Gujarat State Petroleum Corporation Ltd

Ghandinagar, India

Gujarat State Petroleum Corporation Ltd

Ghandinagar, India

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Agarwal G.,Schlumberger | Sagar R.,Schlumberger | Behera B.K.,Gujarat State Petroleum Corporation
Society of Petroleum Engineers - International Petroleum Technology Conference 2012, IPTC 2012 | Year: 2012

In any reservoir modeling exercise, accurate estimation of initial water saturation is crucial to determine the in-place hydrocarbon volumes. The water saturation in a reservoir is a function of the reservoir rock quality and the capillary forces present. Pore throat size distribution and rock quality strongly influence the amount of capillary-bounded water and mobile water in the reservoir rock. A good understanding and proper classification of rock types based on reservoir quality is essential for reservoir property population. Also, in absence of the core data, the practice of using single-well models and well logs to identify capillary pressure curves and hence water saturation distribution is not ideal for a vast heterogeneous reservoir with many wells. A case study is presented in which extensive core data, in particular RCA and SCAL results, are analyzed. These results are integrated with petrophysical interpretation to identify different classes of sand units based on the reservoir rock quality and amount of clay present. It is uniquely noted in this work that volume of clay, Vclay: was a better basis for rock classification in this reservoir. A numerical method is used to unify and integrate SCAL data acquired over a 1000-m section of the reservoir in more than 10 drilled wells. Parameterized equations are derived to populate initial water saturation in the static or dynamic model. The water saturations obtained from these parametric equations are subsequently validated with the well log saturations and vice versa. These results are further validated by history matching the drillstem test result, showing excellent results. Copyright 2011, International Petroleum Technology Conference.


Behera B.K.,Pandit Deendayal Petroleum University | Danpanich S.,PTT Exploration and Production Public Company Ltd | Laprabang W.,PTT Exploration and Production Public Company Ltd | Heath G.,Chevron | And 2 more authors.
Oilfield Review | Year: 2012

High borehole temperatures and pressures pose design challenges for engineers developing formation evaluation tools. Pressure and sampling tools that use motors and pumps require high power to operate and often generate considerably more heat than tools used for basic petrophysical measurements. Traditional solutions to combat temperature and pressure are insufficient for these types of tools. Recent innovations make it possible to obtain downhole pressure measurements and samples and to perform extended well tests in extreme conditions. Copyright © 2012.


Khati M.,Halliburton Co. | Pedrosa L.,Halliburton Co. | Farooqui M.Y.,Gujarat State Petroleum Corporation | Khan Z.A.,Gujarat State Petroleum Corporation
Proceedings of the Annual Offshore Technology Conference | Year: 2010

Gujarat State Petroleum Corporation, Ltd (GSPC) recently decided to evaluate a reservoir in an offshore well on the Indian East Coast where the bottomhole temperature was higher than 433°F. The initial DST had shown significant potential for the zone of interest, and, therefore, GSPC decided to perform isochronal testing to obtain more detailed reservoir pressure information. In this environment, the DST tools would be required to function continuously in the high-temperature conditions for more than 16 days to retrieve the required data without interruption. These conditions would definitely challenge the capabilities of the currently available drill-stem testing (DST) equipment. This paper describes how DST tools rated to 450°F-bottomhole temperature and 15,000-psi differential pressure were configured to maintain integrity and successfully evaluate the well. The tools were annulus pressure responsive (APR) and would be operated with pressure applied to the annulus from the surface. The string included a multi-cycle downhole tester valve, a multi-cycle circulating valve, a blowout preventer (BOP) safety valve, a tubing tester valve, a secondary circulating valve, and safety circulating valves. The multi-cycle circulating valve added the flexibility of displacing the string with nitrogen for well stimulation if the well did not flow. The data describes the careful preparation of the tool string, the extreme conditions in which the DST tools had to operate to evaluate the well successfully, and how the meticulously-prepared tool string was capable of meeting GSPC's requirements. The DST tools performed satisfactorily for more than 16 days during the test. This job set a world record for the service company for a reservoir test performed in these high-temperature conditions and may have set a world record for all testing operations perfonned by other service companies as well. Advantages included elimination of coiled tubing, increased safety for this type of operation, and a reduction of rig time compared to other testing jobs. Copyright 2010, Offshore Technology Conference.


Chatterjee R.,Indian School of Mines | Gupta S.D.,Gujarat State Petroleum Corporation Ltd | Farooqui M.Y.,Gujarat State Petroleum Corporation Ltd
Journal of Geophysics and Engineering | Year: 2012

Low-resistivity pay sands have been identified in four wells, namely: AM-7, AM-8, TA-1 and TA-5, which penetrate the Eocene pay-IV (EP-IV) sand unit of the Kalol formation in the Cambay basin. These wells are located near the Dholka and Kanwara oilfields in the Cambay basin. The main objective of this paper is to evaluate nuclear magnetic resonance (NMR) logs of the low-resistivity reservoirs from these four wells and to determine the petrophysical properties more accurately than conventional logs have done. The thickness of low-resistivity sand varies from 5 to 17m in the wells under the study area. The formation has been characterized by a high surface area; thus irreducible water saturation (S wi) is high. The resistivity of these pay zones varies from 1 to 8 m and the total NMR porosity ranges from 15% to 50%. The free fluid porosity ranges from 2% to 5% in wells TA-1 and TA-5 and 12-20% in wells AM-7 and AM-8. The Timur-Coates/SDR model derived that the permeability of the low-resistivity reservoir ranges from 0.8 to 1.5 md in wells TA-1 and TA-5 and 10-110 md in wells AM-7 and AM-8. © 2012 Sinopec Geophysical Research Institute.


Gupta S.D.,Gujarat State Petroleum Corporation Ltd | Chatterjee R.,Indian School of Mines | Farooqui M.Y.,Gujarat State Petroleum Corporation Ltd
Journal of Geophysics and Engineering | Year: 2012

Unconventional reservoirs such as fractured basalts, shale gas and tight sand are currently playing an important role in producing a significant amount of hydrocarbon. The Deccan Trap basaltic rocks form the basement of the Cambay Basin, India, and hold commercially producible hydrocarbon. In this study two wells drilled through fractured basalts are chosen for evaluating the lithology, porosity and oil saturation of the reservoir sections. Well logs, such as gamma ray, high resolution resistivity, litho density, compensated neutron and elemental capture spectroscopy, have been used in cross-plotting techniques for lithology and mineral identification. Formation micro imagery log data have been analysed to quantify the fractures and porosity in the fractured reservoirs for a well in the south Ahmedabad block of the Cambay Basin. The results of the analysis of two wells are presented and discussed and they are found to be in good agreement with geological and production data. © 2012 Nanjing Geophysical Research Institute.


Murthy T.L.N.,Gujarat State Petroleum Corporation Ltd.
Indian Journal of Environmental Protection | Year: 2015

At present statutory regulations are stringent and every oil and gas operating company should strictly carry out their operations abiding to the rules and regulations of environmental statutory bodies. In addition, these statutory bodies have vigilance on all operations, which can cause pollution of natural resources. Effluent treatment plant is a vital tool for oil and gas operating company to treat their discharge with in limits. Dissolved in effluent plant plays vital role for treating of effluent in secondary stage of operations. Maintaining the dissolved oxygen in aeration tank is always a challenge. In addition there are many more things which could stop the increase of dissolved oxygen in aeration tanks and the water coming to aeration tanks is very tough for reducing the biochemical oxygen demand by activated sludge process. Normally in oil and gas water disposal is a challenge for meeting the statutory parameters for disposal. This paper discusses the challenges and significance of dissolved oxygen. ©2015 - Kalpana Corporation.


Gupta S.D.,Gujarat State Petroleum Corporation Ltd | Chatterjee R.,Indian School of Mines | Farooqui M.Y.,Gujarat State Petroleum Corporation Ltd
International Journal of Earth Sciences | Year: 2012

The Cambay Basin is 450-km-long north-south-trending graben with an average width of 50 km, having maximum depth of about 7 km. The origin of the Cambay and other Basins on the western margin of India are related to the break up of the Gondwana super-continent in the Late-Triassic to Early-Jurassic (215 ma). The structural disposition of the Pre-Cambrian basement-a complex of igneous and metamorphic rocks exposed in the vicinity of the Cambay Basin-controls its architecture. The principal lineaments in the Basin are aligned towards NE-SE, ENE-WSW and NNW-SSE, respectively. Rock physics templates (RPTs) are charts and graphs generated by using rock physics models, constrained by local geology, that serve as tools for lithology and fluid differentiation. RPT can act as a powerful tool in validating hydrocarbon anomalies in undrilled areas and assist in seismic interpretation and prospect evaluation. However, the success of RPT analysis depends on the availability of the local geological information and the use of the proper model. RPT analysis has been performed on well logs and seismic data of a particular study area in mid Cambay Basin. Rock physics diagnostic approach is adopted in the study area placed at mid Cambay Basin to estimate the volume in the reservoir sands from 6 wells (namely; A, B, C, D, E and F) where oil was already encountered in one well, D. In the study area, hydrocarbon prospective zone has been marked through compressional (P wave) and shear wave (S wave) impedance only. In the RPT analysis, we have plotted different kinds of graphical responses of Lame's parameters, which are the function of P-wave velocity, S-wave velocity and density. The discrete thin sand reservoirs have been delineated through the RPT analysis. The reservoir pay sand thickness map of the study area has also been derived from RPT analysis and fluid characterization. Through this fluid characterization, oil-bearing thin sand layers have been found in well E including well D. The sand distribution results prove that this methodology has able to perform reservoir characterization and seismic data interpretation more quantitatively and efficiently. © 2012 Springer-Verlag.


Mitra N.K.,Gujarat State Petroleum Corporation | Gupta S.,Gujarat State Petroleum Corporation
Proceedings of the Annual Offshore Technology Conference | Year: 2015

KG basin in the Eastern Offshore region of India is one of the most complex heterogeneous HPHT reservoirs in the world. Gujarat State Petroleum Corporation (GSPC) operator of the Deen Dayal West Field of KG Basin has successfully performed one of the first of its kind Hydraulic Fracturing (HF) job in world under hostile offshore environment and HPHT conditions in complex inter-bedded gas reservoir. The pressure ranged from 11000 psi to 12500 psi and the bottom hole temperature ranged from 350° F to 420° F. This paper deals with designing from scratch and executing hydraulic fracturing stimulation jobs in the said field by GSPC. It shares the results of the jobs and lessons learnt. The reservoir is sandstone with inter-bedded clay with many gas sands having close proximity to water sands. Petrophysical and reservoir data analysis indicated that the tight reservoir had to be stimulated by HF to optimise productivity. The design phase included comprehensive data gathering, log analysis, target zone selection, tailoring of HF design, finalization of specific fluid recipe for each target zone. Extensive petrophysical modelling was done to identify hydrocarbon bearing zones and underlying water bearing zones, thus the potential candidates for HF. The harsh offshore environment off the Eastern Coast of India, posed a huge logistic hurdle and the HPHT conditions led to various technological limitations in frac fluid selection, maintaining rheology at higher temperatures, proppant selection, constricting fluid damaging properties, pumping capability etc. The HF modelling efforts quantified the expected proppant distribution, propped width, individual fluid stage temperatures and the expected treatment pressure. The designs were developed to accommodate about 100 m of effectively propped fracture length (tip to tip). The stress profile and the proximity of the potential water zone around the gas zones were tested with frac design. Along with HF modelling, extensive lab evaluations of rock mechanics, geomechanics, mineralogy (XRD) as well as frac fluid stability and proppant pack conductivity at expected downhole temperature of 400° F were undertaken. Formation cores were extensively tested for core-frac fluid compatibility with regain gas permeability test, Brinell hardness test, etc. to optimise fluid composition. Rock - frac fluid - proppant interaction was studied to measure effect of frac fluid on proppant pack permeability and proppant embedment. The paper aims at providing an insight to the procedures practiced and the technology used for the stimulation of a tight gas offshore reservoir with HPHT conditions. The results and lessons learned from port frac study as shared in the paper would help the operators worldwide to plan and develop a complex offshore HPHT tight gas field. Copyright 2015, Offshore Technology Conference.


Chatterjee R.,Indian School of Mines | Datta Gupta S.,Gujarat State Petroleum Corporation Ltd | Farroqui M.Y.,Gujarat State Petroleum Corporation Ltd
Journal of Petroleum Science and Engineering | Year: 2013

Full stack seismic data in Cambay basin, India, shows limited contrast between sandstone reservoirs and other lithologies. The seismic inversion result has been used here to convert the seismic reflection data into impedance log at each point and the ratio of every point. Wavelet estimations have been carried out for four wells namely, AM-11, AM-12, AM-13 and AM-14 lying between Sanand and Nawagam oilfields located in the Ahmedabad-Mehsana block of Cambay basin. The combination of P-impedance and compressional wave velocity (Vp) to shear wave velocity (Vs) ratio has been used to delineate the pay sand. Reservoir pay sand in Eocene pay formation has been delineated from these wells. The cross plotting technique between Vp/Vs (from four wells AM-11 to AM-14 under the study area) and P-impedance values has differentiated sand and shale. It is observed that the high P-impedance sand is associated with low porosity (15-18%) values while the low P-impedance sand is associated with relatively high porosity (20-25%) values. © 2013 Elsevier B.V.


Rapolu N.,Gujarat State Petroleum Corporation Ltd | Mandal P.,CSIR - Central Electrochemical Research Institute
Journal of the Geological Society of India | Year: 2014

We present the estimated source parameters from SH-wave spectral modeling of selected 463 aftershocks (2002-06) of the 26 January 2001 Bhuj earthquake, the well-recorded largest continental intraplate earthquake. The estimated seismic moment (Mo), corner frequency (fc), source radius (r) and stress drop (Δσ) for aftershocks of moment magnitude 1.7 to 5.6 range from 3.55×1011 to 2.84×1017 N-m, 1.3 to 11.83 Hz, 107 to 1515 m and 0.13 to 26.7 MPa, respectively, while the errors in fc and Δσ are found to be 1.1 Hz and 1.1 MPa, respectively. We also notice that the near surface attenuation factor (k) values vary from 0.02 to 0.03. Our estimates reveal that the stress drop values show more scatter (Mo0.5 to 1 is proportional to Δσ) toward the larger Mo values (≥1014.5 N-m), while they show a more systematic nature (Mo3 is proportional to Δσ) for smaller Mo values (<1014.5 N-m), which can be explained as a consequence of a nearly constant rupture radius for smaller aftershocks in the region. The large stress drops (= 10 MPa) associated with events on the north Wagad fault (at 15-30 km depth) and Gedi fault (at 3-15 km depth) can be attributed to the large stress developed at hypocentral depths as a result of high fluid pressure and the presence of mafic intrusive bodies beneath these two fault zones. © 2014 Geological Society of India.

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