An Angolan operator needed to perform a coiled tubing (CT) acid micro-wash stimulation on a subsea sand screen completion in order to improve production. The CT simulation showed that the coil would not reach the objective, which was the bottom screen, even with friction reducers, without the assistance of additional forces. The operator chose to deploy a downhole tractor to provide a pulling force to achieve the desired depth. However, this horizontal well had debris which prevented reaching the objective and required changing strategies to accomplish the job. A downhole tractor can be powered by pumping fluids down the coiled tubing, driving a turbine which powers the hydraulic systems in the tractor. The drive fluid will then pass through the tractor and out the bottom of the tool to provide the treatment. Surface testing is performed prior to the job to determine at which pumping rate the tractor will be engaged and disengaged. This testing is performed with and without treating nozzles to gauge tool performance and expected pumping rates for tractoring and treating. In this Angolan operation two runs were required to reach the bottom screen due to debris fill in the completion preventing passage during the first run. On the second run the CT provider used a nozzle that could both clean the well and treat in the same run. This operation demonstrates the effectiveness of using CT tractors, which are under-utilized in the industry, to achieve extended reach beyond the normal CT range. It also demonstrates the quick mobilization and same day deployment, as well as problem solving that can occur when service companies (CT provider and tractor provider) work closely together.

A well with a high gas-oil-ratio (GOR) was experiencing gas coning due to the recycling of injected gas. A gas shut off was recommended to improve gas handling efficiency due to the constraints on surface processing capacity. The strategy was to install a 138 m, retrievable straddle assembly across a zone spanning from 2572 m measured depth (MD) to 2719 m MD in the 5 ½" open hole gravel pack (OHGP) screens. The client's considerations included coiled tubing (CT) and slickline. It was also necessary to be as efficient as possible to keep time and costs down. Based on these considerations, the operator decided to use an electric line (e-line) tractor combined with a hydraulic stroking tool for its high reliability. The stroking tool also provided the benefit of delivering the required force at the exact point where it was needed downhole as compared to coiled tubing, which would exert the force from the surface. The complete straddle packer assembly was successfully installed in 17 runs without any non-productive or lost time incidents. As a result of the intervention, gas production was greatly reduced and oil production was returned to normal levels. The operation was so successful that the client saved nearly 30 days on an operation that was planned for 45 days. Due to the success of the initial operation, the client decided to execute several other, similar water and gas shut off operations in the field replicating the same methodology. This paper highlights the methodology used and the cost and HSE benefits provided by selecting the e-line solution with the tractor and stroking tools to perform the gas shut off. The paper will also discuss the details of the job planning as well as the execution of the operation, marking a first in this West African country.

This investigation analyzed the effect of reactant particle size on the stress development characteristics of NiAl synthesized through self-propagating high temperature synthesis. Four sample combinations of NiAl were synthesized based on initial particle diameters of the reactants: (i) 10 μm Al and 10 μm Ni (S1), (ii) 10 μm Al and 100 nm Ni (S2), (iii) 50 nm Al and 10 μm Ni (S3), and (iv) 50 nm Al and 100 nm Ni (S4). Characterization of NiAl was performed by parallel comparison of the distribution of residual stresses of the samples prior to and after the reaction. Residual stresses were quantified using x-ray diffraction. Upon characterization it was found that combinations S1, S2, and S3 exhibited tensile residual stresses, while combination S4 exhibited compressive residual stresses. Statistical analysis confirmed that self-propagating high temperature synthesis products derived from nanoparticle reactant sizes exhibited compressive residual stresses offering improved fatigue resistance in composite production.