Formation Damage Due to Static and Dynamic Filtration of Water-Based Muds

Abstract

Formation Damage Due to Static and Dynamic Filtration of Water-Based Muds Di Jiao; Di Jiao U. of Texas Search for other works by this author on: This Site Google Scholar M.M. Sharma M.M. Sharma U. of Texas Search for other works by this author on: This Site Google Scholar Paper presented at the SPE Formation Damage Control Symposium, Lafayette, Louisiana, February 1992. Paper Number: SPE-23823-MS https://doi.org/10.2118/23823-MS Published: February 26 1992 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Get Permissions Search Site Citation Jiao, Di, and M.M. Sharma. "Formation Damage Due to Static and Dynamic Filtration of Water-Based Muds." Paper presented at the SPE Formation Damage Control Symposium, Lafayette, Louisiana, February 1992. doi: https://doi.org/10.2118/23823-MS Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Search nav search search input Search input auto suggest search filter All ContentAll ProceedingsSociety of Petroleum Engineers (SPE)SPE International Conference and Exhibition on Formation Damage Control Search Advanced Search AbstractA series of drilling mud invasion experiments were conducted on Berea sandstone cores to measure the extent and depth of formation damage by mud filtrates and mud particles. A specially designed dynamic filtration core particles. A specially designed dynamic filtration core holder was used in this study. Pressure taps along the core holder allowed us to measure the permeabilities for 3 sections of the core while circulating mud. Seven kinds of muds with different salinities and different dynamic filtration rates were circulated across the face of the core for 10 hours. After mud circulation, return permeabilities for brine and oil were measured. The effect of bentonite concentration, the effective particle size, degree of flocculation, polymer additive concentration, and oil saturation in the core were shown to influence the extent of formation damage.IntroductionIt is commonly recognized that near wellbore permeability will be reduced when particle laden fluids are permeability will be reduced when particle laden fluids are introduced into the formation under dynamic conditions. Dynamic solids and filtrate loss are directly related to the extent of formation damage caused by drilling muds. Several papers have been published dealing with this issue. Other papers discuss the characteristics of dynamic filtration and the factors that affect the dynamic filtration loss, such as, shear rate, particle size, rock permeability and differential pressure. permeability and differential pressure. Formation damage during mud circulation occurs as a result of particles forming an internal and external filter cake. It can also be caused by mud filtrates which interact with formation fines or that are incompatible with the reservoir brine.A "mud-off cell" was used by Nowak and Krueger to study the permeability impairment by mud particles. They found that permeability could be permanently reduced by up to 35%. Marx employed a dynamic filtration core holder to circulate mud and concluded that the evaluation of formation damage caused by drilling muds must be carried out under conditions that closely simulate the actual borehole conditions. Peden et al studied formation damage by circulating KCl-polymer and gypsum-lignosulfonate muds in an annulus across the core face. They concluded that the dynamic filtrate loss was significantly affected by the annular velocity and the permeability of the core. They also observed that the range permeability of the core. They also observed that the range of particle sizes in the mud was crucial to the effective depth of invasion of the mud particles.Besides the invasion of mud particles, a mud filtrate incompatible with the formation brine also causes fines release and migration. Below a critical salt concentration of approximately 5,000-10,000 ppm fines migration becomes a potential damage mechanism. Sarkar and Sharma studied damage due to fines migration in both single and two phase flow. The fines will move only if the phase that wets them is mobile. The release and capture of fines from pore surfaces to pore throats is controlled by the potential energy of interaction between the fines and the potential energy of interaction between the fines and the pore surface. Interstitial velocity is another factor pore surface. Interstitial velocity is another factor controlling fines release. Grusbeck and Collius, Gabriel and Inamdar identified a critical interstitial velocity above which fines will be mobilized and redeposited at pore throats. Sharma et al also confirmed the existence pore throats. Sharma et al also confirmed the existence of a critical velocity for fines release. Fresh water muds can, therefore, give rise to regions around the wellbore where damage due to fines migration can be quite severe.In this investigation, a specially designed dynamic filtration cell is used to study permeability impairment under dynamic flow conditions. Drilling mud can be circulated across the face of a core and the dynamic filtration rate can be measured. Pressure drops at different locations in the core can also be measured during mud circulation. Permeability changes measured in this manner help us in Permeability changes measured in this manner help us in studying the depth of invasion of both the mud filtrate and the mud solids and the resulting permeability impairment. After mud circulation, reverse injection of brine and oil can be performed. Return permeabilities and relative permeabilities can, therefore, be measured. permeabilities can, therefore, be measured. P. 491 Keywords: mud filtrate, brine, mud cake, drilling fluid selection and formulation, drilling fluids and materials, filtration rate, filtrate, permeability, experiment, dynamic filtration Subjects: Drilling Fluids and Materials, Drilling fluid selection and formulation (chemistry, properties) This content is only available via PDF. 1992. 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