Available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net Iraqi Journal of Chemical and Petroleum Engineering Vol.23 No.4 (December 2022) 7 – 16 EISSN: 2618-0707, PISSN: 1997-4884 Corresponding Authors: Name: Usama Alameedy, Email: usama.sahib@coeng.uobaghdad.edu.iq, Name: Ayad A. Al-Haleem, Email: dr.ayad.a.h@coeng.uobaghdad.edu.iq, Name: Abdulameer almalichy, Email: Almalichy.Abdulameer.mohsin.kadhim@student.uni-miskolc.hu IJCPE is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License. Well Performance Following Matrix Acidizing Treatment: Case Study of the Mi4 Unit in Ahdeb Oil Field Usama Alameedya, Ayad A. Al-Haleema , and Abdulameer almalichyb a Petroleum Engineering Department-College of Engineering-University of Baghdad. b Petroleum Engineering Department- College of Earth Science and Engineering- University of Miskolc. Abstract The productivity of oil wells may be improved by determining the value of enhancing well productivity and the likely reasons or sources of formation damage after the well has been recognized as underperforming. Oil well productivity may be improved, but the economics of this gradual improvement may be compromised. It is important to analyze the influence of the skin effect on the recovery of the reserve. The acid treatment evaluated for the well AD-12, primarily for the zone Mi4; using a license of Stimpro Stimulation Software to validate the experimental work to the field scale, this software is considered the most comprehensive instrument for planning and monitoring matrix acid treatments and utilizing actual data to provide a far better knowledge of the well's reaction, with methods that represent the reality of what is happening in the reservoir before, during, and after matrix acid treatments, through the post-treatment skin factor, which is the most frequently utilized statistic for analyzing stimulation treatments and relies on the geometry of the wormholed zone. Referring to the previous buildup tests for Ad-12, the skin value of -3.97 is approximately identical to or slightly larger than the skin value estimated by the acid treatment simulation using Stimpro. Moreover, when the simulator was performed, the invading fluid revealed two distinct depths of investigation inside the treated zone. While the fluid invasion in the bottom area has invaded deeply at a distance of 95 inches despite the top layer wormhole penetrating to a depth of 32 inches. Keywords: Mishrif Reservoir, Skin factor, acid treatment, matrix acidizing, and StimPro. Received on 12/06/2022, Accepted on 03/08/2022, Published on 30/12/2022 https://doi.org/10.31699/IJCPE.2022.4.2 1- Introduction The term "formation damage" refers to a reduction in the permeability of the original rock as a consequence of some alteration, such as clay swelling, fines migration, particle clogging, or changes in wettability. Due to scale precipitation, asphaltene deposition, and other causes, formation damage may also occur throughout the productive or injective life of the well. Matrix acidizing treatments restore damage to the formation caused by earlier well operations. The ultimate objective of these treatments is often to restore the original formation's permeability. On the other hand, a matrix acidifying treatment may significantly enhance the formation process in sandstones and shales [1]. The permeability may be considerably improved to values much larger than the initial permeability, up to a distance of possibly tens of feet from the wellbore. Consequently, while hydraulic fracturing is usually projected to provide better results in sandstones or shales than matrix acidizing in carbonate rocks, both procedures are competitive [2]. More work is required to determine the most effective option. As described as a technique of well stimulation, matrix acidizing involves introducing an acid solution into the formation to dissolve a few minerals present and, as a result, restore or increase permeability around the wellbore, among other things [1]. Due to the low velocity of the acid injection, the pressure is maintained below the formation breakdown pressure, and as a result, the reservoir rock does not fracture. Candidate selection and stimulation methods are aided by a decision tree (Fig. 1). The productivity achievement determines the stimulation approach [3]. To meet the productivity objective, matrix stimulation should provide a skin effect of 10 % of the initial damage skin effect for sandstones and 2 to 3 % for carbonates. Aside from hydraulic fracturing, there is no other stimulation method for sandstone reservoirs. Acid fracturing may be cost-effective to boost productivity in carbonate reservoirs (limestones or dolomites). In both circumstances, the reservoir experiences a hydraulic fracture [2]. 2- Design of the Stimulation Treatment Sequence If the well has been recognized as underperforming, then the monetary value of increasing well productivity and the likely formation damage sources have been evaluated [4]–[7]. The engineer must next identify the corrective action. Two nonfracture procedures are utilized to increase oil and gas well productivity. The wellbore is cleaned using chemical and/or mechanical techniques. In http://ijcpe.uobaghdad.edu.iq/ http://www.iasj.net/ mailto:usama.sahib@coeng.uobaghdad.edu.iq mailto:dr.ayad.a.h@coeng.uobaghdad.edu.iq mailto:Almalichy.Abdulameer.mohsin.kadhim@student.uni-miskolc.hu http://creativecommons.org/licenses/by-nc/4.0/ https://doi.org/10.31699/IJCPE.2022.4.2 U. Alameedy et al. / Iraqi Journal of Chemical and Petroleum Engineering 23,4 (2022) 7 - 16 8 order to stimulate the matrix, fluids are pumped into the formation near the wellbore [2]. Typically, matrix stimulation treatments administered below fracture pressure via tubing, drillpipe, or coiled tubing consist of a series of fluids, known as stages. A minimum treatment includes a preflush stage with a nondamaging, nonreactive fluid to set an injection rate, a stage of the main treating fluid, and an overflush stage to remove the main treating fluid from the tubing and displace it into the vicinity of the wellbore. Other auxiliary steps are used in the majority of therapies to improve their efficacy. The next sections examine the selection of chemicals for the stages and the design of the treatment sequence (pumping schedule). [8]. Fig. 1. Candidate Selection and Stimulation Methods [2] a) Preflush Preflushes of hydrochloric acid are used to prepare or condition the formation that will be stimulated so that the acid will be accepted in the most favorable parts. The primary goal of the Preflush is to displace the brine from the wellbore to prevent contact between the hydrofluoric acid and the brine of formation, which contains potassium, sodium, and calcium, which causes precipitation [9]. b) Main (Acid) treatment This stage's goal is to repair the well's damage. The appropriate injection rate is determined by the acidizing task matrix's acidizing or acid fracturing type. In carbonates, wormhole propagation speed increases with injection rate, so a high injection rate is required for rapid wormhole propagation. When acidizing in areas of high- water saturation, low pump rates are also advised. The maximum permitted pressure for the tubing, the surface equipment, and the pump must be considered to determine whether the formation can withstand larger forces [2]. c) Postflush (overflush) The overflush moves the primary acid flush at least four feet away from the wellbore. Since retarded acid's reaction time on creation is longer than its injection period, it might aid in acid penetration. Instead of using potassium chloride as a post flush in acidizing sandstone formations with hydrofluoric acid, ammonium chloride, NH4Cl, is advised [1]. 3- Monitoring the Performance of Acidizing Treatment The post-treatment skin factor is the most often utilized statistic for analyzing stimulation treatments. In matrix acidizing processes in carbonates, the skin factor relies on the geometry of the wormholed zone. Analyzing the injection rate and pressure during injection is recommended for monitoring a matrix acidizing treatment in a carbonate reservoir, in the same way as monitoring a sandstone acidizing treatment is advised [1]. In carbonates, the pressure loss across the wormhole zone is assumed to be insignificant, which means that the wormhole impact on the wellbore skin effect is equivalent to extending the wellbore [10]. The skin's evolution after a carbonate matrix acidizing treatment may be anticipated using wormhole propagation models under this assumption. As the wormhole penetration radius increases in a damaged well with a permeability k, the skin effect is proportional to the wormhole penetration radius as follow: 𝑠 = 𝑘 𝑘𝑠 𝑙𝑛⁡ 𝑟𝑠 𝑟𝑤ℎ − 𝑙𝑛⁡ 𝑟𝑠 𝑟𝑤 (1) As long as the radius of wormhole penetration is greater than the radius of damage, Eq. (1) remains valid. Alternatively, if the well was initially undamaged or if the wormhole radius was higher than the original damage radius, the skin effect during acidification is assumed to be infinite, and the following Eq. (1) is used to represent this: 𝑠 = −𝑙𝑛⁡ 𝑟𝑤ℎ 𝑟𝑤 (2) Eqs. (1) and (2), which assume that the injection rate is kept constant during the treatment for the damaged zone, are used to determine the skin impact expected by the volumetric model during the injection, 𝑠 = − 𝑘 2𝑘𝑠 𝑙𝑛⁡[( 𝑟𝑤 𝑟𝑠 ) 2 + 𝑉 𝑃𝑉𝑏𝑡𝜋𝑟𝑠 2𝜙ℎ ] − 𝑙𝑛⁡ 𝑟𝑠 𝑟𝑤 (3) Furthermore, since wormholes that penetrate beyond the affected zone or there is no damage, 𝑠 = − 1 2 𝑙𝑛⁡[1 + 𝑉 𝑃𝑉𝑏𝑡𝜋𝑟𝑠 2𝜙ℎ ] (4) Both Buijse-Glasbergen and Furui models are used to calculate the radius of the wormhole region for discrete U. Alameedy et al. / Iraqi Journal of Chemical and Petroleum Engineering 23,4 (2022) 7 - 16 9 injection times. The skin factor is calculated using Equation 1or Eq. (2) for each rwh obtained using these models. 4- Max. Δp, Max.-Rate-Procedure by Paccaloni The [11] approach estimates a steady-state skin effect in accordance with Darcy's law to keep track of the development of stimulation treatments. The two most important components of Paccaloni's maximum Δp, maximum-rate technique is: 1. The largest pwf achievable without breaking the formation should be achieved by injecting the acid at the maximum pace possible. 2. Treatments should be evaluated in real-time to ensure the maximum rate aim is fulfilled and detect when enough acid is injected into the formation. 𝑠 = 0.00708𝑘ℎ𝛥𝑝 𝜇𝑞𝑖 − 𝑙𝑛⁡ 𝑟𝑠 𝑟𝑤 (5) Where k denotes the formation's permeability, h indicates the thickness of the pay zone, rw represents the wellbore radius, and rs defines the radius impacted by acid injection. Typical oilfield units for all of the variables. Fig. 2 depicts the treatment of the matrix stimulation design chart. Acid injection rate (qi) and pressure drop Δp are linked to skin variables in Eq. (5). Wang et. Al. [12] builds a pti vs. qi graph using skin factor as a parameter to track a stimulation treatment. A series of parallel lines with varying skin factor values can be seen on the chart, as long as the skin factor is assumed to be the only variable under consideration. The wellhead pressure and injection rate indicate the treatment, and the skin effect may be seen on the chart. This chart also shows the relationship between fracture pressure and injection rate, keeping the rate as high as feasible without breaking the formation. Fig. 2. Treatment of the Matrix Stimulation Design Chart [13] According to Prouvost and Economides [14] and validated by Paccaloni and Tambini [13], it is possible to overstate the skin impact using the Paccaloni approach since it neglects transient flow effects. When the pace of change is sudden, this miscalculation might be catastrophic. However, it's not a big problem for most treatments since the inaccuracy is pretty constant, and the development of the skin impact is more essential than its absolute value itself. Prouvost and Economides [14] developed a method for precisely calculating the changing skin effect during matrix acidization. A thorough post- treatment analysis might benefit from using this method if a defined injection schedule is available. This approach is considered to be among the most helpful design strategies because of the following advantages: • It is possible to evaluate the degree of formation damage using an injection test. • It is likely to estimate the pumping parameters at starting an acidizing matrix process. • Can determine if acid amounts utilized are insufficient, appropriate, or excessive. • At the well site, it is possible to make an informed and timely choice, increasing the likelihood of success. 5- Stimpro Stimulation Software The Stimpro system is intended to give the most complete tools for the planning and analysis of matrix acid treatment. Stimpro's matrix acid simulator, on the other hand, focuses on the practical use of real treatment data. The utilization of actual data provides a far better knowledge of the well's reaction, with methods that represent the reality of what is happening in the reservoir before, during, and after matrix acid treatments (Fig. 3). Operation modes on the Main screen include design and analysis of matrix acid treatment, as well as reservoir modelling. Acidizing Design Mode, Acidizing Analysis Mode, and Production Analysis Mode are the three options available to users[15]. Fig. 3. StimPro's Capabilities [15] a. Acidizing Design Mode Using the Acidizing Design option, a treatment schedule can be generated rapidly and effectively. Stimpro will develop a pumping schedule after assisting in the selection of the proper fluids and acids for the U. Alameedy et al. / Iraqi Journal of Chemical and Petroleum Engineering 23,4 (2022) 7 - 16 10 reservoir's damage. The reservoir penetration may also be specified in this mode. b. Acidizing Analysis Mode Pre-treatment design and real-time data analysis are the main priorities of the Acidizing Analysis mode. The real- data analysis may be done in real-time or post-job, using treatment data that has already been gathered before the project started. c. Production Analysis Mode Wells with or without matrix acid treatments may have their production behavior predicted or matched using the Production Analysis option. Using this method, Stimpro feeds a reservoir simulator with the acid concentration profile it generated using its hydraulic fracture propagation and acid transport models. This is a critical step in establishing the efficacy of previous treatments and the related economics of future ones. 6- Results and Discussion In Stimpro Software's acidization model, sandstones and carbonates respond differently to acidizing, which is taken into account. As a result of acidizing, new channels (wormholes) are formed in carbonates, bypassing damage to the wellbore and allowing water to flow into the well. As an alternative to developing new pore channels, acidizing sandstone displaces the particles that block the existing channels. Acid tends to migrate in a front around the wellbore in sandstone reservoirs. The kinetics of dissolution in sandstones is surface-reaction restricted, which accounts for a major part of the variance in behavior. Carbonates, on the other hand, have a considerably more unstable process. HCl and HF acid are often used in sandstone treatment to reopen and expand pore channels obstructed by clays and siliceous fines. In order to prevent the clays from extracting protons from HF, HCl dissolves any carbonates in the matrix, and HF dissolves slow and fast- reacting silicates and carbonates. The ability to calculate the optimal acid treatment volumes and concentrations is typically a determining factor in treatment efficacy. The precipitation of amorphous silica may occur as a consequence of secondary reactions from spent acid rather than decreasing the skin's appearance. There are times when excessively powerful acids might weaken and destabilize formation faces. Engineers may use the Acidizing Design mode to rapidly and effectively develop a treatment program depending on the requirements of the reservoir. Stimpro will build a pumping schedule after selecting the proper fluids and acids for the reservoir damage type. It will then be able to indicate the desired reservoir penetration. The order in which the fluid patches are administered and their exact time of application are essential factors for designing a stimulation treatment. After the technique of major acid injection, the pre-and post-flushing phases are the most prevalent components of a treatment sequence. It was decided to do the acidizing job on Dec. 2nd, 2011, for the well Ad-12 targeting the Mishrif reservoir, particularly the Mi4 unit, to remove drilling and completion mud damage to the pay zone and improve the performance of the formation by enhancing the permeability; consequently, boost oil production. The whole matrix acidizing job, including the data necessary for operation and the outcomes in a summary report, is clearly shown in Fig. 4. The acid job began with a pre- injection of water. Pump pressure: 12.35-16.90 MPa (1791-2451 psi); Pump flow rate: 0.35 m3/min (2.94 bbl/min); Total pre-injected water volume: 2 m3 (16.78 bbl). followed by the first injection of acid fluid with Pump pressure was 14.48-17.40 MPa (2100-2523 psi), pump rate was 0.38-0.42 m3/min (3.19-3.522 bbl/min), and total acid pumped was 20 m3. The last step was flushed with new water thereafter, by Pump pressure: 12.00-13.00 MPa (1740-1885 psi); Pump flow rate: 0.57- 0.59 m3/min (4.78-4.95 bbl/min); Total volume pumped: 17 m3 (142.5 bbl). In the following scenario, an acidizing carbonate treatment is investigated with Stimpro to illustrate pressure matching of measured and simulated data, skin evolution assessment, and a general analysis of an acidizing carbonate treatment. To begin, create a new file to enter the details such as the well survey, fluid type and specifications, and treatment schedule. Examine all inputs by clicking the Next button to go through the various options. A vertical well Ad-12 with perforated casing completion has a total depth of 3169.37 m from where the acid operation was pumped into the perforation depths (2798.0-2808.0) m and (2808.0-2813.0) m. The reservoir (Mi4) was composed of limestone mainly divided into two sections with a porosity of 0.17-0.19, a pore fluid viscosity of 1.5-1.7 cp, a pore pressure gradient of 0.51 psi/ft, and a fracture pressure gradient of 0.751-0.76 psi/ft respectively. There was a Preflush of 2 percent potassium chloride brine, followed by the pumping of 20 percent hydrochloric acid. Before shutting down, the same brine injected to perform an overflush. The total amount of acid used in the job was 34.5 m3. Surface pressure and pumping rate were recorded during the job. All the entered data is shown in considerable detail in Table 1 to Table 10. Table 1. Acidizing Summary Reservoir Temperature (°F) 200 Average Reservoir Pressure (psi) 4,694 Pore Fluid Permeability (mD) 15-60 Porosity 0.190 Reservoir Viscosity (cp) 1.637 Frac Pressure (psi) 6,995 TVD to Top of Open Section (m) 2,798 TVD to Bott. of Open Section (m) 2,813 Acidizing Type Carbonate Acid Volume (bbls) 103.9 Avg. Surface Pressure (psi) 2,534 Max. Surface Pressure (psi) 2,627 Initial Skin 0 Final Skin -3.97 U. Alameedy et al. / Iraqi Journal of Chemical and Petroleum Engineering 23,4 (2022) 7 - 16 11 Fig. 4. Daily Acidizing Report for Well Ad-12 Table 2. Fluid Parameters Fluid Name 2% KCl Brine Fresh water 15% HCl Gelled Acid Description Preflush/Overflush Fluid fresh water Gelled Acid HCl Conc. (% mass) 0.0 0.0 20.0 Fluid Density 1.000 1.000 1.080 Diffusivity (ft²/min) 4.30e-06 4.30e-06 4.30e-06 Retardation factor 1.00 1.00 1.00 Filtercake Porosity 0.01 0.01 0.01 Filtercake Permeability (mD) 1.00e-04 1.00e-04 1.00e-04 Initial Viscosity (cp) 1.00 1.00 Initial n' 1.000 Initial k' (lbf·s^n/ft²) 2.10e-05 Wellbore Friction Multiplier 1.00 1.00 1.00 Table 3. Formation Layer Parameters Layer # Top of zone MD (m) Lithology Pore Fluid Permeability (mD) Reservoir Viscosity (cp) Compressibility (1/psi) Porosity Pore Pressure (psi) Frac Pressure (psi) 1 0.0 Shale 0.00e+00 2.000 5.00e-06 0.000 3,045 5,000 2 2,798.0 Limestone 15 1.500 5.00e-06 0.170 4,686 6,900 3 2,802.7 Limestone 60 1.700 5.00e-06 0.190 4,698 7,001 4 2,813.0 Shale 0.00e+00 0.030 2.49e-04 0.000 4,015 7,383 U. Alameedy et al. / Iraqi Journal of Chemical and Petroleum Engineering 23,4 (2022) 7 - 16 12 Table 4. Damage Profile Int MD (m) Damage Severity Original Skin Damage Penetration Damage Depth(ft) Damage Composition 1 0 Light 0.0 Shallow 0.00 Shale 2 2,800 Light 3.0 Shallow 0.20 Limestone 3 2,807 Light 3.0 Medium 0.30 Limestone 4 2,813 Light 0.0 Shallow 0.00 Shale Table 5. Drilled Hole Configuration Length (m) Segment Type Eff Diam (in) Bit Diam (in) 2,814 Open Hole 8.500 8.500 Table 6. Casing Configuration Length (m) Segment Type Casing ID (in) Casing OD (in) Weight (lb/ft) Grade 2,814 Cemented Casing 6.520 7.000 17.000 N-80 Table 7. Surface Line and Tubing Configuration Length (m) Segment Type Tubing ID (in) Tubing OD (in) Weight (lb/ft) Grade 2,700 Tubing 2.362 2.875 4.600 N-80 2 Packer 2.370 6.500 0.000 Table 8. Path Summary Segment Type Length (m) MD (m) TVD (m) Dev (deg) Pipe ID (in) Tubing 2,700 2,700 2,700 0.0 2.362 Casing 113 2,813 2,813 0.0 6.520 Table 9: Rock Thermal Properties Rock Type Sandstone Limestone Shale Specific Gravity (sg) 2.71 2.72 2.71 Specific Heat* 0.260 0.210 0.200 Thermal Conductivity** 2.57 0.910 1.01 Table 10. Fluid Thermal Properties Fluid Name 2% KCl Brine Fresh water 15% HCl Gelled Acid Specific Gravity (sg) 1.000 1.000 1.08 Parameters for Heat Transfer Model Surface Fluid Temperature 70.00 (°F) Surface Rock Temperature 70.00 (°F) Reservoir Temperature 200 (°F) Wellbore Heat Transfer Multiplier 1.00 The Stimpro acidizing model considers the intrinsic variances in matrix acid for carbonates and sandstones. As wormholes grow in carbonates, matrix stimulation is more effective because it allows the formation to be penetrating farther than the damaged near-wellbore area allows. Wormhole development in carbonate acidizing may be calculated using two different models in this new edition of Stimpro: A semi-empirical method by [16] is used as the default model, whereas Péclet number theory is used for the alternate model [17]. Carbonate matrix acidizing treatment is optimized by considering both the wormhole skin and the transient radial flow pressure.  Pressure Matching Once all the necessary data and parameters have been input, we begin the simulation using the Semi-empirical model with 𝑃𝑉bt−opt= 0.55 and 𝑉𝑖−opt=0.0322 ft/min stored in the Software database [16]. Afterward, a comparison of the pressure match plot between calculated and measured wellhead pressure is performed and a comparison between calculated and measured bottom- hole pressure. Treatment data with bottom hole and fracture pressures may be shown in Fig. 5, which displays the results of our studies; fluctuating fluid diverting effects cause bottom- hole pressure to vary. For matrix acid treatments, jobs were typically pumping below the hydraulic fracture pressure of the formation pressure. The model's reaction to its experimental work data built-in Software is overstated since the modeled pressure values are substantially lower than the actual data. Therefore, the simulated pressure data does not very well match the observed pressure data. Utilizing our experimental [9] data 𝑃𝑉bt−opt=2.5 and 𝑉𝑖−opt=0.0206 ft/min as input data to enhance the pressure match. Thus, a more accurate match between estimated and observed surface pressures is achieved (Fig. 6). Once sufficient pressure data has been obtained, the changing skin may be anticipated. Figure 5.33 demonstrates that the treatment reduced the wellbore skin from around 3 at the start of the operation to approximately -3.6 at the end of job. Most likely, deep- penetrated wormholes were generated in the carbonate formation, ensuring the effectiveness of this acid treatment. The Fig. 7 illustrates the estimated skin, injection rate, and acid concentration of fluid for three phases of treatment, all of which are proportional to the time spent acidifying the matrix. Referring to the buildup analysis for Ad-12 [9], the skin value of -3.97 is approximately identical to or slightly larger than the skin value estimated by the acid treatment simulation using STIMPRO software. The depth profile is shown in Fig. 8 summarizes the reservoir parameters, formation damage, and the model computation of fluid invasion via the flushed formation in three phases. As can be discriminated, the treated zones are divided into two layers based on the Formation Layer Parameters (Table 5 to Table 9); the first layer is 4.7 m thick with a permeability of 15 md and a porosity of 0.17; the second layer is 10.3 m thickness with a permeability of 65 md and a porosity of 0.19. When the simulator was performed, the invading fluid revealed two distinct depths of investigation inside the treated zone. The fluid invasion in the bottom area has remained steady at a distance of 95 inches (7.91 ft) despite the top layer wormhole penetrating to a depth of 32 inches (2.67 ft). The effective permeability of two layers is 15-60 md; accordingly, utilizing Eq. (5) to compute wellhead or bottom hole injection pressure for various skin factor (S) values since assuming acid injection rates. As a result, the computation is shown in the Fig. 9, which plots many curves of injection rate vs. wellhead pressure, one for each skin component (s). It is found that most predicted wellhead pressures are less than the fracture pressure, indicating that the acid job treatment may be conducted U. Alameedy et al. / Iraqi Journal of Chemical and Petroleum Engineering 23,4 (2022) 7 - 16 13 safely without breaking the formation. The only problem is that if there is formation damage to the skin of 5, and the injection rate exceeds 5 bpm, the bed will frack, indicating that the treatment job will fail. Fig. 5. The Pressure Match between Actual and Calculated for Surface and Bottom Hole of Stimulated Well Ad-12 Fig. 6. The Pressure Match between Actual and Calculated for Surface and Bottom Hole of Stimulated Well Ad-12, using Our Data Set U. Alameedy et al. / Iraqi Journal of Chemical and Petroleum Engineering 23,4 (2022) 7 - 16 14 Fig. 7. Skin Factor Computation for Well Ad-12 Fig. 8. Invasion Profile, Layer Properties and Model Treatments Schedule for Well Ad-12 Fig. 9. Treatment of the Matrix Stimulation Design Chart for Well Ad-12 U. Alameedy et al. / Iraqi Journal of Chemical and Petroleum Engineering 23,4 (2022) 7 - 16 15 7- Conclusions In Stimpro Software, the model's response to its experimental work data has been overestimated since the predicted pressure levels are far lower than the real data. As a result, the simulated data on pressure does not match the actual data on pressure very well. Experiment with a pressure match of PVBt =2.5 and vi= 0.206 ft/min, using our experimental data as input data. As a result, the predicted and measured surface pressures are more closely matched. The changing skin may be predicted if enough pressure data is collected. Wellbore skin was decreased from around 3 at the commencement of the operation down to about -3.6 at the completion of the project. The acid treatment's success was presumably ensured by creating deep-penetration wormholes in the carbonate deposit. STIMPRO's acid treatment simulation predicted a skin value of -3.97 for Ad-12, which is close to or slightly bigger than the skin value predicted by the buildup analysis. References [1] M. J. Economides, A. D. Hill, C. Ehlig-and Economides, and D. Zhu, Petroleum Production Systems, SECODN EDI. PENTICE HALL, 2013. [2] M. J. Economides and K. G. Nolte, Rerservoir Stimulation, 3rd ed. Wiley, 2000. [3] M. J. Economides, A. D. Hill, and C. Ehlig-and Economides, Petroleum Production Systems. 1994. [4] U. S. Alameedy, “Evaluation of Hydrocarbon Saturation Using Carbon Oxygen (CO) Ratio and Sigma Tool,” Iraqi J. Chem. Pet. Eng., vol. 15, no. 3 SE-Articles, pp. 61–69, Sep. 2014. [5] J. A. Al-Sudani and K. M. Husain, “Evaluation of Acid and Hydraulic Fracturing Treatment in Halfaya Oil Field-Sadi Formation,” Iraqi J. Chem. Pet. Eng., vol. 18, no. 4 SE-Articles, pp. 25–33, Dec. 2017. [6] M. Najeeb, F. S. Kadhim, and G. N. Saed, “Using Different Methods to Predict Oil in Place in Mishrif Formation / Amara Oil Field,” Iraqi J. Chem. Pet. Eng., vol. 21, no. 1 SE-Articles, pp. 33–38, Mar. 2020, doi: 10.31699/IJCPE.2020.1.5. [7] U. Alameedy, “EXPERIMENTAL STUDY AND ANALYSIS OF MATRIX ACIDIZING FOR MISHRIF FORMATION-AHDEB OIL FIELD,” PhD, Dissertation, University of Baghdad, 2022, doi:10.13140/RG.2.2.25412.91525. [8] T. O. Allen and A. P. Roberts, Production Operations, 3rd printi. Tulsa, Oklahoma: Vol.2., 1978. [9] U. Alameedy and A. Al-haleem, “The Impact of Matrix Acidizing on the Petrophysical Properties of the Mishrif Formation: Experimental Investigation,” Iraqi Geol. J., vol. 55, no. 1E, pp. 41–53, May 2022, doi: 10.46717/igj.55.1E.4Ms-2022-05-20. [10] U. Alameedy, A. A. Alhaleem, A. Isah, A. Al-Yaseri, M. Mahmoud, and I. S. Salih, “Effect of acid treatment on the geomechanical properties of rocks: an experimental investigation in Ahdeb oil field,” J. Pet. Explor. Prod. Technol., Jul. 2022, doi: 10.1007/s13202-022-01533-x. [11] G. Paccaloni, M. Tambini, and M. Galoppini, “Key Factors for Enhanced Results of Matrix Stimulation Treatments,” Feb. 1988, doi: 10.2118/17154-MS. [12] Y. Wang, A. D. Hill, and R. S. Schechter, “The Optimum Injection Rate for Matrix Acidizing of Carbonate Formations,” SPE Annual Technical Conference and Exhibition. p. SPE-26578-MS, Oct. 03, 1993, doi: 10.2118/26578-MS. [13] G. Paccaloni and M. Tambini, “Advances in Matrix Stimulation Technology,” J. Pet. Technol., vol. 45, no. 03, pp. 256–263, Mar. 1993, doi: 10.2118/20623- PA. [14] L. P. Prouvost and M. J. Economides, “Applications of Real-Time Matrix-Acidizing Evaluation Method,” SPE Prod. Eng., vol. 4, no. 04, pp. 401–407, Nov. 1989, doi: 10.2118/17156-PA. [15] Carbo, “Tutorial manual.” 2021. [16] M. Buijse and G. Glasbergen, “A Semi-Empirical Model To Calculate Wormhole Growth in Carbonate Acidizing,” Oct. 2005, doi: 10.2118/96892-MS. [17] G. Daccord, E. Touboul, and R. Lenormand, “Carbonate Acidizing: Toward a Quantitative Model of the Wormholing Phenomenon,” SPE Prod. Eng., vol. 4, no. 01, pp. 63–68, Feb. 1989, doi: 10.2118/16887-PA. https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/289 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/289 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/289 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/289 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/69 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/69 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/69 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/69 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/541 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/541 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/541 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/541 https://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/541 http://dx.doi.org/10.13140/RG.2.2.25412.91525 https://igj-iraq.org/igj/index.php/igj/article/view/942 https://igj-iraq.org/igj/index.php/igj/article/view/942 https://igj-iraq.org/igj/index.php/igj/article/view/942 https://igj-iraq.org/igj/index.php/igj/article/view/942 https://igj-iraq.org/igj/index.php/igj/article/view/942 https://link.springer.com/article/10.1007/s13202-022-01533-x https://link.springer.com/article/10.1007/s13202-022-01533-x https://link.springer.com/article/10.1007/s13202-022-01533-x https://link.springer.com/article/10.1007/s13202-022-01533-x https://link.springer.com/article/10.1007/s13202-022-01533-x https://link.springer.com/article/10.1007/s13202-022-01533-x https://onepetro.org/SPEFD/proceedings-abstract/88FD/All-88FD/SPE-17154-MS/67691 https://onepetro.org/SPEFD/proceedings-abstract/88FD/All-88FD/SPE-17154-MS/67691 https://onepetro.org/SPEFD/proceedings-abstract/88FD/All-88FD/SPE-17154-MS/67691 https://onepetro.org/SPEATCE/proceedings-abstract/93SPE/All-93SPE/SPE-26578-MS/55234 https://onepetro.org/SPEATCE/proceedings-abstract/93SPE/All-93SPE/SPE-26578-MS/55234 https://onepetro.org/SPEATCE/proceedings-abstract/93SPE/All-93SPE/SPE-26578-MS/55234 https://onepetro.org/SPEATCE/proceedings-abstract/93SPE/All-93SPE/SPE-26578-MS/55234 https://onepetro.org/SPEATCE/proceedings-abstract/93SPE/All-93SPE/SPE-26578-MS/55234 https://onepetro.org/JPT/article-abstract/45/03/256/70458/Advances-in-Matrix-Stimulation-Technology https://onepetro.org/JPT/article-abstract/45/03/256/70458/Advances-in-Matrix-Stimulation-Technology https://onepetro.org/JPT/article-abstract/45/03/256/70458/Advances-in-Matrix-Stimulation-Technology https://onepetro.org/JPT/article-abstract/45/03/256/70458/Advances-in-Matrix-Stimulation-Technology https://onepetro.org/PO/article-abstract/4/04/401/76597/Applications-of-Real-Time-Matrix-Acidizing?redirectedFrom=fulltext https://onepetro.org/PO/article-abstract/4/04/401/76597/Applications-of-Real-Time-Matrix-Acidizing?redirectedFrom=fulltext https://onepetro.org/PO/article-abstract/4/04/401/76597/Applications-of-Real-Time-Matrix-Acidizing?redirectedFrom=fulltext https://onepetro.org/PO/article-abstract/4/04/401/76597/Applications-of-Real-Time-Matrix-Acidizing?redirectedFrom=fulltext https://onepetro.org/SPEATCE/proceedings-abstract/05ATCE/All-05ATCE/SPE-96892-MS/89467 https://onepetro.org/SPEATCE/proceedings-abstract/05ATCE/All-05ATCE/SPE-96892-MS/89467 https://onepetro.org/SPEATCE/proceedings-abstract/05ATCE/All-05ATCE/SPE-96892-MS/89467 https://onepetro.org/PO/article-abstract/4/01/63/76503/Carbonate-Acidizing-Toward-a-Quantitative-Model-of?redirectedFrom=fulltext https://onepetro.org/PO/article-abstract/4/01/63/76503/Carbonate-Acidizing-Toward-a-Quantitative-Model-of?redirectedFrom=fulltext https://onepetro.org/PO/article-abstract/4/01/63/76503/Carbonate-Acidizing-Toward-a-Quantitative-Model-of?redirectedFrom=fulltext https://onepetro.org/PO/article-abstract/4/01/63/76503/Carbonate-Acidizing-Toward-a-Quantitative-Model-of?redirectedFrom=fulltext https://onepetro.org/PO/article-abstract/4/01/63/76503/Carbonate-Acidizing-Toward-a-Quantitative-Model-of?redirectedFrom=fulltext U. Alameedy et al. / Iraqi Journal of Chemical and Petroleum Engineering 23,4 (2022) 7 - 16 16 في حقل نفط Mi4 : دراسة حالة لوحدةحشو الصخري ض التحميأداء البئر بعد معالجة األحدب 2عبد االمير المالكي و 1, اياد عبد الحليم1أسامة العميدي جامعة بغداد –كلية الهندسة -قسم هندسة النفط 1 جامعة ميسكولك –كلية علوم وهندسة االرض –قسم هندسة النفط 2 الخالصة صادر ميمكن تحسين إنتاجية آبار النفط من خالل تحديد قيمة تحسين إنتاجية البئر واألسباب المحتملة أو الضرر الناتج عن التكوين بعد التعرف على أن أداء البئر ضعيف. قد تتحسن إنتاجية آبار النفط، لكن صادي على الحد االقت Skinللخطر. من المهم تحليل تأثير تأثير اقتصاديات هذا التحسن التدريجي قد تتعرض .للخطر Skinواستعادة االحتياطي. قد تتعرض اقتصاديات التحسن التدريجي لتأثير التي ر، متجاوزة األضرايةالكربونالصخور ، تتشكل قنوات جديدة )ثقوب دودية( في معالجة بالحامضلانتيجة بعدزمنيا ضخ ال يتم جدولة Stimpro باستخدام برنامج. ربتدفق المياه إلى البئبئر وتسمح لحقت بجوف ال 2011ديسمبر 2. تقرر القيام بمهمة التحميض في الطبقي التضرراختيار السوائل واألحماض المناسبة لنوع من النتهاء ، إلزالة أضرار طين الحفر وا Mi4مشرف، وال سيما وحدة مكمنالذي يستهدف Ad-12 للبئر Stimpro يستخدم .منطقة الدفع وتحسين أداء التكوين من خالل تعزيز النفاذية، وبالتالي زيادة إنتاج النفط محمضة وإظهار كيف تتوافق بيانات الضغط المقاسة والمحاكاة. للبدء، الصخور الكربونيةلتحليل معالجة .ستحتاج إلى جمع بيانات عن حالة البئر ونوع السوائل وخطة العالج .المعالجة بالحامضمشرف, مكمن الكلمات الدالة: