Welcome To SPWLA - India Chapter

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ONGC is eyeing more value from new-generation technologies and tools, which will, thus, see more use in ONGC’s Logging operations. This emerged during an interactive and informative one-day seminar on ‘New, Emerging and Future Technology in Wireline Logging and LWD’, organized by ONGC’s Logging Services at Mumbai.

Chief Logging Services Mr. Chatar Singh, while delivering the welcome address, informed that “the present seminar has been planned as a sequel to the Key Executives’ Meet held at Dehradun in which C&MD Mr. Subir Raha advised all the Service Chiefs to sign-off the obsolete technology and use only the best to get the best results”. While acknowledging the benefits of the high-end technologies like high-resolution resistivity tools, cased hole formation resistivity (CHFR) for reservoir monitoring and detection of bypassed oil and NMR (Nuclear Magnetic Resonance) tools for lithology independent porosity measurements, the Logging Chief drove home the fact that the induction of the new technology in onshore fields has not yielded substantial gains as compared to offshore.

Chief Drilling Services Mr. U N Bose, the chief guest on the occasion, apprised the gathering on the status of ‘Sagar Samriddhi’, wherein ONGC has drilled six ultra-deep water wells, two deep-water wells and two moderate deep-water wells and hopes to strike fortune soon. Mr. Bose said that “the issues facing ONGC today are deepwater exploration and managing mature fields production decline in a manner that maximizes NPV without lowering ultimate recovery. As more and more large and easy to find reservoirs stand discovered and exploited, the focus continues to shift to more difficult and marginal reservoirs. The dynamics of such a changing scenario keeps triggering the improvement in the state-of-the-art technology to meet the impending challenges effectively”.

Commenting on logging techniques (wire-line and non wire-line), the Drilling Chief emphasized that it commands a premier place in management decision-making because it can provide best details of reservoirs and accurately define the hydrocarbon bearing intervals and their commercial viability.

The seminar clearly defined the need for shifting to imaging tools, realizing the need to unravel smaller, thinner fracturing of low quality reservoirs, which previously had often been poorly rated (economically) and by-passed. While focusing on logging tools like EMI (electrical Micro Imaging), FMI (formation Micro Imager), USIT (Ultrasonic Imager), have yielded results, the new generation of NMR tools have added value to porosity measurements.

Technical presentations of Mr. Michael Claverie, Principal Petrophysicist, Mr. Theodore Klimentos, Principal Petrophysicist, and Mr. Iwan Roberts, Senior LWD (Logging-While-Drilling) interpretation engineer from Schlumberger, were highly informative and thought-provoking, providing a panoramic view of the latest tools for wireline logging and LWD.

The presentations focused on new tools like MRX (Magnetic Resonance eXpert), which provides information on producing capacity of the reservoir; EMI (Electrical Micro Imaging) providing interwell resistivity between two wells and MDT (Modular Formation Dynamics Tester) providing efficient, accurate determination of permeability. The participants were updated on the latest technologies and its benefits through use of CHDT (Cased Hole Drilling Technology), CHFD (Cased Hole Formation Density), CHFP (Cased Hole Formation Porosity), SCMT (Slim Cement Mapping Tool), FSI (Flow Scan Imager), MaxTRAC, PMIT (Platform Multifinger Imaging Tool) and PURE (Perforate for Ultimate Reservoir Management).

(ONGCians from various regions enthusiastically participated in discussions during the Meet, along with presenters from M/s Schlumberger and Baker Hughes)

The emerging technologies like MSIP (Modular Sonic Imaging Platform), Triaxial AIT (Triaxial Array Induction Tool) and XPT (The Pressure Xpress Tool) were further discussed at length along with interpretation techniques like Formation Evaluation in Horizontal Wells, Elemental Spectroscopy and Decision Xpress Service. Light was also thrown upon futuristic technologies like DVD and FPWD. The presentations of Mr. Mike Gillen, Product Line Manager, Dr. Allen Gilchrist, Chief Scientist and Mr. Doug Patterson, Acoustic Programme Manager from Baker Hughes highlighted on the tools like 3DEx, MagTrack, XMAC Elite, Earth Imager and StarTrek.

The seminar was stimulating enough to charge the imagination of ONGCians, which resulted in numerous interactive pauses in between the presentations. The seminar was well attended by Mr. D K Pandey, Basin Manager (WOB), Mr. J L Narsimham, Asset Manager (N&H), Mr. Ashok Kumar, Head Logging Services, Mr. M B Singh, Head Geophysical Services along with several senior officers. The program was anchored by Mr. B V Jacob, SG (W) while Mr. O P Srivastava, Head logging Services, Rajahmundry offered the vote of thanks.

(Page 3 & 4 of this bulletin are devoted to abstracts of papers published / presented by Petrophysicists. In this issue also we are including abstracts of papers presented in Hyderabad-2004, organized by SPG -Editor)

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Application of Step Rate Test (SRT) in Monitoring of Dynamic Layer Pressures in Mumbai High South Field

By R. Saxena, M.M. Panigrahi, U.B. Singh, K.S. Prasad, B.B. Tripathi , S. Ramanan

L-III reservoir of Mumbai High field is a multilayered carbonate reservoir exhibiting widely varying fluid properties both laterally as well as vertically. Most of the wells drilled for exploitation of hydrocarbons from L-III reservoir are completed with commingled flow for economic reasons. Apart from intrinsic porosity and permeability heterogeneity, the layers are also subjected to non-uniform drive mechanisms. Consequently, the individual layers of the reservoir have experienced differential pressure depletion. Application of pattern water flooding in layers of highly contrasting permeability has also contributed to difference in layer pressure.

Periodic monitoring of reservoir pressure is of prime importance in any reservoir management programme. Apart from being critical reservoir simulation input, the layer wise pressure data can be utilized to optimize production from individual wells. This data can further be applied to redesign or modify existing water flooding operations in order to control reservoir dynamics for achieving maximum ultimate recovery. Step Rate Test (SRT) helps in determining layer wise pressures in commingled flow. Methodology adopted is to measure Flowing Bottom Hole Pressure (FBHP) as a function of varying choke size by using conventional Production Logging Tool (PLT) sensors and then analyzing the data for obtaining layer wise pressures.

Step Rate Test (SRT) has been recently conducted in an injector of Mumbai High South. Analysis of SRT data has yielded the pressure of the perforated layers. Besides, layer wise injectivity index also derived from SRT will help in deciding future profile modifications jobs

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An Innovative Approach for Formation Evaluation of Complex Panna Formation in Heera Field, Mumbai Offshore

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Multi-mineral model based upon statistical inverse modelling of well log data is best suited for complex reservoirs which contain an appreciable amount of basement rock fragments apart from the sand, silt, clay, feldspar, mica etc. The rock fragments are not pure minerals but a combination of various minerals like quartz, feldspar, mica, chlorite etc in varying proportions. Hence, it becomes very difficult to assign processing parameters for rock fragments in a multi-mineral model. In the present study, an innovative technique for selection of processing parameters of rock fragments in Panna formation of main Heera field, Mumbai offshore, has been evolved. These parameters have been selected from in-situ log data acquired against the weathered basement section of wells drilled on the crestal part of main Heera field i.e the source of rock fragments. The approach has been successfully applied for data processing of 16 wells of Heera field out of which the results for three wells from different parts of the field are presented in the paper. The results of the study corroborated well with the core data and initial production testing data. The developed methodology will be helpful in realistic formation evaluation during future exploration and development of Panna formation in Heera field. The study can be extended to other similar reservoirs of interest also.

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Lowdown of Resistivity: Effects of Microporosity on Oil Bearing Deltafront Sandstones, North Jotana, Cambay Basin, India and Identification Methods

Realistic imaging and conceptualization of reservoir models relies on linking petrophysical properties to geologic processes. A deliberate strategy adopted in development wells of North Jotana revealed the occurrence of oil in MU-III sequence, hitherto unknown in the area. This involved meticulous examination of drill cuttings and sidewall coring of low resistivity sands. Interesting zones, thus identified were corroborated by test results. Lamina scale heterogeneity comprehended by pore-size distribution and irreducible water saturation revealed the influence of depositional processes in masking the conventional oil response on electrologs. Sandstones deposited in the lower toe part of deltafront deposits of a tide-dominated delta system in North Jotana have indicated lowdown of resistivity owing to predominance of dispersed clay resulting in higher microporosity.

SEM studies revealed grain coating and pore filling with clays occluding the porosity. Increased surface area associated with disseminated clay coating of the grains and filling the pores holds more irreducible water, thus increasing water saturation, which in turn reduces resistivity values. Resistivity logs respond to total water present in the pores and the high water saturation is due to bound water. Evaluation of such low resistive pays requires the interpreters to discard the myth that water saturations above 50% are not hydrocarbon productive. In new wells, close monitoring of well cuttings and sidewall cores backed up with qualitative resistivity- porosity overlay and real time petrophysical examination are imperative for deciphering zones that merit production tests.

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Detection of Structural Elements Using Borehole Imagery Techniques, A Case Study From Krishna-Godavari Basin, India

Fullbore Formation MicroImager tool is part of new generation borehole imaging devices provided by the MAXIS 500 system. It is an extension of traditional dipmeter technology and overcomes the inadequacies of conventional dip data. The Fullbore Formation MicroImager tool has eight pads, including four flaps consisting 192 array electrodes with a vertical and lateral sidewall image resolution of 5mm and image coverage up to 80 percent in 8.5 inch (21.59cm) diameter borehole. The tool offers enhanced vertical resolution, lateral exploration capabilities, high volume of data acquisition with real time processing and image display. A detailed image interpretation and dip evaluation has been carried out in Krishna Godavari Basin. The analysis aimed primarily to recognize structural elements and associated features. In the present study, structural elements like unconformities, fractures, faults, slump deformation structures and foliations were detected and defined. In fact, some faults were recognized even in the absence of distortion. Complex structural features like growth faults and associated antithetic faults were clearly visualized on the images. As exploration and production become critical and geological problems encountered become increasingly complex, the use of borehole imagery techniques will help the geologist, log analyst and production engineer for enhancing the future exploration and exploitation programmes.

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This section includes opportunities, which our Petrophysicists can avail. In this issue we are including 46^th Annual Logging Symposium organized by SPWLA

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The 46^th Annual Logging Symposium is being organized by Society of Petrophysicists and Well Log Analysts during June 26-29, 2005 at New Orleans, Louiana, USA. Abstracts of technical papers are invited for the symposium. Last date for submitting abstracts is October 15, 2004.

Call for Abstracts

Society of Petrophysicists and Well Log Analysts
46th Annual Logging Symposium New Orleans, Louisiana, USA June 26-29, 2005

CALL FOR ABSTRACTS

NOTE TO AUTHORS:
An abstract should contain 200 to 400 words. Avoid the use of equations, trademarks, literature references, and supplementary text. The preferred method of abstract submittal is by on-line submission, although abstracts can be submitted by mail, e-mail, or facsimile. Submit your abstract by one of the methods ONLY ONCE. Do not duplicate submissions. The information contained in the abstract is the principal basis for the acceptance or rejection of the paper. Notification of acceptance will be made in December 2004. If accepted, the abstract will be published in the March-April 2005 issue of Petrophysics. The paper will be scheduled for presentation at the New Orleans Symposium, and a complete manuscript will be required for the Transactions by April 11, 2005. THIS DEADLINE IS FIRM. As in 2004, paper submissions will be by electronic (on-line) means only.

ABSTRACT IS DUE NO LATER THAN OCTOBER 15, 2004

Submit abstracts to:
The Vice-President Technology SPWLA
8866 Gulf Freeway, Suite 320
Houston, TX 77017 USA

Well GSDW-2A was drilled without risers at water Depth of 3024 M which is the second deepest water depth of wells dilled so far in the world. It was a challenge to carry out logging operations in this well. The tools were dropped to the sea floor through Logging cable and then with the help of ROV they were guided in to the hole. The hole diameter was more than 25” due to uncompacted formations. The back up arms of the PEX tool and VSP tool were modified to handle large hole diameters for better Log data acquisition. Logs of Satisfactory quality were successfully recorded. The logs recorded in this well were:

This logging operation was one of the rarest such operation carried out successfully. This set a precedent for logging other Riser Less Deep water wells drilled subsequently.

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Member News

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Following colleagues superannuated recently. JKWLS wishes them best of time.

Following colleagues elevated to CG ( wells ) recently. JKWLS congratulates them

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Technical contributions / articles for publication in JKWLS bulletin are invited from the members. The same may be sent to the editor Shri S. K. Anand via e-mail.

The members are requested to share the bulletin with other members / colleagues as complete details of e-mail addresses of all members are not available with us.

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