Accurate Oil Saturation Determination and Monitoring in a Heavy Oil Reservoir

Harness, P.E.; Shotts, Noel; Hemingway, Jim; Rose, David; Sluis, Roy van der

doi:10.2118/46245-ms

Cited by 16 publications

(8 citation statements)

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“…Oil saturation and fluid phase are both characterized using carbon-oxygen or reservoir saturation tool (RST) logs also taken at the observation wells on the basis of a 3-4 yr cycle time (Harness et al, 1998;Zalan et al, 2003). Although the well spacing is larger for the observation wells than for the production wells, these logs allow for observation of changes in fluid contacts with time, and changes in reservoir saturation.…”

Section: Temperature Saturation and Fluid-phase Modelingmentioning

confidence: 99%

“…Oil saturation is characterized using the RST, as described previously. There is clearly more uncertainty defining oil saturation than other parameters, including comparison of RST calculated oil saturation to core data, shoulder effects on logs, and issues in calibration (see examples in Harness et al, 1998). However, internal quantitative studies show that changes in oil volume at the pattern level highly correlate with produced volumes.…”

Section: Uncertainties In Reservoir Character and Productivitymentioning

confidence: 99%

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Creation and utility of a large fit-for-purpose earth model in a giant mature field: Kern River field, California

Beeson¹,

Hoffman²,

Larue³

et al. 2014

Bulletin

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A B S T R A C TReservoir management studies of California's Kern River field rely on a full-field 155-million cell three-dimensional (3D) earth model. This full-field model provides input for reserves estimation as well as the identification, targeting, and ranking of remaining opportunities. The earth model is regarded as "fit for purpose" in that characteristics of the model are aligned with specific needs for reservoir management. Normalized resistivity logs from more than 12,000 wells are used to establish lithology and reservoir architecture. Temperature, steam, gas, and oil saturation logs from over 650 boreholes provide regular periodic surveillance for identifying changes in fluids and temperature. Changes in fluid contacts and saturations are integrated with reservoir architecture three times each year. These model updates are important to the development teams for staying current on changes in their project area. The integration of these data provides the basis for linked reserves and resource estimation and the identification and development of remaining opportunities. Kern River reserves and resources are estimated from the model for over 130 internal reporting entities. For asset reservoir management purposes, reserves are updated for over 160,000 entities (based on patterns, zones, and reserves) across the 12-sq-mi (31-sq-km) field. The updated reserves supply input to reserves distribution maps and spreadsheets used for evaluating workover and new development opportunities. Some of these opportunities represent heat mining of untapped hot oil zones whereas other opportunities are cold and require the introduction of steam to mobilize the oil. Using multiple reservoir property characteristics as filter criteria for identifying remaining opportunities is an important tool used at

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Section: Temperature Saturation and Fluid-phase Modelingmentioning

confidence: 99%

Section: Uncertainties In Reservoir Character and Productivitymentioning

confidence: 99%

Creation and utility of a large fit-for-purpose earth model in a giant mature field: Kern River field, California

Beeson¹,

Hoffman²,

Larue³

et al. 2014

Bulletin

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show abstract

“…Generally, cased-hole temperature logs are collected yearly, whereas cased hole saturation and fluid phase data are collected every 3 to 4 years, Harnes et al, [11], Zalan et al, [12]. This surveillance data from observation wells is playing a critical role in the dynamic update of the reservoir modeling allowing for monitoring of fluid movements and steam depletion.…”

Section: Available Data and 3d Earth Modelmentioning

confidence: 99%

Identification of Horizontal Well Placement Using Fuzzy Logic

Popa

2013

Day 3 Wed, October 02, 2013

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Estimated to have over 3.5 billion barrels of original oil in place, the 114 year old Kern River Oil Field was a sleeping giant until the late 1960's when steamflooding began and oil production ramped up from 19,000 to over 142,000 BOPD by the mid 1980's. Kern River Field is now in decline, but still produces over 70,000 BOPD, making it one of the largest onshore oil producers in the continental United States. In 2007 the field's cumulative production reached two billion barrels of heavy oil. With the introduction of horizontal wells in 2007, the production decline curve that had been at approximately 6%, began to flatten and today the decline rate is at 2%. Since the discovery of the field, over 19,000 wells have been drilled with the largest producers, horizontal wells, drilled in the last 6 years.Though the oil production is in decline, new opportunities are continuing to be identified and exploited using a broad array of reservoir management tools. The primary tool utilized for both tactical and strategic planning is a full field 3D reservoir model. The static lithologic framework for this full field model uses over 12,500 normalized resistivity logs. Temperature, steam and oil saturation data from a network of over 650 surveillance wells are periodically incorporated into this model to provide current reservoir conditions. Project teams first identify their opportunities in the full field model using a filtering criteria. For example, horizontal infill wells seeking "hot bottom oil" within partially depleted reservoir intervals can be developed around geo-body criteria including property cut-off values for gas saturation, oil saturation, temperature, resistivity and thickness.The filtering criterion was useful in identifying well locations; however, the pool of candidates significantly declined due to the exclusive nature of the hard cut-off approach. The lack of candidates threatened the continued horizontal drilling program. A Fuzzy Logic approach was considered to deal with the imprecise information and aggregate multiple variables with suitable membership functions. The Fuzzy Inference System (FIS) using the Mamdani model incorporated knowledge rules developed by the asset team. Once developed, the system was run for each grid block of the nine productive formations of the field, generating areas of interest for identification and placement of horizontal wells.The output of the system allowed generation of "quality maps" which revealed target areas with substantial potential of horizontal drilling. Moreover, some of these target areas were not even considered in previous searches. In a first pass, approximately 600 new locations were identified.The paper presents a new approach for identification and placement of horizontal wells using fuzzy logic. In addition to the large number of wells identified, the methodology focused the asset team on high potential areas, as well as offered an objective approach to deal with imprecise and uncertain reservoir information. Due to its success in Kern River, the tech...

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“…The poor results of the water flooding in the area was considered to be due to the presence of high permeability streaks (Super-K). Identifying and evaluating the geometry of the "Super-K" streaks in the reservoir is one of the largest factors in determining the success of the reservoir development, particularly with an EOR scheme (9) . The detailed locations and the generation mechanism for the "Super K" streaks have not been possible with the limited amount of available field data.…”

Section: Field Example: Well Amentioning

confidence: 99%

Identification of High-Permeability Dolomitized Zones Using Inelastic Magnesium Yield

Hemingway

Doi²,

Adani

2001

All Days

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractMassive carbonate formations that appear homogeneous over a large vertical interval on conventional openhole wireline logs may actually have permeability that varies by several orders of magnitude. Such was the case for a reservoir in a thick middle Cretaceous carbonate formation in the Arabian Gulf. Production performance indicated the presence of a very high permeability, or "Super K," zone in the reservoir. Identification of this zone and an evaluation of its geometry were crucial for efficient development of the field, which required an enhanced oil recovery (EOR) scheme to compensate for insufficient natural driving forces.The zone was correlated with dolomitization in the carbonate reservoir, providing details on location, geometry and generation mechanism. The correlation was based on the knowledge that replacement of calcium with magnesium in the dolomitization process causes a slight shrinkage and resulting microfracture systems, which thereby significantly increase bulk permeability.Recent developments in full-spectrum PNS measurements have made the direct detection of magnesium possible based on a very pronounced low energy peak in the inelastic gamma ray spectrum. This direct measurement of magnesium enables us to quantify the volume of dolomite within the carbonate formation in a cased hole or openhole environment and to adequately characterize rock properties, which are essential for the establishment of the future development scheme.

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Accurate Oil Saturation Determination and Monitoring in a Heavy Oil Reservoir

Cited by 16 publications

References 0 publications

Creation and utility of a large fit-for-purpose earth model in a giant mature field: Kern River field, California

Creation and utility of a large fit-for-purpose earth model in a giant mature field: Kern River field, California

Identification of Horizontal Well Placement Using Fuzzy Logic

Identification of High-Permeability Dolomitized Zones Using Inelastic Magnesium Yield

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