Shale ///

Downhole sensors optimize gas lift

Downhole gauge and reverse gas lift valves solve a major problem.

Low-power capacitive deionization method shows promise for treating coalbed methane produced water

Small-footprint technology is shown to be effective.

Casing while drilling results in safer drilling, larger wellbores in Lake Maracaibo

Three days and more than $96,000 were saved when drilling the surface section.

Extreme drilling pushes RSS application to a new Alaskan limit

The new tool helped StatoilHydro place a long horizontal section in a thin reservoir.

New Rig Designs: Compact RCR series rigs work in the city, swamp or desert

Dietswell has developed the RCR series, a new drilling concept adapted to tropical and desert conditions.

New Rig Designs: Skidding rigs for pad drill sites

IDM’s new QUICKSKID Rigs are integrated AC drilling systems designed with a focus on pad drilling locations with multiple wellheads

New Rig Designs: Transport features enable land rig mobility over desert terrain

Bentec’s Nomad-Class rig, jointly developed with international drilling contractor KCA DEUTAG is a new land rig designed for desert terrain conditions.

Oil prices driving companies to invest in new Barnett Shale-like plays

Oil prices are again one of the hottest topics in our industry today.

Helicopter survey aids remediation of produced water-contaminated aquifer

Airborne surveys mapped conductivity to help USGS researchers find areas of high salinity in and near East Poplar oil field in northeastern Montana.

Onshore exploration and development update

Vol. 228 No. 11   NOVA SCOTIA CANADA: THE NEXT PLAY Onshore exploration and development update While offshore oil and gas exploration

Rotary steerable systems technology case studies in the Canadian Foothills: A challenging drilling environment

Crossing high-angle faults and highly dipping formations in hard rock tests the mettle of RSS systems.

RSS technology has improved, but can it be made cheaper?

RMOTC takes on increasingly important role in low-cost RSS development.

What's new in exploration

Revisiting the Barnett Shale

Characterizing fracture and matrix heterogeneities in tight gas fields

Well performance is extremely variable in the stacked sequence of tight Devonian and Mississippian carbonates in the northern part of the Waterton complex of Alberta, Canada, despite an extensive fracture system present in all the wells. To determine why some wells penetrated more permeable fractures than others, a full reinterpretation of the geophysical, structural, stress, matrix and dynamic data sets was carried out at West Carbondale field in the complex. Flow simulations at sector scales using discrete fracture network models and full-field continuum modeling were used to test a range of geological and dynamic scenarios. For this field, the best-fit dynamic models consist of a major fracture zone, corresponding to either a seismic scale lineament or zone of enhanced curvature, trending through the area of most prolific wells. Outside this zone, the vast majority of the fracture system makes little contribution to flow in the wells.

Major Chinese field evaluated using combined seismic and well logging methods

In Lunnan field, an Ordovician carbonate buildup in the Tarim basin of western China, the reservoir was identified and characterized using a combination of seismic techniques and well logging methods. The seismic techniques included 3D seismic visualization and seismic attribute analyses such as coherence and root-mean-square amplitude. Well logging methods used were Formation Micro-Imaging (FMI), Electric Micro-Imaging (EMI) and Dipole Sonic Imaging (DSI). The research indicated that the Lunnan Ordovician buried hill is an oil-producing reservoir that developed under the unconformity, with a thickness of 0-150 m. The slope of the buried hill was determined to be the best location for development of the reservoir. Using the above methods, the exploration success rate was increased by 117%, and crude oil production increased to over 300 times its pre-characterization rate. The reservoir characterization also enabled a major upward re-evaluation of Lunnan field’s in situ resources.

Porosity partitioning and permeability quantification in vuggy carbonates

A pilot study of 13 wells in Means oil field of the Permian basin, West Texas, established porosity-permeability relationships for the Permian Queen, Grayburg and San Andres formations. The optimized workflow used borehole image and conventional log processing with calibration to core data. This approach allowed the quantification of porosity and permeability heterogeneity in vuggy carbonate facies in the field. INTRODUCTION Means field was discovered in northeast Andrews County, West Texas, in 1934 with the Humble R. M. Means No. 1 well, Fig. 1. Oil production is from Permian strata, mainly the Guadalupian San Andres, Grayburg and Queen formations, with supporting production from Wolfcampian and Leonardian strata. These formations are predominantly dolomitized marine carbonate platform successions, with the exception of the lower Grayburg, which is a mixed carbonate-siliciclastic reservoir facies. Typical completion strategies are to fracture-stimulate the tighter Grayburg reservoirs and to perforate and acidize the better San Andres reservoirs.

Vertical-tube evaporator system provides SAGD-quality feed water

Water treatment and steam generation methods for heavy oil recovery processes have evolved rapidly. Traditionally, Once-Through Steam Generators (OTSGs), driven by natural gas, have been used to produce about 80% quality steam (80% vapor, 20% liquid) for injection into the well to fluidize the heavy oil, especially for cyclic steam operations. However, the more recent Steam-Assisted Gravity Drainage (SAGD) method requires 100% quality steam for injection. The use of OTSG for SAGD applications requires a series of vapor-liquid separators to produce the requisite steam quality. For both SAGD and non-SAGD applications, pre-treatment of the OTSG feed water has consisted of silica reduction in a hot or warm lime softener, filtration and hardness removal by Weak Acid Cation (WAC) ion exchange. In most cases, the OTSG blowdown is disposed by deep well injection. As the use of SAGD increased, the traditional produced water treatment and steam generation methods were re-evaluated...

What's new in exploration

I expected strong reader response to my August column, “The Fayetteville Shale: An early evaluation,” and I got it. Most reactions were positive, but the negative comments are more interesting and revealing. Critics make some well-reasoned points and legitimate criticism of my analysis. Their comments also illustrate how the industry is divided in its opinion about the Fayetteville and Barnett Shale plays. Several important points emerged: Recently completed Fayetteville Shale wells that used slick-water fracture stimulation should be profitable. Apparently, most of the horizontal wells that I evaluated were completed using less effective stimulation techniques. The application of hyperbolic decline models to preliminary Fayetteville Shale production results in higher economic reserves and longer-lived production than I used in my analysis. Economic models used by some Fayetteville operators incorporate lower lease operating costs than I presented, and some companies do not charge certain overhead costs against production sales as I did.

A low-cost monitoring alternative for unconventional gas

Producers of unconventional gas fields are often forced to rely on group metering, since the cost of metering individual wells by conventional Supervisory Control And Data Acquisition (SCADA) cannot be justified for the lower production volumes in these fields. This can lead to higher operational costs and lower production, because operators do not have data from specific wells that would allow them to optimize service operations, minimize downtime and maximize production. A low-cost monitoring solution has been developed specifically targeted at unconventional wells. Advanced Flow Technologies’ Flow-Net is a Web-based system that is easy to install and non-intrusive, using an acoustic sensor clamped to the outside of the pipe or wellhead. An optional pressure sensor can be added. Pengrowth has applied the monitoring system to the North Twining coalbed methane (CBM) field. The system has been used to monitor new well production, optimize water removal, optimize gathering systems and enhance reporting above and beyond conventional spot-testing methods.

“Farming" late-generation natural gas shows potential

An ultra-shallow glacial aquifer in South Dakota provides perspectives on microbial methane systems in the eastern Great Plains, USA.

Coalbed methane activity cools off

North American CBM drilling has leveled out, and drilling is expected to drop over 22% in 2007.