Standard approaches to optimization under uncertainty in reservoir simulation require use of multiple realizations, with variable parameters representing operational constraints and actions as well as uncertain scenarios. We will show how appropriate use of local optimization within the simulation model, using customized logic for field management strategies, can bring improved workflow flexibility and efficiency, by reducing the effort needed for uncertainty iterations.
To achieve meaningful forecasts for an ensemble of uncertain scenarios, it is important to distinguish between different types of decision. Investment decisions, such as facilities sizing, depend on global unknowns and must be optimized for the complete ensemble. Operational actions, such as closing a valve, can be optimized instantaneously for individual scenarios, using measurable information, although subject to constraints determined at a global level. In this study, we implement local optimization procedures within simulation cases, combining customized objective criteria to rank reactive or proactive actions, with the ability to query reservoir flow entities at appropriate frequencies.
The methods presented in the paper can be used for reactive response modeling for smart downhole control; optimization of ESP/PCP pump performance; and implementation of production plans subject to defined downstream limits. For selected cases, we compare the advantages and disadvantages of the local optimization approach with standardized "big-loop" uncertainty workflows. The methodology can significantly reduce optimization costs, particularly for high-frequency actions, achieving similar objective function values in a fraction of the time needed for post-processing optimizers. Use of tailored scripting provides the capability to modernize the logic framework for field management decisions, with realistic representation of smart field equipment and flow entities at any level of complexity.
Use of efficient workflows as described in this paper can reduce the cost of multiple realization studies significantly, or enable engineers to consider a wider range of possible scenarios, for deeper understanding and better risk mitigation.
This challenging reservoir characterization case study is defined by the interaction between two reservoirs with different production mechanisms: a fractured basement reservoir and an overlying sandstone reservoir. The existing static geologic concept has been significantly enhanced by integrating pressure data from a unique three-year shut-in period to aid modeling of fractured reservoir connectivity. Previously, the seismic dataset was predominantly used to model the fault and fracture network and guide well planning. In the current approach, the full field data set, including all drilling parameters and new reservoir surveillance data were integrated to address uncertainty in the connected hydrocarbon volume and the relative importance of each production mechanism. The result is a reservoir management tool with which to test re-development concepts and effectively manage pressure decline and increasing gas/oil ratio (GOR) and water production.
To achieve a fully integrated history matched model, the first step was to make a thorough review of the existing detailed seismic interpretation, vintage production logging tool runs (PLT's), wireline logs (including borehole image logs (BHI)) and drilling data to find a causal link between hydraulically conductive fractures and well production behavior. In parallel, a material balance exercise was run to incorporate the new pressure data acquired during the field's shut-in period. The results of the material balance analysis were combined with seismic and well data to define the distribution of connected fractures across the field. Additionally, the material balance analysis was used to determine the connected hydrocarbon volume, the distribution of initial oil in-place and the relative hydrocarbon contribution from each production mechanism.
The field is covered by multi-azimuth 3D seismic and 43 vertical to highly deviated development wells, providing significant static and dynamic data for characterizing the distribution of connected fractures. Despite this high quality, diverse and field-wide dataset, prior modeling iterations struggled to sufficiently describe the production behavior seen at the well level. This has resulted in a major challenge to predicting the production behavior of new development wells and planning for reservoir management challenges. Capturing the complex interaction between production variables (including lithology, matrix versus fracture network, geomechanical stresses, reservoir damage and pressure depletion) at a field level instead of at an individual well level resulted in a unified static and dynamic model that reconciles all scales of observation.
This oilfield represents a unique reservoir characterization opportunity. The result is a key example of how iterative, integrated geological and engineering driven reservoir modeling can be used to inform the development in a complex, mature field. This case study provides an excellent analogue for the reservoir characterization of other fractured Basement fields and/or Basement-cover reservoir couplet fields in the early to late phases of their development.
Gas injection is a proven EOR method in the oil industry with many well-documented successful field applications spanning a period of more than five decades. The injected gas composition varies between projects, but is typically hydrocarbon gas, sometimes enriched with intermediate components to ensure miscibility, or carbon dioxide in regions such as the Permian Basin, where supply is available at an attractive price.
Miscible nitrogen injection into oil reservoirs, on the other hand, is a relatively uncommon EOR technique because nitrogen often requires a prohibitively high pressure to reach miscibility. Unlike other injection gases, the minimum miscibility pressure for nitrogen decreases with increasing temperature. In fact, in deep, hot reservoirs containing volatile oil, nitrogen may develop miscibility at a pressure similar to the MMP for hydrocarbon gas or carbon dioxide. The phase behavior is more complicated than what can be captured by correlations and hence requires equation-of-state calculations.
Results from a recent EOR screening study in ADNOC indicate that a couple of high-temperature oil reservoirs in Abu Dhabi may be potential targets for miscible nitrogen injection. This paper discusses key aspects of the EOS modeling. Advanced gas injection PVT data are available to enable a fair comparison between nitrogen, carbon dioxide and lean hydrocarbon gas. In this work, we have modelled and analyzed the phase behavior of two volatile oil systems with respect to nitrogen, hydrocarbon gas, and carbon dioxide injection, as part of a reservoir simulation study, which will be covered in a subsequent publication; see
San Antonio-based Petro Waste Environmental (PWE) announced the opening of its newest state-of-the-art nonhazardous oil and gas waste landfill facility in Howard County, Texas. Milestone Environmental Services has announced the ground breaking for its new oilfield waste-disposal facility south of Midland, Texas.
This course discusses the fundamental sand control considerations involved in completing a well and introduces the various sand control techniques commonly used across the industry, including standalone screens, gravel packs, high rate water packs and frac-packs. It requires only a basic understanding of oilfield operations and is intended for drilling, completion and production personnel with some sand control experience who are looking to gain a better understanding of each technique’s advantages, limitations and application window for use in their upcoming completions.
The interest in on Carbon Capture and Storage (CCS) has increased over the last years with recognition of the ability of CCS to achieve a great reductions in CO2 emission as the fossil fuels will continue to be the main supplier for the world energy demand for the upcoming decades with no other alternatives are forecasted to replace them. The comparison between CCS and the other future alternatives or options relies mainly on the CCS cost -which is the main focus of this paper- removal of CCS deployment barrier in addition to the barriers and costs for the alternative options for CO2 emission reduction.
This study gives an insight comparison between the electricity cost for five different options of power generation including Combined Cycle Gas Turbines (CCGT) without and with CCS, coal and finally the nuclear power plants. In addition, it determines the ranges of fuel and carbon prices at which each option can be economically deployed
The recent coal CCS for Nth of a kind power generation plant cost estimates lie in the region of 60 to 100 $/ton of avoided CO2 which is higher than the previous CCS cost estimated and also greater than the accepted range of the forecasted carbon prices in the upcoming years. The higher costs of coal CCS would suggest the following: Coal CCS power generation plants is way less economical than gas ones for the range of carbon prices less than 60-100 $/ton of avoided CO2 Even at carbon prices higher than 100 $/ton of CO2, coal CCS power plants still produces higher cost electricity when compared to the gas CCS ones as long as the natural gas prices are still lower than 9 $/MBTU Coal CCS electricity costs are still higher when compared to a nuclear power plant option
Coal CCS power generation plants is way less economical than gas ones for the range of carbon prices less than 60-100 $/ton of avoided CO2
Even at carbon prices higher than 100 $/ton of CO2, coal CCS power plants still produces higher cost electricity when compared to the gas CCS ones as long as the natural gas prices are still lower than 9 $/MBTU
Coal CCS electricity costs are still higher when compared to a nuclear power plant option
It is widely believed that the CCS power plants (Gas or Coal) are not expected to be economical over the upcoming years, however introduction of subsidized forms of CCS are likely to take place. Also, CCS technology components are expected to be economically implemented in operations like Enhance Oil recovery (EOR), so, in this paper, an economic evaluation is provided for using of CO2 extracted from natural gas plant into EOR operations. CO2 separation cost in the natural gas processing industry is less than the capture cost of CO2 in power plants as a result of its high gas pressure and the fact that CO2 removal is mandatory to increase the value of a natural gas resource
On the other hand, this is not the case for the CCS of the most industrial emissions, as they are expected to be higher than those of power plants as a result of the smaller scale and wider distributed CO2 streams compared to power generation plants. This shows the importance of the realistic CCS cost estimation as a significant factor in the R&D projects and implementation trials that try to overcome the tackles that face the application of such promising technologies.
This seminar will teach participants how to identify, evaluate, and quantify risk and uncertainty in everyday oil and gas economic situations. It reviews the development of pragmatic tools, methods, and understandings for professionals that are applicable to companies of all sizes. The seminar also briefly reviews statistics, the relationship between risk and return, and hedging and future markets. Strategic thinking and planning are key elements in an organisation’s journey to maximise value to shareholders, customers, and employees. Through this workshop, attendees will go through the different processes involved in strategic planning including the elements of organisational SWOT, business scenario and options development, elaboration of strategic options and communication to stakeholders.
Through data gathering, machine learning, and the use of a supercomputer, a non-profit organization in Texas is seeking to boost oil and gas production on land owned by the states’ two largest university systems. This paper reviews two newly developed novel completion systems that significantly reduce time spent performing multistage stimulation in environments where cost and consequence of failure are high.
Sourcing water for large multifracture stimulations in west Texas is a well-known constraint on oil and gas activities in the area. A 6-month pilot operation demonstrated that produced-water reuse is technically feasible and can be a cost-effective solution. This paper summarizes the benefits of using a bipolymer crosslinking system in environments where water quality cannot be guaranteed. It also demonstrates the yielded cost savings per well that are achievable when reusing 100% produced or flowback water for hydraulic fracturing. This paper reports the completion of a two-lateral well in the Williston basin where produced water (PW), filtered but otherwise untreated, was used throughout the slickwater and crosslinked components of approximately 60 hydraulic-fracturing stages.