Well RXY is located in Cairn’s Ravva offshore field in the Krishna-Godavari Basin in India. One goal for the field was significant crude production by means of a secondary reservoir section. This paper summarizes key engineering discoveries and technical findings observed during the execution of 200 hydraulic-fracturing diagnostic injection tests in the Raageshwari Deep Gas (RDG) Field in the southern Barmer Basin of India. Reliance Industries and BP are going forward with the expansion of a huge field off the east coast of India that is expected to fill 10% of the country’s energy needs. India Asks Big Oil Companies "Where Do You Want to Drill?" India will test whether it can reach its ambitious goal of reducing oil and gas imports by 10% by 2022 with an upcoming auction of oil properties.
SPE is educating the next generation of aspiring engineers, scientists and managers about the oil and gas industry. This is an opportunity for school students in grades 9–12, studying Mathematics, Physics, Chemistry, Geography or interested in Petroleum Engineering are invited to join SPE members from all over the globe to discover the world of Petroleum Engineering. School teachers are invited to bring a group of 10–15 students. Students will be treated to a range of hands-on activities and presentations from renowned engineers. The oil price outlook coupled with the response of each oil and gas company to make ends meet has led to severe exploration budget cuts.
PETRONAS FLNG SATU (PFLNG1) is a floating liquefied natural gas facility producing 1.2 million tonnes per annum (mtpa) of LNG, on a facility that is 365m long, and 60m wide, making it among the largest offshore facility ever built. The PFLNG1 project is the first of its kind in the world and is the first deployment of PETRONASâ€™ Floating Liquefied Natural Gas (FLNG) technology, consolidating the traditional offshore to onshore LNG infrastructure into a single facility. This will see a giant floating facility capable of extracting, liquefying and storing LNG at sea, before it is exported to customers around the globe. The FLNG journey has come a long way since 2006, with many technological options explored to monetise and unlock the potential of small and stranded gas fields. Moving an LNG production to an offshore setting poses a demanding set of challenges â€“ as every element of a conventional LNG facility needs to fit into an area roughly one quarter the size in the open seas whilst maintaining safety and increased flexibility to LNG production and delivery. The keynote address describes the breakthrough features of PFLNG1 â€“ the worldâ€™s first floating LNG facility; and the pioneering innovation that it brings to the LNG industry.
A hydrocarbon find has always been an exploration geologist’s adventure and has remained at the forefront of the E&P cycle for the survival of the oil and gas industry. Big and easy finds are a distant past; therefore, the quest has shifted to go beyond conventional sandstones and carbonates to more complex areas of unconventionals: low porosity, low permeability, low resistivity, tight and ultra-tight, HPHT, shale, CBM, gas hydrates, and any other possible regime including deeper, geologically complex, and seismically opaque features such as salt, basalt, sub-basalt, even basement.
Dutta, Sandipan (Cairn Oil & Gas, Vedanta Ltd.) | Kuila, Utpalendu (Cairn Oil & Gas, Vedanta Ltd.) | Naidu, Bodapati (Cairn Oil & Gas, Vedanta Ltd.) | Yadav, Raj (Cairn Oil & Gas, Vedanta Ltd.) | Dolson, John (DSP Geosciences and Associates LLC) | Mandal, Arpita (Cairn Oil & Gas, Vedanta Ltd.) | Dasgupta, Soumen (Cairn Oil & Gas, Vedanta Ltd.) | Mishra, Premanand (Cairn Oil & Gas, Vedanta Ltd.) | Mohapatra, Pinakadhar (Cairn Oil & Gas, Vedanta Ltd.)
The Eocene Lower Barmer Hill (LBH) Formation is the major regional source rock in the Barmer Basin rift, located in Rajasthan, India, and has substantial unconventional shale potential. The basin is almost completely covered with 3D seismic, providing an opportunity for more surgical mapping of the rapid structural and stratigraphic changes typical with any syn-rift deposit. Thick sections of organic-rich black shales reaching 400 meters thickness with TOC up to 14 wt. %, were deposited during a period of widespread basin deepening. Algal-rich type I oil prone kerogens dominate in north and generate oil, with very little gas. These shales mature at much lower temperatures than the mixed type I and III kerogens in the south, which also generate much larger amounts of gas and oil, and at higher threshold temperatures. The variable kinetics, as well as rapid facies variations typical of rifts, provide challenges to high-grading and testing unconventional shale plays.
Extensive Rock Eval pyrolysis and source rock kinetic databases were combined with petrophysical analysis to determine log-based porosity and saturations and productive potential. Modified Passey techniques calibrated to NMR log porosities provide estimates of organic richness as well as maturity and shale oil saturation. Basin modeling using Trinity software provides probabilistic ranges of generated and expelled hydrocarbons to determine storage capacity. The modeled oil window storage capacity varies between 6 to 13 MMBOE/km2, comparable to the values observed in Eagle Ford and Barnett Shale plays, but in a rifted basin and not broad cratonic shelf deposits.
Excess pore pressure was modeled using the kinetics of kerogen-to-oil conversion, and is noted in some of the deeper wells in tight sandstones, but not confirmed in the undrilled grabens. These pressure-gradient maps, along with oil properties (viscosity and oil mass fractions) derived from the geochemical model, are used to compute the producibility index. Composited storage capacity and producibility index maps have high-graded potential pilot areas.
In contrast to cratonic shale plays such as the Bakken or Eagle Ford, rapid and substantial facies variations occur due to local input of clastics and variable turbidite geometries which form potential targets for horizontal drilling. Increasingly more detailed paleogeographic maps are highlighting both the challenge and potential of the rich source rock in this basin.
This paper will cover how geochemical, structural, paleogeographic, petrophysical and other data are being used to derisk unconventional potential in this rich and complex rift system. Learnings from future testing of the Barmer Basin shale plays will be important to understand how to develop shale plays in other lacustrine rift basins.
Bhardwaj, Charu (Cairn Oil & Gas, Vedanta Limited) | Ranjan, Vishal (Cairn Oil & Gas, Vedanta Limited) | Jetley, Shailendra Kumar (Cairn Oil & Gas, Vedanta Limited) | Tiwari, Shobhit (Cairn Oil & Gas, Vedanta Limited) | Ghosh, Anirban (Cairn Oil & Gas, Vedanta Limited) | Sharma, Swapnil (Cairn Oil & Gas, Vedanta Limited) | Bohra, Avinash (Cairn Oil & Gas, Vedanta Limited) | Kumar, Abhishek (Cairn Oil & Gas, Vedanta Limited) | Beohar, Abhudai (Cairn Oil & Gas, Vedanta Limited) | Sharma, Sidharth (Cairn Oil & Gas, Vedanta Limited)
The Raageshwari Deep Gas (RDG) field, situated within Barmer Basin in the State of Rajasthan, India, was discovered in 2003. The field is a tight gas condensate reservoir, with excellent gas quality of approximately 80% methane, low CO2 and no H2S. Since the permeability (0.01 - 1 md) is low in this reservoir, hydraulic fracturing is required to get substantial recovery from the wells. The field has been under production since 2010. The development of this field has been carried out in three phases and more than 150 fracturing treatments have been pumped in this reservoir till date to achieve sustained economical production. This paper deals with the lessons learnt and changes implemented in choke design through various development phases of the field.
In the initial phase of field development, chokes with a low Flow Coefficient (Cv) were installed to meet the requirement of controlling the wells at low flow rates and high differential pressure. Later as the surface handling capacity increased, the chokes had to be de-bottlenecked, requiring additional Capex for new chokes. To avoid a similar scenario in the future, a comprehensive approach has been followed to envisage Cv requirement, considering well wise production profiles and surface handling capacities throughout the life of field. Since a single trim can't operate over the complete life-cycle of a well, trim interchangeability has been included in the choke design such that low and high Cv trims are interchangeable.
Pre-mature failures of trims were observed in initial phase and a root cause analysis was done to ascertain the reason. Based on the analysis, trim metallurgy has been changed from Tungsten Carbide to ASTM A276 Specific Stainless Steel Grade 440C. Trims with newly selected mettalurgy have been installed in the existing chokes.
The introduction of trim interchangeability has saved MMUSD 0.3 in the future Opex as the requirement of procuring altogether new chokes for late life period of wells is avoided. Initially failures in the trim bodies were observed as early as two months of commissioning but with the change in metallurgy zero failures have been observed with operational life of chokes being higher than four years. This has avoided significant downtime on wells and expenditure on regular trim changeovers.
Although Tungsten Carbide is one of the most common materials used for constructing trims world over, there could be specific cases where-in other metallurgy may add better value. The workflow followed in this paper will help select a suitable metallurgy and can impart a significant value to the industry.
This seminar covers the fundamental principles concerning how hydraulic fracturing treatments can be used to stimulate oil and gas wells. It includes discussions on how to select wells for stimulation, what controls fracture propagation, fracture width, etc., how to develop data sets, and how to calculate fracture dimensions. The seminar also covers information concerning fracturing fluids, propping agents, and how to design and pump successful fracturing treatments. As the industry wrestles with another price cycle, making sense of the world in which the oil and gas industry will operate is important to understanding the actions (by engineers, corporations, and governments) which must be taken today so that the oil and gas industry may prosper in the future. Hydraulic fracturing has been touted as a ‘new technology’ (though a misnomer) which is opening access to un-tapped value (in the USA) and lowering the cost of energy across the globe by shifting the balance between supply and demand.
By International Petroleum Technology Conference (IPTC) Monday, 25 March 0900-1600 hours Instructors: Olivier Dubrule and Lukas Mosser, Imperial College London Deep Learning (DL) is already bringing game-changing applications to the petroleum industry, and this is certainly the beginning of an enduring trend. Many petroleum engineers and geoscientists are interested to know more about DL but are not sure where to start. This one-day course aims to provide this introduction. The first half of the course presents the formalism of Logistic Regression, Neural Networks and Convolutional Neural Networks and some of their applications. Much of the standard terminology used in DL applications is also presented. In the afternoon, the online environment associated with DL is discussed, from Python libraries to software repositories, including useful websites and big datasets. The last part of the course is spent discussing the most promising subsurface applications of DL.
Bhardwaj, Charu (Cairn Oil & Gas, a vertical of Vedanta Limited) | Ranjan, Vishal (Cairn Oil & Gas, a vertical of Vedanta Limited) | Pathak, Shashank (Cairn Oil & Gas, a vertical of Vedanta Limited) | Tiwari, Shobhit (Cairn Oil & Gas, a vertical of Vedanta Limited) | Tripathi, Archit (Cairn Oil & Gas, a vertical of Vedanta Limited) | Beohar, Abhudai (Cairn Oil & Gas, a vertical of Vedanta Limited)
Raageshwari Deep Gas field situated in southern Barmer Basin of India is a retrograde gas condensate volcanic reservoir. More than 150 fracturing treatments have been pumped in this reservoir to achieve sustained economical production. The paper describes the results of a statistical analysis done to find correlations between production data and fracturing design parameters including petrophysical and geo-mechanical properties of the rock, pre-frac diagnostic tests, and fracturing treatment data including both pumping data and pressure matched parameters.
This paper uses the data from multiple production logs to generate stage wise Productivity Index (PI). This PI data was then cross plotted against various parameters and combinations of parameters such as In-situ proppant concentration, formation porosity, net pay, average stress, proppant mass pumped per stage, fracturing fluid recovery rate and percentage, and fracture dimensions. One interesting line of investigation looked at the rate of pressure decline post Step Rate Test (SRT). A method was developed to evaluate the SRT declines even though they were too short to analyze for permeability using post closure analysis.
This paper presents the results of these statistical analysis and where reasonable correlations were obtained. It also shows that for this volcanic formation, the rate of pressure decline after the SRT is a better indicator of Reservoir Quality (RQ) and future stage performance than the log derived porosity and permeability. While the use of short term fall-off data is only qualitative, it does appear to be an effective tool for evaluating the potential of a stage just before fracturing which would allow improved onsite treatment optimization.
Since the quality of a reservoir generally varies across the areal extent of a field, it is very important to ascertain the same either qualitatively or quantitatively. This paper presents a technique for qualitatively defining RQ, which can be useful to validate the pre-existing workflows used for defining RQ.
Tiwari, Shobhit (Cairn India Ltd.) | Tibbles, Raymond Joseph (Cairn India Ltd.) | Pathak, Shashank (Cairn India Ltd.) | Anand, Saurabh (Cairn India Ltd.) | Agustinus, Yudho (Cairn India Ltd.) | Siddharth, Punj (Cairn India Ltd.) | Goyal, Rajat (Cairn India Ltd.) | Ranjan, Vishal (Cairn India Ltd.) | Shrivastava, Pranay (Cairn India Ltd.) | Bharadwaj, Hindul (Cairn India Ltd.) | Shankar, Pranay (Cairn India Ltd.) | Aihevba, Leste (Cairn India Ltd.)
This paper summarizes key engineering discoveries and technical findings observed during the staged development of a volcanic reservoir. Through out the development, 200 hydraulic fracturing diagnostic injection tests and 168 hydraulic fracturing treatments were performed. This program was conducted in one of the few commercially viable thick and laminated volcanic gas reservoirs in the world and were staggered in 5 separate campaigns over an 11-year period.
Due to the low permeability of this gas reservoir, hydraulic fracturing was necessary for sustained economic productivity. As this massive laminated reservoir contained between 15 to 40 vertically separated pay sections, a key design consideration was to connect as much pay as possible with the least number of fracturing stages.
Although a conventional plug and perforation frac technique gives full assurance of optimal fractures for every bit of pay, the completion cost would undermine the project's economics. Therefore, the limited entry technique was selected. The uncertainties and risks were evaluated to maximize the probability of success.
Both methodologies were applied in successive campaigns. Staggering the project into 5 successive campaigns enabled adequate time to evaluate results, acquire data and execute. The results from these learnings are summarized in this paper.
Over 60 DFITs (Diagnostic Fracture Injection Tests), ~90 SRTs and ~50 Mini-Fracs have been conducted. In addition to conventional fracture diagnostics tests, other techniques were applied with successful implementation. One such example was the utilization of multiple step rate tests within the same frac stage to evaluate limited entry efficiency. As a result of the test data, the number of clusters per frac was increased from 3 to 6, increasing the net pay coverage by about 65%.
Another achievement was the reduction of the uncertainty in tubing friction and the evaluation of tubing friction increase due to the addition of proppant. This resulted in a cost effective method of reducing uncertainties in calculated BHPs, thus improving the overall understanding of fracture geometry. This paper also demonstrates that the integration of all of the collected diagnostic data, temperature surveys, frac simulation and geo-mechanic calibration resulted in increased contribution from more zones which was verified with production logs.
This enhanced reservoir understanding greatly helped to save operational time and reduce cost. Completion improvements have resulted in an 80% increase in productivity and a 20% increase in EUR. Screen out rates have dropped from 33% to 5% between the initial and the most recent campaign.
A holistic workflow for conducting diagnostic injection tests in volcanic pays.
Detailed analysis of limited entry controlled hydraulic fracturing and its efficiency.
Representative case histories including, DFITS, Step rate tests, Mini Fracs, Temperature surveys and production logs to back up the production results.