Loading...

Numerical Modeling of Formation Damage Due to Filtrate Invasion into the Formation During Drilling Operations in Vertical and Horizontal Wells

Khalili, Sajad | 2017

469 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 49859 (55)
  4. University: Sharif University of Technology, International Campus, Kish Island
  5. Department: Science and Engineering
  6. Advisor(s): Ghazanfari, Mohammad Hossein
  7. Abstract:
  8. Formation damage in oil and gas wells is mainly induced by drilling operations. Filtrate and particle invasion into formation as the sources of this damage caused serious problems, e.g. reduction of production rates. Therefore numerical modeling of this phenomenon helps us to better understand the process, and as a result, control and reduce formation damage associated with this impairment. In this research, a model to estimate the invasion depth and damage of mud filtrate from water-based mud is presented. Filtrate invasion into the formation is investigated by convection-diffusion equation with regard to dispersion term. The invasion depth is obtained from mud filtrate profile in the formation. Growth of composed mud cake on the formation’s wall that is a function of time is under the influence of contact time of drilling fluid to the formation’s wall, rate of mud cake erosion due to dynamic drilling fluid and also the solid particles passing through the mud cake. In this study, we aimed at solving simultaneous convection-diffusion equation, fluid flow equation, mass balance equation, considering cake erosion effects and fine migration into the formation and obtaining skin factor as a function of time, distance from the wellbore and depth of the well. Effect of Non-Darcy flow around the wellbore is also considered in association with growth of mud cake. It is found that the filtration velocity in this flow system depends on overbalance pressure, formation permeability, mud cake characteristics, and invasion time. In this model, solid particle invasion and irreducible water saturation are taken into account. Therefore, considering the cake porosity changes, cake permeability changes, effect of Non-Darcy flow in association with mud cake growth, solid particles (fines) migration inside the cake and inducing variable pressure in vertical wells are the highlights of this study
  9. Keywords:
  10. Formation Damage ; Erosion ; Dispersion ; Convection ; Drilling Operation ; Horizontal Wells

 Digital Object List

 Bookmark

No TOC