Method of sampling environmental conditions with a self-contained downhole gauge system

Claim 1

A method of controlling the rate at which a battery-powered downhole logging tool samples and records a detected condition within a well bore, comprising the steps of: (a) initializing a sample counter within the tool to zero; (b) selecting the shortest one of a plurality of sample rate intervals; (c) reading and recording in the tool a first sample of the condition at a first sample time; (d) reading a second sample of the condition at a second sample time in correspondence with the selected sample rate interval; (e) reading a third sample of the condition at a third sample time in correspondence with the selected sample rate interval; (f) computing from the first, second and third samples a prediction value for the n-th sample, where n is an integer not less than 2; (g) reading an n-th sample at an n-th sample time; (h) determining whether each n-th sample is within a predetermined threshold of the predicted value for such n-th sample; (i) recording in the tool the (n-1)-th sample, resetting the sample counter to zero, and repeating steps (f) through (i) commencing with the (n-1)-th sample if the n-th sample is not within the predetermined threshold of the predicted value for the n-th sample; (j) incrementing the sample counter if the n-th sample is within the predetermined threshold of the predicted value; (k) determining whether the sample counter has reached a predetermined maximum count; (l) repeating steps (g) through (l) if the sample counter limit has not been reached; (m) increasing the sample interval to the next longer one of the plurality of sample rate intervals if the predetermined maximum count has been reached and repeating steps (f) through (m) commencing with the (n-1)-th sample; (n) monitoring the battery to determine if it is below a predetermined threshold; and (o) changing the sample rate interval to a longer one of the plurality of sample rate intervals if the battery is below the predetermined threshold.

Claim 2

A method of controlling the rate at which a battery-powered downhole logging tool samples and records a detected condition within a well bore, comprising the steps of: (a) initializing a sample counter within the tool to zero; (b) selecting the shortest one of a plurality of sample rate intervals; (c) reading and recording in the tool a first sample of the condition at a first sample time; (d) reading a second sample of the condition at a second sample time in correspondence with the selected sample rate interval; (e) reading a third sample of the condition at a third sample time in correspondence with the selected sample rate interval; (f) computing from the first, second and third samples a prediction value for the n-th sample, where n is an integer not less than 2; (g) reading an n-th sample at an n-th sample time; (h) determining whether each n-th sample is within a predetermined threshold of the predicted value for such n-th sample; (i) recording in the tool the (n-1)-th sample, resetting the sample counter to zero, and repeating steps (f) through (i) commencing with the (n-1)-th sample if the n-th sample is not within the predetermined threshold of the predicted value for the n-th sample; (j) incrementing the sample counter if the n-th sample is within the predetermined threshold of the predicted value; (k) determining whether the sample counter has reached a predetermined maximum count; (l) repeating steps (g) through (l) if the sample counter limit has not been reached; (m) increasing the sample interval to the next longer one of the plurality of sample rate intervals if the predetermined maximum count has been reached and repeating steps (f) through (m) commencing with the (n-1)-th sample; (n) monitoring the battery to determine if it is below a predetermined threshold; and (o) changing the sample rate interval to a longer one of the plurality of sample rate intervals if the battery is below the predetermined threshold.

Claim 3

A method of controlling the rate at which a downhold logging tool samples and records, in a memory, a detected condition within a well bore, comprising the steps of: (a) initializing a sample counter within the tool to zero; (b) selecting the shortest one of a plurality of sample rate intervals; (c) reading and recording in the tool a first sample of the condition at a first sample time; (d) reading a second sample of the condition at a second sample time in correspondence with the selected sample rate interval; (e) reading a third sample of the condition at a third sample time in correspondence with the selected sample rate interval; (f) computing from the first, second and third samples a prediction value for the n-th sample, where n is an integer not less than 2; (g) reading an n-th sample at an n-th sample time; (h) determining whether each n-th sample is within a predetermined threshold of the predicted value for such n-th sample; (i) recording in the tool the (n-1)-th sample, resetting the sample counter to zero, and repeating steps (f) through (i) commencing with the (n-1)-th sample if the n-th sample is not within the predetermined threshold of the predicted value for the n-th sample; (j) incrementing the sample counter if the n-th sample is within the predetermined threshold of the predicted value; (k) determining whether the sample counter has reached a predetermined maximum count; (l) repeating steps (g) through (l) if the sample counter limit has not been reached; (m) increasing the sample interval to the next longer one of the plurality of sample rate intervals if the predetermined maximum count has been reached and repeating steps (f) through (m) commencing with the (n-1)-th sample; (n) detecting when the memory has been filled to a predetermined threshold; and (o) changing the sample rate interval to a longer one of the plurality of sample rate intervals when the memory has been filled to the predetermined threshold.

Claim 4

A method of controlling the rate at which a downhold logging tool samples and records, in a memory, a detected condition within a well bore, comprising the steps of: (a) initializing a sample counter within the tool to zero; (b) selecting the shortest one of a plurality of sample rate intervals; (c) reading and recording in the tool a first sample of the condition at a first sample time; (d) reading a second sample of the condition at a second sample time in correspondence with the selected sample rate interval; (e) reading a third sample of the condition at a third sample time in correspondence with the selected sample rate interval; (f) computing from the first, second and third samples a prediction value for the n-th sample, where n is an integer not less than 2; (g) reading an n-th sample at an n-th sample time; (h) determining whether each n-th sample is within a predetermined threshold of the predicted value for such n-th sample; (i) recording in the tool the (n-1)-th sample, resetting the sample counter to zero, and repeating steps (f) through (i) commencing with the (n-1)-th sample if the n-th sample is not within the predetermined threshold of the predicted value for the n-th sample; (j) incrementing the sample counter if the n-th sample is within the predetermined threshold of the predicted value; (k) determining whether the sample counter has reached a predetermined maximum count; (l) repeating steps (g) through (l) if the sample counter limit has not been reached; (m) increasing the sample interval to the next longer one of the plurality of sample rate intervals if the predetermined maximum count has been reached and repeating steps (f) through (m) commencing with the (n-1)-th sample; (n) detecting when the memory has been filled to a predetermined threshold; and (o) changing the sample rate interval to a longer one of the plurality of sample rate intervals when the memory has been filled to the predetermined threshold.

Claim 5

A method of controlling the rate at which a battery-powered downhole logging tool samples and records, in a memory, a detected condition within a well bore, comprising the steps of: (a) initializing a sample counter within the tool to zero; (b) selecting the shortest one of a plurality of sample rate intervals; (c) reading and recording in the tool a first sample of the condition at a first sample time; (d) reading a second sample of the condition at a second sample time in correspondence with the selected sample rate interval; (e) reading a third sample of the condition at a third sample time in correspondence with the selected sample rate interval; (f) computing from the first, second and third samples a prediction value for the n-th sample, where n is an integer not less than 2; (g) reading an n-th sample at an n-th sample time; (h) determining whether each n-th sample is within a predetermined threshold of the predicted value for such n-th sample; (i) recording in the tool the (n-1)-th sample, resetting the sample counter to zero, and repeating steps (f) through (i) commencing with the (n-1)-th sample if the n-th sample is not within the predetermined threshold of the predicted value for the n-th sample; (j) incrementing the sample counter if the n-th sample is within the predetermined threshold of the predicted value; (k) determining whether the sample counter has reached a predetermined maximum count; (l) repeating steps (g) through (l) if the sample counter limit has not been reached; (m) increasing the sample interval to the next longer one of the plurality of sample rate intervals if the predetermined maximum count has been reached and repeating steps (f) through (m) commencing with the (n-1)-th sample; (n) detecting when the memory has been filled to a first predetermined threshold; (o) increasing the sample rate interval to a longer one of the plurality of sample rate intervals when the memory has been filled to the first predetermined threshold; (p) detecting when the memory has been filled to a second predetermined threshold; and (q) changing the sample rate interval to a still longer one of the plurality of sample rate intervals when the memory has been filled to the second predetermined threshold.

Claim 6

A method of controlling the rate at which a battery-powered downhole logging tool samples and records, in a memory, a detected condition within a well bore, comprising the steps of: (a) initializing a sample counter within the tool to zero; (b) selecting the shortest one of a plurality of sample rate intervals; (c) reading and recording in the tool a first sample of the condition at a first sample time; (d) reading a second sample of the condition at a second sample time in correspondence with the selected sample rate interval; (e) reading a third sample of the condition at a third sample time in correspondence with the selected sample rate interval; (f) computing from the first, second and third samples a prediction value for the n-th sample, where n is an integer not less than 2; (g) reading an n-th sample at an n-th sample time; (h) determining whether each n-th sample is within a predetermined threshold of the predicted value for such n-th sample; (i) recording in the tool the (n-1)-th sample, resetting the sample counter to zero, and repeating steps (f) through (i) commencing with the (n-1)-th sample if the n-th sample is not within the predetermined threshold of the predicted value for the n-th sample; (j) incrementing the sample counter if the n-th sample is within the predetermined threshold of the predicted value; (k) determining whether the sample counter has reached a predetermined maximum count; (l) repeating steps (g) through (l) if the sample counter limit has not been reached; (m) increasing the sample interval to the next longer one of the plurality of sample rate intervals if the predetermined maximum count has been reached and repeating steps (f) through (m) commencing with the (n-1)-th sample; (n) detecting when the memory has been filled to a first predetermined threshold; (o) increasing the sample rate interval to a longer one of the plurality of sample rate intervals when the memory has been filled to the first predetermined threshold; (p) detecting when the memory has been filled to a second predetermined threshold; and (q) changing the sample rate interval to a still longer one of the plurality of sample rate intervals when the memory has been filled to the second predetermined threshold.

Claim 10

A method of controlling the rate at which a downhole logging tool samples and records a detected condition within a well bore, comprising the steps of: (a) initializing a sample counter within the tool to zero; (b) selecting the shortest one of a plurality of sample rate intervals; (c) reading and recording in the tool a first sample of the condition at a first sample time; (d) reading a second sample of the condition at a second sample time in correspondence with the selected sample rate interval; (e) reading a third sample of the condition at a third sample time in correspondence with the selected sample rate interval; (f) computing from the first, second and third samples a prediction value for the n-th sample, where n is an integer not less than 2, said step of computing including: computing a sample difference, d, wherein d equals [(s3-s1)/2+(s2-s1)]/2, where s1=(n-1)-th sample, s2=n-th sample and s3=(n+1)-th sample; and computing the predicted n-th sample point, sn, wherein sn equals s1+(n-1)(d); (g) reading an n-th sample at an n-th sample time; (h) determining whether each n-th sample is within a predetermined threshold of the predicted value for such n-th sample; (i) recording in the tool the (n-1)-th sample, resetting the sample counter to zero, and repeating steps (f) through (i) commencing with the (n-1)-th sample if the n-th sample is not within the predetermined threshold of the predicted value for the n-th sample; (j) incrementing the sample counter if the n-th sample is within the predetermined threshold of the predicted value; (k) determining whether the sample counter has reached a predetermined maximum count; (l) repeating steps (g) through (l) if the sample counter limit has not been reached; and (m) increasing the sample interval to the next longer one of the plurality of sample rate intervals if the predetermined maximum count has been reached and repeating steps (f) through (m) commencing with the (n-1)-th sample.

Claim 11

A method of controlling the rate at which a downhole logging tool samples and records a detected condition within a well bore, comprising the steps of: (a) initializing a sample counter within the tool to zero; (b) selecting the shortest one of a plurality of sample rate intervals; (c) reading and recording in the tool a first sample of the condition at a first sample time; (d) reading a second sample of the condition at a second sample time in correspondence with the selected sample rate interval; (e) reading a third sample of the condition at a third sample time in correspondence with the selected sample rate interval; (f) computing from the first, second and third samples a prediction value for the n-th sample, where n is an integer not less than 2, said step of computing including: computing a sample difference, d, wherein d equals [(s3-s1)/2+(s2-s1)]/2, where s1=(n-1)-th sample, s2=n-th sample and s3=(n+1)-th sample; and computing the predicted n-th sample point, sn, wherein sn equals s1+(n-1)(d); (g) reading an n-th sample at an n-th sample time; (h) determining whether each n-th sample is within a predetermined threshold of the predicted value for such n-th sample; (i) recording in the tool the (n-1)-th sample, resetting the sample counter to zero, and repeating steps (f) through (i) commencing with the (n-1)-th sample if the n-th sample is not within the predetermined threshold of the predicted value for the n-th sample; (j) incrementing the sample counter if the n-th sample is within the predetermined threshold of the predicted value; (k) determining whether the sample counter has reached a predetermined maximum count; (l) repeating steps (g) through (l) if the sample counter limit has not been reached; and (m) increasing the sample interval to the next longer one of the plurality of sample rate intervals if the predetermined maximum count has been reached and repeating steps (f) through (m) commencing with the (n-1)-th sample.