Available online at http://ijcpe.uobaghdad.edu.iq and www.iasj.net Iraqi Journal of Chemical and Petroleum Engineering Vol.20 No.3 (September 2019) 75 – 79 EISSN: 2618-0707, PISSN: 1997-4884 Corresponding Authors: Name: Ayad A.Alhaleem A.Alrazzaq , Email: ayadah62@yahoo.com IJCPE is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License. Development of East Baghdad Oil Field By Clusters of Horizontal Wells Ayad A.Alhaleem A.Alrazzaq Engineering College-University of Baghdad Abstract There are varieties of reasons lead for drilling horizontal wells rather than verticals. Increasing the recovery of oil, especially from thin or tight reservoir permeability is the most important parameter. East Baghdad oil field considered as a giant field with approximately more than 1billion barrel of a proved reserves accompanying recently to low production rate problems in many of the existing wells. It is important to say that presence of of horizontal wells in East Baghdad field especially by converting some of already drilled wells by re-entry drilling horizontal sections may provide one of best solutions for the primary development stage in East Baghdad field which may be followed by drilling new horizontal wells or using multilateral wells. Advance software (Well Test/FAST) has been used to convert the production data for the already drilled vertical wells to horizontals to simulate the productivity. It can be concluded that no measurements available for the ratio of anisotropy (Kv/Kh); in East Baghdad Oil Field therefore, the wells productivity has been estimated using wide range of anisotropy ratios that will help the field operator to determine exactly wells productivity. Moreover, it helps to recommend the effectiveness of applying hydraulic fracturing in improving horizontal well productivity. The results show that it could be used well EB-32 as a re-entry horizontal well with an optimum section length of 1500-2000ft wich give the best production rate. The same result could be stated for EB-10 with somewhat higher productivity than EB-32. Keywords: Horizontal wells, Productivity, Vertical permeability, Reentry drilling wells Received on 19/03/2019, Accepted on 27/07/2019, published on 30/09/1029 https://doi.org/10.31699/IJCPE.2019.3.10 1- Introduction Horizontal drilling represents a tool to reduce drilling operations costs of an oil field due to two concerns; first improving formation production, and second the cost of rig operations and mobilization will be minimized because drilling more than one well in the same land or platform ‎[1]. In other words, horizontal wells are of great interest in petroleum industry because they provide an attractive means for improving both production rate and recovery efficiency ‎[2]. It was found that the factors (well length, permeability ratio, reservoir thickness, skin factor, drainage radius and well radius) affect the pressure drop between the well bore and the reservoir which affect the productivity index in horizontal wells ‎[3]. Also an analytical method could be applied in any position within the entire reservoir area to provide the tilt of originally oil-water contact in all directions in horizontal wells ‎[4]. East Baghdad oil field was discovered by seismic survey which was carried in 1960 and 1974. The first well was drilled and completed in the south part of the field in 1975 and till now already drilled and completed many exploration delineation and production wells in different parts of the field. East Baghdad Field has actually multi reservoirs, main of them are Tanuma, Khasib and Zubair with different grades of crude oil 21 - 23and 35 API in Zubair formation ‎[5]. East Baghdad oil field considered as giant field with proved reserves estimated at more than11billion barrels and probable reserves to about 17 billion barrels. The geological structure of East Baghdad oil field is very complicated due to presence of many faults. In the same time the field is locating under treated agriculture lands and urban areas .The total area of the field is about 660 km 2 . In 1985 diction was taken to develop the field by clusters and directional wells .Thirteen clusters 700 by 800 m and 49 emergency drilling locations were fixed and reserved to develop that part of the field to reach production rate at 120000 bbl per day. The development of the field was planned to do by stages and the first stage was done to produce 20000 barrel per day and that stage called the Pilot Project and the selected area was in Rashdya region. The project was completed and the facilities were commissioned in Aug 1990. The average grade of produced crude was 21-23 API from two reservoirs Tanuma and Khasib by 21 producers and 6 injector's wells with dual completions. https://doi.org/10.31699/IJCPE.2019.3.10 A. A.Alhaleem A.Alrazzaq / Iraqi Journal of Chemical and Petroleum Engineering 20,3 (2019) 75 - 79 67 Eighteen wells were drilled directionally from two clusters by modified skid mounted rigs moved by jacking system on skidding rails gantry slot ‎[6]. One's decision was taken to continue the development of East Baghdad oil field by clusters and directional wells, it is advisable to drill and complete some or reentry drilling horizontal wells for economic reasons and reduction the number of wells. According to the last study done by reservoir engineering department shows that upper Khasib has six layers with total thickness about 70 m and these layers are connected between them vertically ‎[6]. 2- Reservoir Selection Consider the thicker interval with total thickness of 25 m which is the main productive zone of Sw=0.37, so according to that it is recommended to drill the first horizontal well to produce from this layer of upper Khasib formation. It is possible on lateral horizontal drilling to produce from multilayer or more than one reservoir. Actually, horizontal drilling recently used in development of Iraqi oil fields due to high production rates presence of thick reservoirs. The major purpose of drilling horizontal wells is to enhance reservoir contact and there by enhance well prod activity also in reservoirs with water and gas coning problems; horizontal wells have been used to minimize conning problems ‎[7]. In general, a horizontal well is drilled parallel to reservoir bedding plane ‎[8], that means a horizontal well is a well which intersects the reservoir bedding plane at 90 degree. A typical horizontal well project is different from a vertical well project because productivity of a well depends upon the well length. 3- Selection Horizontal Well Type There are five types of horizontal wells that have evolved for reasons of hydrocarbon reservoir requirements or to designate the equipment required to drill the wells. The types of wells have become known as ‎[8],‎[9]: 1- Long – Radius 2- Medium- Radius 3- Short – Radius 4- Tangent 5- Combination In this study, it is recommended to choose the first type (long- radius) because the depth of productive zone (2000-2200m) allows drilling such types of drilling. The builds section it takes longer time than the other types but the long-radius wells are usually drill with standard directional equipment while short – radius wells require an assortment of special equipment. Vertical well drains cylindrical volume whereas horizontal well drains an ellipsoid; three-dimensional ellipse. Since, horizontal wells expectable to drain larger reservoir volume than vertical wells ‎[10]. 4- Work Development Advance software technology (F.A.S.T well test) (Appendix A) has been used to convert the production data for the already drilled vertical wells to horizontals to simulate the productivity ‎[11]. The converted horizontal wells have been simulated to oil production assuming the cases of (1- No- communication exist between the layers, 2- Degree of communication exist between the layers). The simulated results show that the first assumption led to incorrect results, while the second assumption led to give the most reliable results. Two vertical wells EB-10 and EB-32 have been selected to be converted to horizontal wells and simulated for different lateral section lengths (260-3000 ft). Moreover two values of skin factor (S=0 and S= -4) have been processed to analyze the sensitivity of simulation the hydraulic fracturing in production increment. It can be stated that no measurements available for the ratio of anisotropy (Kv/Kh); therefore the wells productivity has been estimated using wide range of anisotropy ratios that will help the field operator to determine exactly wells productivity soonest getting this value. Moreover, it helps to determine the effectiveness of hydraulic fracturing in improving horizontal well productivity. 5- Results and Discussion Fig. 1 shows the effect various lateral horizontal lengths (500-2500 ft) for different estimated (Kv/Kh) ratios for well EB-32. Fig. 1. Production /rate versus (Kr) for different lateral section length. Well No. (32) Also, it could be noticed that increasing well lateral section in low (Kv/Kh) ratio has little effects in increasing well production rate. Fig. 2 shows the variation of the productivity index versus different ratios of (Kv/Kh) with different lateral section lengths (well EB-32). A. A.Alhaleem A.Alrazzaq / Iraqi Journal of Chemical and Petroleum Engineering 20,3 (2019) 75 - 79 66 Fig. 2. Productivity index versus (Kr) for different lateral section length (Le.) Well No. (32) In the same trend, Fig. 3 shows the productivity index versus lateral section lengths for different Kr ratios for well EB-10. It could be noticed that the well EB-32 requires higher flowing pressure in lateral section length less than 1500 ft especially in low (Kv/Kh) ratios as shown in Fig. 4. A comparison for the productivity index versus lateral section length for the two wells has been made shown in Fig. 5. The results show the same trend for both wells with some what little higher values for well EB-10. The production capacity for the well EB-32 is also simulated for two simulation values of (S=0 and S= -4) for various vertical to horizontal permeability ratios (Kr) as shown in Fig. 6 and Fig. 7 respectively. Fig. 3. Productivity index versus lateral length for different (kr) ratios, well no. (32) Fig. 4. Following well pressure drop versus lateral length for two different (kr) , well no. (32) with s=0 Fig. 5. Comparison for the Productivity Lateral Section Length for two wells Fig. 6. Production rate versus lateral section lenght for different (kr) ratio well no. (32) with s=0 Fig. 7. Well production rate versus lateral section length for different (kr) ratios, well (eb-10) with s=-4 For the well EB-32, the results show that the production capacity could be increased between (30%-100%) than the production capacity for that of vertical well for each (100 ft) lateral section length increment depends on the vertical to horizontal permeability ratios (Kr), notice that minimum section length in which the production capacity will be equal to that of vertical well should be not less than (260 ft). While, the well shows high sensitive to the acids stimulation activity (-S) and could be response to increase the production capacity between (68%-80%) for each degree of stimulation (S= -1). Meanwhile, the well shows poor response to stimulation by fracturing stimulation. A. A.Alhaleem A.Alrazzaq / Iraqi Journal of Chemical and Petroleum Engineering 20,3 (2019) 75 - 79 67 6- Conclusion and Recommendations Investigating Figures 1 and 6; it could be noticed that increasing well lateral section in low vertical to horizontal permeability ratios (Kr) has little effects in increasing well production and then could be recommend to use small lateral section lengths (1000 – 2000 ft) and by adding the effects of acid stimulation activity to those wells to extra increase the production rate as shown in Figure 7. Moreover, it could be seen from Figure 4 the wells will need for high flowing pressure drop in low vertical to horizontal permeability ratios (Kr) when using lateral sections less than (1500 ft), while the required flowing pressure drop could be much lower when using lateral section lengths of (2000 – 3000 ft). However, wells of lateral section greater than (2000ft) may not cause a considerable minimizing the flowing pressure drop, that conclusion led us to recommend converting well EB-32 to a re-entry horizontal well with lateral section of (1500- 2000 ft) keeping in mind acid stimulation process to increase the production rate. It can be concluded that no measurements available for the ratio of anisotropy (Kv/Kh); in East Baghdad Oil Field therefore, the wells productivity has been estimated using wide range of anisotropy ratios that will help the field operator to determine exactly wells productivity. Moreover, it helps to recommend the effectiveness of applying hydraulic fracturing in improving horizontal well productivity Nomenclatures API: American Petroleum institute EB: East Baghdad Oil Field Kv: Vertical Permeability Kh: Horizantal Permeability Kr: Relative Permability PTA: Pressure Transient Analysis S: Skin factor Sw: Water Saturation References [1] Hasan Ali N. ,Ayad A.Alhaleem,"Torgue and Drag Forces Problems in Highly Deviated Oil Well", Iraqi Journal of Chemical and Petroleum Engineering,Vol.19,No.3,p.p.19-31,Septemper 2018. [2] Mohammed S.AL.J,A.A.AL-Dabaj and Hassan A.Hadi,"Design of Horizontal Well Program for Ajeel Field", Iraqi Journal of Chemical and Petroleum Engineering,Vol.15,No.1,p.p.59-63,March 2014. [3] Ghanim M.F.,Maha R.Abdulamir," Formulation of New Equation to Estimate Productivity Index of Horizontal Wells", Iraqi Journal of Chemical and Petroleum Engineering,Vol.15,No.2,p.p.61-73,June 2014. [4] Jalal Abdulwahid Al-Sudani," Analytical Model for Detection the Tilt in Originally Oil Water Contacts", Iraqi Journal of Chemical and Petroleum Engineering,Vol.15,No.3,p.p.51-60,September 2014 [5] Mid Field Oil Company "Final Well Reports", Iraq, 2005. [6] Mid Field Oil Company "Final Well Reports", Iraq, 1999. [7] M.S. Al-Blehed et.al. “Horizontal wells Find Varied Applications in Saudi Fields”, Oil and Gas Journal,May-2000. [8] Abdullah M. Al-Qahtani, and Habib Menouar" New Correlations for Optimizing Horizontal Wells Completions",SPE37768-1997. [9] Michael J. Economides,” Completion Technology for Unconsolidated Formation”, Rev.2-1995. [10] Joshi, S. D., "Horizontal Well Technology", Penn. Well Publishing Company, Tulsa, OK, USA, 1991. [11] Fekete Associates “Advance Software Technology”,Version-2009. Appendix A F.A.S.T Well Test TM is used to perform pressure transient analysis (PTA) to interpret reservoir flow characteristics and predict future reservoir production. The information contained within this help document describes the appropriate PTA theory and terminology used in the software Horizontal Model The horizontal model simulates the pressure response in a horizontal well within a rectangular shaped reservoir with anisotropic heterogeneities (differences in permeability in the x, y, and z directions) or dual porosity characteristics. The anisotropy is handled using a conformal mapping procedure which adjusts the boundary sizes accordingly to mimic the effect of increased or decreased permeability in each direction. The horizontal well is oriented in the x-direction and may be at any location within the reservoir and support infinite no flow, and constant pressure boundaries. Note that the effective wellbore length (Le) defines the wellbore area open to fluid flow. Thus, classical configuration like a well near a sealing fault or a constant pressure boundary near intersecting faults can be easily modeled . No flow boundaries are modeled using the method of images. The result is superposed in time based on the rate history provided. https://doi.org/10.31699/IJCPE.2018.3.3 https://doi.org/10.31699/IJCPE.2018.3.3 https://doi.org/10.31699/IJCPE.2018.3.3 https://doi.org/10.31699/IJCPE.2018.3.3 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/269 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/269 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/269 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/269 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/278 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/278 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/278 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/278 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/278 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/288 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/288 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/288 http://ijcpe.uobaghdad.edu.iq/index.php/ijcpe/article/view/288 https://www.ogj.com/home/article/17215008/horizontal-wells-find-varied-applications-in-saudi-fields https://www.ogj.com/home/article/17215008/horizontal-wells-find-varied-applications-in-saudi-fields https://www.ogj.com/home/article/17215008/horizontal-wells-find-varied-applications-in-saudi-fields https://doi.org/10.2118/37768-MS https://doi.org/10.2118/37768-MS https://doi.org/10.2118/37768-MS http://www.uomisan.edu.iq/eng/ar/admin/pdf/96959566883.pdf http://www.uomisan.edu.iq/eng/ar/admin/pdf/96959566883.pdf https://www.osti.gov/biblio/5798453 https://www.osti.gov/biblio/5798453 https://www.osti.gov/biblio/5798453 A. A.Alhaleem A.Alrazzaq / Iraqi Journal of Chemical and Petroleum Engineering 20,3 (2019) 75 - 79 68 تطوير حقل شرق بغداد النفطي بواسطة مجاميع من اآلبار االفقية الرزاق عبد الحليم عبد أياد بغداد جامعة-اليندسة كمية الخالصة استخالص زيادة.اآلبارالعمودية عمى االفقية اآلبار حفر تفضيل الى تؤدي التي االسباب من العديد توجد من الطريقة ىذه الختيار العوامل اىم من يعتبر النفاذيو القميمة المكامن او السمك القميمة التراكيب من النفط .الحفر نفطي برميل مميار 11 يتجاوز مؤكد باحتياطي العمالقو النفطية الحقول من النفطي بغداد شرقي حقل يعتبر االفقية اآلبار استخدام دراسة فان لذلك. الموجودة اآلبار من العديد في القميل االنتاج مشكمة حاليا معو يترافق يعتبر قد افقيا منيا المقاطع بعض حفر باعادة المحفورة اآلبار بعض تغيير وخصوصا بغداد شرقي حقل في متعدد الحفر استخدام او افقية آبار بحفر يتبع ان يمكن والذي الحقل ىذا في التطويرية الحمول افضل من واحدا لتحسين افقية الى الحالية العمودية اآلبار لتغيير( التحويرات بعض مع)متطور برنامج استخدام تم. االذرع .االنتاج في( االفقيو النفاذيو/ العموديو النفاذيو)لمنسبو حقميو قياسات التوجد انو استنتاج يمكن انو الدراسو نتائج تبين النفاذيو تباين نسب من واسع مدى باستخدام تخمينيا تم قد االبار انتاجية فان وعميو النفطي بغداد شرقي حقل في تساعد فانيا ذلك الى اضافة. دقيقة بصورة االبار انتاجية معرفة او حساب في الحقل مشغمي ستساعد والتي .النفطي بغداد شرقي حقل في االفقيو االبار انتاجية لتطوير اليايدروليكي التشقيق تقنية استخدام بكفاءة التوصية ( 2000-1000) بطول افقي مقطع امثل مع جديد افقي كبئر EB-32 البئر استخدام يمكن انو النتائج اظيرت انتاج معدل مع EB-10 البئر مع النتيجة نفس عمى الحصول يمكن و انتاج معدل افضل سيعطي والذي قدم EB-32 بالبئر مقارنة اعمى الكممات الدالة: االبار االفقية, االنتاجية, النفاذية العمودية