Curing Losses While Drilling & Cementing

Abstract

Abstract The global imbalance between supply and demand for Oil and gas is growing. This trend is was the turn behind studies from numerous oil organizations related to cementing. One of the important functions of cement sheaths is to provide hydraulic zonal isolation between different reservoirs in the well bore. Lost circulation or lost returns is known as the total or partial loss of drilling fluid or cement while drilling. It can be an expensive, time consuming or disastours as a blow out and loss life. The significant and continuing losses of mud and/or Cement slurry to a formation during drilling operations affects the oil industry. These problems have negative impact on well economics, well integrity and well life cycle. It has been globally estimated that these problems cause financial loss of billions dollars per year in addition to extensive additional rig resources The significant and continuing loss of mud and/or cement slurry to a formation during drilling operations is one of the most troublesome problems affecting the Oil Industry. These problems mostly translate in negative impact on well economics. Loss circulation problems have been identified as one of the most costly and time consuming problems faced in the oil and gas industry. It has been globally estimated that these problems causes drilling industries close to a billion dollars annually in rig time, materials, and other resources. This paper will describe in detail the nature of the losses and application used to resolve it. The use of cement spacer technology is a viable means of resolving most of these problems. This technology, can be applied to strengthen a wellbore, with high degree of losses as a preventive method. In addition, it can also be used as a corrective method in cases where the wellbore has been fractured due to hydrostatics or because of the effects of ECD. Case histories will be presented describing curing losses from seepage, moderate, severe or complete loss of returns. The applications include very low fracture gradients wells, where it was impossible to cement with dual slurry with lightweight slurries. Additional benefits of the spacer is that It is a non-damaging fluid, minimizes filtrate invasion, damage and induced losses while cementing, and it forms a barrier at the wellbore wall to strengthen the wellbore for long-term zonal isolation. The spacer's shows near 100% return permeability. The spacer has low rheological values which does not cause significant increases in ECD