The main objective of a primary cement job is to provide complete and permanent isolation of the formations behind the casing. To do this, cement must displace all mud from the annulus. After having used rules of thumb or semi-empirical models to design this displacement process for years the industry started to use displacement simulators in the late 90s. The most significant improvements made regarding these numerical simulations over the last years will be presented and the practical limitations of these new simulators discussed. Since the eccentricity of the casing is playing a key role on this process it will also be attempted to answer to the following question: how accurate are the predictions of the casing inside the hole and how might this impact the quality of cement placement?
Designing cement placement with a reliable simulator does not guarantee that uncontaminated cement will be uniformly distributed in the annulus and bonded to the casing and formation. Acoustic logging has become the industry’s tool of choice for detecting cement behind casing and assessing the quality of the bond. During the last ten years new techniques were introduced like LWD sonic and measurements based on flexural wave propagation. The added value and limitations of these techniques will be compared to those of the more conventional sonic and ultrasonic techniques. The benefit of data integration in the overall cement evaluation process will be discussed.