Investigation of Formation damage Based to Additions of Oil Based Mud; Laboratory Study

atrotary drilling generally we use two kind of drilling fluid ; water based mud (WBM), OIL based mud (OBM) . Continuous phase at OBM is a kind of liquid hydrocarbon that in iran uses gas Oil no.2(diesel no.2) as continuous phase. In OBM there is more advantage than WBM , but high initial cost & pollution of this mud, cause that we don't use OBM sometime. formation damage is a big challenge in reservoir & production that exists by various methods , one of them is drilling fluids . we must investigate the chemical & mineral mud additions until decrease skin effect. at this paper we used investigation with laboratory studies and laboratories design of OBM , then investigated the effect of each addition. the result showed OBM changed the wettability which existed the sizeable effect on the reservoir. at the end we used the composition of the additions which have minimized skin effect.

Keywords:

oil based mud , formation damage , wettability , permeability.