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Collaborating Authors
Well Completion
Abstract The prudent management of resources is a vital part of any company's operation. Unconventional gas plays place demands on companies as they require the development of safe operations without the loss of a Social Licence. The accomplishment of a social licence to operate requires corporations to go beyond conforming to legislation and embrace society's needs. International concern has been voiced about the mature unconventional shale gas exploration and exploitation in North America. This has occurred because of society's lack of understanding of fracking, their perception of the risk and Corporation's lack of engagement. The oil industry worldwide follows the standards laid down by the American Petroleum Institute (API). These standards have served the oil industry well. However, fulfilment of these standards has not always been achieved by all operators. Established technology of fracking introduces a sequencing of high pressure cycles into casing and cementing systems in both vertical and horizontal wells. In shale fracking a well is deviated from the vertical to the horizontal. In doing so, will joints in the casing hold under all circumstances; is cement evenly placed between the steel casings and within geological formation? The risk experience in drilling operations is one concern, others include, financial, health, safety and the environment risk is gauged by stakeholders. The possibility of a methane flow into the aquifer opens the potential of environmental impact on fresh water resources. Methane without adequate capture in populated areas increases the risk to human and animal health. Society has reacted to past failure of mining operations or extractive industries by enacting laws to encourage companies to adopt safer methods of operation. Consequent on the USA experience, more than nineteen States and Countries have legislated to reverse the burden of proof of liability by enacting a series of bills that form the basis of a โRebuttable Presumption of Liabilityโ. Corporations must not fail to control operations. They must identify the potential of damage to the environment and human health. Failure to mitigate risks will result in loss of competitiveness, damage to reputation, legal liability arising from failure to abide by regulations and/or private litigation. The maintenance of a social licence to operate underpins corporate success.
- North America > United States (1.00)
- North America > Canada (1.00)
- Europe (1.00)
- Oceania > Australia > South Australia (0.28)
- Government > Regional Government > North America Government > United States Government (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Government > Regional Government > Oceania Government > Australia Government (0.94)
- North America > United States > Wyoming > Powder River Basin (0.99)
- North America > United States > Montana > Powder River Basin (0.99)
- Europe > Russia > Northwestern Federal District > Komi Republic > Timan-Pechora Basin > Pechora-Kolva Basin > Usa Field (0.96)
- (3 more...)
Abstract Effective fracture properties that contribute to the flow in the tight formations are very important in stimulation job evaluation, productivity estimation, and production forecast. However, there are no direct measurements on the volume of stimulated region or the effective permeability of fracture because hydraulic fractures not only stimulate local matrix, but also connect natural fractures. Therefore, the effective drainage volume contributing to production can be much bigger than the extension of hydraulic fractures. After a high initial rate, production data for stimulated tight formation has an extended transient flow period in which the matrix functions as a source and behaves in a transient fashion. This behavior can be captured by a dual-porosity model with transient matrix performance under a constant bottom-hole pressure. This paper studies the problem from an inverse perspective and couples the production data with an interporosity flow model to estimate the effective drainage volume that a well controls as well as the effective permeability that can be used for production rate forecast. The problem is solved in Laplace domain. The proposed model is validated with the numerical simulation and the field production data from Mississippian Lime. Furthermore, the interporosity model is sufficient to forecast the production trend from the given examples.
- North America > United States > Oklahoma (1.00)
- North America > United States > Kansas (0.89)
- North America > United States > Texas > Meramec Formation > Meramec Formation > Mississippi Chat > Mississippi Lime > St. Louis Formation (0.99)
- North America > United States > Texas > Meramec Formation > Meramec Formation > Mississippi Chat > Meramec Formation > St. Louis Formation (0.99)
- North America > United States > Texas > Meramec Formation > Meramec Formation > Meramec Formation > Mississippi Lime > St. Louis Formation (0.99)
- (23 more...)
- Well Completion > Hydraulic Fracturing (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Naturally-fractured reservoirs (1.00)
- Reservoir Description and Dynamics > Reservoir Simulation (1.00)
- (5 more...)
Abstract Multistage fracturing technique has considerably improved gas production from tight gas reservoirs all over the world. Well production is one of the main determining factors to assess the success of a fracturing treatment. In this paper, numerous vertical and horizontal wells drilled in the high pressure high temperature heterogeneous reservoirs have been evaluated to confirm effectiveness of stimulation treatments and benefits derived from the use of novel technologies. Among many variables that were analyzed include drilling, completion, and stimulation parameters such as well azimuth, completion types, fluid characteristics, acid strength, etc. A database for stimulated wells was created and various parameters have been grouped and assessed to provide correlation and understand the effectiveness of fracture treatments and optimize development plan. Correlations were drawn using the Pearson correlation coefficient equation to compute data trend and ensure good quality data. Numerous, very useful plots are constructed and presented that show the different trends of the variables evaluated and how they affect production rate. Analyses results indicate that use of real-time geomechanics is important to predict reservoir pressure and mud weight as wells are laterally drilled in the preferred minimum in-situ stress (ฯmin) direction. This is because when wells are drilled along ฯmin, they tend to become more unstable due to the higher stress acting on the wellbore. Accuracy in predicting stresses and pressures are keys to the drilling of such wells. The completion assemblies were selected between open hole multistage and plug and perforation cased hole approaches based of reservoir properties and hole conditions. The impact on production performance by using of non-damaging low gel loading fracturing fluids, high strength proppants, and optimal fluid and acid volumes have been demonstrated using actual field examples. The paper also illustrates the use of novel fracturing approach such as channel fracturing and its impact on sustained gas production in tight gas and making low productivity wells commercial.
- Well Completion > Hydraulic Fracturing > Multistage fracturing (1.00)
- Well Completion > Hydraulic Fracturing > Fracturing materials (fluids, proppant) (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Tight gas (1.00)
Abstract The use of nano-laminated metallic coatings is an emerging technology that is generating products with material property combinations heretofore not possible. Through a patented electrochemical controlled deposition process, precisely defined configurations of layered metal alloys can be applied to a variety of substrates or as near net shapes. The deposition process can be controlled to produce nano-scale layers with unique interfacial properties resulting in corrosion resistance, elastic modulus, strength, hardness, and fracture toughness combinations uniquely different from conventional material processing. This paper will describe the patented process, characterize the as-deposited material, explore the application of nano-laminated nickel based alloys for downhole service environments and evaluate the potential of this coating to improve corrosion resistance, extended service life and improved safety/integrity of pump, valve and tubular assets.
- Well Completion > Well Integrity > Subsurface corrosion (tubing, casing, completion equipment, conductor) (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs (1.00)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Corrosion inhibition and management (including H2S and CO2) (1.00)
- (2 more...)
Abstract The natural fracture system of coal is the primary conduit for gas flow. Low permeability is in many cases attributed to low fracture porosity and/or connectivity. Mineral occluded coal cleats are known to considerably reduce coal permeability. Whilst cleat demineralisation has been found to increase coal permeability, its influence on compressibility is poorly understood. In this study, we investigated the influence of mineral dissolution and secondary mineralisation on the compressibility of coal (Cf) following acidification with hydrochloric and hydrofluoric acid (HCl-HF). In-situ HCl core flooding and core immersion in 3% and 15% HF yielded a less compressible core (Cf = 0.006 from 0.020 bar) with sustained, enhanced permeability to brine (k = 0.40 from 0.10 mD). We attribute improved stress resilience and better fluid flow characteristics to the dissolution and subsequent secondary mineralisation of the core's circumferential periphery. Predictive geochemical speciation using OLI Analyzer 9.1, for surveying mineral solubilities and precipitation tendencies, identified the formation of radio-dense neofluoride salts K2SiF6 and CaF2 Structural modifications and mineralogical changes detected from scanning electron microscopy-electron diffraction spectroscopy (SEM-EDS), confirmed the presence of these salts. Results suggest that mineral alteration and subsequent secondary mineralisation of the core periphery following HCl-HF acidisation yielded well-formed crystalline salts, apparently serving as in-situ generated proppants buttressing newly created void spaces for enhanced fluid flow and improved resistance to increasing confining stress.
- Geology > Mineral (1.00)
- Geology > Rock Type > Sedimentary Rock > Organic-Rich Rock > Coal (0.49)
- Well Completion > Hydraulic Fracturing (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Naturally-fractured reservoirs (1.00)
- Reservoir Description and Dynamics > Reservoir Fluid Dynamics > Flow in porous media (1.00)
Abstract The unconventional reservoir engineer is required to evaluate increasingly complex data. In additional to the rapid advancement of technology used to complete and stimulate unconventional resources, there has been a proliferation of type curve procedures (i.e. pressure and rate transient analysis), decline techniques, and reservoir modelling strategies in the literature. Specific challenges are the analysis of single and multi-phase flow form hydraulically stimulated horizontal and multi-lateral wells. Although state of the art simulation techniques can be used to model any complex reservoir and well architecture, restrictions on data quality, project schedules, and budgets do not always allow for detailed simulation and analysis. Furthermore, initialization of the numerical model often requires some form of analytical modelling as a precursor to the larger model. However, complex scenarios production analysis or forecasting of horizontal wells, dual and tri-laterals, fracture horizontals as well heterogeneous reservoirs can be simplified by using an proxy model which is accurate (if not exact) with respect to long-term deliverability and resource/reserve estimation. Complex wells and reservoirs can be modelled and analyzed by using a simple homogenous reservoir with effective permeability, skin, and wellbore radius combinations. Examples will demonstrate this procedure would allow for the use of simple analytical software tools in lieu of simulation, or the generation of reliable forecasts in the absence of completion/reservoir data
- Well Drilling > Drilling Operations > Directional drilling (1.00)
- Well Completion > Hydraulic Fracturing (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Shale gas (1.00)
- (8 more...)
- Information Technology > Modeling & Simulation (0.68)
- Information Technology > Software (0.48)
Abstract Microseismic data is evaluated with surface seismic and analyzed in addition to treatment data to understand the variance in performance of frac stages at three wells drilled in the Longmaxi formation, China. In well H1, the microseismic is dominated by fault reactivations, and is of little use in analyzing the performance of individual frac stages. In the wells H2 and H3, the use of maximum curvature derived from surface seismic showed strong qualitative correlation with microseismicity. To quantify the effects of shale properties on the frac stage performances, seismic attributes were used to derive geologic models of porosity, total gas, fracture density and Poisson's Ratio which were combined to form the Shale Capacity. The comparison of the Shale Capacity with the production log of H1 demonstarates how the model explains the performance of the frac stages away from the faults. The same observations could be made using the extent of good Shale Capacity away from the faults to explain the important difference in production between H2 and H3. Given the importance of the faults and their geomechanical impact on the performance of the frac stages, a geomechanical workflow able to simulate the interaction between the hydraulic and natural fractures is applied to the H1 well. The resulting strain and J Integral are able to explain the performance of the frac stages in H1 thus confirming the importance of the natural fractures and the need to account for their geomechanical effects.
- Asia > China (1.00)
- North America > United States > North Dakota (0.28)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (1.00)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Government > Regional Government > Asia Government > China Government (0.94)
- North America > United States > Texas > Permian Basin > Yeso Formation (0.99)
- North America > United States > Texas > Permian Basin > Yates Formation (0.99)
- North America > United States > Texas > Permian Basin > Wolfcamp Formation (0.99)
- (32 more...)
- Well Completion > Hydraulic Fracturing > Multistage fracturing (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Naturally-fractured reservoirs (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Reservoir geomechanics (1.00)
Abstract The structure of the fracture network formed by hydraulic fracturing operation is one of the key parameter in production from unconventional shale reservoirs. The standard approach to obtain such information is usually through well-testing coupled with micro-seismic monitoring. Unfortunately, the micro-seismic mapping is not always carried out and the conventional well-test techniques often fall short in describing the flow in shale reservoir in particular the contact area of the fractures open to flow. The other alternative technique to get insight into structure of the fracture network is to use chemical tracer tests. In this study, we propose a new simple and cost efficient technique to estimate the fracture contact area by tracking the major exchange cations in shale reservoirs. The idea behind the proposed technique is to replace the major cations on fracture surfaces in shale by increasing the concentration of one of the major cation in fracturing fluid. The current technique is satisfied the industry standard practice as the high concentrated K+ is part of hydraulic fracturing fluid composition and therefore cation exchange with other major cations (Na+, Ca++ and Mg++) is expected to occur. In order to test the feasibility of the proposed techniques, a set of laboratory tests were conducted where a shale sample was milled and sieved to three different sizes to have different contact area. They are then placed in a high pressure cylinder (built for this study) and were washed by concentrated NaCl solution under high pressure and controlled temperature. The effluent was collected successively and analysed for major cations using ICP-MS. Correlation relating the cation exchange mass content to contact surface is proposed and calibrated using the data obtained from laboratory tests.
- North America > United States (0.70)
- Asia > Middle East > Saudi Arabia (0.29)
- Oceania > Australia > Queensland (0.28)
- Oceania > Australia > Queensland > Surat Basin (0.99)
- Oceania > Australia > New South Wales > Surat Basin (0.99)
- Well Completion > Hydraulic Fracturing (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Shale gas (1.00)
Abstract In this paper, the problem of a hydraulic fracture interacting with a pre-existing natural fracture has been investigated by using a cohesive zone finite element model. The model fully couples fluid flow, fracture propagation and elastic deformation, taking into account the friction between the contacting fracture surfaces and the interaction between the hydraulic fracture and the natural fracture. The effect of the field conditions, such as in-situ stresses, and rock and fracture mechanical and geometrical properties, intersection angle and the treatment parameters (fracturing fluid viscosity and injection rate) on the hydraulic fracture propagation behavior has been analyzed. The finite element modeling results provide detailed quantitative information on the development of various types of hydraulic fracture โ natural fracture interaction, fracture geometry evolution and injection pressure history, and allow us to gain an in-depth understanding of the relative roles of various parameters. The value of a parameter calculated as the product of fracturing fluid viscosity and injection rate can be used as an indicator to gauge if crossing or diverting behavior is more likely. In addition, using a finite element approach allows the analysis to be extended to include the effects of fluid leakoff and poroelastic effect, and to study hydraulic fracture height growth through a system of nonhomogeneous layers and their bedding planes.
- Well Completion > Hydraulic Fracturing (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Naturally-fractured reservoirs (1.00)
Abstract The Changbei basin centred gas reservoir is located in the Palaeozoic clastic sandstone of the Shaanxi formation, Ordos basin, P.R. China. After more than a decade of successful tight gas production history, the development of the field is being expanded to include new target reservoirs. Because of its low intrinsic permeability, hydraulic fracturing stimulations are required to achieve commercial production rates from the target formation. Fracture diagnostics suggests high fluid efficiencies in a normally faulted stress regime. Recent monitoring data of hydraulic fracturing stimulations during an appraisal campaign indicate fracture height growth containment which is not readily predicted by the current numerical simulators. Non-radioactively traced proppant and post-injection temperature logs suggest that fracture height may be controlled by a combination of stress barriers and shale laminations. However, the current numerical simulators tend to have difficulty predicting the termination of height growth without calibration to post-job data. A new hydraulic fracturing code currently under development has been used to simulate the fracture treatments in the target formations. This study briefly describes the input data workflow for the new software and highlights the underlying models the simulations are based upon. The discrepancies between the model results are discussed and possible explanations put forward. The study concludes that the new code is a useful addition to the existing software, and that the thermodynamic module enables genuine comparisons with the temperature logs, which in this case are important for investigating the fracture development. The code also gives promisingly accurate pressure evolutions during the treatment when compared to measurements from a well equipped with a downhole gauge.
- Asia > China > Shaanxi Province (1.00)
- Asia > China > Shanxi Province (0.71)
- Asia > China > Gansu Province (0.71)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (0.37)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Sandstone (0.35)
- Geophysics > Borehole Geophysics (1.00)
- Geophysics > Seismic Surveying > Passive Seismic Surveying > Microseismic Surveying (0.68)
- Asia > China > Shanxi > Ordos Basin > Changqing Field (0.99)
- Asia > China > Shaanxi > Ordos Basin > Changqing Field (0.99)
- Asia > China > Shaanxi > Ordos Basin > Changbei Field (0.99)
- (3 more...)
- Well Completion > Hydraulic Fracturing > Fracturing materials (fluids, proppant) (1.00)
- Well Completion > Completion Installation and Operations > Perforating (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- (6 more...)