|TDSP™ II spacers work as the surfactant wash stage to disperse any residual mud from tubular surfaces. They consist of a turbulent flow spacer with concentrated surfactants, which disperse any residual mud from the tubular surfaces and are specifically designed for the mud type. The TDSP II spacer is designed to provide a minimum of 2,000 feet of coverage and a minimum of 10 minutes contact time in the largest annular section of the wellbore. While maximum pumping rates are often limited by pump capabilities, an annular velocity of 180 ft/min is recommended in each annular interval.
Another essential design factor in the TDSP II spacer is to ensure that sufficient TDSP II is available to incorporate the entire volume of anticipated drilling mud residue that may be present. In some cases, this consideration overrides the annular coverage and contact time recommendations mentioned above. This consideration requires extensive testing of the TDSP II spacer for its maximum residue capacity. It is always desirable to perform these tests on a sample of the mud from the wellbore to be displaced.