Study On Transforming Development Regime Of Extra-heavy Oil Reservoirs In Member 3 Of Dongying Formation Of Wa-38 Block In Liaohe Oilfield

Block Wa38 locates on the north of south of the central uplift of Liaohe fault. The main target reservoir is Paleogene member 3 of Dongying Formation. It has accessed to the medium to late development period with low steam soak production, formation energy serious shortage and deteriorating team stimulation index. In order to enhance oil recovery ratio, it has been studied that the development conversion from steam soak to steam drive in member 3 of Dongying Formation which based on the successful experience from inland and abroad .The research methods include reservoir engineering method, comprehensive application of dynamic analysis and comparative analysis method. Based on the study of the fine reservoir geology research of member 3 of Dongying Formation, main research topics include: the result of comparing study of the guide experiment of member 3 of Dongying Formation, the steam flooding and conclusions of economic evaluations. Steam flooding program was designed with comprehensive application of the above research.Studies suggested that member3 of Dongying Formation developed delta front sedimentary system, and the main micro sedimentary facies were mouth bar and frontal sheet sand. The sediments were fairly well sorted, and the reservoir belonged to medium porosity and medium permeability reservoir. The reservoir had good connectivity with stable barriers. Geology condition is suitable for steam flooding.Test results of steam drive pilot test with small-scale in Block Wa38 indicated that steam drive is an effective way to improve deep heavy oil recovery. Steam drive is not only suitable for extra- heavy oil reservoir after the huff and puff but also can achieve better economic performance. Using numerical simulation and reservoir engineering to optimize well pattern of steam flooding, begin-ning time of the steam flooding and well spacing will achieve better development effect. Dynamic tracking control and adjusting will improve deep extra-heavy oil reservoir development effect with suitable technology in the process of steam flooding.This paper provides a basis for transforming development regime of the similar heavy oil reservoir. Steam drive is a main stage of thermal recovery and it can enhance oil recovery for extra- heavy oil reservoir more than the huff and puff especially for the deep reservoir. The steam drive process is one of the effective means for improving deep extra-heavy oil recovery and provides a better learning at home and abroad.