Method for in-situ transformation and exploitation of shale oil and gas in medium and low maturity shale oil with large well spacing

Abstract

The invention provides a method for in-situ conversion and exploitation of shale oil and gas with medium and low maturity shale oil with large well spacing, comprising deploying at least 3 horizontal wells with an odd number of wells at a well spacing of 15-50 meters in the reservoir group; fracturing the reservoir, dividing the fractures into three sections at equal intervals from the central injection well to the production well, and injecting different types of proppant into the three sections in three stages; injecting hot gas into the central injection well and electrically heating it, Produced from the production well; when the temperature between the central injection well and the first-line wheel injection well reaches the complete pyrolysis temperature, the central injection well stops electric heating and injects normal temperature gas into it; the first-line wheel injection well turns on electric heating; when the first-line and second-line wheel injection wells After the temperature between the wells reaches the complete pyrolysis temperature, the center injection well stops injecting normal temperature gas; the first wheel injection well stops electric heating, and injects normal temperature gas into it; The temperature of the reservoir between the injection wells adjacent to the last line reaches the complete pyrolysis temperature.

Description

technical field [0001] The invention relates to a method for in-situ transformation and exploitation of shale oil and gas with large well spacing of middle and low maturity shale oil, and belongs to the technical field of shale oil exploitation. Background technique [0002] Oil shale is a sedimentary rock containing solid combustible organic matter, which is generally called kerogen or kerogen, and is often gray-brown or black. In the natural state, natural oil shale is a kind of argillaceous shale with extremely low permeability and porosity, and kerogen exists in the oil shale in solid form and is integrated. The micro-bedding inside the oil shale is completely closed in situ underground. Among all fossil fuels, if the reserves are converted into calorific value, oil shale ranks second only to coal; the shale parent oil reserves in the world are quite large, and if converted into shale parent oil, oil shale ranks second. More than 400 billion tons, equivalent to more th...

AI Technical Summary

Problems solved by technology

Since the invention requires that the injection well and the production well be rotated at intervals during the production process, a large amount of injection heat is converted to the output of the original heat injection well of the production well during the rotation process, resulting in an ineffective circulation of heat; in addition, due to the expansion of high-temperature shale oil, In addition, during the water steam injection process, the shale oil mainly containing clay minerals expands with water, causing the fractures to reclose, making the fracturing fractures unable to serve as channels for transmitting hot steam. It will float on the top of the shale oil layer near the injection well, and repeatedly heat the cap rock, making the cap rock very prone to high-temperature cracks and the risk of cap rock being broken through, resulting in safety accidents

[0007] None of the above shale oil production methods can solve the two major problems in the process of high-temperature in-situ conversion of shale oil: the problem of heat transfer with large well spacing and the problem of continuous and effective thermal cracking of fracturing fractures

Images