Layer | Fill | Outline |
---|
Map layers
Theme | Visible | Selectable | Appearance | Zoom Range (now: 0) |
---|
Fill | Stroke |
---|---|
Collaborating Authors
complexity
_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper URTeC 3871303, โUsing a Multidisciplinary Approach to Reservoir and Completion Optimization Within the Woodford Shale Play of the Arkoma Basin,โ by Stephen C. Zagurski, SPE, and Steve Asbill, SPE, Foundation Energy Management, and Christopher M. Smith, Advanced Hydrocarbon Stratigraphy, et al. The paper has not been peer reviewed. _ Subsurface complexities related to the formation of peripheral foreland basins can have significant effects on unconventional resource development. In the Arkoma Basin of southeast Oklahoma, the onset of thrusting and tectonic loading induced a complex series of dip/slip and strike/slip faults during basin formation. The operator used a series of technologies to increase understanding of the reservoir and its hazards and provide insight into economic implications for future development plans and strategies. Introduction The Woodford is primarily a Type II kerogen source rock. The formation typically is classified as either siliceous mudstone or cherty siltstone. Variable thermal maturity across the basin places the Woodford in both the wet-gas and dry-gas phase windows (moving west to east across the basin). Complex faulting regimes within the Arkoma add a layer of complexity to horizontal development of the Woodford. The operator wanted to increase the understanding of the Woodford and the effects of faulting through the reservoir in a recent development unit in the liquids-rich fairway. The development unit consists of an existing parent well (Well X) and a pair of child wells (Well Y and Well Z). The background of Unit XYZ begins with the completion of parent Well X 4โ6 years before infill development. In this portion of the basin, Well Xโs initial production rate and its cumulative production to date rank it in the top 25% of wells. The wellbore is subjected to a pair of faults and was drilled in the upper half of the Woodford. Placement of Well X is substantially further east than most parent wells because it is approximately 1,600 ft from the unit boundary. This limited infill development to two wells instead of three; the Arkoma typically has seen spacing of four, and sometimes five, wells per section. Wells Y and Z were planned and drilled east of Well X with 1,100โ1,600 ft of well spacing. Well spacing in the unit was slightly hindered by surface location limitations and limited true vertical depth (TVD) between surface casing and landing point. Structural complexity within the unit partially impaired infill development of the unit. Specifically, Well Y and its lateral length was shortened. In this portion of the Arkoma, fault-derived water production typically is the highest-weighted variable in a wellโs operating expenditure. Thus, the ability to limit excess water production within Unit XYZ and the surrounding acreage is of paramount importance.
- Geology > Geological Subdiscipline > Geochemistry (1.00)
- Geology > Petroleum Play Type > Unconventional Play > Shale Play (0.91)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock (0.54)
- North America > United States > Oklahoma > Arkoma Basin > Cana Woodford Shale Formation (0.99)
- North America > United States > Oklahoma > Anadarko Basin > Cana Woodford Shale Formation (0.99)
- North America > United States > Arkansas > Arkoma Basin > Cana Woodford Shale Formation (0.99)
William (Bill) Abriel received his BS in Earth Science (1975) and his MS in Geophysics (1978) from the Pennsylvania State University. He joined Chevron Oil Company in the fall of 1978 and worked for Chevron in New Orleans, Los Angeles, Perth Australia, and San Ramon California from 1978 to the present. During this time, he has been involved in many interesting projects in operations, seismic research and deployment. Bill was the first Chevron user or developer of the following technologies: 3D subsalt depth migration, 3D prestack depth migration, reservoir estimates from 3D seismic amplitudes, reservoir characterization from seismic data for reservoir simulation, 3D AVO, 3DDMO, dual sensor bottom cable acquisition, turning wave migration, and forming a team of geology, geophysics and reservoir engineering. During this time, Bill has worked on projects in areas including Gulf of Mexico offshore and onshore, North Atlantic (USA, Canada, UK, and Africa), West Australia, Brazil, China, and Saudi Arabia.
- North America > United States > Louisiana > Orleans Parish > New Orleans (0.26)
- Oceania > Australia > Western Australia > Perth (0.25)
- North America > United States > California > Contra Costa County > San Ramon (0.25)
- Information Technology > Knowledge Management (0.40)
- Information Technology > Communications > Collaboration (0.40)
Figure 8.5-10 shows the zero-offset wavefield responses of a point diffractor buried in media with varying degrees of complexity. The traveltime trajectories associated with the point diffractors buried in a constant-velocity medium, beneath an overburden with mild to moderate lateral velocity variations, and beneath an overburden with strong lateral velocity variations, all are single-valued. Therefore, ray tracing through such models would produce unambiguous traveltimes for Kirchhoff summation. The zero-offset traveltime trajectory associated with the point diffractor buried beneath an overburden with severe lateral velocity variations, however, is multivalued (Figures 8.5-10d). From the zero-offset wavefields associated with a diffractor buried in a medium with varying complexity shown in Figure 8.5-10, it can be inferred that the minimum-time strategy may be suitable for cases of moderate to strong lateral velocity variations (Figure 8.5-10b,c), whereas the maximum-energy strategy may be imperative for a case of a complex overburden with severe lateral velocity variations (Figure 8.5-10d).
- Information Technology > Knowledge Management (0.40)
- Information Technology > Communications > Collaboration (0.40)
Removal of opacity is applied to either a horizontal time slab with a specified thickness, typically a few to tens of time samples, or to a depositional unit bounded by the time horizons derived from structural interpretation. Figure 7.5-29 shows opacity removal applied to a thin horizontal slab that includes the water bottom, the horizontal slab slightly deeper than the water bottom, and the depositional unit labeled as H1 in Figure 7.5-28. Note the enhanced images of a complex channel system at the water bottom, and the intensive fracture system that begins to develop immediately below the water bottom and increases in complexity as we go deeper in the image volume. When we reach horizon H3 as labeled in Figure 7.5-28, we observe a highly complex fault system (Figure 7.5-30). Now we look inside a specific depositional unit, in this case the unit bounded by horizon H3 on top as labeled in Figure 7.5-28.
- Information Technology > Knowledge Management (0.40)
- Information Technology > Communications > Collaboration (0.40)
Paul Hatchell joined Shell in 1989 after receiving his PhD in Theoretical Physics from the University of Wisconsin. He began his career at Shell's Technology Center in Houston and worked on a variety of research topics including shear-wave logging, quantitative seismic amplitude analysis, and 3D AVO applications. Following a four-year oil and gas exploration assignment in Shell's New Orleans office, Paul returned to Shell's technology centers in Rijswijk and Houston where he is currently a member of the Areal Field Monitoring team and Shell's principal technical expert for 4D reservoir surveillance. His current activities include developing improved 4D seismic acquisition and interpretation techniques, seafloor deformation monitoring, and training the next generation of geoscientists. Paul presented three lecture topics.
- North America > United States > Wisconsin (0.25)
- North America > United States > Louisiana > Orleans Parish > New Orleans (0.25)
- Europe > Netherlands > South Holland > Rijswijk (0.25)
- Information Technology > Knowledge Management (0.40)
- Information Technology > Communications > Collaboration (0.40)
This workshop addressed challenges and share best practices and technological breakthroughs in presalt and subsalt exploration, appraisal, and development through a multi-disciplinary approach. The global focus on exploration and development of subsalt resources, including presalt areas, has challenged the oil industry to find advanced technical solutions to the unique complexities of this emerging play concept. Brazil, including the presalt play, has attracted international attention as one of the newest and biggest frontiers in exploration. Subsalt discoveries have also been made in deepwater West Africa, including recent presalt success. The Gulf of Mexico has an extensive track record of technical innovation in managing subsalt challenges from exploration to production.
- South America > Brazil (0.96)
- Africa (0.62)
- Energy > Oil & Gas > Upstream (0.65)
- Government > Regional Government > South America Government > Brazil Government (0.35)
- Information Technology > Knowledge Management (0.40)
- Information Technology > Communications > Collaboration (0.40)
John P. Castagna is a Professor of Geophysics and the Sheriff Chair of the Department of Earth and Atmospheric Science at the University of Houston [1]. He was awarded the 2005 Reginald Fessenden Award, along with Matthew L. Greenberg, for their work in shear-wave velocity estimation in porous rocks. AVO modeling and its successful application to exploration programs are directly related to the timely publication of the article "Shear-wave velocity estimation in porous rocks: Theoretical formulation, preliminary verification, and applications" in Geophysical Prospecting. The Greenberg and Castagna technique has withstood years of close scrutiny by being compared to both wireline and laboratory measurements. In fact, it is not uncommon to utilize this shear-wave estimation technique even when in-situ S-wave logs are available.
- Geophysics > Seismic Surveying > Seismic Processing (1.00)
- Geophysics > Borehole Geophysics (1.00)
- Geophysics > Seismic Surveying > Seismic Modeling > Velocity Modeling (0.94)
The work flow for building a depth migration velocity model includes several interpretive tasks which are critical to timely execution and successful completion of a depth migration project. These tasks involve correlation of horizons which define intervals and bodies having distinctly different velocity character. Automatic versus manual tracking of these horizons depends on the signal-to-noise ratio (S/N) and image fidelity of the seismic data, and the mode of tracking can be expected to change both vertically and laterally as these elements of data quality vary[1]. Where there are multiple overlying or irregularly-shaped salt bodies, which can be envisioned as at any point within the 3D survey area where a vertical well would penetrate more than one top of salt (and, necessarily, more than one base of salt), steps 2 and 3 in this sequence must be repeated to image successively deeper salt bodies properly. In conjunction with processing geophysicists and project managers, interpreters decide whether or not to repeat these steps based on the extent and degree of salt complexity, the imaging accuracy required for acceptable definition of subsurface targets, and the time and funding available for additional processing and interpretation.
- Geophysics > Seismic Surveying > Seismic Processing > Seismic Migration (1.00)
- Geophysics > Seismic Surveying > Seismic Modeling > Velocity Modeling (1.00)
- Information Technology > Knowledge Management (0.40)
- Information Technology > Communications > Collaboration (0.40)
Figure 8.2-1 shows a velocity-depth model for a salt pillow. The aspect ratio of the horizontal and vertical axes is 1; hence, the diagram exhibits the true shape of the diapiric structure. The model can be treated in three parts -- the constant-velocity overburden above the salt, the salt diapir itself, and the substratum that includes the flat reflector below. So far as the flat reflector is concerned, the salt diapir constitutes a complex overburden structure with strong lateral velocity variations. Note the significant velocity contrast across the top-salt boundary and the undulating reflector geometry of the base-salt boundary -- both give rise to ray bending that can only be handled by imaging in depth.
- Information Technology > Knowledge Management (0.40)
- Information Technology > Communications > Collaboration (0.40)
Research on Drilling Technologies of Ultra-Thick Salt Domes in Middle Asia and Pre-Salt Strata in Middle East: Lessons Learnt from a Pilot Well in Kenkyak Oilfield and an HPHT Well in Halfaya Oilfield
Jin, Fu (CNPC Engineering Technology R&D Company Ltd) | Wanting, Jia (CNPC Engineering Technology R&D Company Ltd) | Longlian, Cui (CNPC Engineering Technology R&D Company Ltd) | Guobin, Yang (CNPC Engineering Technology R&D Company Ltd) | Chen, Chen (CNPC Engineering Technology R&D Company Ltd)
Abstract Pre-salt strata are more and more common in recent years, challenging the petroleum industry. The reservoir in Kenkyak Oilfield (Kazakhstan) is found in deep formation beneath the ultra-thick salt dome, which brings lots of challenges such as mud loss, well kick, pipe-sticking, borehole caving, low ROP and so on. As for Halfaya Oilfield in Iraq, HF-10 is expected to be drilled as the first vertical exploration well in the region, targeting Baluti/Kurra Chine, but the complicated multiple pressure regime, cross-bedded high-pressure and low-pressure formations has been challenging the operator for decades, especially the two high-pressure formations above Yamama, one is the Lower Fars layer featured by salt-gypsum and a high pore pressure coefficient. How to safety and efficiently penetrate pre-salt strata and ultra-thick salt domes are rather important issues. Logging data of all wells that had been drilled previously in the region were studied to analyze causes of low ROPs and downhole complexities of all kinds. A pilot well was drilled in Kenkyak Oilfield and optimized drilling technologies were applied on it, so as to make a comparison between it and adjacent wells. Rock cores in the salt-gypsum formation were collected to analyze its creep deformation law on a basis of rock mechanics and establish the creep deformation formula. Important findings have been analyzed, in order to deal with the similar scenarios in Iraq. The upper Mesozoic formation contains sandstones and intercalated mudstones with ooze, which increases permeability and hydration grade. However, problems such as mud loss, borehole collapsing and bit ball-up always happen. Shallow secondary gas with a limited volume and high pressure was drilled in the pilot well in Kenkyak Oilfield. The polymeric mud system and integrated solid control devices were used for the large diameter borehole to deal with mudstone hydration. In the Permian ultra-thick salt dome salt and gypsum dissolve to cause borehole caving and creep deformation. Therefore, a mud system that resists to salt and gypsum contamination and a more advanced maintenance system was adopted. Compatible techniques and tools have been deployed to enhance ROP and mitigate potential challenges. As for HF-10 in Iraq, Low Fars that is featured by abnormally high pressure contains salt, thus two feasible well schematics have been proposed, in order to address challenges of creep deformation of salt-gypsum. Feasible mud systems have also been proposed, in order to mitigate loss, borehole sloughing and pipe sticking in the salt bed and pre-salt strata. Bit selection has been finalized, while a feasible vertical drilling tool has been proposed to mitigate deviation caused by salt. 42 wells were drilled in Kenkyak, among which 29 wells were abandoned due to engineering complexities. As for the pilot well, no downhole complexity happened, the average ROP in the salt dome was improved by twice. The mud density has been optimized. HF-10 that is expected to be drilled in 2026 is going to be the deepest vertical well in Halfaya Oilfield, integration of all of the solutions to challenge pre-salt strata contributes to reduction of risks and costs.
- Phanerozoic > Mesozoic (1.00)
- Phanerozoic > Paleozoic > Permian (0.92)
- Phanerozoic > Paleozoic > Carboniferous (0.69)
- Geology > Structural Geology > Tectonics > Salt Tectonics (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock (1.00)
- Geology > Mineral > Halide > Halite (1.00)
- North America > Canada > Alberta > Western Canada Sedimentary Basin > Alberta Basin > Cold Lake Field > Clearwater Formation > 995053 2D Cold Lake 2-10-63-2 Well (0.99)
- Asia > Middle East > Kuwait > Ahmadi Governorate > Arabian Basin > Widyan Basin > Ratawi Formation (0.99)
- Asia > Middle East > Iraq > Maysan Governorate > Arabian Basin > Widyan Basin > Mesopotamian Basin > Halfaya Field > Mishrif Formation (0.99)
- (31 more...)