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Transient Pressure Behavior and Formation Damage Evolution of Wells During Matrix-Acidizing Operations

عنوان مقاله: Transient Pressure Behavior and Formation Damage Evolution of Wells During Matrix-Acidizing Operations
شناسه ملی مقاله: IPEC03_065
منتشر شده در سومین کنگره ملی مهندسی نفت در سال 1390
مشخصات نویسندگان مقاله:

Abdolhossein Mohammadi - Sepanir Oil & gas Energy Engineering Co. / Young Researchers Clubs; Tehran- Iran / Senior Specialist of Drilling Engineer
Abdollah Mohammadi - Iranian Central Oil Field Company / Science and Research Branch, Islamic Azad University, Tehran, Iran.

خلاصه مقاله:
The transient pressure response and the evolution of formation damage of a well during a matrix-acidizing operation, performed at constant injection rate, is studied in this paper. Solutions are derived from a novel fully-implicit numerical model which simulates the mechanics of a matrix-acidizing process along with the mechanics of compressible flow in a porous media. The dynamic changes of permeability and porosity due to dissolution of up to two mineral species are considered in the reservoir flow equation. A damaged zone with petrophysical properties and mineral content different from the rest of the reservoir is included; the injection of a batch of inert fluid prior to the acid is also accounted for.It is found that the pressure behavior and the evolution of formation damage during acidization depend mainly on the acid capacity number, NAc, the Damage number, NDa, the initial formation damage, So, and the radius of the damaged zone, rsD. Typically, the early time pressure response of an acidized well might show a semilog straight line of slope 1.151, if NAc and NDa are small enough. As formation damage is being removed, there is a continuous decrease in the slope of the PwD vs. tD curve which eventually takes on negative values. At later times, when formation damage is removed, all curves converge to the stimulation with no damage case and positive slope values are reassumed. Major benefits of acidization are found with large So and small rsD. Large Damage numbers seem to perform better al early stimulation times and worst afterwards, suggesting that variable injection rates could yield the best stimulation results. Acid capacity number was found to have a major effect over PwD and formation damage evolution.

کلمات کلیدی:
Transient Pressure – Formation Damage – Matrix Acidizing

صفحه اختصاصی مقاله و دریافت فایل کامل: https://civilica.com/doc/260040/