Method and system for exploiting lamellar super-heavy oil deposit

Abstract

The invention relates to a method and a system for exploiting lamellar super-heavy oil deposit. The method comprises the following steps of: arranging a multi-bore well, a central steam injection well and a producing well in an exploitation region; closing the central steam injection well and the producing well and performing steam stimulation by using the multi-bore well until the temperature ofeach oil layer reaches the temperature corresponding to a second-order inflection point of a crude oil viscosity-temperature relation curve; opening the multi-bore well and the central steam injection well and injecting steam into the oil layers; closing the multi-bore well and the central steam injection well for soaking; and opening the producing well to perform steam driving exploitation. In the method, the multi-bore well is used for performing the steam stimulation according to the characteristics of the multi-layer super-heavy oil deposit; a plurality of branch wells are drilled in a main pitshaft by a side-tracking method and are embedded into each oil layer of the oil deposit; the whole exploitation range is heated comprehensively and three-dimensionally; steam waves and regions as big as possible are formed with the cooperation of the central steam injection well; and the mobility of the super-heavy oil and the oil-water mobility ratio are improved, and the problems that the lamellar super-heavy oil has high viscosity and is difficult to drive and the steam sweeping range is small are solved.

Description

technical field [0001] The invention relates to a thermal recovery method and system for super-heavy oil (viscosity greater than 50000mPa.s), in particular to a production method and system for layered super-heavy oil reservoirs. Background technique [0002] According to my country's heavy oil classification standards, crude oil with a viscosity greater than 50,000mPa.s belongs to super-heavy oil. Taking the super-heavy oil in Shuyi District of Liaohe Oilfield as an example, the viscosity of super-heavy oil ground degassed crude oil is as high as 20×10 4 At about mPa.s, the flowable temperature is about 80°C. When the oil layer temperature is lower than 80°C, the crude oil does not flow under the underlying conditions, and the oil well production drops rapidly to zero. Due to the poor fluidity of ultra-heavy oil, the investment in thermal recovery of super-heavy oil is relatively high, and the risk of exploitation is greater than that of ordinary oil reservoirs. Therefore, ...

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Problems solved by technology

However, as a pressure-reducing production method, with the increase of steam huff and puff rounds, the pressure of the oil layer near the wellbore decreases, and the flow of ultra-heavy oil in the far wellbore area is difficult, so that the huff and puff production decreases rapidly. Therefore, the production principle of steam huff and puff determines its ultimate The recovery rate is not high, and the recovery rate of super heavy oil developed by steam huff and puff is generally 10%-20%

Due to the high temperature and high pressure relief area formed by steam huff and puff near the wellbore, subsequent steam flooding is difficult to achieve

At present, there is no suitable displacement technology after steam huff and puff to increase the recoverable reserves of layered super heavy oil, and fundamentally reverse the situation of rapid decline in huff and puff production and insufficient displacement production in layered super heavy oil reservoirs

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