Method of estimating electrical parameters of an earth formation with a simplified measurement device model

A processor-readable medium on which processor-executable logic may be stored, the processor-executable logic disposed to generate instructions to a computer processor, the instructions disposed to cause the computer processor to follow a method of estimating electrical parameters of an earth formation using a measuring device disposed to be deployed in a borehole, the measuring device disposed to collect formation data, the measuring device having a pre-established model associated therewith, the pre-established model governing the processing of the formation data to determine electrical parameters regarding the earth formation, method comprising:

• (a) providing a simplified model associated with the measuring device, the simplified model making at least one simplifying assumption about the pre-established model;
• (b) receiving a set of collected formation data regarding the earth formation, the set of collected formation data collected by the measuring device;
• (c) normalizing the set of collected formation data to derive a renormalized dataset, wherein the renormalized dataset is substantially consistent with each of the simplifying assumptions in (a);
• and
• (d) applying the renormalized dataset to the simplified model to estimate at least one electrical parameter of the earth formation.

A method of estimating electrical parameters of an earth formation using a measuring device disposed to be deployed in a borehole, the measuring device disposed to collect formation data via analysis of an electrical signal transmitted by the measuring device, the measuring device having a pre-established model associated therewith, the pre-established model governing the processing of the formation data to determine electrical parameters regarding the earth formation, the method comprising:

• (a) providing a simplified model associated with the measuring device, the simplified model making at least one simplifying assumption about the pre-established model;
• (b) receiving a set of collected formation data regarding the earth formation, the set of collected formation data collected by the measuring device;
• (c) normalizing the set of collected formation data to derive a renormalized dataset, wherein the renormalized dataset is substantially consistent with each of the simplifying assumptions in (a), said normalizing including transforming the set of collected formation data into the renormalized dataset according to a predefined one-dimensional look-up table comprising a plurality of sets of table data, each set of table data matched to a corresponding one of a plurality of hypothetical earth formations, each set of table data further including a predicted measurement and a corresponding renormalized measurement that are each indicative of an electrical parameter of the corresponding hypothetical earth formation, wherein transformation from each predicted measurement to its corresponding renormalized measurement substantially reflects application of one of the simplifying assumptions to the predicted measurement;
• (d) applying the renormalized dataset to the simplified model to estimate at least one electrical parameter of the earth formation.

A method of estimating electrical parameters of an earth formation using a measuring device disposed to be deployed in a borehole, the measuring device disposed to collect formation data, the measuring device having a pre-established model associated therewith, the pre-established model governing the processing of the formation data to determine electrical parameters regarding the earth formation, the method comprising:

• (a) providing a simplified model associated with the measuring device, the simplified model making at least one simplifying assumption about the pre-established model;
• (b) receiving a set of collected formation data regarding the earth formation, the set of collected formation data collected by the measuring device;
• (c) normalizing the set of collected formation data to derive a renormalized dataset, wherein the renormalized dataset is substantially consistent with each of the simplifying assumptions in (a), said normalizing including transforming the set of collected formation data into the renormalized dataset according to weighted sums, the weighted sums comprising:
• 38 g a ′ = ∑ i = 1 N ⁢ c ia ⁢ f ia ⁡ ( g a ) g p ′ = ∑ i = 1 N ⁢ c ip ⁢ f ip ⁡ ( g p )
• where ga and gp represent collected formation data, g′a and g′p represent corresponding members of the renormalized dataset, i=1 to N terms in the weighted sums, ƒia and ƒip are functions representing preselected transformations between mandrel and point-dipole data over prescribed trajectories in the ga, gp plane, and cia and cip are coefficients chosen to produce values for g′a and g′p that approximate point-dipole values over an anticipated range of ga and gp.;
• and
• (d) applying the renormalized dataset to the simplified model to estimate at least one electrical parameter of the earth formation.