Experimental Approach to Evaluate Non-Damaging Drill-in Fluid

Mislav Halilovic

Research output: ThesisMaster's Thesis


Preventing formation damage is the primary objective of a drill-in fluid. Damage can occur through many different mechanisms including emulsion blocks, water blocks, polymer/filter/particle invasion, precipitates, and improper wetting of formation. Damage can be remediated by stimulating the formation through fracturing, acidizing, or improving flow-back with chemical treatments; however, these post-drilling treatments can significantly increase well construction costs. One of the critical factors in designing non-damaging fluids to prevent fluid invasion is by sizing particles in the system to obtain a surface bridge on the formation face with minimum in-depth solids penetration. The other one is conventional drilling fluid additives need to be replaced with non-damaging ones. Evaluating formation damage and filter cake degradation is usually done by Permeability Plugging Apparatus (PPT) and static high-pressure high-temperature filter press (HPHT). These two devices mimic only the flow in one direction which occurs while drilling. The mast of drill-in fluid vendors claims that the internal and external filter cake, that has been developed while drilling, could be removed once the production started due to differential pressure applied in the reservoir during production. However, prove this concept in the lab using the HPHT filter press can be done by adding specific engineering design features to the existing HPHT filter press. In this regard, the ultimate goal of this thesis is to develop a pioneering apparatus that can be used to evaluate the degradation of the filter cake by measuring two intrinsic indexes. The developed apparatus is designed in a way that it can be integrated with devices used to evaluate the static filter cake. It has two modes of operation, closed mode and flowing mode. The closed mode is used to measure the filter cake lift-off pressure, whereas the flowing mode is used to evaluate the filter cake removability index. The resultant indexes can be used as Key performance indicators to compare the potential formation damage caused by different Drill-In Fluids or to compare the efficiency of different breakers used to remove filter cakes. In order to test the functionality of the developed apparatus and establish standard test procedures, several experiments based on short term static filtration tests have been performed. The experiments were conducted using a drill-in fluid with various formulas and under carefully selected conditions. The results demonstrate that the newly developed tool capable of measuring the intended indexes smoothly within a short time and without troubles.
Translated title of the contributionExperimenteller Ansatz zur Bewertung einer nicht schädigenden Bohrspülung
Original languageEnglish
Awarding Institution
  • Montanuniversität
  • Thonhauser, Gerhard, Supervisor (internal)
  • Elmgerbi, Asad, Co-Supervisor (internal)
Award date18 Dec 2020
Publication statusPublished - 2020

Bibliographical note

embargoed until 15-07-2025


  • Non-damaging
  • Drill-in Fluid
  • HPHT filter press
  • Formation damage
  • Filter cake

Cite this