Http Www.halliburton.com Premium.aspx Content= Premium Ss Contents Brochures Web H03131

8/8/2019 Http Www.halliburton.com Premium.aspx Content= Premium Ss Contents Brochures Web H03131

1/13

StrataSteer 3D Geosteering Service

Sperry Drilling Services' StrataSteer 3D geosteering service utilizes an iterative process

combined with innovative technologies, applications, and people to improve reservoir deliverability

through optimal wellbore positioning. This comprehensive service integrates the following

components:

StrataSteer 3D service geosteering specialist Sperry Drilling Services deep-reading and azimuthal LWD sensors Sperry Drilling Services matched drilling systems, including the Geo-Pilot rotary steerable system

StrataSteer 3D geosteering applications software INSITE data acquisition and applications software Real-time operations as the preferred service delivery methodThere are three phases to the service:

Pre-drill well plan optimization through the use of forward modeling Real-time operations to actively geosteer a wellbore into the optimum position in the reservoir by

determining the stratigraphic position based on LWD real-time measurements

Post-well detailed analysis and refinement of the geological and petrophysical models for future wellsThe StrataSteer 3D geosteering, modeling, and well plan optimization service is designed to

minimize the risk through the optimization of the pre-drill well plan. This process starts with the

quantification of uncertainty in the geological model due to seismic resolution and time to depth

conversions, structural dip errors, and lateral variations in the stratigraphic sequence. The various

uncertainties and their effect on the target well path are then evaluated by generating numerous

computer models of the various scenarios. This allows the well to be drilled in the computer

multiple times. The well path is then modified to give the best percentage chance for success by

reducing the overall risk that each of these uncertainties introduces. The result is an optimized,

yet flexible, well path that attempts to mitigate the potential risks of the project. In addition, this

allows a series of scenarios to be worked through in detail with the asset team so that a decision

tree can be built that will aid in timely decision making during the real-time operations phase.

This decision tree clearly defines the possible outcomes and the appropriate decisions, along with

the contact list for the decision makers.


2/13

As these scenarios are played out, the StrataSteer 3D geosteering specialist will customize an

operational plan that details the various likely scenarios and the resulting recommended course of

action in a decision tree. This operational plan will also include LWD sensor, telemetry format, and

data communications recommendations. This customized solution attempts to reduce the risk

through a careful analysis of the geology, the well plan, and the requirements of the target well

and reservoir. The StrataSteer 3D service specialist mentors the asset group through a

collaborative well planning process. For example, the geosteering specialist may recommend that

the ALD (azimuthal lithodensity) tool be used to obtain the real-time density image in the build

section prior to landing the well in order to determine the structural dip and dip direction so that

the well can be oriented correctly along strike at the landing point. He may also recommend that

a combination of attenuation and phase difference resistivities from the EWR-PHASE 4 sensor be

transmitted in real time based on the forward-modeling results to give the best look-ahead

capability to avoid a bed or fluid boundary.

The real-time phase of the StrataSteer 3D geosteering service includes 24/7 monitoring,

interpretation, and consulting through the use of two StrataSteer 3D service specialists. These


3/13

specialists are a resource to the asset team or geologist, providing:

StrataSteer 3D application software expertise Geosteering operations expertise Sperry Drilling Services LWD sensor response interpretation, modeling, and operations expertise Geosteering actions recommendations (The asset geologist is responsible for making the decisions, and

the StrataSteer 3D service specialist is there to advise.)

Communications of geosteering actions to the Sperry Drilling Services directional drillerThe main focus during the real-time geosteering phase is the correlation of model logs to

measured LWD log responses, geological and petrophysical model refinement, and well path re-

planning to optimize wellbore position. This immediately results in a new, corrected well plan and

a new set of operating parameters for the directional drilling tools.

When combined with the petrophysical and geological models, an interactive geosteering model is

created that can be used during the real-time execution of the job. As drilling progresses, the

formation properties and wellbore position are measured and updated. The stratigraphic position

is evaluated based on the correlation of the measured and modeled logs to correct the earth

model. The original well plan is modified so that the geological targets are updated and the

forward-looking well path intersects them. This process is repeated very quickly using the

StrataSteer 3D software to continuously correct for uncertainty and to update the wellbore

position.

The preferred delivery method for the real-time phase is through the use of real-time operations

from a customers office, although it can also be provided at the wellsite. Regardless of the

delivery method, an asset geologist is required to work with the StrataSteer 3D service

specialist and to ultimately make the final decisions. The real-time operations solution provides for

optimal utilization of these highly skilled people and enables a high-end service delivery that

allows collaborative decision making.

During the post-well analysis, the goal is to refine the geologic and petrophysical models and to

capture the knowledge gained during the real-time geosteering operations phase. During real-

time geosteering operations, the goal is to qualitatively correlate the model and LWD logs with the

goal of keeping the wellbore in the desired location. The time frame for these decisions precludes

absolute refinement of the model to obtain a quantitative correlation. However, in the post-well

analysis phase, the focus shifts to trying to accurately depict the encountered geology and to

quantitatively correlate the model log to the actual recorded LWD log. Once this is accomplished,

then this petrophysical model can be used for formation evaluation and as input to any new


4/13

geosteering projects in the same area. In addition, a final report is generated that details the

evolution of the correlation and decisions made in real time. This can then be used as a learning

tool to define a set of best practices for future jobs.

The post-well analysis can also be provided as a stand-alone service to perform a post mortem on

poorly performing wells.

The StrataSteer 3D software integrates a digital 3D geological earth model, directional well

plans, a petrophysical model, and real-time LWD sensor data into a dynamic, interactive, and

intuitive geosteering application. The service uses Landmark Graphics ZMAP ASCII output as the

geological framework for its initial model, which is later adjusted or modified according to the

actual petrophysical responses from downhole sensors. These surfaces are later accurately refined

and given back to the customer as a by-product of the geosteering process.

The StrataSteer 3D software is an INSITE systembased application that combines data from

several disciplines into a single application framework that is purpose built for geosteering

operations. These data sets include:

Offset well formation evaluation logs Offset well directional surveys and surface coordinates Target well directional well plan and surface coordinates Target well forward modeled logs Interpreted 3D geological surfaces from Landmark Graphics or others Real-time LWD logsThe StrataSteer 3D service is the first forward-modeling application to support a realistic 3D

geology model. The offset well, target well, and geology are fixed with respect to each other in 3D

space. Then the offset log is run through the square log application in the StrataSteer 3D

software to generate petrophysical log parameters, which results in a petrophysical model. The

petrophysical model is then projected to the target well using a method called pseudolog, which

constrains the method of projection based on the geological model. Once the petrophysical model

is transferred to the target well path, the forward-modeling engine can then generate synthetic

logs along the target well path that are synchronized with the intersection of the well path and

geology.


5/13


6/13

The real-time operations phase is focused on determining the stratigraphic position of the wellpath while drilling in real time. As new real-time LWD measurements are received, they are

plotted against the model logs. The StrataSteer 3D service specialist correlates the model to the

measured logs, which results in adjustments to the geology. In addition, the well path is updated

as new surveys are received, and the forward-looking well plan is dynamically and automatically

updated to hit the targets. If it is not mathematically possible to hit the next target given the

defined dogleg capability of the drilling tools that are being used, the program ignores that target

and tries to line up for the next target. If the geology modifications move the target formation

away from the dynamic well plan, the StrataSteer 3D service specialist can graphically modify

the targets by dragging them with the mouse into the desired zone. The well plan is recalculated

and updated as the targets are moved so that he can see the results of the modification. This

allows him to dynamically plan the well in the geology, ensuring optimum wellbore positioning.

This case illustrates the StrataSteer 3D services complex geology modeling capability. This

particular well was to be drilled on the flank of the structure where the sand pinched out, as can


7/13

be seen in the Gross Thickness map below. This combined with the Top of Structure map would

be utilized to manually construct a geological cross-section in the StrataSteer 3D software.

The offset well logs were loaded into the SquareLog section of the software to generate the

petrophysical parameters that would be used to calculate the synthetic model resistivity and

pseudo logs.


8/13

The geological cross-section was then built into the system by first entering several planar

geological surfaces and then modifying these based on the customer-supplied structural and

isopach maps.

First we shaped the bottom of the reservoir using the interactive geological features the program

has. A pinch out was hand drawn because digital maps were not available. The StrataSteer 3D

software uses digital 3D maps from such programs as Landmark Graphics ZMAP as the geological


9/13

input without any limitations as to the number of surfaces that can be input. In this case such

data were not readily available, and the maps therefore had to be hand made into the model.

After completing the bottom part of the reservoir, the top was drawn and a new theoretical well

plan was developed based on the new geological cross-section. Compare previous resistivity and

gamma ray modeled responses to those generated by the new geology.

With the new cross-section and well plan in place, different possible scenarios were then modeled,

such as the well exiting the bottom of the pay and through the top. Both models were then

calculated and stored.


10/13

The well was then drilled with the StrataSteer 3D software running in real time. Below the logs

are being correlated in the build section as they are compared to the respective modeled logs.


11/13

Drilling continued, and there was the need to adjust the depth for the casing point. This action

was taken with enough lead time before it was too late for any other actions, saving the well from

a costly sidetrack. Casing was then run, and the well was ready for the next section.

After casing was set, the StrataSteer 3D software was used again to navigate the remaining

lateral section. Extreme caution had to be taken to avoid exiting either top or bottom due to


12/13

mechanical instability associated with those rocks. Decisions had to be made to steer up and

down in several locations due to the irregular shape of the reservoir, which could be predicted by

using the geological/petrophysical modeling capabilities that are built into the software. The next

pictures show the whole lateral section and what the actual pinch out looks like.

This view shows the 3D geological map generated by the top of the sand. The map may be output


13/13

as an ASCII file that ZMAP can read back and the geologist can re-interpret for future drilling

projects. Also shown: TVD offset log (lower left corner); real-time resistivity (upper track), model

resistivity (next down); real-time gamma (red) and model gamma (green); interactive geological

cross-section with the actual well path (bottom).

w w w . H a l l i b u r t o n . c o m

11/21/2008

Send questions or comments about this site toHalliburton Service Centeror

call U.S. (877) 263-6071 or outside U.S. (281) 983-4900.

Copyright 2008 Halliburton. All Rights Reserved.

Terms and Conditions Privacy
mailto:[email protected]:[email protected]://www.halliburton.com/public/common/headers/terms_conds.asphttp://www.halliburton.com/public/common/headers/privacy.asphttp://www.halliburton.com/public/common/headers/privacy.asphttp://www.halliburton.com/public/common/headers/privacy.asphttp://www.halliburton.com/public/common/headers/terms_conds.aspmailto:[email protected]

Http Www.halliburton.com Premium.aspx Content= Premium Ss Contents Brochures Web H03131

Documents