Lost circulation pattern in the vug-fractured limestone formation

Huiwen Pang; Mian Chen; Hanqing Wang; Yan Jin; Yunhu Lu; Jiabao Li

Energy Reports (Dec 2023)

Lost circulation pattern in the vug-fractured limestone formation

Huiwen Pang,
Mian Chen,
Hanqing Wang,
Yan Jin,
Yunhu Lu,
Jiabao Li

Affiliations

Huiwen Pang: State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum-Beijing, Beijing, China; College of Science, China University of Petroleum-Beijing, Beijing, China
Mian Chen: State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum-Beijing, Beijing, China; College of Petroleum Engineering, China University of Petroleum-Beijing, Beijing, China; Corresponding author at: State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum-Beijing, Beijing, China.
Hanqing Wang: Petroleum Exploration and Production Research Institute, SINOPEC, Beijing, China
Yan Jin: State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum-Beijing, Beijing, China; College of Petroleum Engineering, China University of Petroleum-Beijing, Beijing, China
Yunhu Lu: State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum-Beijing, Beijing, China; College of Petroleum Engineering, China University of Petroleum-Beijing, Beijing, China
Jiabao Li: State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum-Beijing, Beijing, China

Journal volume & issue: Vol. 9
pp. 941 – 954

Abstract

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Due to numerous leakage zones, such as vugs, fractures, and caves appearing in carbonate rocks, lost circulation, the main issue, restricts safe and effective drilling. The lost circulation pattern of the vug-fractured limestone formation has been extensively studied using the Mishrif formation of the H oilfield in the Middle East as the research sample. The equivalent physical models of three different types of leakage zones, including vug, natural fracture, and induced fracture, were built based on the interpretation of FMI (Formation MicroScanner Image) logging. By embedding discrete fractures into a variable permeability matrix and solving it using the finite element method (FEM), a three-dimensional fluid–solid coupling mathematical model of mud loss rate was established. The study focused on the effects of drilling fluid performance parameters on lost circulation as well as the parameters of the single leakage zone (vug, natural fracture, or induced fracture) on lost circulation. Additionally mentioned were the variable characteristics of mud loss rate and cumulative mud loss volume in various combined ways of leakage zones. The findings indicate that there are considerable differences in how various types of leakage zones affect lost circulation properties. Fractures, particularly induced fractures, can result in more severe lost circulation than those brought on by vug for the creation of a single leaking zone. Mud loss rate and cumulative mud loss volume are greatly influenced by fracture width and dissolved radius, both of which have thresholds. Due to the enhanced flow conductivity, the lost circulation is more severe the more complicated the leakage zone combination mode is. The numerical model developed in this research provides a new perspective on how to analyze the lost circulation pattern of vug-fractured limestone formations and provides theoretical direction for lost circulation control of drilling in this kind of formation.

Published in Energy Reports

ISSN: 2352-4847 (Online)
Publisher: Elsevier
Country of publisher: United Kingdom
LCC subjects: Technology: Electrical engineering. Electronics. Nuclear engineering
Website: http://www.journals.elsevier.com/energy-reports/

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