Samana Suk Formation Research Articles

Cathodoluminescence Petrography and Stable Isotope Geochemistry of Carbonate Rocks to Evaluate Diagenetic Evolution of the Middle Jurassic Samana Suk Formation (SSF), Kahi Section, Nizampur Basin, NW Himalayas, Pakistan

Cathodoluminescence Petrography and Stable Isotope Geochemistry of Carbonate Rocks to Evaluate Diagenetic Evolution of the Middle Jurassic Samana Suk Formation (SSF), Kahi Section, Nizampur Basin, NW Himalayas, Pakistan

Reservoir heterogeneities due to diagenesis in Jurassic Samana Suk Formation Kahi section Nizampur Basin North West Himalayas Pakistan

The porosity and permeability determine the reservoir quality of sedimentary rocks, which is fundamentally influenced by both depositional and diagenetic processes. The Jurassic carbonates are targeted in many regions for oil and gas exploration. The current study is carried out to elaborate on the diagenetic alterations and their effect on reservoir properties. A thick outcrop of the Jurassic Samana Suk Formation is studied in the Kahi section of Nizampur Basin Northwest Himalayas, Pakistan, to study and relate the trend of lithological variations and depositional settings. Field investigation revealed that the Samana Suk Formation is extensively distributed in the area and primarily made up of interbedded limestone and dolomite units. The original unaltered limestone has a thick-bedded and oolitic to bioclastic nature. Different types of dolomites have been recognized based on colour contrast and sedimentary features. Moreover, saddle dolomite cement, calcite cementation, and mechanical and chemical compaction have also been observed. The petrographic studies show different types of diagenetic alterations that affected the Samana Suk Formation, including micritization, bioturbation, mechanical and chemical compaction in the form of fractures and stylolites, various calcite cementation, which includes the various cement types that range from isopachous, blocky, granular equant, fibrous, and dog tooth cementation, along with dissolution that occurred in different diagenetic realms. Pyritization was rarely observed. Moreover, different phases of dolomites were identified, ranging in size and shape, i.e., finely crystalline to coarse crystalline and planar euhedral to non-planar anhedral. The stable oxygen isotope values of these dolomites show depletion from original marine signatures and suggest burial-related fault-controlled dolomitization events. Overall, diagenetic processes like dissolution, fracturing and dolomitization increased the reservoir potential. On the contrary, the overburden and cement precipitation result in a decrease in the reservoir properties.

Detailed Investigation of Dolomites in the Middle Jurassic Samana Suk Formation, Kahi Section, Nizampur Basin, NW Himalayas, Pakistan

Detailed Investigation of Dolomites in the Middle Jurassic Samana Suk Formation, Kahi Section, Nizampur Basin, NW Himalayas, Pakistan

Physico-Mechanical and Petrographic Appraisal of Carbonate Rocks as Construction Aggregate: A Case Study from Lesser Himalaya, Pakistan

Owing to the exceptional role of crushed rock aggregates in construction, their prospective reserves fulfilling qualitative and economic parameters should be identified to meet their ever-increasing demand. This research aims to unlock new sources of high-quality construction materials, thereby optimizing concrete performance and meeting the requirement for sustainable building materials. The study investigated the physicomechanical and petrographic properties of Jurassic, Cretaceous, and Eocene limestones of the Kawagarh Formation (KF), Samana Suk Formation (SSF), and Margalla Hill Limestone (MHL) along the Abbottabad–Nathiagali roadside section, as per the American Society for Testing and Materials (ASTM) and British Standards Institute (BSI). The results of geotechnical investigations are flakiness and elongation index (19.6–34.85% and 17.53–31.2%), specific gravity (2.64 to 2.67), water absorption (0.34–0.63%), unconfined compressive strength (41.72–80.65 MPa), loss angeles abrasion value (15.63–19.08%), impact value (15.38–19.36%), and the soundness (0.9–1.97%). These results showed values within the acceptable range according to ASTM and BSI standards. Petrographically, the KF is classified as mud and wackestone, the SSF was mainly classified as wacke-packstone and grainstone, while the MHL was classified as bioclastic wacke and packstone. The dominancy of micrite matrix favors the strength of aggregate, whereas porosity, microfractures, stylolites, and allochems adversely affect the mechanical properties of rock aggregates. Based on reserve estimation, the studied sections possess significant exploitable reserves and are feasible for quarry operations. The studied rocks can be utilized to produce high-strength concrete, optimizing its performance and quality.

Integrated sedimentary and diagenetic constraints for delineating the reservoir potential of Jurassic carbonate sequences in the autochthonous Samana Suk Formation, Attock-Cherat Nizampur Area, Pakistan

Integrated sedimentary and diagenetic constraints for delineating the reservoir potential of Jurassic carbonate sequences in the autochthonous Samana Suk Formation, Attock-Cherat Nizampur Area, Pakistan

Depositional and diagenetic studies of the middle Jurassic Samana Suk Formation in the Trans Indus Ranges and western extension of Hill Ranges, Pakistan: an integrated sedimentological and geochemical approach

Depositional and diagenetic studies of the middle Jurassic Samana Suk Formation in the Trans Indus Ranges and western extension of Hill Ranges, Pakistan: an integrated sedimentological and geochemical approach

Litho- and biostratigraphy and hydrocarbon source-rock potential of the Jurassic–Paleogene strata in the Kala Chitta Range, northwestern Himalayas, Pakistan

In this study Jurassic–Paleogene strata were investigated to understand the litho- and biostratigraphic framework and hydrocarbon source-rock potential of various stratal packages. Biostratigraphic controls were used to establish the chronostratigraphic framework of Jurassic–Paleogene strata in the area. The Lower Jurassic (Hettangian) clastics saw an unconformity during the Sinemurian–Pliensbachian, while the Lower Jurassic (Toarcian)–Middle Jurassic (Bajocian) clastic–carbonate mixed strata is also separated by a Bathonian unconformity from the Middle Jurassic (Callovian) to the Upper Jurassic (Tithonian) carbonate sequence. The Upper Jurassic Oxfordian strata are missing, while the Upper Jurassic (Kimmeridgian)–Lower Cretaceous (Valanginian) glauconitic sandstone and clays are the conformable sequences. The Lower Cretaceous (Hauterivian)–Upper Cretaceous (Turonian) clastics is a conformable sequence that is separated by a Coniacian–Santonian unconformity from the Upper Cretaceous (Campanian) pelagic carbonates. The Cretaceous–Tertiary boundary is marked by laterites, while the Paleocene (Thanetian) sequence is represented by a shale- and sandstone-dominated sequence. The Paleocene (Thanetian)–Early Eocene (Ilerdian) siliciclastic–carbonate mixed sequence marks the last episode of Tethyan sedimentation. Total organic content (TOC), organic petrography and Rock-Eval pyrolysis (REP) techniques were used to evaluate the hydrocarbon source-rock potential, kerogen type and level of maturity of the hydrocarbons. The majority of studied samples show the occurrence of type IV kerogen. However, the Middle Jurassic (Callovian)–Upper Jurassic (Tithonian) carbonate sequence of the Samana Suk Formation, the Kimmeridgian–Valanginian Chichali Formation, the Paleocene (Thanetian) sequence of the Hangu Formation and the Paleocene (Thanetian)–Early Eocene (Ilerdian) Patala Formation confirms the Type III kerogen, poor–fair source-rock quality, immature–mature, gas- and oil-prone indigenous hydrocarbon occurrence in the region.

Assessment of Potential Alkali-Carbonate Reactivity and Petrographic Analysis of Limestone from Samana Suk Formation Dhamtaur Area, District Abbottabad, Pakistan to Use as Aggregate

A detailed Limestone from the Samana Suk Formation in Dhamtaur, Pakistan, was studied to assess itspotential as a construction aggregate. The limestone contains variable amounts of dolomite, which can be harmful toconcrete. Petrographic analysis and ACR tests showed that the dolomite content is low and the limestone has low alkalireactivity. Engineering laboratory tests confirmed that the limestone meets ASTM and AASHTO standards foraggregate properties. Therefore, the limestone from Dhamtaur can be used as an aggregate in concrete and asphaltworks. The results of the engineering laboratory tests indicate that limestone from the Samana Suk Formation, locatedin the Dhamtaur area, exhibits specific gravity (2.84g/cm3), water absorption (0.0781%), Los Angeles abrasion value(20%), and sulfate soundness (2.23%). These findings strongly support the viability of utilizing these rocks asaggregate, aligning with the established standards of ASTM and AASHTO. A petrographic examination indicates thepresence of dolomite in a minor proportion (2-15%) with a Porphyrotopic-S type texture. Analysis of ACR resultsdemonstrates a slight expansion in the limestone (0-0.01%), implying low reactivity to alkali. Consequently, it isreasonable to propose the utilization of these rocks as a source of aggregate in concrete and asphalt projects.

Sedimentological Attributes of the Middle Jurassic Samana Suk Formation Exposed in Village Rani-Wah Haripur, Southern Hazara Basin (NW Himalayan Fold and Thrust Belt, Pakistan)

Sedimentological Attributes of the Middle Jurassic Samana Suk Formation Exposed in Village Rani-Wah Haripur, Southern Hazara Basin (NW Himalayan Fold and Thrust Belt, Pakistan)

Sedimentology and reservoir characteristics of Jurassic Samanasuk Formation of Salt Range and Hazara areas, Upper Indus Basin, Pakistan

Sedimentology and reservoir characteristics of Jurassic Samanasuk Formation of Salt Range and Hazara areas, Upper Indus Basin, Pakistan

Sedimentological, Diagenetic, and Sequence Stratigraphic Controls on the Shallow to Marginal Marine Carbonates of the Middle Jurassic Samana Suk Formation, North Pakistan

This study presents a thorough analysis of the sedimentology, diagenesis, and sequence stratigraphy of the Middle Jurassic Samana Suk Formation in the Hazara Basin of northern Pakistan. Focusing on two sections, namely Mera Rehmat and Por Miana, the research aims to unravel the complex geological processes within the formation. The examination of microfacies reveals nine distinct depositional textures, ranging from mudstone to wackestone, packstone, and grainstone, indicating various inner ramp environments such as open marine, lagoon, and coastal settings. Petrographic investigations shed light on diagenetic processes, including micritization, cementation, dissolution, compaction, neomorphism, and dolomitization. Six cementation types are identified, and the dolomitization patterns vary, providing insights into lagoonal environments and mudstone replacement. Sequence stratigraphic analysis uncovers intriguing patterns within the Samana Suk Formation. The high-stand system tract is characterized by mudstones, pelloidal grainstones, and dolomitized mudstones, indicating periods of high sea level. In contrast, the transgressive system tract displays ooidal grainstones, pelloidal packstones, and pel-bioclastic grainstones, representing transgression and inundation of previously exposed areas. A significant finding is the impact of diagenesis on reservoir quality parameters, specifically porosity, and permeability. Diagenetic processes, cementation types, and dolomitization patterns have significantly altered the pore network, highlighting the importance of considering diagenesis in assessing the Samana Suk Formation as a hydrocarbon reservoir. This research provides a comprehensive understanding of the sedimentology, diagenesis, and sequence stratigraphy of the Middle Jurassic Samana Suk Formation. The findings contribute to our knowledge of similar carbonate reservoirs globally, enhancing the exploration and development of hydrocarbon resources in comparable depositional environments.

Processes Associated with Multiphase Dolomitization and Other Related Diagenetic Events in the Jurassic Samana Suk Formation, Himalayan Foreland Basin, NW Pakistan

Foreland fold and thrust belts always represent a complex diagenetic history of carbonate succession, particularly multiphase dolomitization, due to the multi-sourcing nature of fluids affecting syn-to post-depositional successions. The present work documents a comprehensive study on the diagenetic changes, particularly dolomitization patterns in the Jurassic carbonates (Samana Suk Fm) in the Lesser Himalayan fold and thrust belt, NW Pakistan. To better understand the processes involved, integrated field/petrographic, geochemical, isotopic, and micro-thermometric studies were carried out. Field observations indicate that dolostones appear as light grey to brown stratabound and patchy units within the formation. Petrographic analysis reveals that fabric destructive matrix dolomite (RD-I) and fabric preserving replacive dolomite (RD-II) phases are present as distinct units. In addition, saddle dolomite cement (SD) and fracture-filling calcite (CC) are also observed in association with replacive dolomite cement. Geochemical analysis (EPMA) showed that Fe, Mn, and Ba concentrations in matrix dolomite are relatively less than those of replacive/saddle dolomite and fracture-filling calcite, suggesting a hydrothermal source of replacive/saddle dolomite in reducing conditions. Furthermore, stable isotope studies of RD-I showed non-depleted δ18O values, which represent coeval seawater signatures of Jurassic carbonates. RD shows depleted δ18O values and non-depleted δ13C, respectively, indicating burial or elevated temperature of dolomitization. Fracture-filled calcite represents lighter δ18O values and δ13C, indicative of relatively high temperatures. 87Sr/86Sr ratios of all diagenetic phases range from 0.707718 to 0.710747, showing more radiogenic values indicates interaction fluids with more radiogenic sources. Fluid inclusion micro-thermometry data of saddle dolomite shows TH ranging from 102.8 to 186 °C, and salinity ranging from 11.7 to 19.4 eq. wt.% NaCl, suggesting hot saline brines are responsible for the dolomitization. Fracture-filling calcite shows TH ranging from 68.0 to 98.4 °C and salinity ranging from 6.9 to 13.1 eq. wt.%. NaCl suggests moderately hot and saline solutions are responsible for their formation. In conclusion, the above-mentioned studies indicate two distinct processes of dolomitization are involved in the formation of matrix and replacive/saddle-type dolomites. RD-I has formed in the evaporative setting, whereas RD has formed due to the interaction of hydrothermal fluids during burial. Fracture-filling calcite is produced from hot subsurface solutions during uplift related to the Himalayan orogeny.

Facies Analysis, Sequence Stratigraphy and Diagenetic Studies of the Jurassic Carbonates of the Kohat Basin, Northwest Pakistan: Reservoir Implications

AbstractThe present study deals with the depositional facies, diagenetic processes and sequence stratigraphy of the shallow marine carbonates of the Samana Suk Formation, Kohat Basin, in order to elucidate its reservoir quality. The Samana Suk Formation consists of thin to thick‐bedded, oolitic, bioclastic, dolomitic and fractured limestone. Based on the integration of outcrop, petrographic and biofacies analyses, the unit is thought to have been deposited on a gentle homoclinal ramp in peritidal, lagoonal and carbonate shoal settings. Frequent variations in microfacies based sea‐level curve have revealed seven Transgressive Systems Tracts (TSTs) and six Regressive Systems Tracts (RSTs). The unit has undergone various stages of diagenetic processes, including mechanical and chemical compaction, cementation, micritization, dissolution and dolomitization. The petrographic analyses show the evolution of porosity in various depositional and diagenetic phases. The fenestral porosity was mainly developed in peritidal carbonates during deposition, while the burial dissolution and diagenetic dolomitization have greatly enhanced the reservoir potential of the rock unit, as is further confirmed by the plug porosity and permeability analyses. The porosities and permeabilities were higher in shoal facies deposited in TSTs, as compared to lagoonal and peritidal facies, except for the dolomite in mudstone, deposited during RSTs. Hence good, moderate and poor reservoir potential is suggested for shoal, lagoonal and peritidal facies, respectively.

Aggregate Evaluation and Geochemical Investigation of Limestone for Construction Industries in Pakistan: An Approach for Sustainable Economic Development

The present study investigates the aggregate suitability and geochemical characteristics of limestone (LS) from the Samana Suk Formation, Pakistan, for the construction industry. With the advent of CPEC, the demand for construction materials has seen a manifold increase. The Sheikh Budin Hills and Trans Indus Ranges comprise huge deposits of limestone and provide great potential for source rocks for construction materials in the region. In the Upper Indus Basin of Pakistan, the Samana Suk Formation is acknowledged as the most significant carbonate deposits of Mesozoic strata. The results of aggregate parameters reveal that specific gravity (SG = 2.6); water absorption (WA = 0.47%); bulk density (BD = 1.58 g/cm3); flakiness index (FI = 16.8%); elongation index (EI = 16.39%); soundness (S = 1.6%); aggregate impact value (AIV = 14%); Los Angeles Abrasion value (LAAV = 23.51%); clay lumps (CL = 0.35%); uniaxial compressive strength (UCS = 86.7 MPa); point load test (PLT = 5.18 MPa); ultrasonic pulse velocity (UPV = 5290 m/s); and Schmidt hammer rebound test (SHRT = 49 N) are in accordance with the ASTM, ISRM, and BSI. Petrographically, the LS is dominantly composed of ooids, peloids, bioclasts, and calcite mineral (CaCO3) with a trace concentration of dolomite [(Ca,Mg)CO3]. The mineralogical and geochemical study (n = 18) revealed that the LS is dominantly composed of calcite (95.81%); on average, it is composed of 52.08 wt.% CaO; 1.13 wt.% SiO2; 0.66 wt.% MgO; 0.80 wt.% Al2O3; and 0.76 wt.% Fe2O3, and loss on ignition (LOI) was recorded as 42.13 wt.%. On the other hand, P2O5, TiO2, MnO, K2O and Na2O were found in trace amounts. The regression analysis demonstrated that the empirical correlation equation for estimating uniaxial compressive strength with ultrasonic pulse velocity is more reliable than the Schmidt hammer rebound test and point load test. Consequently, the feasibility of using LS of the Samana Suk Formation as an aggregate for construction materials and cement manufacturing is recommended based on the testing results of mechanical, physical, and geochemical properties.

STRUCTURAL ANALYSIS AND RESERVOIR CHARACTERISATION OF CRETACEOUS SEQUENCE IN KOHALA BALA, KHYBER PAKHTUNKHWA, PAKISTAN

The southeastern Hazara is a portion of the Himalayan Fold-Thrust Belt, formed by the interaction of the Indian Plate with the Eurasian Plate. The present research was conducted to analyse the structural geometry and assess the reservoir potential of the Cretaceous sequence (Chichali Formation and Kawagarh Formation) in southern Hazara, Pakistan. The mapped stratigraphic units range from Late Jurassic, Samana Suk Formation to early Eocene, Margalla Hill Limestone, along with unconformities. The research area is under intense deformation and is characterised by the thrust faults with accompanying folds. The fore-thrust faults are steeply dipping towards the north with associated back-thrust dipping southward, and the folds are mainly asymmetric anticlines and asymmetric synclines along with symmetric anticline (Barkot). The structures trend mainly NE-SW, indicating NW-SE compressive stresses. Reservoir quality is evaluated by using petrographic image analysis, SEM analysis, plug porosity, and permeability analysis. The porosity observed varies from 0.282% – 10.89%, 0.016% – 1.78% in Chichali (Sandstone) Formation and Kawagarh (Limestone) Formation, respectively. Simultaneously, the measured permeability in Chichali and Kawagarh Formation varies from 0–0.064 mD and 0–0.014 mD, respectively. The primary porosity type was intergranular/interparticle, intragranular, fracture, and vuggy porosity. SEM analysis shows that microporosity is present in the Cretaceous sequence and, calcite, dolomite, quartz, feldspar, and pyrite are the major minerals. The reservoir studies show that the Chichali Formation can be proven a good (Tight) reservoir rock, and Kawagarh Formation may prove as a reservoir (if the fractures in the subsurface, formed by severe tectonic deformation are not filled with cementing material) and seal/cap rock.

Petrography and Geochemistry of Dolomites of Samanasuk Formation, Dara Adam Khel Section, Kohat Ranges, Pakistan

Replacement dolomite occurs in Jurassic Samanasuk Formation in Dara Adam khel area of Kohat ranges, North-Western Himalayas, Pakistan. This study, for the first time, document the process of dolomitization and evolution of strata bound dolomitic bodies. Field investigation, petrography and geochemistry helped in unraveling the formation of several dolomitic bodies. Petrographically dolomites comprises of: (1) medium grain crystalline planer subhedral dolomite (Dol-I); (2) fine grained crystalline anhedral non-planer dolomite rhombs (Dol-II); (3) medium to coarse grained crystalline subhedral-anhedral non-planer dolomite (Dol-III) and coarse to very coarse grained crystalline saddle dolomite cements (SD). The saddle dolomites (SD) postdate the replacement dolomites and precede telogenetic calcite (TC) cements. Stable O and C isotope analysis shows that these dolomites have δ18Ovpdb ranging from -4.09% to -10.4 whereas the δ13Cvpdb ranges from +0.8 to +2.51. Major and trace elements data show that Sr concentrations of 145.5 to 173 ppm; Fe contents of 2198 to 8215 ppm; and Mn contents of 93.5 to 411 ppm. Petrographically replacive dolomites, saddle dolomite, and δ18Ovpdb values depicts neomorphism of replacement dolomites that were formed earlier were exposed to late dolomitizing fluids. As a result of basin uplift during the Himalayan orogeny in Eocene time, dolomitization event was stopped through occurrence of meteoric water. The Main Boundary Thrust (MBT) and its splays were most likely essential conduits that channelized dolomitizing fluids from siliciclastic rocks that were buried deeply into the Jurassic carbonates rocks, leading to more extreme dolomitization.

An integrated approach to evaluate the hydrocarbon potential of Jurassic Samana Suk Formation in Middle Indus Basin, Pakistan.

The Indus Basin is considered as prolific hydrocarbon-bearing province of Pakistan. The study area is located in the Middle Indus Basin. Two wells (Bagh-X-01 and Budhuana-01) were drilled in the vicinity of the study area to determine the hydrocarbon potential of the area. Both wells show no hydrocarbon reserves and are thus abandoned. The present study emphasizes two-dimensional subsurface seismic interpretation and rock physics evaluation to estimate reservoir properties of the Jurassic Samana Suk Formation. Data from nine 2-D seismic lines and two wells have been utilized to evaluate the potential. The time contour maps indicate the existence of subsurface structural features in the study area. With the help of the 3-D geological model, the faults are marked in the Samana Suk Formation and the structure is identified as a monocline. The 3-D geological modeling results also reveal that Samana Suk Formation tends to become thin in the northeast, and thick in the southwest. The petrophysical interpretation was performed to find the hydrocarbon potential of the Formation. The cross plot between P-impedance and Vp/Vs ratio shows that the lithology cannot be differentiated by the logs. Rock physics parameters such as Poisson’s ratio, bulk modulus, shear modulus, shear wave velocity, primary wave velocity, Vp/Vs ratio, and density indicate that there are no considerable hydrocarbon reserves in the Samana Suk Formation.

Seismic Data Interpretation and Petrophysical Analysis of Kabirwala Area Tola (01) Well, Central Indus Basin, Pakistan

Well logging is a significant procedure that assists geophysicists and geologists with making predictions regarding boreholes and efficiently utilizing and optimizing the drilling process. The current study area is positioned in the Punjab Territory of Pakistan, and the geographic coordinates are 30020′10 N and 70043′30 E. The objective of the current research work was to interpret the subsurface structure and reservoir characteristics of the Kabirwala area Tola (01) well, which is located in the Punjab platform, Central Indus Basin, utilizing 2D seismic and well log data. Formation evaluation for hydrocarbon potential using the reservoir properties is performed in this study. For the marked zone of interest, the study also focuses on evaluating the average water saturation, average total porosity, average effective porosity, and net pay thickness. The results of the study show a spotted horizon stone with respect to time and depth as follows: Dunghan formation, 0.9 s and 1080.46 m; Cretaceous Samana Suk formation, 0.96 s and 1174.05 m; Datta formation, 1.08 s and 1400 m; and Warcha formation, 1.24 s and 1810 m. Based on the interpretation of well logs, the purpose of petrophysical analysis was to identify hydrocarbon-bearing zones in the study area. Gamma ray, spontaneous potential, resistivity, neutron, and density log data were utilized. The high zone present in the east–west part of the contour maps may be a possible location of hydrocarbon entrapment, which is further confirmed by the presence of the Tola-01 well.

Microfacies Analysis and Depositional Environment of Middle Jurassic Samana Suk Formation, Chichali Nala Section, Surghar Range, Pakistan

The Middle Jurassic age Samana Suk Formation, exposed in Chichali Nala section of Surghar ranges has been investigated by field work, petrographic study and XRD analysis to understand the microfacies, depositional environment and fault related dolomitization of the Samana Suk Formation. This formation is widely distributed in the upper Indus basin of Pakistan and considered the most prominent stratigraphic unit of the Jurassic period. The project area lies in the Chichali Nala Section of Surghar range (Trans Indus Salt Ranges). In this section, Samana Suk Formation constitutes the lithology of carbonate having CaCo3 as a major mineral, where dolomite is present in minor amount, which is restricted to fluids along fault zone. During the study two major microfacies have been identified including the Grainstone microfacies and Mudstone-Wackestone microfacies. Samana Suk. Formation was formed under stormy influence in the environment of deposition of Formation. Its depositional environment is the inner-middle shelf which suggests the marine shelf depositional environment.

Source Rock Potential of Chichali and Samana Suk Formations Deposits in Panjpir Oilfield Subsurface, Punjab Platform, Pakistan

By using total organic carbon (TOC) and Rock-Eval pyrolysis analysis measurements, the hydrocarbon source rock potential of Chichali and Samana Suk formations found in the subsurface of Panjpir oilfield in Punjab platform located in the eastern part of the middle Indus Basin was investigated. Twenty two core samples were collected from producing well. The analysed samples of Chichali formation contains TOC ranging between 0.99-4.61 wt.% having average TOC of 1.51 wt.% and the S2 values of Rock-Eval show the poor to fair generative potential with values ranging from 0.99-3.08 mg HC/g rock. The samples have low hydrogen index values ranging from 21-302 mg HC/g TOC and also most of the samples have low T_(max ) values ranging from 422-432 °C and have OI values ranging from 15-82 mg CO2/g TOC. Samana Suk formation samples have TOC ranging between 0.28-1.38 wt.% having average TOC of 0.84 wt.%. S2 values of Rock-Eval shows poor generative potential with values ranging from 0.05-2.99 mg HC/g rock. The samples have low hydrogen index values ranging from 13-322 mg HC/g TOC and T_(max) values ranging from 423-435 °C, and have OI values ranging from 41-182 mg CO2/g TOC. On the basis of analysis performed only one sample from Chichali and five samples of Samana Suk formations have entered early maturity zone, while all remaining samples lie in immature zone as indicated by HI vs T_(max) plot. HI vs OI plot and HI vs T_ (max) indicates the presence of kerogen Type III. All of the samples from Samana Suk formation shows poor generative potential as compared to Chichali formation having fair generative potential as indicated by S2 vs TOC plot. Hence, from the results some minor gas could be expected to have been generated from Chichali formation in Panjpir oilfield subsurface.