This section addresses drilling, downhole completions and servicing technology, borehole integrity, and reservoir treatments performed downhole. For each there appears to be a continual delivery of innovative technology offering incremental improvements to performance and/or cost. Indeed, there is a widely held view that improvements in this area will now always be incremental - evolutionary rather than revolutionary.

Contributions to lower costs/increased efficiency come from various sources including:

• drilling and deploying downhole equipment more quickly;

• using more reliable/more durable equipment to reduce downtime for maintenance, repair and replacement;

• increasing automation/de-manning;

• using less expensive (and standardised) technology;

• using lighter weight equipment, especially in drilling;

• using less or less expensive consumables (reducing downstream costs in subsequent clean-up treatment and/or reducing recurrent costs);

• avoiding formation damage/preventative sand control;

• getting things right first time in terms of well placement, drilling and other downhole operations.

With many, often interdependent factors influencing the success and cost of downhole operations, an important, underpinning goal is process and technology optimisation. This may not require RTD in all cases but does need knowledge of and the appropriate use of best available technology and working practices. It also requires a multi-disciplinary rather than a wholly procedural approach to design and operations.

There is merit in improving the systematic collation of knowledge and experience which otherwise may be held only in the heads of individual engineers or individual asset teams. Access to computer-based expert systems appear to be the way ahead but developments to date have not always delivered what was claimed, leaving a negative view of their usefulness with many engineers. However, there will be increasing business pressure to ensure that for each well drilled, maximum use is made of previous corporate/industry knowledge of local or analogous conditions to minimise the learning curve and avoid unnecessary costs.

With continued demand for further drilling efficiency, gains in performance from incremental improvements to traditional methods are likely to lead to diminishing returns. Step-out thinking for a new generation of drilling technology will be at a premium: at present it is probable that coiled tubing (CT) technology offers one key to the development of innovative approaches. An integrated system incorporating robust CT, reliable downhole motors to drive/control the bit, enhanced downhole instrument actuation/control and data telemetry, real-time geo-imaging, interpretation and response, offers exciting new opportunities in the decade ahead.

Of course an alternative route to cost reduction is to drill fewer wells while still achieving acceptable reservoir evaluation and/or production. Technology challenges impacting upon this include improved reservoir rock and fluid imaging by remote means (reducing need for appraisal drilling and reducing in-fill drilling failures). Other factors which should be addressed include:

• the quality and quantity of data required to undertake development of a small field;

• the application of multilateral/multibranch technology.

The relevant RTD topics are presented in Tables 9 to 15.

Table 9 Drilling

Table 10 Artificial lift technology

Table 11 Downhole technology for extended research, horizontal and multilateral / multibranch wells

Table 12 Materials for downhole HP/HT service

Table 13 Well-bore integrity

Table 14 Reservoir simulation

Table 15 Production chemistry