Peter E. Clark

THE RHEOLOGICAL BEHAVIOR OF FRESH CEMENT PASTES

Abstract The rheology of fresh cement pastes is difficult to obtain and data is often difficult to reproduce. Factors involving mixing, testing techniques, test geometries, etc contribute to the measurement problems. This review addresses these problems and comments on the analysis of experimental data.

Characterization of crude oil-in-water emulsions

Abstract Emulsions can be important in almost all phases of drilling, completion and production of hydrocarbon reservoirs. In addition, heavy (viscous) crude oils have become an increasingly important source of hydrocarbons in many parts of the world, and transportation of these viscous crudes from the source to the refinery can be a problem. Both water-in-oil and oil-in-water emulsions are important in various phases of drilling, completion and production of wells. A knowledge of the rheological behavior of these emulsions, under both laboratory and field conditions, is important. In this study, emulsion rheology was reviewed, and four different viscous crude oil emulsions were used to develop data on the factors affecting emulsion rheology. The viscosities of the crude oils ranged between 2000 and 500,000 (estimated) centipoise (2.0–500 Pa s). The oil-in-water emulsions ranged from 60 to 72.5% oil in tap water and stabilized with an emulsion stabilizer. Rheological measurements were carried out with a tube flow viscometer equipped with three tube sizes and a concentric cylinder viscometer (Rheometrics Pressure Rheometer). The data obtained showed that the shear stress-shear rate behavior of the emulsions are highly dependent on oil droplet size. For a given oil concentration, the non-Newtonian character and the apparent viscosity increased with decreasing droplet size. The majority of the emulsions showed shear thinning behavior at low shear rates (below 50 s −1 ) and Newtonian behavior at shear rates above 1000 s −1 . These data show that the power law model is insufficient for the whole range of shear rates. A three parameter model needs to be considered. Results show that oil droplet size is the dominant factor in the behavior of emulsions studied. The influence of mixing intensity and duration while preparing the emulsion and emulsifier concentration on the resulting droplet size were investigated. Pipe flow data were collected for scale-up studies. Both the laminar and turbulent flow regimes were examined. This study reveals that careful laboratory testing and scale-up is needed prior to designing systems for the use and transportation of emulsions.

Drilling Mud Rheology and the API Recommended Measurements

Drilling fluids are, among other things, expected to transport cuttings and control fluid loss. The rheology of drilling fluids plays an important roll in both of these aspects of drilling fluid performance. A number of years ago the American Petroleum Institute established a set of standards for evaluating the rheology of drilling fluids. While drilling fluid technology has evolved and drilling fluids have become more rheologically complex, the standards have not changed sufficiently to adequately characterize the new generation of drilling fluids.

Evaluation of Polymers for Oilfield Use: Viscosity Development, Filterability and Degradation

Water soluble polymers are used extensively throughout the oil producing industry for a variety of applications. Such applications begin with the drilling of a well, progress through chemical and hydraulic treatments designed to stimulate production, include workover operations which maintain production, and are significant in secondary and tertiary recovery operations.