Prediction and Localisation of Erosion Prone Areas along Non-Compliant Sand Control Completions

Abstract

Sandface completions such as standalone screen completions have suffered from erosion problems for many years. A significant amount of catastrophic screen failures are considered to be the result of high velocities of solid's laden hydrocarbons creating hot spot areas in the interface between the sandface and the completion. Previous researchers investigated the change in permeability of failed rock into annular gaps generated in non-compliant sand control completions and identified that packed material in this space can result in severe distortion to flow patterns and restrictions. This paper describes the development and testing process for a new methodology that allows identification of the erosion prone areas in the annular space between the sandface and the screen. Detailed investigation, supported by laboratory testing, reviewed oil and gas well conditions at the startup, during a cleanout and after hydrocarbon's production have been stabilised. Radial flow, mode of sand collapse, compaction, voidage, sand quality and formation petro-physical properties were tested and analysed using high and low pressure flow cells in order to quantify the changes in pressure drops through the collapsed rock material. The results indicated that flow rate, viscosity, voidage, grain shape and volume are the main contributors to the variations in pressure drops across failed sand material in the annular space. On the basis of these tests, a continuous (foot-by-foot) analytical model was developed that allows identification of the specific location and variation in pressure drops across the annular packed material for oil and gas wells. The model is composed of five (5) main elements; a reservoir inflow module, a fluid drag module, a grain size and volume module, a pressure drop module and an erosion prediction module. The model was tested using data from a North Sea field and the results, algorithms and field samples will be discussed and presented in detail.

Mechanical and Flow Behaviour of Collapsed Wellbores in Non-Compliant Sand Control Completions

“…The opposite scenario is one where after the initiation of production, a severe impairment of flow is noted and high drawdowns have to be applied to the wellbore. In this scenario a high level of compaction of the collapsed rock might have occurred (Tovar et al 2011) however, other factors such as formation skin and screen plugging can cause a similar effect.…”

“…They identified what they called the two permeability zone in which deformation of rock material at the wellbore wall produces a change in permeability that has an impact on inflow. Further researchers (Schutjens 2004, Pyatakhin 2004, 2006, Tovar et al 2007, 2011, MacDonald 2011 have investigated the changes in petrophysical properties at the near wellbore. This research concluded that the change in porosity and permeability at the near wellbore can be investigated through plasticity and deformation principles such as those utilised in the analysis of reservoir deformation (Ricard et al 2001, Bercovici et al 2001, Wong et al 1997.…”

Study on the Erosion of Screen Pipe Caused by Sand-Laden Slurry

“…Another study (Cameron and Jones, 2007) reported the influence of different fluid types, flow velocities, sand contents, and particle sizes on the failure of sand screen through experimental and theoretical analyses and proposed a model for predicting the time of failure of the screen. Based on the experimental results, some researchers (Navaira et al, 2009;Svela et al, 2009;Tovar and Zheng, 2011) proposed a method for positioning screen zones with erosion hazards and, based upon different sand control methods, came up with a method for judging the screen failure under different environmental conditions. The same authors reported that the change in flow channel and flow pattern by screen and annulus plugging constituted an important factor for the failure of a screen.…”