Achieving Better Understanding of Reservoir Connectivity through the Application of FPWD, Complemented by Advanced LWD Measurements

Fey, Scott²; Platt, Chris¹; Kienast, Val¹; Watcharanatakul, Rattana¹; Oglesby, Chris¹; Maeso, Carlos²; Duangprasert, Tanabordee²
¹Pearl Oil Thailand, Bangkok, Thailand.
²Schlumberger, Kuala Lumpur, Malaysia.

For the past decade the petroleum industry has become more aware that reservoirs previously thought to be laterally expansive and connected may have a moderate to high degree of compartmentalization. Depositional settings may result in formations that appear similar when evaluated using petrophysical techniques, but in fact can be separate reservoir compartments. Faults commonly exist on a sub-seismic level which can reduce the effective lateral reservoir extent. Further complicating reservoir understanding, as a reservoir progresses through production life faults may change character from sealing to non-sealing and vice versa. Poor understanding of reservoir connectivity can negatively impact reservoir modeling and production forecasting, result in improper completion placement or type, and in the worst cases can lead to premature field abandonment.

For years the industry has made a common practice of using pressure measurements to distinguish where compartments exist and establish zonal connectivity. This has become more challenging with the industry move to deviated and horizontal drilling in development drilling in an effort to establish more reservoir contact. In many cases, operators have assumed uniform pressure connectivity simply because there was previously no reasonable means to measure pressure in long horizontal or extended reach wells. With the advent of Formation Pressure While Drilling (FPWD) tools, we now have the capability to convey a formation testing tool in the drilling BHA through the most challenging well paths.

In this paper we will review how an operator in the Gulf of Thailand used FPWD in a series of development wells to better understand reservoir connectivity. The pressure data provided insight to remaining zones with commercial potential, zones being depleted from nearby producers, and zones not yet produced at the far length of the offset wells. The latest LWD measurements complemented the FPWD tool to identify possible target sands and place the well in the best part of the reservoir.

Six wells and multiple reservoir units were evaluated using FPWD technology. The results will be discussed, along with best practices and lessons learned. The paper will demonstrate that using FPWD technology is a low risk solution to increasing reservoir understanding while drilling highly deviated and horizontal development wells.

AAPG Search and Discovery Article #90155©2012 AAPG International Conference & Exhibition, Singapore, 16-19 September 2012