Master of Science in Petroleum Engineering (MSPE)
Fluid injection has been increasingly implemented in oil and gas producing fields to optimize hydrocarbon production in both young and mature oil fields across the globe. This situation arises from the realization that early planning of second and tertiary recovery methods may improve project economics significantly. Injectors are then intended to perform at high injection rates with low bottomhole flowing pressures for as long as possible. In the case of injectors drilled in unconsolidated formations, deficient performance often times seems to be the norm. With a majority of these fields being offshore developments in which capital expenditures are high, a profound need for solutions arises. From a wide range of problems leading to injectivity impairment in injectors targeting poorly consolidated formations, research on rock failure caused by fluid injection operations appears to be at its earliest stages hence it is the main subject of the present study. Some studies trying to address this issue intend to modify existing fracture mechanics theory to explain rock failure. Although many of the proposed theories properly explain some observations and are founded on well derived scientific principles, they fail to explain formation sand erosion and transportation often perceived at these wells. To study poorly cemented sands’ failure, dynamic fluid flow equations are implemented using Finite Element Methods coupled to an erosional model. Different scenarios are implemented in two and three dimensions. It can be seen from the study that the drag forces created by injecting fluid weaken and damage the target formation. The damage caused is consequence of the pressure gradient as the fluid travels through the porous media. The latter observation leads to the conclusion that limiting injection rates to avoid damage may not be sufficient and a more appropriate approach is to control the fluid velocity at the sandface given a fluid viscosity, relative permeability and porosity. If proper injection parameters are achieved, the injectivity declines in these wells can be minimized. The observations from this study can be used to better design wells and how to complete them.
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Bautista Barake, Juan Felipe, "Modelling of Channelization in Unconsolidated Formations Due to Liquid Injection" (2015). LSU Master's Theses. 1505.
Dahi Taleghani, Arash