A Quantitative Water Injection Method for Fracture-vuggy Carbonate Reservoirs

Abstract

The invention discloses a method of quantitatively injecting water into a fracture-cavity carbonate rock oil reservoir. A dynamic analysis is made of an oil-water well of a fracture-cavity carbonate rock oil reservoir. The method comprises the following steps: detecting the liquid production capacity Q1 in an energy drop period, detecting the density Rho of produced liquid, detecting the liquid level difference Delta H between the early stage of energy drop and the late stage of energy drop, and calculating the liquid production capacity per unit pressure drop EEI according to the formula EEI=Q1 / (Rho*g*Delta H); detecting the height M1 of a moving liquid level and the height M2 of a liquid level needing to be restored at the late stage, and calculating the pressure Delta P of the liquid level needing to be restored according to the formula Delta P=Rho*g*(M1-M2) / 1000; quantitatively injecting water into the stratum of the oil well to supplement energy, and calculating the amount of quantitatively injected water needed by the stratum according to the formula Q2=Delta P*EEI; and pushing the liquid level of the wellbore to rise through soil-water separation so as to improve the fluid supply capacity of the oil well. The long-time problem on how to realize refined water injection development of a fracture-cavity oil reservoir is solved. Through quantitative water injection, the oil increment by water injection is obviously increased.

Description

technical field [0001] The invention relates to the technical field of oilfield development, in particular to a quantitative water injection method for a fractured-cavity carbonate reservoir. Background technique [0002] In the case of low oil prices, the oil industry is facing the challenges of narrowing investment, cost squeeze, and increasing losses. Looking at the situation, only low cost can have vitality, and low-cost development has become the main weapon against the cold winter. The cost of water injection development per ton of oil is only 48 yuan / ton (at the same period, the cost of gas injection per ton of oil is 790 yuan / ton, and the cost of measures is 805 yuan per ton of oil). . [0003] Although water injection in fractured-cavity reservoirs was developed earlier, due to the intricate system of dissolved caves, pores and fractures in carbonate fractured-cavity reservoirs and strong heterogeneity, the spatial distribution of reservoirs and the internal geomet...

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Problems solved by technology

[0003] Although water injection in fractured-cavity reservoirs was developed earlier, due to the intricate system of dissolved caves, pores and fractures in carbonate fractured-cavity reservoirs and strong heterogeneity, the spatial distribution of reservoirs and the internal geometric structure are difficult to be effective Characterization and description

Therefore, how to carry out quantitative water injection has been in the exploration stage, especially for different types of well-reservoir relationships, water injection pressure changes of different fracture-cavity structures, the distance between water injection volume and producing reservoirs, and the relationship between producing reserves. There is no substantive research progress, which seriously restricts the precise, scientific and efficient development of water injection in carbonate fracture-cavity reservoirs. The current conventional empirical water injection has a low oil-water replacement efficiency (3.66 cubic meters / ton), which seriously affects the economic benefits of water injection development