Saddok Benaissa

Down-hole simulation cell for measurement of lubricity and differential pressure sticking

The impact of lubricity and differential sticking on well cost is becoming more important, due to activity increase in deviated and extended reach wells through depleted reservoirs. Drilling fluid characteristics play a major role in this area. A better understanding of the mechanism of differential sticking and proper evaluation of the lubricating characteristics of different drilling fluid systems, under simulated down-hole conditions, is becoming more important. A specially designed fully automated device permits accurate and reproducible measurements of coefficient of friction between metal and mud filter cake. It also monitors the variation of the filter cake pore pressure and permeability, corresponding forces and sticking time. Testing principle is based on cylindrical captor equipped with sensors (rotational for lubricity and non-rotational with axial motion for differential sticking test). Displacement into the cylindrical filter cake is made automatically through lateral motion of a measurement cell that can be rotated 360 degrees. The main advantage of this apparatus is the fact that the pressure and force sensors are located inside the cell, allowing for direct measurements. Evaluation of both water and oil based fluids differential sticking potential can be achieved, and data generated can be a useful tool to take corrective measures in selecting a suitable stable drilling fluid/additives, that will help prevent differential sticking and reduce torque and drag. A series of differential pressure sticking tests have been conducted. Data generated were used to understand the phenomenon, to characterize the risk of differential pressure sticking associated with drilling fluids, and, also, will be used to further validate numerical models. This paper describes specifications and measurement principle of this special equipment, as well as first results on differential pressure sticking tests.

Oil Field Applications of Aluminum Chemistry and Experience With Aluminum-Based Drilling Fluid Additive

Applications of aluminum chemistry to solve drilling, completion, and production problems are discussed. Field application of a more recently developed aluminum-based product demonstrated the ability of this additive to control hydration and dispersion of drill solids and to enhance borehole stability.

Invert Emulsion Fluid System with Enhanced Rate of Biodegradation. Part 2

In the last few years, regulations to minimize environmental impact from drilling operations have lead the industry to generate several environmentally friendly synthetic based drilling fluids. Base fluid toxicity and their chemical biodegradation in a marine environment are important parameters in assessing the impact of discharging fluids used on offshore drilling operations. Discharge of cuttings at sea is being evaluated around the world, to further protect the marine environment. Increasingly, cuttings are shipped onshore and processed or re-injected. In both cases, it burdens the cost of the drilling operations, and still may have a negative impact on the environment. This paper will discuss a newly developed and optimized process to enhancehe rate of biodegradation of currently used mineral, synthetic or ester based fluids. The process consists of using a treatment comprising organic nitrogen and phosphorus compounds combined with fatty acids which are added to a typical synthetic-based drilling fluid. Extensive laboratory work and research have been conducted. Results indicate this non-toxic and more readily biodegradable approach will have a greater reduced impact on the environment than the currently available synthethic fluids.