The Benefits of Logging While Drilling (LWD) for Formation Evaluation in the Dulang West Field

1998 ◽  
Vol 1 (06) ◽  
pp. 496-503
Author(s):  
Zarool Hassan Bin Tajul Amar
Keyword(s):  
Gamma Ray ◽  
Cost Savings ◽  
Sufficient Information ◽  
Neutron Density ◽  
Borehole Stability ◽  
Formation Evaluation ◽  
Petrophysical Analysis ◽  
Measurement While Drilling ◽  
Logging While Drilling ◽  
Competitive Pricing

Summary Ever since the first electric log was run in 1927, the oil industry relied on wireline-conveyed logging for the acquisition of formation data for petrophysical analysis. It was not until 1978 that the first measurement while drilling (MWD) tools were introduced in the field. The industry did not pay too much attention to them then because they did not offer sufficient information for petrophysical analysis. Furthermore, the reliability of such tools was notimpressive and their cost was unattractive. However, over the last 6 years, the drilling services industry has shifted its focus from just directional MWD to a complete directional and logging while drilling (LWD) package. The LWD tools that are built into special drill collars provide measurements of resistivity, neutron, density, and gamma ray. Significant improvements in the reliability of the tools and competitive pricing, as compared to conventional wireline logging, has offered advantages in running LWD in fields that have drilling and completion constraints (e.g., borehole stability) or difficult well trajectories. This paper discusses the benefits to Petronas Carigali of using LWD for formation evaluation. In the development of the Dulang West field, LWD was used extensively to acquire formation log data. The quality of the data and cost savings are addressed. A comparison between the wireline-conveyed and LWD data acquired in this field is also presented. The acquisition of formation data by use of LWD in Dulang West has made a significant contribution to the overall cost per barrel of oil produced, without compromising data quality. P. 496

scholarly journals Facies Analysis and Depositoinal Environment of D-3 Reservoir Sands Vin Field, Eastern Niger Delta

2019 ◽  
pp. 1-19
Author(s):  
Onyewuchi, Chinedu Vin ◽  
Minapuye, I. Odigi
Keyword(s):  
Seismic Data ◽  
Niger Delta ◽  
Depositional Environment ◽  
Gamma Ray ◽  
Facies Analysis ◽  
Depositional Environments ◽  
Width Ratio ◽  
Neutron Density ◽  
Wireline Logs ◽  
Isopach Map

Facies analysis and depositional environment identification of the Vin field was evaluated through the integration and comparison of results from wireline logs, core analysis, seismic data, ditch cutting samples and petrophysical parameters. Well log suites from 22 wells comprising gamma ray, resistivity, neutron, density, seismic data, and ditch cutting samples were obtained and analyzed. Prediction of depositional environment was made through the usage of wireline log shapes of facies combined with result from cores and ditch cuttings sample description. The aims of this study were to identify the facies and depositional environments of the D-3 reservoir sand in the Vin field. Two sets of correlations were made on the E-W trend to validate the reservoir top and base while the isopach map was used to establish the reservoir continuity. Facies analysis was carried out to identify the various depositional environments. The result showed that the reservoir is an elongate , four way dip closed roll over anticline associated with an E-W trending growth fault and contains two structural high separated by a saddle. The offshore bar unit is an elongate sand body with length: width ratio of >3:1 and is aligned parallel to the coast-line. Analysis of the gamma ray logs indicated that four log facies were recognized in all the wells used for the study. These include: Funnel-shaped (coarsening upward sequences), bell-shaped or fining upward sequences, the bow shape and irregular shape. Based on these categories of facies, the depositional environments were interpreted as deltaic distributaries, regressive barrier bars, reworked offshore bars and shallow marine. Analysis of the wireline logs and their core/ditch cuttings description has led to the conclusion that the reservoir sandstones of the Agbada Formation in the Vin field of the eastern Niger Delta is predominantly marine deltaic sequence, strongly influenced by clastic output from the Niger Delta. Deposition occurred in a variety of littoral and neritic environment ranging from barrier sand complex to fully marine outer shelf mudstones.

scholarly journals Petrophysical Properties and Digenetic Evolution of Shuaiba Formation in Nasiriyah Oil Field, Southern Iraq

2021 ◽  
pp. 4810-4818
Author(s):  
Marwah H. Khudhair
Keyword(s):  
Gamma Ray ◽  
Water Saturation ◽  
Middle Part ◽  
Effective Porosity ◽  
Oil Field ◽  
Neutron Density ◽  
Petrophysical Properties ◽  
Secondary Porosity ◽  
Primary Porosity ◽  
Gamma Ray Log

     Shuaiba Formation is a carbonate succession deposited within Aptian Sequences. This research deals with the petrophysical and reservoir characterizations characteristics of the interval of interest in five wells of the Nasiriyah oil field. The petrophysical properties were determined by using different types of well logs, such as electric logs (LLS, LLD, MFSL), porosity logs (neutron, density, sonic), as well as gamma ray log. The studied sequence was mostly affected by dolomitization, which changed the lithology of the formation to dolostone and enhanced the secondary porosity that replaced the primary porosity. Depending on gamma ray log response and the shale volume, the formation is classified into three zones. These zones are A, B, and C, each can be split into three rock intervals in respect to the bulk porosity measurements. The resulted porosity intervals are: (I) High to medium effective porosity, (II) High to medium inactive porosity, and (III) Low or non-porosity intervals. In relevance to porosity, resistivity, and water saturation points of view, there are two main reservoir horizon intervals within Shuaiba Formation. Both horizons appear in the middle part of the formation, being located within the wells Ns-1, 2, and 3. These intervals are attributed to high to medium effective porosity, low shale content, and high values of the deep resistivity logs. The second horizon appears clearly in Ns-2 well only.

AUTO-NAVIGATION ON PRESSURE AND SAMPLING LOCATION IN WIRELINE AND LWD: BIG DATA CHALLENGES AND SOLUTIONS

2021 ◽  
Author(s):  
Mehdi Alipour K ◽  
◽  
Bin Dai ◽  
Jimmy Price ◽  
Christopher Michaell Jones ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Expert Knowledge ◽  
Sampling Location ◽  
Neutron Density ◽  
Reserve Estimation ◽  
Pressure Test ◽  
Single Well ◽  
Application Deployment ◽  
Exploratory Data ◽  
Petrophysical Logs

Measuring formation pressure and collecting representative samples are the essential tasks of formation testing operations. Where, when and how to measure pressure or collect samples are critical questions which must be addressed in order to complete any job successfully. Formation testing data has a crucial role in reserve estimation especially at the stage of field exploration and appraisal, but can be time consuming and expensive. Optimum location has a major impact on both the time spent performing and the success of pressure testing and sampling. Success and optimization of rig-time paradoxically requires careful and extensive but also quick pre-job planning. The current practice of finding optimum locations for testing heavily rely on expert knowledge. With nearly complete digitization of data collection, the oil industry is now dealing with massive data flow giving rise to the question of its application and the necessity to collect. Some data may be so called “dark data” of which a very tiny portion is used for decision making. For instance, a variety of petrophysical logs may be collected in a single well to provide measures of formation properties. The logs may include conventional gamma ray, neutron, density, caliper, resistivity or more advanced tools such as high-resolution image logs, acoustic, or NMR. These data can be integrated to help decide where to pressure test and sample, however, this effort is nearly exclusively driven by experts and is manpower intensive. In this paper we present a workflow to gather, process and analyze conventional log data in order to optimize formation testing operations. The data is from an enormous geographic distribution of wells. Tremendous effort has been performed to extract, transform and load (ETL) the data into a usable format. Stored files contains multi-million to multi-billions rows of data thereby creating technology challenges in terms of reading, processing and analyzing in a timely manner for pre-job planning. We address the technological challenges by deploying cutting-edge data technology to solve this problem. Upon completion of the workflow we have been able to build a scalable petrophysical interpretation log platform which can be easily utilized for machine learning and application deployment. This type of data base is invaluable asset especially in places where there is a need for knowledge of analogous wells. Exploratory data analysis on worldwide data on mobility and some key influencing features on pressure test and sampling quality, is performed and presented. We further show how this data is integrated and analyzed in order to automate selection of locations for which to formation test.

Dynamic Formation Evaluation to Reduce Uncertainty and Confirm Completed Intervals in Brown Fields

2021 ◽  
Author(s):  
Muhamad Aizat Kamaruddin ◽  
Ayham Ashqar ◽  
Muhammad Haniff Suhaimi ◽  
Fairus Azwardy Salleh
Keyword(s):  
Real Time ◽  
Optical Sensors ◽  
Sensor Technology ◽  
Innovative Technology ◽  
Fluid Type ◽  
Formation Evaluation ◽  
Reservoir Fluid ◽  
Logging While Drilling ◽  
Dynamic Formation

Abstract Uncertainties in fluid typing and contacts within Sarawak Offshore brown field required a real time decision. To enhance reservoir fluid characterisation and confirm reservoir connectivity prior to well final total depth (TD). Fluid typing while drilling was selected to assure the completion strategy and ascertain the fluvial reservoir petrophysical interpretation. Benefiting from low invasion, Logging While Drilling (LWD) sampling fitted with state of ART advanced spectroscopy sensors were deployed. Pressures and samples were collected. The well was drilled using synthetic base mud. Conventional logging while drilling tool string in addition to sampling tool that is equipped with advanced sensor technology were deployed. While drilling real time formation evaluation allowed selecting the zones of interest, while fluid typing was confirmed using continually monitored fluids pump out via multiple advanced sensors, contamination, and reservoir fluid properties were assessed while pumping. Pressure and sampling were performed in drilling mode to minimise reservoir damage, and optimise rig time, additionally sampling while drilling was performed under circulation conditions. Pressures were collected first followed by sampling. High success in collecting pressure points with a reliable fluid gradient that indicated a virgin reservoir allowed the selection of best completion strategy without jeopardising reserves, and reduced rig time. Total of seven samples from 3 different reservoirs, four oil, and three formation water. High quality samples were collected. The dynamic formation evaluation supported by while drilling sampling confirmed the reservoir fluid type and successfully discovered 39ft of oil net pay. Reservoir was completed as an oil producer. The Optical spectroscopy measurements allowed in situ fluid typing for the quick decision making. The use of advanced optical sensors allowed the sample collection and gave initial assessment on reservoir fluids properties, as a result cost saving due to eliminating the need for additional Drill Stem Test (DST) run to confirm the fluid type. Sample and formation pressures has confirmed reservoir lateral continuity in the vicinity of the field. The reservoir developed as thick and blocky sandstone. Collected sample confirmed the low contamination levels. Continuous circulation mitigated sticking and potential well-control risks. This is the first time in surrounding area, advanced optical sensors are used to aid LWD sampling and to finalize the fluid identification. The innovative technology allowed the collection of low contamination. The real-time in-situ fluid analysis measurement allowed critical decisions to be made real time, consequently reducing rig downtime. Reliable analysis of fluid type identification removed the need for additional run/service like DST etc.

Real Time Borehole Stability Monitoring and Pre-drill Model Calibration using LWD Sonic — A Case Highlight.

2015 ◽  
Author(s):  
Sophia Weaver ◽  
Xiaohui Xiao ◽  
Rob Vines
Keyword(s):  
Model Calibration ◽  
Weight Optimization ◽  
Borehole Stability ◽  
Acoustic Data ◽  
Stability Monitoring ◽  
Development Costs ◽  
Stability Model ◽  
Logging While Drilling ◽  
Geophysical Log ◽  
Productive Time

Abstract Borehole instability challenges can account for a significant percentage of non-productive time and associated costs in drilling. This is even more so in deepwater subsea wells due to high development costs coupled with the subsurface complexities associated with turbidite reservoirs. Pre-drill borehole stability studies in this field case were performed by evaluating offset well history and geophysical log data and calibrating these against direct well measurements and drilling experiences, with the objective of recommending the appropriate mud weight. However, the validation of the pre-drill borehole stability model derived from sonic data taken in the only offset well in the field was deemed necessary for effective borehole stability monitoring in this case. Additionally, the inability to run wireline in a highly deviated well fuelled the need for acoustic data acquisition using logging-while-drilling (LWD). Sonic data was acquired by LWD (a first in the field) and this aided mud weight optimization to successfully drill the well to TD without any borehole stability problems. This paper describes the application of this solution to managing well delivery uncertainties in a deepwater field and highlights the process, results and lessons from the event to aid future applications.

Gamma-ray, Spectral Gamma-ray, and Neutron-density Logs for Interpretation of Ordovician Volcanic Rocks, West Cumbria, England

2002 ◽  
Author(s):  
David Millward ◽  
Simon R. Young ◽  
Brett Beddoe-Stephens ◽  
Emrys R. Phillips ◽  
Chris J. Evans
Keyword(s):  
Gamma Ray ◽  
Volcanic Rocks ◽  
Neutron Density
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