Abstract

Utilizing all information and technologies available is the key to successful application of horizontal wells in Oil industry. Recent advances in horizontal drilling, measurement-while drilling (MWD) and three-dimensional (3-D) seismic techniques have made horizontal well drilling a routine practice. In today's drilling decisions, horizontal wells are always strong alternatives to vertical wells. Due to higher costs associated with horizontal wells, proper selection of a candidate is a prerequisite. The use of a simplified or ‘generic’ model approach to estimate horizontal well performance for various reservoir drive mechanisms is discussed in this paper. Typical horizontal drilling projects are multi-disciplinary; involving geological, geophysical, reservoir, drilling, completion and production engineering support. A good geological description of the reservoir is critically important. Reservoir simulation and 3-Dseismic analysis can improve the chances of success. Improper placement of an initial horizontal borehole in the reservoir could lead to subsequent drilling of a second leg side/racking from the original hole in an attempt to find more productive reservoir rock. This could be avoided if effective geosteering and real-time control drilling were applied when drilling the horizontal section. If proven successful, this approach could be applied in exploration. Post-drilling analysis is also important to optimize and ensure future success of similar projects. Field examples are presented to illustrate the need for an integrated approach for horizontal well developments.

Introduction

The need for integrating advances in information technology, horizontal drilling technology, measurement-while-drilling (MWD), logging-while-drilling (LWD) and 3-D seismic is an important aspect of making horizontal drilling a routine practice. Numerous technologies are converging which can significantly decrease the cost and improve the effectiveness of horizontal well development. These include advances in bit and drilling motor design, MWD Data gathering, transmission and processing, vertical well re-entry options, geological computer applications and geosteering. Information technology ties together advances in3-D seismic, logging and geosteering with real-time control drilling and computer visualization techniques to precisely track bit location and minimize the need for sidetracking. Applications of current communications technology could permit experienced home office personnel to assist field drilling personnel in real-time adjustments of drilling operations. The resultant increase in drilling speed and accuracy, and the effective processing and interpretation of substantially larger amounts of drilling data, should minimize exposure of the horizontal wellbore to drilling fluids and over pressurization, reducing drilling and completion costs and minimizing wellbore damage. Cost control is critical in older and depleted reservoirs, where vertical wells are not economic and horizontal wells can be justified only if they perform up to expectations. In many cases vertical wells are have watered out and precision drilling is necessary) to control or delay water production in these oil-over-water reservoirs. Recovery of additional hydrocarbons can be accomplished in these reservoirs, with the proper application of horizontal drilling technology. The business environment is also changing rapidly the ongoing process of downsizing, "de-layering" and mergers has created a need for rapid and accurate screening of horizontal well prospects.

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