging time under high temperature and high pressure on the allround properties of integrated working fluid like rheological property and activity. The mud cake from integrated working fluid could solidify with that on borehole wall through activation and forming a continuous whole, cementation quality between solidified mud cake and cement is good. The application results of the integrated working fluid on 8 wells show that which can come from several water based drilling fluid, allround properties of which achieve the technical requirements for drilling and cementing safely, rate of overcut of pilot well within 3.2% to 6.9%, success ratio of operation and qualification rate of cementing both are 100%. The integrated working fluid technology can improve cementing quality effectively and be adapt to complex well operation such as interstice well in permeable strata and directional well.