Jaisalmer: Prospective petroleum and natural gas basin of India

Jaisalmer Basin : An Integrated Exploration Study

(Geological,Geophysical and Fluid Inclusion Stratigraphy Study)

Research Carried By Mr. ALOK SHUKLA 2010JE0419 Mentor: Prof A S Venkatesh Dept. of Applied Geology Indian School of Mines, Dhanbad

Jaisalmer Basin 2

The Jaisalmer basin extends over 30,000 km in southwest Rajasthan. It extends to the Mari region of Pakistan and forms part of the Indus Basin . The basin is controlled by wrench-fault tectonics (Misra et al. 1993) and is divided into four tectonic elements; the Mari-Jaisalmer high shown by the Kanoi and Ramgarh faults , the Shahgarh sub-basin , the Miajalar sub-basin and the monoclinal Kishangarh sub-basin. The lowermost horizon in the Jaisalmer region is the Lathi Formation, which is of Jurassic age and named after Lathi village on the Pokaran-Jaisalmer road . This horizon comprises a fluvial sequence of conglomerate and sandstone. The sandstone comprises several silicified land plant fossils (Das Gupta, 1975). After deposition of the Lathi Formation, a marine transgression occurred and the Jaisalmer basin formed. Marine sedimentation began with the Jaisalmer Formation, followed by the Baisakhi, Bhadasar, Pariwar and Habur Formations. The Tertiary sequence in Jaisalmer basin is represented by the Sanu, Khuiala, Bandah and Shumar Formations.

Tectonic Setting of Jaisalmer Basin and its Evolution : Evolution of sedimentary basins took place in the Barmer, Jaisalmer and Bikaner regions during K-T (Cretaceous-Tertiary) time in western Rajasthan, India. These intra-cratonic rift basins developed under an extensional tectonic regime from early Jurassic to Tertiary time. Rift evolution resulted in alkaline magmatism at the rift margins. This magmatism is dated at 68.5 Ma and has been considered to be an early phase of Deccan volcanism. Deccan volcanism, sedimentary basin development and the alkaline magmatism of western Rajasthan have thus been considered to be the products of Reunion plume

activity. However, sedimentary basin evolution began in western Rajasthan prior to Deccan volcanism and K-T alkaline magmatism. Gondwanaland fragmentation during the Mesozoic caused the development of the rift basins of Gujarat and western Rajasthan. This resulted in the opening of the Jurassic rift system and mildly alkaline magmatism at ca. 120 Ma in western India. This event is pre-K-T and plume activity has not hypothesized for it. Continental fragmentation under an extensional tectonic regime during K-T time resulted in the magmatism and basin tectonism in western Rajasthan. Crustal development during the K-T period in western Rajasthan results from an extensional tectonic regime and is not the manifestation of Reunion plume activity. The northwestern Indian shield has a unique evolutionary history extending from Precambrian to Tertiary time The crust in the region evolved through orogenic, anorogenic, magmatic, and granulite-exhumation phases during Precambrian time. The Phanerozoic geological evolution of this region has largely centered around formation of rift basins in response to global tectonic processes that resulted in separation of the Indian plate from Gondwana during Jurassic and Cretaceous times. The growth and geometry of Mesozoic to Tertiary basins have largely been controlled by NW–SE and NE–SW trending fracture systems.

K-T magmatism in western Rajasthan Mundwara Igneous Complex Coulson (1933) reported a suite of igneous rocks, popularly called the Mundwara igneous complex, west

and northwest of the village of Mundwara in the Sirohi region. This complex contains plutonic, hypabyssal and volcanic members ranging from ultrabasic to alkaline in composition. Srivastava (1988) on the basis of the intrusive nature of rocks at Sarnu and Tavidar into Cretaceous sandstones, proposed a Paleocene age for these rocks. Basu et al. (1993) reported a 68.5 Ma age

Tavidar Volcanic suite Agarwal (1984) described the petrography and geochemistry of the Tavidar volcanics . Upadhyaya et al. (1988), on the basis chemical discrimination, divided the Tavidar volcanics into two groups: a) rhyolite, quartz-trachyte and trachyte, and b) basalts, including hawaiite and mugerite. The distribution behavior of major- and trace elements, and field relationships, indicate that the intermediate and acidic volcanics in the area are cogenetic, whereas the basalts are younger. 40 39 Rathore (1995) reported a Ar/ Ar age of 64-66 Ma for the felsic rocks. The alkaline complex of Sarnu-Dandali The Sarnu-Dandali region is located at the eastern margin of the Cambay-Barmer basin in the Barmer region of Rajasthan . The mildly alkaline igneous rocks (ca 120 Ma,) occur below Lower Cretaceous Sarnu sandstone in the Sarnu region (Chandrasekaran, 1987). Later, a variety of acidic, intermediate and alkaline magmatism took place during K-T time. Basu et al. (1993) reported a mean age of the Sarnu-Dandali alkali pyroxenite of 68.57 ± 0.08 Ma.

-Structural Map of Jaisalmer Basin including all important geological places as well tectonics.

Stratigraphy of Jaisalmer Basin and study of Depositional Environment Litho-stratigraphy of Jaisalmer Basin as well Tectono-magmatic activities related to western Rajasthan.

Jaisalmer Basin : Palaeontological Aspects Ammonites Study of the Jurassic Rocks of Jaisalmer Basin Intensive field works were carried out in the area around Jaisalmer to study different litho‐packages and collect ammonite fauna to establish biozonation. The marine Jurassic succession of Jaisalmer basin has been classified into three distinct formations namely Jaisalmer, Baisakhi and Bedesar Formations in ascending order of antiquity. These are underlain by non‐marine sequence of Lathi Formation The arenaceous non‐marine Lathi Formation is succeeded by calcareous rocks of Jaisalmer Formation which has been subdivided into five members viz., Hamira, Joyan, Fort, Bada Bagh and Kuldhar in ascending order of Superposition. In general, the formation comprises calcarenite, calcareous sandstone, marl, shale and oolitic limestone. The ammonite Clydoniceras of Middle Bathonian age was for the first time reported from the Bada Bagh Member The top Kuldhar Member is the treasure house of ammonite and dated as Early Callovian to Late Oxfordianin age. lowermost three members (Hameera, Joyan & Fort) have not yet yielded any datable fauna (ammonite). The calcareous Jaisalmer Formation is followed upward sequence by siliciclastic sediments of Baisakhi formation. The Baisakhi Formation in general, comprises shale, sandstone, siltstone and ironstone and is subdivided into Rupsi , Lodorva and lanella members in ascending order. The Rupsi and Lanella Members of the Formation contain profuse ammonites and can be dated as Early kimmeridgian to Late Kimmeridgian in age. The middle Lodorva Member is unfossiliferous. BIOSTRATIGRAPHY Jurassic rocks of Jaisalmer are the treasure house of the invertebrate fossils. In the present study only ammonites were taken into consideration because they show shortest vertical range and wide geographical distribution. Other faunas are long ranging. The ammonite first appeared at the top of Bada Bagh member of Jaisalmer Formation (Prasad, 2000) but their profuse occurrences only marked from the basal part of the youngest Kuldhar member of the Jaisalmer Formation. The precise collection of ammonite from different stratigraphic levels enabled the author to propose 11 biozones and 10 subzones from the Middle to Late Jurassic strata of Jaisalmer area. The proposed zones are: Macrocephalites, Reineckeia, Properisphinctes, Peltoceratoides, Mayaites, Dichotomoceras (in Kuldhar Member of the Jaisalmer Formation), Torquatisphinctes(partly) and Katroliceras ( in Baisakhi Formation); Virgatosphinctes, Anvirgatites and Substeuroceras ( in Bedesar Formation) in ascending order.

Brissid echinoid The Khuiala Formation

Age

Formation

Pleistocene to Sub-Recent Middle Eocene

Shumar

Early Eocene

Khuiala

Bandah

Member (Surface)

Member (Subsurface)

Bakhri Tibba Batrewala Limestone Khinsar

Bakhri Tibba Batrewala Limestone

Tetakkar Limestone Palaeocene

Sanu

Cretaceous

Abur/Pariwar

Mohammaed Dhani

Upper Khinsar Sirhera Lower Khinsar Tetakkar Limestone Kharatar Mohammaed Dhani

Description: The specimens are characterized by a large, oval test with mild frontal sinus, convex aboral surface, flat oral surface, highest point of the test at the centre of the test, margin tumid and well rounded. The test is longer than wide and wider than high, truncated towards posterior side and moderately keeled. Apical system anteriorly eccentric, ethmolytic with four small and circular genital pores, the two anterior genital pores are closer than the posterior ones. Paired ambulacra petaloid and flush with the test. Petal III indistinct, petals I & V longer than the petals II & IV. Poriferous zones slightly depressed and consists of inner circular and oval to slit like outer pores which are conjugated by a deep groove. Periproct longitudinally oval, lies on the vertical posterior truncation and not visible from the aboral side. Peristome on oral surface, anteriorly eccentric and kidney-shaped. The peripetalous fasciole passes around the petals and do not indent

in the interambulacral areas. The subanal fasciole, however, is not visible. The test is ornamented with imperforate, non-crenulated tubercles which are sunken in small scrobicules. These are large, scarce and circumscribed by the peripetalous fasciole on the aboral side while orally these are dense and small.

The age of echinoid-bearing horizon of the Khuiala Formation (calcareous sandy marl) is constrained by the presence of index larger foraminifer Assilina lacunata Cizancourt (Srivastava et al., 2008) which indicates an Early Eocene (Ypresian) age.

Ichno Fossils Study of Jaisalmer Basin :

Fluid Inclusion Stratigraphy and its application in Hydrocarbon Exploration Fluid Inclusions

Fluid Inclusions are microscopic bubbles of liqid/gas or both trapped in crystal. As minerals are formed from aquous fluid so there is probability these aquous fluid can be trapped into the crystal structure. Microscopic size Can be found in various environments. Found within cementing material of sedimentary rock In gangue mineral ie Quartz/Calcite as hydrothermal In fossils and in deep of ice beds. Fluid Inclusions are faithful indicators of pore fluid Chemistry and are not subject to Evaporation. Fluid inclusions are indicator of paleo temperature, pressure condition. Can be in form of either liquid , gas or both.

Petroleum Inclusions in source rock and Fluid Inclusion Stratigraphy (FIS) : •Petroleum Inclusions are microscopic traces of past or present-day subsurface fluids that become entrapped in rocks during burial. They are completely encapsulated within their host minerals, hence are distinctive from adsorbed or residual fluids in open porosity. •persist in the geologic record even after the parent fluids have moved on;

FIS : Technique that involves the rapid, complete analysis of fluid inclusions in core or outcrop samples using •Quadrupole Mass Spectrometry •Fluid Inclusion Petrography •Microthermometry •Fluoroscence Microspectrometry •Micro Laser Raman Spectrometry

Quadropole Mass Spectrometry: •After Crushing volatiles are released and dynamically pumped Through QMS. •Molecular comp. are ionised by Electron bombardment & separated According to mass/charge ratio. •Separation occur by radio waves And DC electric field. Electronic multipliers detect the Signals which is processed and Create Mass Spectrum. •Mass Spectrom consists of CO2 CH4, H2S, Alkanes, Heavy organics Benzene/Toluine, H2O

Fluid Inclusion Petrography: •Doubly polished slides are prepared. •Proper interpretation of FI is done by Textural Relationship between FI and Host mineral. •Primary Inclusions: present in form of monophase & Bi phase. Shapes varied from rounded to subrounded. •Secondary Inclusions: must have been developed After complete crystal growth and fluid must have Been trapped between microscopic cracks. Some of the Quartz grain shows cross cutting relationship which can be decided on the basis of intersection. * This gives us TIMING of fluid implacement

On the basis of Petrography multiple Phases of petroleum inclusions are Predicted.

Micro thermometry : provides very specific information on physical properties of fluids, and conditions of entrapment, such as temperature, salinity and API gravity. •Record different phase transition within the primary and secondary hydrocarbon bearing fluid inclusions. Application: •Evidence of liquid petroleum migration. •Defining paleo oil water contact. •Evidence of coexisting oil and gas in a reservoir. •Maximum burial temperature. Example of CH4 Gas : Most of the inclusions consist of methane gas/liq at room temp. few FI also containwater. Around -8 ’ te pheterozenisation was observed in FI rich in methane. On further cooling more liq separated from gas at - 8 ’ . This represe t Triple point methane. And again on heating the Fluid inclusions were homogenised at -85’ temp

Compiled by Prof A S Venkatesh, Dept of Applied Geology (Indian School of Mines, Dhanbad) Fluoroscence Microspectrometry : The main fluorescing components in petroleum are aromatic hydrocarbon, shows fluoroscence from saturated fraction of petroleum with intensity maxima at blue-green colour. •Yellow Bright Colour : lower maturity oils with long chain alkanes/aromatics. •Yellow Green Colour : high maturity oils with more alkanes and less aromatics.

Photo micrograph : Micro photographs Are transportable. •In this pic trails of secondary FI are shifted Due to cementation.

Micro laser Raman Spectrometry : Identify Chemical composition of Fluid Inclusions. Characterisation of molecular structures and to study the effects of Bonding. Plot between Raman Intensity and Raman Shift. Earlier peaks defines Parafins and Aromatics Later peaks are related To CO2. Detect as monophase or Biphase FI. More peaks so it is poly phase inclusion.

Jaisalmer Basin Exploration ( Bankia , Khartar , Ghotaru Field ) 1.Fluid Inclusion Studies of Goru, Parivar Formation : Characterization of Hydrocarbon-bearing Fluid Inclusion in Sandstones of Jaisalmer Trapping of fluid inclusions in the host minerals may occur at different stages of basin development, but were most common in the deeper parts of the earth’s crust. Mostly aqueous fluids were dominating in sedimentary systems, and were actively participating in diagenetic processes. Details of samples selected for the present studyS No.

Well No.

Stratigraphic/ Formation Name

Depth of core within range (m)

Sample location

1

DND-1

Upper Guru and Jaisalmer

1240 -1245 3050-3055

N 27°44'31" E 70°08'15"

2

DND-21

Lower Guru

1921-1925

N 27°46'31" E 70°08'58"

3

TOT-8

Pariwar

2029-2038

N 27°50'56" E 70°12'20"

FLUID INCLUSIONS PETROGRAPHY :

A proper interpretation of fluid inclusions could be made only when textural relationships between fluid inclusions and the host mineral are understood. The primary fluid inclusions as well as secondary fluid inclusions were found in the tiny quartz grains of sandstones. Primary fluid inclusions were best identified by their relationship to growth zonation of a host mineral or crystal. Growth zonation was identified through the, (i) fluorescence (ii) cathodoluminescence and (iii) variations in the distribution pattern of different fluid inclusions trails. Based on the number of the phases present within a fluid inclusion at room temperature (~25 to 28°C) and the nature of origin of fluid inclusions, they can be sub categorized into different types. These fluid inclusions appear to have been developed during lithification or diagenesis. Observed fluid inclusions were mostly found containing hydrocarbon (liquid/ gas) and aqueous fluids (H2O). Aqueous fluids mostly dominate in sedimentary systems, and must have been actively participating in diagenetic processes. The hydrocarbon bearing fluid inclusions appeared yellowish to brownish colour in transmitted light whereas CO2 bearing fluid inclusions have darkish (high relief) and aqueous (H2O) are little faint (low relief), sometimes with small gas bubbles inside the inclusions

Overgrowth of quartz grain in sandstone

Primary fluid inclusions : The primary fluid inclusions were present in the form of monophase as well as biphase. Shapes and sizes of these monophase fluid inclusions were varied from rounded, sub-rounded to circular and within the size range of 01 to 25 µm. The shapes of the biphase fluid inclusions are varied i.e. oval, elongated, rounded, equant to negative crystal cavity and within the size range of 01 to 25 µm. Majority of both the monophase and biphase fluid inclusions were up to 15 µm in size. Carbonic biphase inclusion

Hydrocarbon rich bi phase fluid inclusion

Carbonic bi phase inclusion

The secondary fluid inclusions found in the host quartz grains of sandstone must have been formed after the complete crystal growth of particular grain and fluid generally must have been trapped along the microscopic rehealed cracks ). Depending upon the paleo-temperature and paleo-pressures in sandstone host rock, the secondary fluid inclusions must have been trapped in re healed cracks with different liquid, gas/vapor ratios. A few of the hydrocarbon bearing fluid inclusion might have been trapped during homogeneous conditions, while other fluid inclusions appeared to be trapped under heterogeneous conditions. Some of the quartz grain showed cross- cutting relationship with each other, which was identified on the basis of their continuity and intersection with other trails. Fluid inclusions trapped by re healing of micro fractures typically occurred in planar arrays or along curved arrays that cut across the growth zonation of the primary host quartz. The mono phase and bi phase fluid inclusion range in size from 1 to 25 µm. Majority of fluid inclusion were up to 10 µm in size.

MICRO THERMOMETRY : The main purpose of the study was to observe and record the different phase transitions, within the primary as well secondary hydrocarbon bearing fluid inclusions in quartz grains from different sandstone host rocks. Most of the primary monophase fluid inclusions were dominated by CH4 (gas/liquid) at room temperature (~ 25 to 28°C). The presence of methane was inferred based on its characteristic appearance. A few of the primary monophase fluid inclusions rich in aqueous phase (H2O) were also observed and studied during cooling of gas rich monophase fluid inclusions. Around,-82°C, heterogenization was observed in the said fluid inclusion rich in CH4. During further cooling with the help of liquid nitrogen, more liquid got separated from gas and around, -182°C, liquid, solid and vapour of CH4 coexisted. This represents the triple point of methane On heating (i.e. after stopping of freezing process) the fluid inclusions were homogenized (Th°C) at around, 85°C. Primary biphase hydrocarbon rich fluid inclusions had pseudo-brownian motion at room temperature (~ 25 to 28°C) and gas bubble appeared to be yellowish brown. These fluid inclusions also showed low salinity and low temperature of homogenization, +100 to +150. The frequency of temperature of homogenization of these fluid inclusions and their salinity (primary monophase as well as primary biphase fluid inclusions) The secondary fluid inclusions of monophase nature showed similar characteristic as those of primary monophase hydrocarbon rich fluid inclusions, but indicated slightly higher temperatures of homogenization (Th°C).The temperature of homogenization of this type of fluid inclusions varied from,– 80 to -90°C. The biphase secondary hydrocarbon rich fluid inclusions appear similar to the primary biphase fluid inclusions (CH4 + CO2) but have slightly higher temperature of homogenization, +130°C to +160°C. A few of these fluid inclusions were identified during heating and freezing studies as mixture of H2O- NaCl-CO2. The main features of this type of inclusions are the formation of ‘clathrate’. On cooling of these fluid inclusions, the aqueous phase froze with the formation of tiny dark solid at around, -25°C to -35°C. This is referred to the first freezing/or initiating of freezing. On further cooling the dark bubble collapsed and the entire fluid inclusion was frozen at around, -50°C to -60°C, and no further change was observed. On heating (i.e. after stopping of freezing process) ice present in tiny fluid inclusion starts melting around, -30°C to -40°C, and the final ice crystal melting was recorded in the range of, -4°C to -5°C. The clathrate melting took place around, +8°C to +10°C. Homogenisation of this type of fluid inclusions was observed between, +140°C to +165°C.

FLUORESCENCE MICRO SPECTROSCOPY Fluid inclusions are generally fluorescent if they contain cyclic or aromatic hydrocarbons or fluorescent daughter The relationship between fluorescence and chemical composition of petroleum are highly complex. The main fluorescing components in petroleum are aromatic hydrocarbons. fluorescence from the saturated fraction of petroleum with intensity maxima at low wavelengths in the blue–green range. The fluorescence of the saturated fraction was, however, most probably caused by contamination of minute quantities of aromatic hydrocarbons. The bright yellow fluorescence of the primary fluid inclusions was typical of lower maturity oils with long chain n-alkanes and aromatics.

Exploration for Deeper Unconventional Aquifers The Kharatar, Ghotaru, Manhera Tibba and Bankia area is the most prospective area having possibility of finding reasonably non-saline water aquifer in the depth zone up to 1000m. It is, therefore, suggested that low salinity areas, viz., Kharatar, Ghotaru, Bankia, Manhari Tibba may be considered for further detailing to carry out the intensive study including geophysical survey, drilling and testing of wells and preparation of project plan for exploitation of deep aquifers (up to 1000m) based on the intensive study. Prospectivity of Class – II type of water, defined as moderately saline exists in this area and thickens towards west and southern part. However, it is relatively thinner occurring at shallower depth in the eastern and central part of the basin. The study demonstrates the possibility of using existing knowledge base and vast repository of sub-surface data acquired for oil exploration, in spear-heading future studies and formulating broad strategy for deep seated aquifer investigations on a regional scale.

Application of Fluid Inclusion Stratigraphy In Hydrocarbon Exploration : 1. Identification of Hydrocarbon bearing zone/ pay zone : C1-C13 petroleum species, BTEX compounds, Sulfer bearing H2S, SO2,CS2 and CO2 Are identified and plotted with respect to depth. Individual mass spectrum of each sample is plotted.

2. Proximity to Pay Indicator : Presence of water soluble organic indicates hidden Hydrocarbon zones. Anomalies thought to represent diffusive transport of water soluble organic compounds away from the accumulation through intervals of high water saturation zone , it indicates further exploration in that zone.

3. Seal Identification : Highly cemented nature of seal rocks is reflected by low values of gas production. Seals are identified on the basis of Methane content. If fluid inclusion geo chemistry of two reservoirs are different , they may come through different source rock.

4. Producing vs Non-producing well Fluid Inclusion of well containg plenty amount of CH4, CO2, H2S, Organics called producing well

Well 1- Dark blue Well 2 – Pink Well 3- Yellow Well 4- Sky Blue •As well 3 (yellow colour ) is deficient in the amount of CO2, N2, CH4, H2S •Hence Well 3 is a dry well

5. Fracture Identification in well :

Geophysical Exploration of Jaisalmer Basin :

Our Field of Study are of western Rajasthan in Jaisalmer District near Pakistan Border Bankia Field Ghotaru Field Khartar Field

KHARTAR FIELD 1. Seismic Data Interpretation NW-SE Trending Seismic Sections (from top section to bottom towards SW)

Section#1

Section#2

Section#3

Section#4

Structural Interpretation KHARTAR Field : As in section#1 and section#4, Reservoir Bottom is marked at depth and in section#2, section#3, Reservoir bottom is marked at shallow depth , Hence it is Structural Anticline, with closure NW-SE and associated with faults mainly tending towards eastwards. From time depth conversion reservoir depth in sections is found asSection#1 = 3600 m

Section#4 = 3500 m

Section#2 = 2500 m

Section#3 = 1700 m

Wire-line Logging Data Interpretation : Well K#A

K#B K#C K#D

Zone of Interest (m) 1006-266 787-266 787-00 787-263 268-00 1040-24 1000-268 2424-253 2428-1035 3002-267 2990-984

Type of Log DLL-MSFL-GR-SP-CAL CDS-CDL-GR BCS-GR SGR-Dipmeter SP-GR DLL-MSFL-GR-SP-CAL CDL-CNS-GR-CAL DLL-MSFL-GR-SP-CAL SONIC DLL-MSFL-GR-SP-CAL SONIC

Reservoir Description : Khartar Field has reservoir both in tertiary and Mesozoic sediemnts. STRATIGRAPHY AGE Upper Eocene Eocene

Eocene Eocene Eocene

Mesozoic

Paleocene

Eocene

BANKIA Field : Seismic Data Interpretation :

NE-SW Trend

NE-SW Trend

Graben Type Structure

Formation Evaluation of BANKIA Field: Geological Time Tertiary

Mesozoic

Stratigraphy

Depth

Interpretation

Shumar Bandah

195-255 255-342

Found qualitative but not for hydrocarbon

Khuiala Shanu Parh Lower Goru

342-465 465-612 612-866 1131-1142 1214-1215.5 1218.5-1220.5 1342-1346 1350-1352

Pariwar Fmn

Not reservoir Intervals are interpreted as hydrocarbon bearing

Sands are water bearing

Sand & clay, R=5-7 Compact Lst, R=30-40, increase in resistivity due to compactnes

Ghotaru Field Ghotaru Field is located 100 km NW from Jaisalmer Town and falls in Jaisalmer Mari High Area of Jaisalmer Field. 2.5 km from Ghotaru- Longewala road. 1. Structural Interpretation : Ghotaru field is a domal structure with faults towards east, west and north situated at the western limit of Jaisalmer Mari High. Hydrocarbon accumulation is in multiple pay in Tertiary and Mesozoic sequences and entrapment is mainly structural trap. Ghotaru field is almost a domal fold having faults towards east, west and north at Lower Cretaceous level. At Tertiary level the structure is a doubly plunging anticline with eastern and western limiting faults.

2. Well Log Data Interpretation : Well

Formation

Depth Interval

Interpretation

G#A

Jaisalmer Jaisalmer Jaisalmer Bhadashar Baishakhi Pariwar Goru Goru Sanu Khuiala

3266-3270 3123-3127 2299-2303 2248-2254

Water bearing with salinity 2.92 to 33.345 gpl

G#B

Pariwar Lower Goru Lower Goru

1307-1303 1265-1262 1210-1205

Water bearing with dissolved gas Dry

G#C

Jaisalmer

Water bearing, salinity 146.80 gpl Observed self flow of water

G#D

Jaisalmer Pariwar Lower Goru Lower Goru Lower Goru

2944-2936 2629-2624 2350-2343 1243-1220 1312-1315 1202-1226 1135-1141 1261-1265

Water with salt Oil with gas

G#E

Pariwar Lower Goru Lower Goru

1197-1202 1144-1149 969-975 415-417 366-372

Water zone Gas zone Gas zone Gas zone Gas zone

To be taken up for testing Dry Water bearing Water bearing

3. Stratigraphy and Depositional environment of Ghotaru Field

Conclusion of the study: As according to the seismic section study , wireline logging data interpretation and Fluid inclusion study of Jaisalmer field, the major conclusions are - Jaisalmer basin has prospect of hydrocarbon, as it has structural trap which can form reservoir for accumulation of hydrocarbon, and faulting leads to prove migration mechanism for hydrocarbon. - Stratigraphically Jaisalmer basin contains rocks of Tertiary as well Mesozoic time period which is sufficient time for Hydrocarbon maturation, Hence Goru and Pariwar formation rocks are source rock for hydrocarbon and Shanu, Khuiala, Bandah formations of Tertiary time period are main target zone for exploration. - Fluid inclusion study suggest potential of hydrocarbon presence in fluid inclusions of Goru and Pariwar formation rocks. - Wireline logging data, clearly interpret depth of presence of gas in Bankia, Khartar and Ghotaru field , on matching it with time depth relation the gas zone mainly lies in Tertiary and Mesozoic formation rocks. - With the help of Fluid inclusion study , fracture depth, orientation can be easily found and it can help during hydro fracturing and anisotropic study of subsurface. - Fluid inclusion study can also depict composition of source rock so with help of further studies, exploration of oil/gas or unconventional reservoir can be carried out. - Jaisalmer field is under exploration and Fluid inclusion study signify presence of hydrocarbon source rock , migration of hydrocarbon, tectonic disturbance. Seismic study proves it as structural anticlinal trap with faults which indicate another condition of hydrocarbon occurance. Wireline logging data gives direct significance of presence of Gas in Lower Goru and Pariwar formations of Mesozoic age and in Khuiala, Sanu, Bandah formation of tertiary age, Hence Jaisalmer Basin is the most probable basin for energy requirement of the nation.

Future Prospect: - Fluid inclusion stratigraphy technology can be improved so that real time subsurface fluid inclusion study of formation rock can be done easily along with wire line logging. - Exploration of gas in tight formation is required and exploration of shale gas is major aspect of Jaisalmer field as present reservoirs do not contain natural methane gas. - To exploit Shell gas reservoir , hydro fracturing technology should be focused in Jaisalmer Field.

- Jaisalmer Field has signature of hydrocarbon in deep so deep drilling and exploration is

References: 1. Fluid Inclusion Geothermometry, Prof A S Venkatesh, Dept of Applied Geology Indian School of Mines, Dhanbad 2. Timing diagenesis in the Tartan Reservoir (UK North Sea): constraints from combined cathode luminescence microscopy and fluid inclusion studies, S. D. Burley* Geologisches Institut, Universit~it Bern 3. FLUID INCLUSION STRATIGRAPHY: NEW METHOD FOR GEOTHERMAL RESERVOIR ASSESSMENT PRELIMINARY RESULT (Lorie M. Dilley1, David I. Norman1, and Brian Berard2) 4. Characterization of Hydrocarbon-bearing Fluid Inclusion in Sandstones of Jaisalmer Basin, Rajasthan: A Preliminary Approach (DHANANJAI VERMA1, G. N. JADHAV2, T. K. BISWAL2, S. K. JENA3 and N. SHARMA) 5. Provenance of Late palaeocence sandstone of Jaisalmer basin ( A. Patra, B.P. Singh, V.K. Srivastava) 6. ICHNOFABRIC ANALYSIS OF THE TITHONIAN SHALLOW MARINE SEDIMENTS (BHADASAR FORMATION) JAISALMER BASIN (Bhawanisingh G Desai* and Rajendra Dutt Saklani) 7. Brissid echinoid Eupatagus L. Agassiz, 1847 from The Khuiala Formation, Jaisalmer district (D. K. Srivastava1 and Hukam Singh2) 8. KT magmatism and basin tectonism in western Rajasthan resulted from extensional tectonic and not from reunion of plume activity (Kamal K Sharma)