Salts scale is one of the most important problems found in the oil and gas industry. Precipitation of salts can occur near wellbore as well as in the wellbore. The resulting reduces drastically well performance and causes a significant decrease in production rate. In order to remove salt deposits as well as prevent the precipitation of salt, fresh water treatments are performed at regular intervals during production operations. In drilling activity, shale is the most common rock types encountered while drilling wells. The combination of KCl/Polymer in water base mud (WBM) reduced frequency and severity of shale instability problems. In the order, all polymers are not able to resolve problems and inhibition mechanism comprehension still complex. Chemical treatment is an alternative approach to inhibit salts formation and shale instability. Bad inhibitor selections or/and high concentration provide limited performance and will cause damage which mechanism still unclear. In addition, it is extremely difficult to test salts formation and shale inhibition in the laboratory under reel conditions. Research shows that variation on temperature and pressures affect seriously inhibition mechanisms. In this way, our work tends to follow salts crystallization and shale swelling by using two methods: X-ray diffraction wet-cells for the in situ monitoring of fine powder reactions and displacement tests to follow permeability reduction under reservoir conditions. The possible mechanisms of halite and shale inhibition are discussed. Some experiences combining with using fines minerals particles to simulate compacted rock are realized. The following conclusions have been drawn:
- At ambient conditions, the contact between the water mixture and fines reservoir rock shows that crystallization was increased with time and affected by fines particles compaction and surface rugosity,
- Technique of chemical inhibition restrain salt deposit (60% of crystallization reduction) and enhances shale stability,
- A minimum polymer inhibitor concentration effectively was confirmed by X Ray Wet-Cell and Dynamic test under reservoir conditions.