Productivity evaluation and influential factor analysis for Sarvak reservoir in South Azadegan oil field, Iran

Production pattern of oil wells and influential factors on productivity for the massive carbonate reservoir in the Middle East were researched by productivity evaluation on Sarvak and analysis of properties impact on production. Based on dynamic performance of Sarvak production test, the relationship between daily oil production, tubing pressure, cumulative oil production and choke size was analyzed and reasonable productivity prediction model was established by applying Poettman model, and the effect of physical properties and fluid parameters on productivity were analyzed further by numerical simulation. The study shows that daily oil production is linearly correlated with oil pressure under certain working regime, and daily oil production is power law correlated with choke sizes before and after working regime adjustment. The average designed single well productivity should be about 270 m3/d by depletion to ensure a three-year plateau period. Sarvak is a blocky carbonate reservoir, when developed with horizontal wells, interbeds distributed between layers and permeability property have the strongest impact on production of horizontal wells. So, highly deviated wells should be used to reduce the effect of interbeds and acidizing should be considered to improve the reservoir physical properties.