Press Room

Abstract: In April 1998, a program for continuous deep disposal of drill cuttings and open pit materials was initiated on the North Slope of Alaska. This ongoing injection project is commonly referred to as GNI, or "Grind and Inject.?? Accumulated drilling cuttings and mud slurry are injected into a receptive Cretaceous soft sandstone in three wells: GNI-1, GNI-2, and GNI-3. Typical operations involve injecting slurry into one of the three wells continuously for a number of days and then switching injection to another well. The average injection rate is approximately 30,000 B/D. As of 30 September 2002, project injection has included 12.7×106 bbl of water, 30.9×106 bbl of slurry containing 2.0×106 tons or 2.2×106 cubic yards of excavated frozen reserve pit material and drilling solids, and 1.31×106 bbl of fluid from ongoing drilling operations.

Abstract: The disposal domain concept is arguably accepted as the prevalent storage mechanism during the batch injection of drill cuttings. The disposal domain is best thought of as an elliptical realm surrounding the well. This phenomenon is well documented by field and laboratory observations and has been addressed in previous work. Most studies and field operations have centered around vertical or near vertical wells. Rarely have horizontal wells been designed for conversion to injectors or used for disposal and therefore, the effect of batch injection and the created disposal domain have not been addressed. The current paper will provide an integrated look at the fracturing process that occurred in a horizontal disposal well. The well is located in the Valhall Field, North Sea, and offshore Norway. The well has multiple perforated intervals. The work will address a modified disposal domain concept as it applies to horizontal wells. The paper illustrates a history of the fracture nature (geometry and extent) and propagation across the various layers. Comparison of the field pressure history and the simulation results will be addressed.

Authors: K. S. Zaki, Advantek International; T. G.Kristiansen, BP Norway; A. S.Abou-Sayed, C. W. Summers, G. G. Wang, and M. D. Sarfare, Advantek International

Copyright 2005, Society of Petroleum Engineers

Abstract: Drilling waste disposal through downhole hydraulic fracturing is often the preferred waste management option because it can achieve green operation and often has favorable economics. Most field situations are comprised of injection in either a dedicated well or in the annulus of an existing well. Containment of the disposed waste must be ensured and one of the questions in drilling waste injection operations is; what is the capacity of a disposal well or annular scheme? The answer to this question depends on downhole waste storage mechanisms. It is evident from laboratory simulation studies and field operation experience that multiple fractures are created in drill cuttings injection (DCI) operations and the capacity of a disposal well is much larger than that estimated from single fracture simulations. More importantly, as more solids are injected into the disposal formation, the local stress is modified. Because of this change in local stress, fracture shapes, and extents at the beginning of a DCI; operations can be significantly different from the fracture shapes and extents at the end the operation. Modeling of this fracturing evolution process is necessary and essential to ensure the safe containment of the disposed waste and to estimate accurately the disposal capacity of a drilling waste disposal well.

Authors: Abou-Sayed, A.S., Guo, Q., and Meng, F.

Copyright 2003, Society of Petroleum Engineers

Abstract: Many of the largest fields yet to be developed around the world contain oil, water, and high concentrations of sour gas. The fact that they are still undeveloped reflects the significant political and economic hurdles they have yet to overcome. Successful production of such fields will require careful management of surface resources (land, water, and power), subsurface resources (hydrocarbons), and associated streams (produced water, non-salable products, and E&P wastes). Several fields in the Caspian Sea are awaiting full development because they are burdened by the high expected cost and severe legal and economic risks associated with high hydrogen sulphide (H2S) content. Advantek International was contracted to undertake a comparative analysis of the engineering requirements, environmental impact risks, and economics for disposal of several associated streams in a Caspian field with 20% acid gas (CO2 and H2S).

Authors: Abou-Sayed, A.S., Zaki, K., Summers, C.

Copyright 2005, Society of Petroleum Engineers

Abstract: Many of the world's Mega-fields (> 1 billion barrels of reserves) contain sour gas, a blend of natural gas and hydrogen sulfide (H2S), either alone or in combination with carbon dioxide (CO2). H2S gas is extremely toxic, the combination of H2S and CO2 (Acid Gas - AG), can be highly corrosive, the elemental sulphur reacts with water to form acid rain, and CO2is now recognized as a significant greenhouse gas. Where there is a demand for the natural gas, and capacity to separate the components, the H2S and CO2 can be separated out. However, these components must be managed in a cost-effect way and according to regulatory requirements to maximize recovery of hydrocarbons and minimize AG safety and environmental impacts. To date, the CO2 components have typically been vented to the atmosphere, and sulphur has been produced for industrial uses. Novel step changes are needed to handle the large sour gas volumes to be produced by the mega-fields under development in the Caspian Sea and Middle East regions.

Authors: Abou-Sayed, A.S., Zaki, K., C. Summers, Advantek International Corporation

Copyright 2004, Society of Petroleum Engineers

Abstract: Key factors in framing a produced water management (PWM) strategy include a company's internal and external environments, technology and business drivers. Emerging trends for establishing an environment-friendly PWM position can comprise these declared policies:

• Move toward zero emission
• No discharge to surface or seas
• Waste-to-Value conversion
• Incremental and progressive separation
• Pro-activity to influence partners, regulators and environmental laws

This paper covers the technical approaches for addressing production, separation, and disposal/injection segments of water injection and reservoir water flooding and the basis for selecting strategy components and PWM actions. Best practices result from both comprehensive assessments of current PWM tools and insights from a decade-long, joint industry project (JIP) on produced water re-injection (PWRI).

Abstract: Flow distribution plays an important role in Produced Water Re-Injection operations. This is especially true when the injection horizon contains isolated hydraulic units that are individually capable of accepting part of, or the entire injection rate. The hydraulic units may be separated by an impermeable barrier, shale, and/or have variations in the minimum horizontal stress. Under normal operating conditions fractures initiated in one or more of these units would not intersect or combine. The fracture growth becomes a coupled problem where growth in one hydraulic units is dependent on growth or retardation in other units. Retardation might be caused by solid and oil deposition in the fracture that would plug its tip and damage its faces. Plugging would decrease available fracture length for leak off below the actual total length of the fracture. Such scenarios become difficult to control if not initially planned or designed for and can lead to undesirable effects such as inefficient sweep or uncontrolled fracture growth.

Authors: Abou-Sayed, A.S., Sarfare, M.D., Zaki, K.

Copyright 2006, Society of Petroleum Engineers

Abstract: This paper provides a comprehensive and critical review of external filter cake formation during dynamic (cross-flow) filtration with main focus on petroleum engineering applications. Numerous researches have been done during the last several decades to investigate the cake buildup mechanisms, structure and effects of various parameters on cake properties, flux decline and stabilisation. However, a consistent hypothesis to explain the main cake buildup mechanisms and structure has not been devised yet due to numerous laboratory and field observations that can be attributed to different physics mechanisms.

Authors: Zaki, K., Sarfare, M.D., Abou-Sayed, A.S.

Copyright 2006, Society of Petroleum Engineers

Abstract: The objective in Hydraulic Fracturing is to increase well productivity and enhance or accelerate hydrocarbon recovery. Yet in soft formations, where hydraulic fracturing provides the secondary benefit of sand control, FracPack operations may result in adverse effects. These effects are more prominent in Gulf of Mexico (GOM) deepwater fields, where sands are over-pressured and highly compactive. Porosity loss around the fractured well normally occurs during FracPacks. This paper addresses this issue and quantifies the permeability loss in FracPack treatments.

Authors: Sarfare, M., Zaki, K., Abou-Sayed, A.S.

Copyright2006, Society of Petroleum Engineers

Abstract: Traditionally, hydraulic fracturing simulations have been based on elastic theories. Although this is adequate for hard rocks the fracture geometry predictions fall short when applied to fracturing soft rocks that are at incipient plasticity, or that are prone to compaction. These phenomena are usually encountered during fracturing for sand control, FracPacks and disposal of slurries and drilling cuttings in soft layers. The capacity of the created fracture to store solids, the conditions of the rock strength near the fracture faces and the near well/fracture rock permeability are all highly impacted by the rock compaction during fracture propagation.

Authors: Zaki, K.; Meng, F.; Wang, G. and Abou-Sayed, A.S.

Abstract: The widespread use of FracPack technology in deepwater reservoirs has been a growing practice. Its purpose is sand control and well stimulation. To-date, field applications and fracture treatments have been designed using traditional hydraulic fracturing simulators that apply LEFM theories. While this is adequate for hard rocks (e.g., tight gas formations), the fracture geometry predictions fall short when applied to fracturing soft rocks. Soft rocks are normally at incipient plasticity and, hence, are prone to compaction.

Authors: Abou-Sayed, A.S., Zaki, K., Wang, G., Meng, F., and Sarfare, M., Advantek International Corp.

Copyright 2004, Society of Petroleum Engineers

Abstract: This paper attempts to discuss current gaps in understanding the intricacies and details of coupling farfield deformation to well completion. Examples are shown where reservoir compaction or dilatancy is explicitly coupled to near-wellbore behavior, with specific application for assessing well performance and survivability. The analyses can use reservoir simulations coupled with analytical predictions of stresses and deformations in individual simulator blocks. The predicted stresses and deformations form the boundary conditions for finite element modeling that can focus in on the details around the completion itself. This is in contrast to the current approaches that use explicit coupling of pressure and deformation in complete massive finite element representations, with refined gridding around the completion.

Authors: McLennan, J.D. and Abou-Sayed, A.S.

Copyright 2002, Society of Petroleum Engineers

Abstract: Flow experiments were performed on a ten-inch diameter by fifteen-inch long thick-walled cylindrical sample of poorly consolidated sandstone, with a 1.25-inch diameter borehole. The purpose was to evaluate the effect of changing stress regimes on near-wellbore permeability and liner loading. A one-inch diameter screened liner was installed in the wellbore to preclude sand production. The liner was instrumented with strain gages, in order to determine stresses resulting from borehole deformation during production. The cylindrical sample was instrumented with pore pressure probes, placed at different distances from the wellbore, in order to assess variation in formation permeability with evolving effective confining stresses and production regimes.

Authors: Khodaverdian, M.F., Abou-Sayed, A.S., Ramos, R., Guo, Q. and McLennan, J.D.

Copyright 1998, Society of Petroleum Engineers

Abstract: Thermal and mechanical rock properties were evaluated with special laboratory tests and logs to analyze a Steam Assisted Gravity Drainage (SAGD) project by MARAVEN S.A. (now part of PDVSA Exploración y Producción) in the heavy oil Tía Juana field on the eastern side of Lake Maracaibo, Venezuela. This SAGD project is the first application of this technology in Venezuela and consisted of two parallel horizontal wells on top of each other where steam is injected in the upper well and oil is produced in the lower well.

Authors: Abou-Sayed, A.S., Guo, Q., Vasquez, A.R., Sanchez, M.S., Portillo, F., Poquioma, W., Blundun, M., and Mendoza, H.

Copyright 1999, Society of Petroleum Engineers

Abstract: This paper outlines a solution approach for evaluating the stability of casing and faults due to reservoir compaction. Firstly, a geomechanics model is presented for the evaluation of casing failure due to reservoir compaction. Secondly, a three dimensional finite element analysis is coupled with the developed geomechanics compaction model for the detailed casing failure analysis. Deformations and stresses are determined on a cylindrical surface surrounding the length of the newly drilled or completed wellbore in the regions of interest. This cylindrical surface is sufficiently remote from the wellbore so that the wellbore has no or little influence on the stresses and displacements due to the reservoir compaction on this surface. The calculated displacements on the cylindrical surface are then used as boundary conditions for a focused near-wellbore stress and strain analysis using finite element technology. This hybrid analysis affords evaluating the near wellbore details that are often glossed over with a fastly compacted solution not requiring multimillion FEA cells. Yet, it preserves the fine details around the wellbore and allows for incorporating fault loading and macro influences of geologic structures and reservoir extent. It preserves the material balance and does not alter the pressure volume relationship in the reservoir void space. Interface elements can account for the slippage between the casing and the cement and between the formation rock and the cement. Field cases are presented for both the geomechanics model and hybrid finite element model.

Authors: Abou-Sayed, A.S., F. Meng, and G. Wang, Advantek International Corporation

Abstract: Various geomechanical-modeling approaches, which cover a wide range of techniques and complexity, have been developed to assess the stability of a borehole and/or the integrity of well casing. The ability to confidently use these models can be limited, however, because they generally do not allow the model user to consider the "real-world" variability of the input parameters defined in the models. Often, these geomechanical models do not adequately accommodate the innate variability of the rock properties (mechanical and petrophysical) of the target reservoirs. Consequently, this deterministic approach too often results in uncertainty about the "correct" value of a critical parameter to use and insecurity in the model results. Decisions based on these results can later, not surprisingly, be found to be incorrect. Model users attempting to overcome the limitations noted above have tried various techniques. Subjective estimation, arbitrary "minimums", grading techniques, and stepwise estimation have all been commonly used.

Authors: Abou-Sayed, A.S., Guo, Q., and Meng, F., Advantek International Corporation

Copyright 2004, Society of Petroleum Engineers

Abstract: The paper discusses the impact of reservoir production on wellbore integrity and survivability when the compacting reservoir behaves as a deformable permeable body. The discussion is carried out using results of a numerical geomechanics model developed for estimating reservoir compaction, the subsequent surface/mudline subsidence; and the displacements, stresses and strains along the wellbore trajectories.

Authors: Abou-Sayed, A.S., Guo, Q., Meng, F., Noble, J.E.

Copyright 2003, Society of Petroleum Engineers

Abstract: A computational method is outlined for modeling the three-dimensional development of hydraulic fractures due to the injection of a non-Newtonian fluid at the well bore. The rock formation is modeled as an infinite, homogeneous, isotropic, elastic solid with in situ stresses that vary with depth. This three- dimensional problem is made two-dimensional by reducing the elasticity problem to an integral equation that relates pressure on the crack faces to crack openings and by pressure on the crack faces to crack openings and by neglecting the component of the fluid velocity in the direction perpendicular to the fracture plane.

Authors: Abou-Sayed, A.S., and Clifton, R.J.

Copyright 1985, Society of Petroleum Engineers

Abstract: A synthesis of treatment design parameters, treatment procedures in the field, quality control, and analysis of procedures in the field, quality control, and analysis of created fracture parameters is essential to improve and optimize hydraulic fracture treatments in a particular field. This paper provides a step-by-step approach to treatment design optimization that combines laboratory, field and analytical efforts.

Authors: Abou-Sayed, A.S., Ahmed, U., Jones, A.H., and Schatz, J.F.

Copyright 1982, Society of Petroleum Engineers

Abstract: The role of in-situ stresses in controlling hydraulic-fracture geometry and extent has been widely recognized. This paper describes the results and applications of several research programs carried out over the past few years to optimize the design of hydraulic-fracture stimulation treatments using information pertaining to in-situ stress action within the reservoir.

Authors: Voegele, M.D., Abou-Sayed, A.S., and Jones, A.H.

Copyright 1983, Society of Petroleum Engineers

The American Petroleum Institute estimates that about 1.21 bbl of drilling waste are generated for every foot drilled in the U.S., nearly 50% of which is solid waste. Though various federal and local laws and regulations govern the disposal of oilfield waste, regulatory compliance is not itself a sufficiently high standard to ensure the industry’s license to operate. Especially in this period of declined oil prices, with operators driven to cut costs wherever possible, it is critical that as an industry we recognize those technologies that provide a high degree of environmental surety while reducing near-term and long-term costs. We must demonstrate that we can manage our wastes in ways that improve the economic and environmental sustainability of our developments.