Cooperative Mechanism and Technology Parameters Optimization of Multi-thermal Fluid Huff & Puff Development in Heavy Oil Reservoir

Abstract

The extra-heavy oil reservoirs in Central Asia have the characteristics of shallow burial, high crude oil viscosity, and strong reservoir heterogeneity. Conventional steam huff&puff have good initial development effects, but because energy cannot be replenished in time, steam huff&puff in the later stages huff&puff production declined fast and the effective production time is short. According to the current situation of oil reservoir development, a development technology combining multi-thermal fluid huff&puff and steam huff&puff is proposed. At the initial stage of production, steam is used to reduce viscosity, and in the later stage, N₂ in the multi-thermal fluid is used to pressurize, expand the steam chamber volume, and dissolved CO₂ to reduce viscosity. For single wells of different modes, using numerical simulation to design reasonable combined development modes and injection parameters, the research shows that multi-thermal fluid huff&puff after 5 cycles of steam huff&puff can achieve the best oil increase effect, and the best steam injection intensity 10t/m, gas injection intensity of 1500m3/m, 29 wells have been implemented in M heavy oil field in Central Asia. after use the multi-thermal fluid and superheated steam huff&puff coordinated development methods, the average well daily oil increment reached 0.6-4t/d, the water cut is reduced by 10-21%, the oil-steam ratio is increased by 0.4-0.6, realizing the efficient development of shallow buried extra-heavy oil reservoirs.