Profiles, production

Keywords exploration, appraisal, feasibility, development planning, production profile, production, abandonment, project economics, cash flow... 

Development planning and production are usually based on the expected production profile which depends strongly on the mechanism providing the driving force in the reservoir. The production profile will determine the facilities required and the number and phasing of wells to be drilled. The production profile shown in Figure 1.1 is characterised by three phases ... 

Over the last decade some of the major oil companies have been using vast amounts of outcrop derived measurements to design and calibrate powerful computer models. These models are employed as tools to quantitatively describe reservoir distribution and flow behaviour within individual units. Hence this technique is not only important for the exploration phase but more so for the early assessment of production profiles. 

The characteristic production profile for a reservoir developed by solution gas drive is shown in Figure 8.3. 

Figure 8.3 Production profile for solution gas drive reservoir...

Figure 8.8 Characteristic production profile water drive...

The aquifer response (or impact of the water injection wells) may maintain the reservoir pressure close to the initial pressure, providing a long plateau period and slow decline of oil production. The producing GOR may remain approximately at the solution GOR if the reservoir pressure is maintained above the bubble point. The outstanding feature of the production profile is the large increase in water cut over the life of the field, which is usually the main reason for abandonment. Water cut may exceed 90% in the final part of the field life. As water cut increases, so oil production typically declines a constant gross liquids (oil plus water) production may be maintained. 

In contrast to an oil production profile, which typically has a plateau period of 2-5 years, a gas field production profile will typically have a much longer plateau period, producing around 2/3 of the reserves on plateau production in order to satisfy the needs of the distribution company to forecast their supplies. The Figure 8.9 compares typical oil and gas field production profiles. 

Figure 8.9 Comparison of typical oil and gas field production profiles...

The production profile for oil or gas is the only source ofrevenueior most projects, and making a production forecast is of key importance for the economic analysis of a proposal (e.g. field development plan, incremental project). Typical shapes of production profile for the main drive mechanisms were discussed in Section 8.2, but this section will provide some guidelines on how to derive the rate of build-up, the magnitude and duration of the plateau, the rate of decline, and the abandonment rate. 

The following sketch shows the same ultimate recovery (area under the curve), produced in three different production profiles. 

The most reliable way of generating production profiles, and investigating the sensitivity to well location, perforation interval, surface facilities constraints, etc., is through reservoir simulation. 

Finally, external constraints on the production profile may arise from... 

For a particular type of development, the production profile can be estimated using the... 

The type of development, type and number of development wells, recovery factor and production profile are all inter-linked. Their dependency may be estimated using the above approach, but lends itself to the techniques of reservoir simulation introduced in Section 8.4. There is never an obvious single development plan for a field, and the optimum plan also involves the cost of the surface facilities required. The decision as to which development plan is the best is usually based on the economic criterion of profitability. Figure 9.1 represents a series of calculations, aimed at determining the optimum development plan (the one with the highest net present value, as defined in Section 13). 

At the stage of field development planning, reservoir simulation would normally be used to generate production profiles and well requirements for a number of subsurface development options, for each of which different surface development options would be evaluated and costs estimated. 

In addition to fluid properties it is important to know how volumes and rates w change at the wellhead over the life of the well or field. Production profiles are required for oil, water and gas in order to size facilities, and estimates of wellhead temperatures and pressures (over time) are used to determine how the character of the production stream will change. If reservoir pressure support is planned, details of injected water or gas which may ultimately appear in the well stream are required. 

In the feasibility phase the project is tested as a concept. Is it technically feasible and is it economically viable There may be a number of ways to perform a particular task (such as develop an oil field) and these have to be judged against economic criteria, availability of resources, and risk. At this stage estimates of cost and income (production) profiles will carry a considerable uncertainty range, but are used to filter out unrealistic options. Several options may remain under consideration at the end of a feasibility study. 

As discussed in Section 13.2, the technical, fiscal and economic data gathered to construct a project cashflow carry uncertainty. An economic base case is constructed using, for example, the most likely values of production profile and the 50/50 cost estimates, along with the best estimate of future oil prices and the anticipated production agreement and fiscal system. 

Product data Hterature, Globe MetaHurgical Sales Inc., Cleveland, Ohio, 1996. Product profile Hterature, Hickman, WHHams and Company, Lakewood, Ohio, 1996. 

Figure 6 Product profile of LLDPE with respect to density and MFR, (From Ref. 13.)...

The effect of substrate structure on product profile is further illustrated by the reactions of cis- and trons-stilbene oxides 79 and 83 with lithium diethylamide (Scheme 5.17) [32]. Lithiated cis-stilbene oxide 80 rearranges to enolate 81, which gives ketone 82 after protic workup, whereas with lithiated trans-stilbene oxide 84, phenyl group migration results in enolate 85 and hence aldehyde 86 on workup. Triphenylethylene oxide 87 underwent efficient isomerization to ketone 90 [32]. 

De Bruijn et al.26 30 used chromatographic and spectroscopic techniques to analyze the effect of reaction variables (such as pH and monosaccharide concentration) on the product profile and developed a reaction model (see Fig. 9) that emphasized the role of a-dicarbonyl compounds. Some of the features of the model shown in Fig. 9 are ... 

These so-called Pareto-based techniques do not force consolidation over multiple criteria in advance and aim to return a representation of the set of optimal compounds. They support discussion between team members who may have different views on the downstream impacts of different risk factors perhaps, for example, one team member may know that there is a reliable biomarker for one potential side-effect. This would then mean that assessing this risk need not consume much development time and cost, and the risk factor can have a reduced weighting within the target product profile being evolved by the team. 

Bayesian networks for multivariate reasoning about cause and effect within R D with a flow bottleneck model (Fig. 11.6) to help combine scientific and economic aspects of decision making. This model can, where research process decisions affect potential candidate value, further incorporate simple estimation of how the candidate value varies based on the target product profile. Factors such as ease of dosing in this profile can then be causally linked to the relevant predictors within the research process (e.g., bioavailability), to model the value of the predictive methods that might be used and to perform sensitivity analysis of how R D process choices affect the expected added... 

Fig. 2. Reactant and intermediate product profiles for Mg0-Al203 catalyst. Temperature 230°C, catalyst 2wt%, CH3OH/0H =12 1.

Figures 2 and 3 illustrate the reactant and intermediate product profiles at different reaction times for Mg0-Al203 and Ti02-S04 catalysts, respectively. The results in Fig. 2 show that over 95% triglyceride (TG) is converted to methyl ester and intermediate products within 3 h and the intermediate products of monoglyceride (MG) and diglyceride (DG) remain at a very low concentration level of 1.5% and 4%, respectively.

The catalytic pyrolysis of R22 over metal fluoride catalysts was studied at 923K. The catalytic activities over the prepared catalysts were compared with those of a non-catalytic reaction and the changes of product distribution with time-on-stream (TOS) were investigated. The physical mixture catalysts showed the highest selectivity and yield for TFE. It was found that the specific patterns of selectivity with TOS are probably due to the modification of catalyst surface. Product profiles suggest that the secondary reaction of intermediate CF2 with HF leads to the formation of R23. 

Field data obtained from three oil producing wells on the Gullfaks field correlated with H2S production profiles obtained using the hiofilm model but could not be explained by the mixing zone model. 

Figure 5.254. The product profiles indicate that no inhibition is present, since P is everywhere less than Kj/Km-...

A broad-spectrum antimicrobial target must be conserved across all pathogens of interest within a therapeutic product profile, essential for bacterial growth, and either absent, substantially different or non-essential in humans. PDF meets all of these criteria and is one of the most promising unexploited bacterial targets in the search for new antibiotics with a novel mode of action. 

SCHEME 9.15 Product profiles formed by QM3 depend on the fast and reversible addition of nucj in competition with the slow and irreversible addition of nuc2. 

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