Detecting Compartmented Gas Reservoirs through Production Performance

Lord, M. E.; Collins, Richard

doi:10.2118/22941-ms

Cited by 17 publications

(5 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The predominant assumption that is made in applying material balance equations is that measured pressure represents uniform static pressure throughout a contiguous reservoir (13,14) . Thus, it is critical to be able to deconvolve the effects of reservoir compartmentalization and local transient effects over continuous reservoir.…”

Section: Materials Balance Analysismentioning

confidence: 99%

The Importance of Comprehensive Gas Field Surveillance

Baker

2005

Journal of Canadian Petroleum Technology

View full text Add to dashboard Cite

Outline of Problem Gas field surveillance historically has not been given the same priority as oil field surveillance because of a couple of significant stumbling blocks: first, the apparent simplicity of gas reservoirs- at least upon initial examination; and, second, the historically low commodity prices of gas relative to oil. The presumption that gasfield surveillance was easily derived from the knowledge that, in most gas pools, single phase flow existed, leading to the assumption that "tank like" behaviour was occurring. However, on examination of hundreds of gas pools, my viewpoint on that matter has changed dramatically. Of course, today's commodity prices are also changing both the relative and absolute perceptions about the economic importance of gas. Initially, in the Western Canadian Sedimentary Basin (WCSB), industry encountered and dealt with very high quality gas resources, such as those found in Leduc reservoirs. These reservoirs had high permeability and were not compartmentalized; this naturally led to the "tank model" approach. These pools had behaviour as illustrated by Figure 1(a). In the last few years, we have moved from what I would term "Tier One" resources to lower quality ones, as shown in Figure 2. Indeed, a large portion of reservoirs do not exhibit that "tank like" behaviour shown in Figure 1(a); instead, there is often a fairly large pressure gradient across pools and non-tank like behaviour, such as that shown in Figure 1(b). This paper stresses the importance of comprehensive surveillance for those types of fields, using simple methods of production analysis and pressure diagnostic tools. There has been an explosion of research on using gas rate decline methods to characterize reservoirs with an effective permeability less than 0.1 mD (k < 0.1mD). However, the transient gas rate decline and practical analysis of such low permeability gas reservoirs are not the focus of this paper. This paper instead focuses on gas field surveillance for multi-well pools in which wells are in boundary dominated flow. The objectives of any gas surveillance program are relatively simple:What is the Original Gas in Place (OGIP)?;What is the current gas in place?;Where is the current gas in place located?;What is the permeability or capacity (kh) of the wells and pool?;What are the limiting considerations to gas recovery factor (low permeability, liquid lifting problems, low continuity, high back pressure, or water influx)?;What can be done to improve the rate of recovery and the recovery factor? and,Can this be done economically? In order to understand the above questions, we must relate the static model (geological/petrophysical) to the dynamic (production/ pressure data) one. Surveillance Methodology The following work flow has proven to be useful in determining the true potential of gas reservoirs:Examine the production profile of individual wells and the field. Examine the initial production rates (IP), interference effects, types of decline, and decline rates (production diagnostics);

show abstract

Section: Materials Balance Analysismentioning

confidence: 99%

The Importance of Comprehensive Gas Field Surveillance

Baker

2005

Journal of Canadian Petroleum Technology

View full text Add to dashboard Cite

show abstract

“…Another way that long-term pressure data may be used to infer the presence of a partially drained reservoir compartment in communication with an already producing reservoir is by using gas well material balance or "p/z" analysis. This approach has been described elsewhere (Lord andCollins, 1991,1992), and it was used extensively in the Gulf Coast phase of the Bureau's Secondary Gas Recovery research.…”

Section: P/z Analysismentioning

confidence: 99%

“…As the figure shows, as gas from the secondary compartment migrates into the primary compartment, it acts to maintain the average reservoir pressure at a level higher than would be anticipated, causing the flattening in the p/z curve. In some instances, using these data and the G-WIZ software developed as part of the Gulf Coast research (Lord andCollins, 1991,1992), quantitative estimates of both primary and -248-…”

Section: -Vf 'mentioning

confidence: 99%

Secondary natural gas recovery: Targeted applications for infield reserve growth in midcontinent reservoirs, Boonsville Field, Fort Worth Basin, Texas. Topical report, May 1993--June 1995

Hardage¹,

Carr²,

Finley³

et al. 1995

View full text Add to dashboard Cite

“…Pressure discontinuities often observed during field development can be indicative of reservoir compartmentalization. 1,2 Well production histories can also provide important evidence of reservoir compartmentalization in oil and gas reservoirs 2 . A compartmentalized reservoir system consists of two or more distinct reservoirs that may be in hydraulic communication.…”

Section: Introductionmentioning

confidence: 99%

Identifying Reservoir Compartmentalization and Flow Barriers Using Primary Production: A Streamline Approach

Parikh

Datta‐Gupta

et al. 2002

SPE Annual Technical Conference and Exhibition

View full text Add to dashboard Cite

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractReservoir compartmentalization and flow barriers such as sealing faults or continuous low permeability trends can have a significant impact on the field development strategy. Identifying the location and spatial distribution of such barriers will be critical to optimizing infill well locations, particularly in the early stages of field development with limited well data.Recent advances in streamline modeling allows us to compute drainage volumes during primary production using a 'diffusive' or 'pressure' time of flight during streamline simulation. We propose a novel approach that utilizes the streamline-based drainage volume computations to infer reservoir compartmentalization during primary production. Our approach consists of two steps. First, we perform a traditional decline type curve analysis of the primary production data to identify well communications and estimate the drainage volume of individual wells. Second, starting with a geological model the drainage volumes of each well are recomputed using a streamline-based flow simulation. Finally, reservoir compartmentalization and flow barriers are inferred through a matching of the streamline-based drainage volumes with those from the decline curve analysis. Our approach is completely general and can be applied to reservoirs in the early stages of field development and with very few wells. It relies on commonly available data, that is, primary production and bottom-hole pressure data. Also, the results are relatively insensitive to the fine-scale heterogeneity that can be difficult to characterize.We demonstrate the power and utility of our proposed method using synthetic and field examples. The synthetic examples validate the approach and include a 3D compartmentalized reservoir with multiple wells. The field example is from a field in the Gulf of Mexico. Starting with a reservoir model based on well log and seismic data, reservoir compartmentalization and flow barriers are identified from three years of primary production response. The results are verified via performance forecasting and subsequently utilized to optimize field development and infill well locations.

show abstract

Detecting Compartmented Gas Reservoirs through Production Performance

Cited by 17 publications

References 9 publications

The Importance of Comprehensive Gas Field Surveillance

The Importance of Comprehensive Gas Field Surveillance

Secondary natural gas recovery: Targeted applications for infield reserve growth in midcontinent reservoirs, Boonsville Field, Fort Worth Basin, Texas. Topical report, May 1993--June 1995

Identifying Reservoir Compartmentalization and Flow Barriers Using Primary Production: A Streamline Approach

Contact Info

Product

Resources

About