Optimum Matrix Acidizing Treatment Methodology for Wells Located in The Haoud Berkaoui Field, Algeria

摘要

The most common reason of formation damage is thedrilling operations. Mud invasion is the major problem thataffects well productivity in HAOUD BERKAOUI field. Asthe source of damage is known, different types of acid systemsare proposed by service companies to improve the nearwellbore formation permeability. Matrix acidizing treatment issuccessful and economic when either no excess volume orinsufficient volume is used. The determination of acid volumeis complicated and is generally based on field experience orusing rules of thumb. Rules of thumb may not be convenientand always over estimate or underestimate the volume.Selection methods based on laboratory experiments, however,are more close to real estimates since they take intoconsideration the rock mineralogy.In this study, laboratory tests are discussed and theirresults are shown to determine the mineralogy and formationcharacteristics of HAOUD BERKAOUI field. Acidizing testsof 4 different acids are conducted and discussed to select theoptimum fluids. Visual observations of cores using SEM arealso used as interpretation tools. Besides, optimum volume ispredicted based on the laboratory acid response curves.Laboratory test results show permeability improvementfor 3 systems. However; one system proposed to treatinjection wells gave mediocre results. Tests also show the riskof emulsion and/or precipitations for some acids. Acid system3 with 6% HCl and 1.5% HF is found to be the optimal fluidto treat both injection and production wells. This systempresents a good permeability improvement with less damagingprecipitates and no risk of emulsion. Guidelines for acidvolumes based on 6% HCl -1.5% HF acid are provided andcould be used as a starting point in acidizing job design forHAOUDBERKAOUI field.