Abstract

Due to the fact that there is a wide range of drilling fluids, it is difficult to discuss drilling fluid composition that is completely accurate for all mud types in all drilling situations. The approach taken here is description of drilling fluids as two-phase systems. Formate base fluids have been utilized in a wide variety of drilling operations in terms of its applicant and lower expenses rather other fluids. These types of fluids have a number of benefits. One of the main aims of these fluids in comparison with the conventional high pressure high temperature (HPHT) and completion fluids is to minimize the damages in the formation. Furthermore, they maintain the properties of these additives on high temperatures, reduce the resistant of hydraulic flow, utilize less potential energy for differential striking processes and reduce the rate of corrosion which are preferred for use in well operations. Formate-based fluids could be administered among deep layers of drilled hole, shaly layers and those formations which include gas and salt. Therefore, this experimental procedure was done at a temperature of 260°F over a period of 14 h. For these tests, six types of salty formate fluids were made by different polymers. All samples formulation regarding their type and amount of water used in preparing fluids and the volume of salts used were simultaneously kept constant.

Key words: Salty formate fluids, high pressure, high temperature.

Abbreviation

OBM, Oil based mud; PV, plastic viscosity; AV, apparent viscosity; WBM, water based mud; YP, yield point; API, American petroleum institute; PAC-R, polyanionic cellulose- regular viscosity; HT-PM, high technology polymer materials; PHPA, partial hydrolyzed poly acryl amid; Ca , calcium carbonate; , sodium carbonate.