We have invented, developed and patented novel, innovative methods for shale oil EOR.
Our shale oil EOR processes, with registered trademarks SuperEORTM and UltraEORTM:
recover far more oil and gas from shale oil and shale gas condensate reservoirs than natural gas or CO2 huff and puff EOR processes - as much as five times primary oil recovery.
enable oil production at less than half the cost of primary, e.g., less than $14/bbl.
can be efficiently operated at lower BHP, greatly reducing or precluding interwell communication.
utilize far less injectant, with short injection and long production periods, to recover far more oil, over a shorter period of time.
do not involve the injection of dry or separator natural gas, carbon dioxide or other gases, and do not require compression.
mitigate the need for artificial lift
are applicable to undersaturated, saturated oil and gas condensate shale reservoirs
enable robust scalability, expanding projects from one or two wells to multiple wells on multiple adjacent pads, providing significant economies of scale.
significantly reduce the environmental impact of shale oil production, by greatly increasing the volume of oil recovered per well, while reducing the energy, and air, water and noise emissions and surface impacts per barrel of oil recovered.
Solving The Problem of Interwell Pressure Communication
As shale oil development has progressed using horizontal wellbores completed at increasingly closer lateral spacing, multistage fracture stimulation treatments often propagate fractures that extend to offset wells and cause these wells to be in hydraulic or pressure communication. And, in some areas, natural fractures may extend between these wellbores, that are in hydraulic or pressure communication. As a result, implementation of cyclic natural gas or CO2 EOR processes in these wells may result in poor incremental oil recovery, as pressure buildup during injection cannot be achieved sufficient to drive the injectant gas into the matrix oil, and injected gas may move away from the well to offset wells and/or be unrecoverable. This problem has been observed in several of the Eagle Ford shale natural gas EOR projects. Efforts to mitigate this problem have included methods such as pressuring up wells offset the injector with water, shutting offset wells in, or pressuring up offset wells with natural gas. These efforts may work to some extent, but EOR oil recoveries are usually much lower than needed for good project economics.
The SuperEORTM process can operate very effectively to recover far more oil than natural gas or COE cyclic EOR, at much lower bottomhole pressures.
The graph below shows the recovery of oil via SuperEORTM in an Eagle Ford shale well at varying maximum buttonhole pressures. As shown, cumulative oil recovery at just 1500 psig maximum BHP is just 13% lower than cumulative oil recovery when the maximum injection BHP is 4500 psig.
The degree of interwell hydraulic or pressure communication will vary from well to well and across areas of a shale basin, as well completions determine hydraulic fracture lengths, fracture permeabilities, fracture spacing and fracture orientation, and geologic conditions provide for natural fracturing and in-situ stress conditions.
In many cases of interwell communication, the degree of pressure and hydraulic (gas or fluid movement) communication is limited to the duration of high pressure injection events. Therefore, injection into a well at pressures well below the initial reservoir pressure in most cases will limit interwell hydraulic or pressure communication.
The SuperEORTM process should be therefore applicable in wells that have exhibited interwell hydraulic or pressure communication, and reservoir simulation model matching of this appears to confirm this.
The Bakken shale of the Williston Basin is perhaps the most naturally fractured shale oil play in the United States. There have been several attempts to test cyclic injection of gas such as lean and rich natural gas and CO2 in Bakken producing wells, but with little success as the injected gas tends to move far away from the injection well. Likewise the complex natural fracture patterns and low matrix permeability have hindered attempts to test continuous gas or water injection. SuperEORTM conducted at pressures well below the initial reservoir pressure may enable excellent EOR oil recovery.
SuperEORTM Project Development Process
Development of a shale oil EOR project begins with the development of an accurate compositional reservoir simulation model. The compositional reservoir simulation model incorporates as much geological, geophysical, petrophysical, reservoir fluids and well completion and production data as possible, in order to develop an accurate mathematical representation of the reservoir and wells.
Of particular importance is the acquisition of accurate, detailed reservoir PVT data, collected from wells just following completion and flowback of frac fluids, as this data is used to develop an Equation of State for use in the compositional reservoir simulation model. We prefer reservoir simulation modeling software from the Computer Modeling Group, and believe it to be the most advanced and accurate software in the oil industry. CMG software is used by more than 600 companies in 60 countries.
Once the compositional reservoir simulation model is developed, including the well completion, and historical production and pressure data, the simulation model is run and key model variables are adjusted in order to obtain an accurate history match of production and pressure data. Once the match is obtained, the model may be used to forecast oil production under a variety of EOR operational scenarios, with a goal of determining the EOR operating conditions that will yield the greatest NPV.
Once optimum EOR operating parameters are determined from simulation modeling, an EOR field test or pilot project may be designed, in order to validate the model forecast. The field test is then conducted, and the results compared to the simulation model forecast, with adjustments made to the model based on actual field results. Once the field test results can be modeled with accuracy, a multi-well EOR project may be designed and implemented using the simulation model.