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The Technical Programme Committee of APOGCE 2021 invites you to submit a paper proposal and contribute to this flagship event. A proper review of your paper proposal requires that it contain adequate information on which to make a judgment. Download our instructions guide to assist you with preparing your paper proposal. The paper proposal should have the necessary clearance before it is submitted to APOGCE 2021. Prospective authors should advise of any clearance problems when the paper proposal is submitted.
The basic objective of this course is to introduce the overview and concept of production optimisation, using nodal analysis as a tool in production optimisation and enhancement. The participants are exposed to the analysis of various elements that help in production system starting from reservoir to surface processing facilities and their effect on the performance of the total production system. Depth conversion of time interpretations is a basic skill set for interpreters. There is no single methodology that is optimal for all cases. Next, appropriate depth methods will be presented. Depth imaging should be considered an integral component of interpretation. If the results derived from depth imaging are intended to mitigate risk, the interpreter must actively guide the process.
A new stage-by-stage analytical framework to identify and control high water influx stages in horizontal wells was successfully used in a multi-layer reservoir in Southeast Saskatchewan, Canada. The wells of interest were drilled in the Midale formation and hydraulically fractured through coil with cemented liners using a borate cross-linked guar gellant. The objective of the project was to develop a robust method to aggregate and analyze multidisciplinary data to identify stages with prolific water inflow and employ multi-cycle closeable sleeves to isolate them. When the correct data is available this framework can be applied at the time of completion to improve well economics through reduced lifting and disposal costs. A multivariate approach is necessary to begin to understand flow per stage in the absence of production logging.
This framework involves collecting all available data: geological, geophysical, raw data-van feeds, pressure signatures, frac fluid viscosity profiles, break times, production and tracer concentrations to build a model for targeting sleeve closures. Data collected through on-site laboratories during the hydraulic fracturing treatment allow early identification of stages for further analysis. Stages where full breaking of frac fluids under reservoir conditions is not observed are identified as candidates for possible intervention. High frac fluid viscosities have the potential to increase fracture height growth and connect the wellbore to layers that have mobile water, depending on fracture height growth limiting mechanisms (Fisher, M. K. et al 2012). Particulate water tracers allow for water inflow to be uniquely attributed to individual stages, where higher concentrations are associated with higher inflow. Combined with pressure signatures and initial swabbing data, this technique can allow the operator to better optimize the well from day one. Production analysis before and after closing sleeves serves as the ultimate score-card for this framework.
Mitigation of unwanted water influx was achieved using this framework to shut in certain stages early in the well's life. On-site quality control, detailed data collection during hydraulic fracturing, tracer concentrations and initial swabbing provided the necessary signals. Closeable sleeves permitted the fractures to heal immediately after the completion, but also allowed for the optionality to mitigate high water inflow if it was identified. This paper details the results from a well, where the water production decreased by approximately 30% while the oil rate increased.
This framework allows for real-time data driven decision making. This enables significant efficiency gains in completion and intervention costs, equipment sizing, facility infrastructure, and lifting costs. This is accomplished through combining multiple datasets, including detailed on-site and after-the-fact frac analysis and solid particulate water tracers to leverage closeable sleeve technology. Potential areas for further applications of this framework include infill drilling in legacy waterfloods or when drilling wells in close vertical proximity to aquifers. This framework is most applicable when attempting to optimize fracture designs when working in new areas and new reservoirs.
Conformance is a measure of the uniformity of the flood front of the injected drive fluid during an oil recovery flooding operation and the uniformity vertically and areally of the flood front as it is being propagated through an oil reservoir. This page provides an overview of selected chemical systems and technologies that promote improved conformance during oil recovery operations. See Conformance problems for a discussion of the underlying problems creating the need for conformance improvement. Conformance improvement systems and technologies include fluid systems for use during oil recovery flooding operations in which the fluids promote sweep improvement and mobility control (e.g., polymer waterflooding) and oilfield conformance improvement treatment systems (e.g., "small-volume" gel treatments). A conformance improvement fluid system for promoting flood sweep improvement and mobility control involves injecting a volume of an oil recovery fluid that constitutes a significant fraction of the reservoir pore volume.
Gels are a fluid-based system to which some solid-like structural properties have been imparted. In other words, gels are a fluid-based system within which the base fluid has acquired at least some 3D solid-like structural properties. These structural properties are often elastic in nature. All of the conformance improvement gels discussed are aqueous-based materials. Gels discussed in this page, when formed in a beaker for example, constitute a single and continuous gel mass throughout its entire volume within the beaker.
Figure 1 shows the type of production response that is possible when applying a polymer gel treatment to a waterflood injection well to improve sweep efficiency. The figure shows the combined production-response of the four direct offsetting production wells to the gel-treated injection well. The gel treatment was applied for waterflood sweep-improvement purposes to the naturally fractured Embar carbonate formation surrounding Well O-7 of the highly mature SOB field in the Big Horn basin of Wyoming. The wide variations in water/oil ratio (WOR) and oil production rate are quite common in many of the well patterns of this highly fractured reservoir. Sydansk provides more details regarding the 20,000 bbl gel treatment.
The first step in designing a gel treatment is to correctly identify the nature of the conformance problem to be treated. This includes, during water- or gas-shutoff treatments, identifying the flow path of excessive water or gas production from its source to the production wellbore. The following procedure for gel technology selection is highly generalized, and the procedure should be modified as dictated by the actual reservoir conformance problem to be treated. If a service company or a company specializing in conformance treatment gels is to be involved, they should be consulted during each step of the selection process. A prerequisite is to eliminate all gel technologies, if any, that are prohibited by locally applicable safety or environmental regulations. First, determine the type of problem that is to be treated. That is, whether it is a matrix-rock problem or a high permeability anomaly problem, such as fractures.
Proper placement of conformance improvement gels is key to achieving the desired results within the reservoir. The flow properties of a gelant or gel as it is being placed are important parameters. To date, for all known gelant solutions used in conformance improvement treatments (including polymer gelant solutions), these gelant solutions place themselves in all matrix-rock geological strata according to Darcy flow considerations and do so without any special selective placement in only the high-permeability strata and flow paths. Any placement of gel into, and the associated permeability reduction of, a low-permeability and/or high oil saturation strata in the near-wellbore region surrounding a radial-flow matrix-rock-reservoir well will almost always be counter productive to improving the conformance of that well. Thus, when applying a gel treatment, especially a near-wellbore gel treatment, to treat a vertical conformance problem of a radial-flow well in a matrix rock reservoir, mechanical zone isolation must be used to assure that the gelant is injected only into the high-permeability and/or low-oil-saturation geological strata to be treated.
Conformance is a measure of the uniformity of the flood front of the injected drive fluid during an oil recovery flooding operation and the uniformity vertically and areally of the flood front as it is being propagated through an oil reservoir. The remediation, or partial remediation, of the first conformance problem is exemplified by a mobility-control polymer flood conducted in a reservoir containing a viscous oil and/or a reservoir that is characterized as being relatively homogeneous. Successful conformance improvement treatment is dependent on correctly assessing the nature of the conformance issue. Vertical conformance problems, which are probably the most pervasive and most easily remedied conformance problems in matrix-rock (unfractured) reservoirs, are commonly manifested by geological strata of differing permeability overlying one another. In matrix-rock (unfractured) reservoirs, areal conformance problems, also referred to as "directional" high-permeability trends, can exist.