Advancement and Application of Thermal Recovery Technology in Heavy Oil Reservoir in Shengli Petroleum Province

Abstract

Abstract The main features of heavy oil reservoir in Shengli petroleum province are as bellow: deep reservoir (>1300m),most with active edge and bottom water,thin net pay (<6m),complicated types.The incremental reserves of heavy oil have low quality in Shengli petroleum province, such as thin net pay, sensitive to water and extra heavy oil reservoirs. The mature fields are going to the development stage characterized by multiple turns of huff and puff, high water cut and low oil producing rate. In this paper, focusing on the bottle-neck and other development technology problems, the novel thermal recovery technologies are studied, such as chemical aided stream drive, water drive turning to thermal recovery and application of horizontal wells in marginal heavy oil reservoir, and thermal chemical huff and puff in extra heavy oil reservoir, in order to improve the heavy oil recovery and low quality reserves effectively developed. The chemicals were designed, the key technological limits were researched, and the composite mechanics of steam, oil displacement and foaming agents were researched in order to improve vertical sweep efficiency of steam drive, flooding efficiency of hot water and low dryness steam flooding recovery in medium and deep heavy oil reservoir. The feasibility of conventional water drive heavy oil reservoir under high pressure and the key technology of water drive transferring to steam drive were studied. The water drive recovery had been significantly improved in conventional heavy oil reservoir. HDCS (horizontal well, dissolver, carbon dioxide and steam) was applied to ultra heavy oil reservoir. The technological limits of horizontal well, new sand control and steam injection technologies were studied in marginal heavy oil reservoir such as thin reservoir, then this type of reservoir were effectively developed and its recovery were improved. Some studies progresses had a breakthrough and were applied in the field. The annual production of thermal recovery increased significantly in Shengli petroleum province. In 2010, the oil production was 4.21 million tons and the increment of low quality reserves developed was 186 million tons and the increment of the recoverable reserves was 59.18 million tons both in mature and new fields. A good economic benefit was obtained. Introduction Shengli petroleum province is known as being rich in onshore heavy oil resources, with a variety of reservoir characteristics, and complex conditions for thermal recovery. The extraction of the producing reserves has come to the late period of huff and puff and approach to the economic limit, with high water cut (87.5%), low recovery ratio (15.9%), and low periodic oil-steam ratio (0.34). But the non-producing reserves are mainly of ultra heavy oil reservoir (>100,000mPa·s), thin heavy oil reservoir and water-sensitive heavy oil reservoir, the conventional development techniques (huff and puff, steam drive, SAGD) are hard to play its role in such reservoirs. The annual output of heavy oil in Shengli petroleum province have been up to 2.34 million tons in 1995, but reduced rapidly to 1.42 million tons in 2000 because the development techniques could not meet the production requirements (Fig.1).