Executive Summary Block Magallanes 1
Table of Contents Page 1. General Description of the Block 3 1.1 General Description 3 1.2 General properties of the reservoirs 8 1.3 Geological Characteristics 8 1.4 Drilling Characteristics 17 1.5 Social and Environmental Conditions 18 2 Development of the Block 19 2.1 Seismic 2D and 3D 19 2.2 Wells drilled, shut in, plugged and in production 25 2.3 Drilling Results 26 2.4 Well Maintenance 27 2.5 Production History 28 2.6 Infrastructure Facilities 31 2.7 Facilities Maintenance 43 3 Block Potential 46 3.1 Hydrocarbon Reserves and Cumulative Production 46 2
1. General Description of the Block 1.1 General Description The Magallanes Block belongs to investment project Ogarrio Magallanes of the Cinco Presidentes Asset, in the Region Sur (RSUR) of Pemex Exploration and Production (PEP.) Geographically is located in Southeast Mexico north of morphotectonic depression known as Istmo de Tehuantepec which is approximately at 50 km east of the city of Coatzacoalcos in the state of Veracruz. The Block is located in a sedimentary basin Salina del Istmo on the west side of state of Tabasco (Figure 1.) Figure 1 Geographic location of the project Ogarrio Magallanes The block in geographical coordinates is located between the parallels 18º3 0 and 18º14 0 of latitude north and the meridians 94º0 0 y 93º50 0 of longitude west. To delineate the extension of the block the following polygon was generated together the respective geographic coordinates (Figure 2) 3
Figure 2 Corners of the surface polygon Block Otates Magallanes 4
SURFACE POLYGON CORNER X LONGITUDE Y LATITUDE 1 93.8499813430 93 51 00" 18.2166663134 18 13 00" 2 93.8499724437 93 51 00" 18.0666680635 18 04 00" 3 93.9000273406 93 54 00" 18.0666764669 18 04 00" 4 93.8999549713 93 54 00" 18.0833575540 18 05 00" 5 93.9499765693 93 57 00" 18.0833376589 18 05 00" 6 93.9499678698 93 57 00" 18.0666693939 18 04 00" 7 93.9833024521 93 59 00" 18.0666666031 18 04 00" 8 93.9833046532 93 59 00" 18.1333331971 18 08 00" 9 93.9332883086 93 56 00" 18.1333285115 18 08 00" 10 93.9333113063 93 56 00" 18.1999997887 18 12 00" 11 93.8999711401 93 54 00" 18.1999964040 18 12 00" 12 93.8999804303 93 54 00" 18.2166666563 18 13 00" Table 1 Geographic Coordinates of the corners of the surface polygon The access to the Otates field is located on the km 338 of federal highway Coatzacoalcos Villahermosa using an asphalt road of 2.7 km. The field Sanchez Magallanes can be reached using the road La Venta Magallanes an asphalt road of 18 km.it is also a connection to the federal highway to Villahermosa, Tabasco at the km 351 using a road of 14 km. 5
OTATES FIELD LOCATION MAP OF WELLS UTM COORDINATES Figure 3 Map of well locations field Otates 6
MAGALLANES FIELD LOCATION MAP OF WELLS UTM COORDINATES 7
1.2 General Properties of the Reservoirs Figure 4 Map of well locations Sanchez Magallanes field The Magallanes Block covers an area of 169.06 sq km. It is made up of numerous sandstone reservoirs between depths of 2,000 to 3,500 meters and contains light crudes of 31 to 34 API. Field Field area (km2) Reservoir Type Otates 12.44 Structural Stratigraphic S. Magallanes 78.51 Structural Stratigraphic PETROPHYSICAL PROPERTIES Rock Type Porosity (%) Permeability (md) Gross Thickness (m) Net Thickness (m) Depth (m) Sandstones 19 25 11 155 45 33 2,200 Sandstones 11 26 10 151 90 60 2,500 FLUID PROPERTIES Field Density (*API) GOR Qoi (m3/m3)(bpd) Initial Pressure (kg/cm2) Current Pressure (kg/cm2) u@sc (cp) Temp (*C) Boi Rsi (m3/m3) (m3/m3) P.Sat (kg/cm2) Otates 34 252 250 186 245 60 220 5.27 6.4 71 89 1.56 191 237 186 245 S. Magallanes 33 234 277 100 301 80 246 8.02 15.99 54 100 1.2 1.6 86 145 135 226 Boi = Oil Formation Volume Factor at Initial Pressure, u = Viscosity, @sc = Surface conditions Table 2 Reservoir Properties 1.3 Geological Characteristics The reservoirs of the Otates and Sanchez Magallanes fields are of Tertiary age. A total of eighty six (86) sands have been identified 20 in Otates and 66 in Sanchez Magallanes within the Upper and Lower Concepcion and Encanto formations. Mapping of the structural blocks of the various horizons indicates the presence of more than 159 reservoir blocks. The majority of production is from the Encanto formation, which is made up of turbidite deposits in a mini basin of salt structures. Stratigraphically 8
above the Encanto is the Lower Concepcion, which is made up mainly shale units with interspersed producing sands. Above it is the Upper Concepcion formation which is a deltaic front system made up of sands that contain primarily water. These sandstones were deposited as submarine fans in continental slope basins that were developed by the activity and movement of salt bodies. The salt bodies in their migration or movement to shallow water areas, contributed to the generation a system of normal faults with general dip and which jointly with salt tops make up the seals for reservoirs of the producing sequences (Figure 5.) Figure 5 Typical Geological Column There is a clear relation between the producing zones of the Tertiary reservoirs, which are primarily mini basin turbidite deposits between salt structures, and the location of the structural highs of salt. The surface of the tops of the producing formations are governed by the structural distribution of the salt (anhydrite formation) which is an anticline with a structural high cut by normal faults and discordances, compartmentalizing the reservoir into several blocks. This compartmentalization, because 9
of the same tectonic reasons and associated fracturing, is congruent with the lateral and vertical variations, both structural and stratigraphic. The existence of an important set of regional faults, contemporaneous to the opening of the Gulf of Mexico, defines the control of the structural systems of the different fields conditioning the development and design of the other faults (Figure 6.) Figure 6 Structural style of the sands, continuity of seismic events and the geometry of the salt For the Otates field, the structural interpretation was done by correlating electric logs of wells drilled until April 1971 and it become the model for the production geology for the PEP asset. The Otates field is located in the Salina del Istmo basin. It is a secondary high of an asymmetric salt dome of the Ogarrio field and is located to the NW of Ogarrio field. This structure was discovered using seismic back in 1964. A later study, combining seismic and subsurface geology confirmed the existence of the structure in the north portion of the Ogarrio field in the NW direction. The geological model mentioned above was based on subsurface interpretation, geology, production data form drilled wells and qualitative and quantitative analysis of well logs. 10
OTATES FIELD TOP OF SAND 14 Figure 7 Top of Sand 14, field Otates 11
OTATES FIELD Structural Section Y 5 Figure 8 Structural Section Y 5, field Otates Based on the correlations performed it was defined that the structural stratigraphic configuration of the Otates field is controlled mainly by twenty two (22) faults, pinch out (wedging) and lateral facies changes. Of the mentioned faults, six (6) are considered as main faults because of the magnitude of displacement and the influence they exert in the accumulation of hydrocarbons; the remaining faults are classified as secondary. The identification of the formations in the type geological column for the field is based on paleontology from cuttings, from some wells and generalized to other wells through correlation of electrical well logs. The traps defined are structural, stratigraphic and a combination of both. Below we show the stratigraphic column for the field Otates: 12
AGE Formation DEPTH (m) THICKNESS (m) Pleistocene Cedral Outcrops 600 Plio Pleistoceno Paraje Solo 600 500 Plioceno Filisola 1100 430 Mioceno Upper Concepcion 1530 120 Mioceno Lower Concepcion 1650 150 Mioceno Encanto 1800 1200 Mioceno Deposito 3000 150 Triásico Jurásico Salt Anhydrite 3150 20 m penetrated Table 3 Typical stratigraphic column, field Otates The geological model for the Sanchez Magallanes field, obtained from the interpretation of 2D seismic lines, is consistent with the geological model obtained from wells. The tops of the Encanto, Lower and Upper Concepcion formations are governed by the structural distribution of salt (formation anhydrite) that is an anticline with a structural high in the north side of the field, at a depth of 1,500 meter below sea level and located between the wells SM 14, SM 5, SM 6 and SM 119. The surfaces of the Encanto, Lower and Upper Concepcion formations are defined by an anticline affected by normal faults and unconformities. The normal faults have a strike direction primarily SW NE and divide the field into four main blocks. The structural high, especially in the tops of Lower and Upper Concepcion formations, stretches fives spaces to the west (Figure 9.) 13
Figure 9 Seismic section, field Sanchez Magallanes The increment of the salt movement, after the sedimentation of the Concepcion formation, created a fault system zone throughout.. The deposits in the field Sanchez Magallanes are structurally compartmentalized and can be broken down into six (6) structural compartments separated by three (3) main fault systems and by salt extrusions that have been affected by the development of salt canopies. 14
SANCHEZ MAGALLANES FIELD TOP OF SAND 28 Figure 10 Top of Sand 28, field Sanchez Magallanes 15
SANCHEZ MAGALLANES FIELD Structural Section Y 20 Location SM 1411 Figure 11 Structural Section of Field Sanchez Magallanes Three (3) areas can be identified in the field: the northern area shows a few sands, generally not in very thick packets, and divided by thick shale layers and the wells are identified by numbers 500s, 600s, 700s and 800s. The southern region is characterized by sands that in general have high clay content; the wells have numbers 400s, 900s and 1000s. The central area is the most prolific with the best quality sands with high potential and the wells are numbered from 2 to 447. 16
The stratigraphic column for the field Sanchez Magallanes is the following: AGE Formation DEPTH (m) THICKNESS (m) Pleistocene Cedral Outcrops 700 Plio Pleistoceno Paraje Solo 700 600 Plioceno Filisola 1300 450 Mioceno Upper Concepcion 1750 250 Mioceno Lower Concepcion 2000 200 Mioceno Encanto 2200 850 Mioceno Deposito 3050 200 Triásico Jurásico Salt Anhydrite 3250 Table 4 Stratigraphic column typical field Sanchez Magallanes 1.4 Drilling Characteristics Recently in fill deviated wells have been drilled in the south area of S. Magallanes and Otates fields. The drilling is normally done in three (3) stages using casing of 20, 13 3/8, 9 5/8, 7 and 6 5/8. Completions are done using production piping of 2 3/8 and 2 7/8 (Table 5 and 6). TYPE Diameter (inches) Depth (meters) Mud (grams/cm3) Line 13 3/8 30 1.08 Intermediate 9 5/8 500 1.10 1.12 Production 7 2850 1.16 1.30 Table 5 Piping utilized in the Otates Field 17
TYPE NORTHERN AREA CENTRAL AREA SOUTHERN AREA Diameter Depth Mud Diameter Depth Mud Diameter Depth Mud (inches) (meters) (g/cm3) (inches) (meters) (g/cm3) (inches) (meters) (g/cm3) Line 20 25 1.15 1.20 13 3/8 30 1.20 20 20 1.08 Surface 13 3/8 305 1.15 1.20 9 5/8 503 1.20 1.27 13 3/8 500 1.08 1.12 Intermediate 9 5/8 1785 1.15 1.20 6 5/8 1975 1.20 1.27 9 5/8 2000 1.12 1.24 Production 6 5/8 3500 1.20 1.63 6 5/8 3850 1.24 1.67 Table 6 Piping utilized in the S. Magallanes Field The bits utilized currently are PDC drill bits that have greatly improved the rate of penetration (ROP) of the tri cones bits. The connections of surface control, preventers used during the drilling and the tree have a capacity of 5,000 lbs/sq in. The average temperature and pressure of the reservoir ranges between 89 92 Celsius and 120 kg/cm2 of pressure respectively. 1.5 Social and Environmental Conditions The current situation of the surface area covered by the Magallanes Block is an environment modified by the replacement of the original vegetation by productive human originated (anthropogenic) which have taken place over the last few years. The predominant vegetation now is pastures and agricultural products for auto consumption. The predominant activity in the area occupied by the field is cattleranching and therefore the soil shows, in general, a certain level of physical biotic degradation of the habitat and there are very few representative communities of native flora and fauna due mainly to the displacement and destruction of natural habitats occurred in the recent past due to human activity. The strict compliance to certain recommendations, listed below, will assure timely and full completion of the operational programs of the exploitation plan to be proposed and will reduce the associated risks generated by socio political conflicts making more feasible the development of project of the Magallanes field re activation. The recommendations are: mitigating measures, the compliance to established legislation, sticking to safety measures, protection and conservation of the environment, the 18
maintenance programs, the policy of zero discharges and the application of programs of sustainable development for the communities through early management and fair and satisfactory negotiations.from socio economic point of view, the re activation of the Magallanes field is expected to cause a great positive impact that will benefit the local economy with the hiring of local labor for services and the utilization of low qualified personnel. 2 Development of the Block 2.1 Seismic 2D and 3D This block is geologically located in the province known Tertiary Basins of the Southeast. It belongs to the Salina del Istmo sedimentary basin which is of the passive marginal type. The tectonic history of the basin is related to two (2) major events: the Laramide orogeny that occurred at the end of the Mesozoic that originated the characteristic NW SE folding of carbonates and the Chiapaneca orogeny (Miocene) that caused mobilization of salt intrusions and dolomitization of the carbonate sequences. In 2005, PEP acquired, using the services of Compañía Mexicana de Exploraciones, S. A. de C.V. (COMESA) a 722 sq km 3D seismic survey named Cabritos 3D that covers the fields included in the block: Otates and Sanchez Magallanes, 19
Figure 2.1 Location of the seismic 3D cubes Antonio Cabritos and Rodador The processing of the seismic information was made through a 3D study named: Union of Cabritos 3D and Rodador 3D, also made using the services of COMESA Compañía Mexicana de Exploraciones, S. A. de C. V. The processing of this seismic project was made in two main stages: 1. Post Stack Migration of the complete Cabritos 3D cube including 200 sq km of the cube Rodador 3D. 2. Pre Stack Time Migration of the complete cube and including 200 sq km of the cube Rodador 3D. The seismic study Cabritos/Rodador 3D covers the southeast portion of Mexico. The northern portion of the study was re processed with the objective to improve the section from previous processing studies. The processing project presented two key difficulties. First the difficulties that emerged during the acquisition of the data due to an irregular grid. Second was the complexity of structural geology of the region that includes structures of anhydrite (calcium sulfate) and salt, commonly found in the Tertiary basins of the SE of Mexico. Despite these factors, the seismic response observed was good during all phases of the project. The post stack processing of all data was completed in 2006. The PSTM phase was completed between December 2005 and May 2006. In general the quality of the data is good; however the first reflections were difficult to pick without ambiguity. Special care was given using a detailed analysis of four (4) velocities, attention and the interaction and collaboration of the Pemex personnel. 20
Seismic Data Acquisition Parameters Below is a list of the parameters of data acquisition and equipment utilized: Source: Dynamite Seismograph: Box Geophones: 30 CT 10 Hz. Longitude of Registration: 8 seg. Sample Interval: 2 mseg. Original Format: SEG D Receiver Line Interval: 450 m Distance between receivers: 50 m Source Line Interval : 550 m Shot Interval 50 m Number of Channels: 1820 Receivers/Swath 10 lines/swath Coverage: 60 Offset Min: 30 m. Offset Max: 5000 m. Anti Alias: 206 Hz. 276 db/oct. Table 2.1 Data Acquisition field parameters for 3D cube Cabritos The topographic coordinates X Y, the altitudes, depth of charges and shot times were recovered from the seismic traces recorded in SEG Y format provided by Pemex. There was no other support information available. Editing o the seismic traces was done manually, record by record, using the interactive software Sageview. Once the correction type Linear MoveOut was applied, consistent stack for shots and receivers were done. The final grid of the 3D study Cabritos/Rodador was 1036 cross lines (E W) by 2180 in lines (N S). The interval between in lines and cross lines is 25 meters. 21
In line Cross line X Coordinate Y Coordinate 1 1 368207.7 1978698 1 1036 359784.4 2003163.6 2180 1036 411292.2 2020897.1 2180 1 419715.4 1996431.5 Table 2.2 Coordinate of the seismic Processing grid Below as an example are shown some of the results of the processing 3D study Cabritos/Rodador Figure 2.2 Inline 1850: stack with DMO 22
Figure 2.3 Inline 1200: Post stack Migration 23
Figure 2.4 In line 1200: Pre stack Migration Figure 2.5 Typical Seismic Section 24
Figure 2.6 Location of the 2D seismic lines in the area 2.2 Wells drilled, shut in, plugged and in production The hydrocarbon reservoirs in the Block are in the Encanto, Deposito formation and to a lesser extent in the Upper and Lower Concepción formations. A total of 775 wells were drilled in this block. As of September 30, 2010, there were 54 active wells, 329 shut in wells, 84 wells pending plugging and 308 25
wells plugged. Currently Sanchez Magallanes has 35 active wells (34 in flowing and 1 on artificial lift) producing at a rate of 3,700 bpd of oil and 4.92 MMcfd of gas. The Otates field has 19 active wells producing at a rate of 3,133 bpd of oil and 8.67 MMcfd of gas (Table 2.3.) Field Active Wells Shut In Pending Plugging Plugged Otates 19 10 10 25 64 Total S. Magallanes 35 319 74 283 711 TOTAL AREA 54 329 84 308 775 Table 2.3 Status of wells as of September 2010 of the block Magallanes 2.3 Drilling Results Below are the results of the drilling activity performed in Otates and S Magallanes fields in the last three (3) years. Year 2007 Well Drilling Duration (Days) Initial Oil Production (BPD) Initial Gas Production (MMcfd) P A P A P A Sánchez Magallanes 1421 27 27 250 200 0.3 0.8 Sánchez Magallanes 1939 30 31 250 63 0.2 0 Sánchez Magallanes 1422 37 26 250 46 0.3 0.1 2009 Sánchez Magallanes 1401 55 26 250 0 0.3 0 2010 Otates 500 40 38 200 358 0.6 0.3 Otates 501 36 30 300 195 0.2 0.04 Otates 502 36 25 300 321 0.2 0.5 Otates 503 18 15 250 302 0.2 0.3 Otates 504 25 29 250 273 0.5 0.5 Otates 505 35 41 250 321 0.5 0.7 Otates 506 35 23 250 201 0.5 0.1 26
Otates 507 35 32 250 264 0.5 0.5 Otates 508 23 28 250 208 0.1 0.2 Otates 509 23 26 250 258 0.0 0.4 Otates 515 36 15 300 0 0.2 2.0 Table 2.4 Drilling activities in the Block Magallanes, Projected (P) vs. Actual (A) 2.4 Well Maintenance Year Well Workover Duration (Days) Initial Oil Production (BPD) Initial Gas Production (MMcfd) P A P A P A Sánchez Magallanes 1434 1 5 312 519 0.3 0.4 Sánchez Magallanes 1009 35 28 100 250 0.1 0.2 Sánchez Magallanes 215Q 30 37 80 215 0.1 0.2 Sánchez Magallanes 1414 1 4 75 179 0.1 0.1 Sánchez Magallanes 216T 27 38 80 49 0.1 0.1 Sánchez Magallanes 1049 2 1 56 20 0.1 0.0 Sánchez Magallanes 227 30 36 75 88 0.1 0.5 Sánchez Magallanes 278 30 23 60 0 0.1 0.0 Sánchez Magallanes 912 59 59 80 0 0.1 0.0 Sánchez Magallanes 924 3 3 50 417 0.1 0.3 Sánchez Magallanes 1912 3 3 60 266 0 0.3 Sánchez Magallanes 329 35 29 80 334 0.1 0.4 Sánchez Magallanes 1402 1 37 50 108 0.1 0.2 Sánchez Magallanes 1039 20 2 40 62 0 0.1 Sánchez Magallanes 955 60 82 100 67 0 0.1 Otates 26 D 38 37 80 0 0.1 3.3 Otates 52 30 28 100 105 0 1 Otates 32 29 7 26 0.1 0 0.1 Sánchez Magallanes 1414 19 28 100 153 0.2 0.2 Sánchez Magallanes 1936 46 99 100 147 0.2 0.1 Sánchez Magallanes 1422 1 1 100 124 0.1 0.2 Sánchez Magallanes 1939 1 2 100 115 0.1 0.1 Sánchez Magallanes 1421 29 2 100 51 0.2 0 Otates 53 8 8 100 310 0.2 0.7 Otates 17 16 17 50 50 0.1 0.1 Sánchez Magallanes 1418 30 24 120 302 0.2 0.4 Sánchez Magallanes 158 30 17 80 110 0.1 0.1 27
Year Sánchez Magallanes 926 30 44 120 145 0.1 0.2 Sánchez Magallanes 951 30 10 120 245 0.2 0.6 Sánchez Magallanes 953 11 9 75 109 0.1 0.1 Sánchez Sá h Magallanes M ll 948 1029 11 1 6 4 50 75 104 85 0.1 01 0.1 01 Sánchez Magallanes 971 30 53 120 26 0.2 0.1 Otates 501 5 8 250 143 0.5 0.2 Otates 14 30 14 100 179 0.2 0.2 Otates 37 D 30 31 75 120 0.1 0.1 Otates 52 6 2 75 0 0.1 0.9 Table 2.5 MAJOR Workovers in the Block Magallanes, Projected (P) vs. Actual (A) Well Workover Initial Oil Initial Gas Duration (Days) Production (BPD) Production (MMcfd) P A P A P A Sánchez Magallanes 214T 15 10 52 46 0.1 0.1 Sánchez Magallanes 272D 13 13 44 29 0 0 2007 Sánchez Magallanes 973 30 41 30 0 0 0 Sánchez Magallanes 924 30 11 30 1 0 0 Sánchez Magallanes 1039 20 35 450 0 0.4 0 Sánchez Magallanes 1401 20 16 0 126 0 0.1 Sánchez Magallanes 273 11 11 50 176 0.1 0.1 2008 Sánchez Magallanes 50D 16 7 42 38 0 0 Sánchez Magallanes 61 18 9 50 52 0 0 Sánchez Magallanes 237 17 17 49 50 0 0 2009 Sánchez Magallanes 237 9 9 50 82 0.1 0 2010 Sánchez Magallanes 953 13 13 40 107 0.0 0.1 Table 2.6 MINOR Workovers in the Block Magallanes, Projected (P) vs. Actual (A) 2.5 Production History The Otates field was discovered in October 1965 with the drilling of the Otates 1 well, which produced 34 API oil and gas from the Lower Miocene Encanto formation at a depth of 2,277 2,284 m. The initial measured production rate was Qo = 250 bopd, Qg = 0.27 mmcfd, GOR =194 m3/m3 flowing through a choke of 3/16 and with Ptp = 58 kg/cm². 28
In 1968 the field reached its maximum production rate of 7,500 bpd of oil from twenty eight (28) wells. The oil production was maintained above 6,000 bpd until 1973 when a steep decline was experienced in all reservoirs. In 1981, water injection was initiated in the depleted reservoirs, which helped reduce the oil decline and obtain increases of almost 3,000 bpd in 1988. Later, there were increases in both the GOR and the water cut to 575 m3/m3 y 60%, respectively. The large volumes of injected water caused increased water saturation in some areas of the reservoirs forcing the closure of some wells because of high water production (Figure 2.7.) 29
Figure 2.7 Historical production behavior for the Field Otates, information as of Sep/30/2010 Exploratory drilling in the field Sanchez Magallanes was started in 1957 with the drilling of Sanchez Magallanes 3 well, which begin production on December 27, 1957. Using a dual completion, it produced oil of 33 API and gas from three (3) sands: 1292 1294, 1248 1251 m (lower zone) with an initial production of 277 bpd, GOR of 98 m3/m3 and TP pressure of 28kg/cm2 and 1167 1183 m (upper zone) with initial oil production rate of 138 bpd, GOR of 86 m3/m3 and TP pressure of 32 kg/cm², all from the Encanto formation of the Lower Miocene. The first phase of the exploitation of the field, between 1957 and 1966, was characterized by a massive drilling program. A total of 383 wells were drilled achieving a maximum production rate of 26,000 bpd of oil and 32.5 MMcfpd of gas. Between 1966 and 1967, a steep production decline was experienced due to presence of paraffin and sand in the wells. This problem was solved by placing sieves and using 30
chemical products. Production was re established and reached 28,000 bpd of oil and 34.0 MMcfpd of gas between 1969 and 1972. Beginning in 1973, the field showed an almost constant decline, with an increase in water production and GOR, until production dropped to 7,900 bpd of oil and 12 MMcfpd of gas. For that reason in 1978 a water injection system was installed for the reservoirs that had experienced the larger pressure drops (depressured wells.) The later observed behavior showed a medium response to the water injection despite the large injected volumes (low efficiency). These strong periodic volumes of injected water may have contributed to the considerable increase in the water cut due to premature emergence of the water in the producing wells. In 1986, six wells were completed in a wet gas reservoir six (6) wells that produced 21 MMcfpd of gas. The reservoir experienced pressure drop and within a year only three (3) wells were producing 5 MMcfpd from the reservoir. The field continued to show a steady decline and the number of active wells decreased until 2003 when an infill drilling program was initiated in the Southern portion of the field which resulted in a small increase in production (Figure 2.8.) 31
Figure 2.8 Historical production behavior for the Field Sanchez Magallanes, information as of Sep/30/2010 2.6 Infrastructure Facilities The infrastructure for management of the production of oil and gas of the fields in the Block is as follows. Otates has a separator (separation battery) and one compressor. It has no dehydration plant. The current production of Otates is 3,133 bpd of oil with a water cut of 21% and 8.67 MMcfpd of natural gas. Sanchez Magallanes has two (2) separators (Magallanes 1 and 7) and an additional four (4) separation batteries not operating (Magallanes 3, 4, 5 and 6). It also has a compression station in operation and an injection plant out of operation. The field currently produces 3,700 bpd of oil with a water cut of 22% and 4.92 MMcfpd of gas. 32
The mixture of oil, gas and water produced by the wells flows, via collection pipes, to the batteries. Gas is separated from the liquids using the two phase separators at a pressure between 2 and 4 kg/cm2 and it passes through a primary rectifier and then to the compression stations. The oil is stored in tanks and then pumped, using oil lines to a dehydration plant in a central gas processing complex named Complejo Procesador de Gas La Venta (CPGLV) located in La Venta, Tabasco. The water is disposed using the water injection plant of the Cinco Presidentes field to be re injected into reservoirs before treatment. The dehydrated oil is measured and pumped to station Palomas. Figure 2.9 Separation batteries for the management of Oil 33
Figure 2.10 Network of principal oil pipeline 34
Below is presented the infrastructure capacity of the Block Magallanes: 35
Table 2.7 Technical Description and Nominal Capacity of Battery OTATES 36
Table 2.8 Technical Description and Nominal Capacity of Battery MAGALLANES 1 37
Table 2.9 Technical Description and Nominal Capacity of Battery MAGALLANES 7 38
Generally each battery has the following equipment: Wellhead from incoming wells Two phase separation and primary rectification Fixed roof storage tanks Pumping Auxiliary services The information on the type and capacity of the compression stations is shown in the table below: Compression Station Quantity Service RECC/BN Capacity Recollection (mmcfd) Capacity Pneumatic Pumping (mmcfd) Otates 5 5 / 0 20 0 S. Magallanes 9 7 / 2 28 40 14 48 40 Table 2.10 Compression Systems 39
Figure 2.11 Compression Stations for Gas Management 40
Figure 2.12 Network of Pneumatic Pumping field Otates 41
Figure 2.13 Network of Pneumatic Pumping NORTH area of field Sanchez Magallanes 42
Figure 2.14 Network of Pneumatic Pumping CENTRAL area of field Sanchez Magallanes 43
Figure 2.15 Network of Pneumatic Pumping SOUTH area of field Sanchez Magallanes 44
2.7 Facilities Management The maintenance of the production facilities of PEMEX is applied in accordance to specific requirements of each type of equipment and function it performs, with the objective of making sure they operate free of failures, avoid risks to the personnel, the installations, the environment and the production at competitive costs and in accordance with the strategic business plan. The Cinco Presidentes Asset, aligned with the strategic objectives of PEP to optimize the resources using improved maintenance systems and processes, installed a system of maintenance administration known as SAM which, using the integration of world class best practices, offers a model for standardization and optimization for maintenance management. The SAM model is supported by four (4) phases of maturity of the maintenance organization, beginning at stage zero, named reactive maintenance. The four phases are: Planned Maintenance Proactive Maintenance Optimal management of the assets Reliability focused design Below, as an example are shown the maintenance plan of the main production facilities of the fields Otates and Sanchez Magallanes. 45
Table 2.11 YEARLY Maintenance Programs for the separation batteries 46
47 Magallanes Block Mature Fields
Table 2.12 MONTHLY Maintenance Programs for the Compression station Otates 48
Table 2.13 MONTHLY Maintenance Programs for the Compression station Magallanes 49
3. Block Potential 3.1 Hydrocarbon Reserves and Cumulative Production As of January 1, 2010 the Sanchez Magallanes field has cumulative Oil production (Np) of 182.6 million barrels and cumulative Gas production (GP) of 201.7 billion cubic feet. Otates field has cumulative Oil production of 34.0 million barrels and cumulative Gas production of 74.8 billion cubic feet. Well spacing ranges from 150 to 400 meters. The certified remaining 3P reserves for the block are 92.7 MMb of oil and 93.4 Bcf of gas. The cumulative production of oil at the same date is 216.6 MMb of oil and 276.5 Bcf of gas. Due to the characteristics of the reservoirs that make up the Otates and Sanchez Magallanes fields and their remaining reserves, this block has a large opportunity for potential development (Table3.1.) Field Reservoir REMAINING RESERVES OIL Original Volume @S.C. Np 1P 2P 3P MMb MMb MMb MMb MMb S. Magallanes Area 400 1000 174.4 32.9 11.4 22.6 22.6 Area 600 700 116.8 11.1 0.2 0.2 32.5 Area central 739.3 138.6 3.2 3.2 32.7 Sub Total 1,030.5 182.6 14.8 26.0 87.8 Otates 213.8 34.0 3.7 4.9 4.9 Total Area 1,244.4 216.6 18.5 30.9 92.7 Field Reservoir REMAINING RESERVES GAS Original Volume @S.C. Gp 1P 2P 3P Bcf Bcf Bcf Bcf Bcf S. Magallanes Area 400 1000 140.5 60.2 13.3 23.6 23.6 Area 600 700 73.3 11.6 0.1 0.1 31.8 Area central 357.1 118.1 3.1 3.1 31.2 Encanto GH 45.7 11.9 Subtotal 616.6 201.7 16.5 26.8 86.6 Otales 485.9 74.8 5.4 6.7 6.7 Total Area 1,102.5 276.6 21.9 33.5 93.3 Table 3.1 Hydrocarbon Reserves and Cumulative Production Block Magallanes as of Jan/1/2010 50