Heavy oil is defined as liquid petroleum of less than 20 API gravity or more than 200 cp viscosity at reservoir conditions. No explicit differentiation is made between heavy oil and oil sands (tar sands), although the criteria of less than 12 API gravity and greater than 10,000 cp are sometimes used to define oil sands. The oil in oil sands is an immobile fluid under existing reservoir conditions, and heavy oils are somewhat mobile fluids under naturally existing pressure gradients. Unconsolidated sandstones (UCSS) are sandstones (or sands) that possess no true tensile strength arising from grain-to-grain mineral cementation. Many heavy oil reservoirs are located in unconsolidated sandstones.
Digital transformation (abbreviation DT, or sometimes DX) is defined as "the transformation of business by revamping the business strategy or digital strategy, models, operations, products, marketing approach, objectives etc., by adopting digital technologies." Transforming an enterprise, whether in Oil & Gas or any other sector, can be viewed as a more or less ambitious (or tactical vs. strategic) scale. Digital transformation is considered an umbrella term that covers a number of different approaches, listed below under "Topics" and described in separate pages.
How these and related factors affect subsea processing design are discussed below. The value of subsea processing is determined primarily by reservoir characteristics and water depth. Well productivity index (barrel per psi drawdown or PI), which is a function of reservoir permeability, is one of the keys. A high PI will leverage the reduced backpressure provided by subsea processing to higher production rates. This can have enormous economic implications for low-pressure reservoirs in deep water.
As oil and gas production moves into deeper water, the cost of surface production platforms becomes prohibitively high. The industry has found that surface facilities must be kept to a minimum and shared by satellite fields to be commercial. Subsea processing is a key toward a cost-effective, "hub-and-spoke" development (Figure 1), allowing the industry to operate successfully in deeper water. Subsea processing refers to the separation of produced fluids into gas and liquid--or gas, oil, and water--for individual phase transport and disposal (in the case of water). The liquid stream can be pumped to a central facility for final processing.
Separation of gas and liquids is a key processing function for any production operation. Several approaches exist to accomplishing this separation subsea, as described on this page. Which is most appropriate to use depends on the fluids and conditions specific to the particular location. By separating the gas and liquid phases and pumping the liquid stream, this simplest of systems will capture most of the benefits of subsea processing. It will reduce backpressure to the wells and eliminate problems associated with multiphase flow.
Although many measurements are taken while drilling, the term MWD refers to measurements taken downhole with an electromechanical device located in the bottomhole assembly (BHA). Telemetry methods had difficulty in coping with the large volumes of downhole data, so the definition of MWD was broadened to include data that were stored in tool memory and recovered when the tool was returned to the surface. Power systems in MWD generally may be classified as one of two types: battery or turbine. Both types of power systems have inherent advantages and liabilities. In many MWD systems, a combination of these two types of power systems is used to provide power to the MWD tool so power will not be interrupted during intermittent drilling-fluid flow conditions.
This page lists events (conferences, exhibitions, etc.) related to digital transformation. Emphasis is given to SPE events, although other events, including those from commercial event organizers, may provide learning and networking opportunities. Events organized by the Industrial Internet Consortium (IIC), with which SPE has a liaison agreement, are also highlighted. The first three days of IIC events are reserved for member company personnel, while the fourth day only is open to non-members. The possibility of greater access to SPE members who are not employees of an IIC member company is under discussion.
The diagnostic plot is a log-log plot of the pressure change and pressure derivative (vertical axis) from a pressure transient test vs. elapsed time (horizontal axis). Figure 1 shows an example of a diagnostic plot. The diagnostic plot can be divided into three time regions: early, middle, and late. At the earliest times on a plot (the early-time region), wellbore and near-wellbore effects dominate. These effects include wellbore storage, formation damage, partial penetration, phase redistribution, and stimulation (hydraulic fractures or acidization).