Gan, Thomas (Shell Trinidad & Tobago Ltd) | Kumar, Ashok (Shell Trinidad & Tobago Ltd) | Ehiwario, Michael (Shell Exploration & Production Company) | Zhang, Barry (Quantico Energy Solutions) | Sembroski, Charles (Quantico Energy Solutions) | de Jesus, Orlando (Quantico Energy Solutions) | Hoffmann, Olivier (Quantico Energy Solutions) | Metwally, Yasser (Quantico Energy Solutions)
Borehole-log data acquisition accounts for a significant proportion of exploration, appraisal and field development costs. As part of Shell technical competitive scoping, there is an ambition to increase formation evaluation value of information by leveraging drilling and mudlogging data, which traditionally often used in petrophysical or reservoir modelling workflow.
Often data acquisition and formation evaluation for the shallow hole sections (or overburden) are incomplete. Logging-while-drilling (LWD) and/or wireline log data coverage is restricted to mostly GR, RES and mud log information and the quality of the logs varied depending on the vendor companies or year of the acquisition. In addition, reservoir characterization logs typically covered only the final few thousand feet of the wellbore thus preventing a full quantitative petrophysical, geomechanical, geological correlation and geophysical modelling, which caused limited understanding of overburden sections in the drilled locations and geohazards risls assessment.
Use of neural networks (NN) to predict logs is a well-known in Petrophysic discipline and has often used technology since more than last 10 years. However, the NN model seldon utilized the drilling and mudlogging data (due to lack of calibration and inconsistency) and up until now the industry usually used to predict a synthetic log or fill gaps in a log. With the collaboration between Shell and Quantico, the project team develops a plug-in based on a novel artificial intelligence (AI) logs workflow using neural-network to generate synthetic/AI logs from offset wells logs data, drilling and mudlogging data. The AI logs workflow is trialled in Shell Trinidad & Tobago and Gulf of Mexicooffshore fields.
The results of this study indicate the neural network model provides data comparable to that from conventional logging tools over the study area. When comparing the resulting synthetic logs with measured logs, the range of variance is within the expected variance of repeat runs of a conventional logging tool. Cross plots of synthetic versus measured logs indicate a high density of points centralized about the one-to-one line, indicating a robust model with no systematic biases. The QLog approach provides several potential benefits. These include a common framework for producing DTC, DTS, NEU and RHOB logs in one pass from a standard set of drilling, LWD and survey parameters. Since this framework ties together drilling, formation evaluation and geophysical data, the artificial intelligence enhances and possibly enables other petrophysical/QI/rock property analysis that including seismic inversion, high resolution logs, log QC/editing, real-time LWD, drilling optimization and others.
A well was drilled into a prospective new unconventional mudstone play offshore Norway. Two of five coring runs were successful while the rest yielded little to no core recovery. Investigations attributed the poor recovery to sub-optimal coring practices, equipment failure and operational errors. Recently, the accompanying petrophysical logs and seismic data were revisited, and upon detailed investigation several unusual responses were observed to correspond with intervals of poor core recovery. Subsequent investigation of the core itself substantiated that the coring issues largely had natural causes. This understanding is being applied to two imminent coring operations and has driven selection of drilling, coring and wireline technology and procedures, in addition to informing casing design.
Wireline nuclear magnetic resonance (NMR) and cross dipole acoustic data, logging whilst drilling (LWD) density (including azimuthal images), neutron porosity and resistivity was acquired over the interval of interest for standard formation evaluation purposes. This interpretation was conducted immediately after the initial drilling and showed the formation to be a series of highly porous oil bearing mudstones. However, no in depth advanced interpretation was conducted at the time. Recently, advanced analysis including high resolution log enhancement, NMR 2D porosity and saturation analysis, acoustic azimuthal anisotropy, near wellbore imaging, fracture interpretation, and borehole image interpretation were performed on the log data, and new and improved 3D seismic data was interpreted. When interpreted in detail it could be observed that unusual responses in the logs showed a close correspondence to the intervals of poor core recovery. In particular, high azimuthal anisotropy was observed, and when this was compared to the near wellbore reflection image a significant planar reflecting feature was identified which is determined to be a fault. Indications of this feature was subsequently found in seismic data. When then compared to the azimuthal density image after resolution enhancement was applied, although the image is still of too low resolution to directly image the fault, disturbed bedding was observed which is commonly associated with faulted intervals. Several core fragments proved to have extensive small-scale fracturing not noticed previously, and slickenlines were found along several larger fractures previously presumed to be drilling induced.
The investigations of the log data revealed that a previously unknown sub-seismic fault was present right below the depth where coring problems were encountered. The detailed interpretation was able to determine the precise location of the fault and its extent in the formation. Knowledge of this subsequently explained the coring problems encountered and helps to optimise imminent coring in the same formation. Lessons learned and the methodology likely also applies to similar formations.
In this paper we discuss coring issues encountered in a new and unconventional play offshore, present new data and interpretation that sheds light on them and describe the methodology of the detailed integrated interpretation that uncovered the previously unknown root cause. We then discuss how these findings can be (and are) used to optimise both drilling, coring, and logging operations in future wells.
Schlumberger's North America recruiting team hosted a selection of universities, including Rice University, Texas A&M, the University of Houston, and the University of Texas at Austin for a 1-day Engagement Workshop at its Sugar Land Campus facility located in Sugar Land, Texas. The participants took a tour of some of the different facilities housed at the campus, and Leila Otoso, a field engineering recruiter at Schlumberger, led the sessions. Freshmen to junior level students from several engineering backgrounds participated in the workshop and were able to see firsthand Schlumberger's technologies and equipment. The students were also able to engage with experts and discuss potential future career paths with them. "As a recruiter, I have the opportunity to change people's lives. I'm able to informally coach these students and help them understand how they can better develop themselves. Programs like these workshops allow me to get to know these outstanding people and expose them to different experiences all while uncovering their hidden skills. I'm also able to help guide them to their perfect fit when it comes to their career choices," said Otoso.
The SPE Student Development Committee (SDC) was born 40 years ago, although under a different name. While its name has changed, its mission has remained the same: to encourage students to develop and enjoy the advantages of SPE membership. The SDC, which is composed of SPE volunteers, recommends student programs to be initiated at the global society level and works with staff members to implement approved programs. The SDC encourages SPE sections to develop active student-relations programs with student chapters in their areas. Additionally, the SDC implements and monitors the Regional and International Student Paper Contests and the SPE Outstanding Student Chapter Program.
Al-Azmi, Mejbel Saad (Kuwait Oil Company) | Al-Otaibi, Fahad (Kuwait Oil Company) | Kumar, Joshi Girija (Kuwait Oil Company) | Tiwary, Devendra (Kuwait Oil Company) | Al-Ashwak, Samar (Kuwait Oil Company) | Dzhaykiev, Bekdaulet (Baker Hughes, a GE Company) | Shinde, Neha (Baker Hughes, a GE Company) | Hardman, Douglas (Baker Hughes, a GE Company) | Noueihed, Rabih (Baker Hughes, a GE Company) | Gadkari, Shreerang (Baker Hughes, a GE Company)
The complex nature of the reservoir dictated comprehensive formation evaluation logging that was typically done on wireline. The high angle designed for maximum reservoir exposure, high temperature, high pressure (HTHP), differential reservoir pressure and wellbore stability challenges necessitated a new approach to overall formation evaluation. The paper outlines Formation Evaluation strategy that reduced risk, increased efficiency and saved money, while ensuring high quality data collection, integration and interpretation.
After review of all risks, a decision to utilize Managed Pressure Drilling (MPD) for wellbore stability, Logging While Drilling (LWD) to replace wireline and Advanced Mudlogging Services was implemented. The Formation Evaluation team utilized LWD resistivity, neutron, density and nuclear magnetic resonance logs supplemented with x-ray diffraction (XRD), x-ray fluorescence (XRF) and advanced mud gas analysis to ensure comprehensive analysis. The paper outlines workflows and procedures necessary to ensure all data from LWD, XRF, XRD and mud gas are integrated properly for the analysis.
Effects of Managed Pressure Drilling on mud gas interpretation as well as cuttings and mud gas depth matching are addressed. Depth matching of all data, mud gasses, cuttings and logs are critical for detailed and accurate analysis and techniques are discussed that ensure consistent results. Complex mineralogy due to digenesis and effect of LWD logs are evident and only reconciled by detailed XRF and XRD data. The effects of some conductive mineralogy are so dramatic as to infer tool function compromise. The ability to determine acceptable tool response from tool failures eliminates unnecessary trips and leads to efficient operations. The final result of the above data collection, QC and processing resulted in a comprehensive formation evaluation interpretation of high confidence.
Finally, conclusions and recommendations are summarized to provide guidelines in Formation Evaluation in similar challenging highly deviated, HTHP, complex reservoir environments on land and offshore.
Digital technologies serve as a primary theme of this year’s group, with a few environmentally conscious firms included in the mix. The well will immediately be brought on production and is expected to flow at more than 100 MMscf/D of gas and 3,000 B/D of associated condensate, the company said. The main goal of production logging is to evaluate the well or reservoir performance. The shale sector is studying the results of a 23-well experiment in the southeastern corner of New Mexico to learn what the wider implications might be. The shale sector is making moves to consolidate amid investor pressure to increase cash flow.
Petroleum geomechanics is defined as the interaction between the evolving earth stresses and the overburden and reservoir rock mechanical properties. A comprehensive understanding of rock mechanical behaviour is key to successful field appraisal and development. For example, 70% of the world’s oil and gas reserves are contained in reservoirs where rock failure and sand production will become a problem at some point. Wellbore stability issues have been estimated to cost the industry USD 8 billion annually. Around 80%–90% of data comes from “traditional” core and log petrophysics, but the importance of data quality control and a rigorous and consistent petrophysical interpretation is often overlooked by well construction and production engineers.
Drilling operations require the services of many support groups. Evaluating the types of support services that will be needed and estimating the cost of those services is an important component of well planning that must be reflected in the authority for expenditure (AFE) for the well. Support service groups are used, because they can do a particular job more efficiently than the rig crew. An example of this efficiency is casing crews who are experienced in running large-diameter tubulars. Other support groups may provide services that cannot be performed by the rig crew or operator (i.e., well logging, pipe inspection, or specialized completions).