Evaluation method for describing compressibility of shale reservoir

A technology for shale reservoirs and evaluation methods, which can be used in earth-moving drilling, wellbore/well components, etc., and can solve the problems of high risks and high operating costs

Active Publication Date: 2017-06-20
CHINA PETROLEUM & CHEM CORP +3
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  • Abstract
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  • Claims
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Problems solved by technology

[0005] Staged fracturing of shale reservoirs in horizontal s

Method used

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  • Evaluation method for describing compressibility of shale reservoir

Examples

Experimental program
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Effect test

example 1

[0056] Example 1: Well J-1HF in Jiannan Gas Field

[0057] In Well J-1HF in Jiannan Gas Field, the horizontal section of the shale gas-rich shale reservoir is 1000m long and the vertical depth in the middle is H=630m (6.3hm) through mud logging and logging interpretation. The formation pore fluid pressure gradient FPG of the shale reservoir is 1.05MPa / hm, and the arithmetic mean value of the rock density of the overlying formation within the range of 10-60m above the shale reservoir is DEN=2.65g / cm 3 , the maximum horizontal stress of shale reservoir Kimax=2.65*6.3(MPa), Kimin=(2.65+1.05) / 2*6.3(MPa)=1.85*6.3(MPa), according to △K i =(Kimax-Kimin) / Kimin=(2.65-1.85) / 1.85=0.43. According to △K i The formula =(DEN-FPG) / (DEN+FPG) calculates the horizontal in-situ stress difference coefficient of shale reservoirs △Ki=0.43. The calculation results of the two formulas are the same, both showing that the evaluation results of shale reservoir compressibility are medium ( Class II). ...

example 2

[0059] Example 2: Well JY-1HF in Fuling Shale Gas Field

[0060] Well JY1-HF in the Fuling shale gas field, the horizontal section of the shale gas-rich shale reservoir (gas layer) is 1008m long, and the vertical depth of the central part of the shale gas layer is H=2380m (23.8hm). The formation pressure monitoring while drilling shows that the formation pore fluid pressure gradient FPG of the shale reservoir is 1.45MPa / hm, and the arithmetic mean density of the rock density of the overlying formation within the range of 10-60m above the shale reservoir is 2.70g / cm 3 , △Ki=(2.70-1.45) / (2.70+1.45)=0.30, indicating that the evaluation result of shale reservoir compressibility is good (Class I). Pilot well core tests of this shale gas horizontal well show that the maximum horizontal stress Kimax of the shale reservoir is 63.5MPa, the minimum horizontal stress Kimin of the shale reservoir is 48.4MPa, and the horizontal stress difference coefficient of the shale reservoir is △ Ki=...

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Abstract

The invention relates to an evaluation method for describing the compressibility of a shale reservoir. The evaluation method comprises the following steps that material contents including a well-site design report of a well to be evaluated, well-logging materials and well-measuring materials of the well to be evaluated are collected; according to the collected materials, the shale reservoir and the vertical depth H of the middle of the shale reservoir are determined, the fluid pressure gradient (FPG) of a stratum pore of the shale reservoir is determined, and the density (DEN) of stratum rock overlaying the shale reservoir is obtained; according to the FPG and DEN, the largest horizontal crustal stress Kimax and the smallest horizontal crustal stress Kimin of the shale reservoir are calculated; and the diversity factor delta Ki of the horizontal crustal stress of the shale reservoir is calculated, the compressibility of the shale reservoir is evaluated, and an evaluation result is output. The diversity factor delta Ki of the horizontal crustal stress of the shale reservoir is calculated through parameters of the FPG, the DEN and the like, and the compressibility of the shale reservoir is evaluated according to the delta Ki. The evaluation method is applied in more than 300 wells among shale gas wells in areas such as the middle Yangtze area, the Jiannan gas-field and the like, and the verification coincidence rate of the staged fracturing effect is 97.1%.

Description

technical field [0001] The invention belongs to the field of evaluation of unconventional oil and gas exploration and development of shale reservoirs, and in particular relates to an evaluation method for describing the compressibility of shale reservoirs. Background technique [0002] Shale oil and gas is a new type of energy, especially shale gas is a very good new type of clean energy. Its development and utilization have important practical significance for the sustainable development of the national economy and the current haze control. [0003] Shale oil and gas are self-generated and self-storage in organic-rich shale, which is quite different from conventional oil and gas formed by buoyancy accumulation. The permeability of shale itself is extremely low, and shale oil and gas wells usually have no natural production capacity. It is necessary to drill high-quality shale oil and gas intervals through horizontal wells, and adopt staged fracturing methods for oil and gas...

Claims

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Application Information

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IPC IPC(8): E21B49/00
CPCE21B49/00
Inventor 杨国圣胡德高潘军王振兴廖勇叶应贵张建平廖如刚冯爱国石文睿赵红燕饶海涛石元会季运景龚然程国良
Owner CHINA PETROLEUM & CHEM CORP
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