Schlumberger Technology Corporation

Min-Yi Chen

Ian D Bryant

Bhavani Raghuraman

Michael G Supp

Jose Navarro

Jeffrey A Tarvin

Brian Oliver Clark

Anthony Louis Collins

Terizhandur S Ramakrishnan

David J Rossi

Peter Allan Goode

Rod Nelson

Austin Boyd

Raj Kumar Michael Thambynayagam

Carlos Torres-Verdin

Brindesh Dhruva

Alberto Malinverno

Metin Karakas

Brian Spies

Earth formations are characterized by using an array of electrodes which can measure streaming potentials in the formation, and by interpreting the data obtained by the electrodes. The electrodes are placed on a wireline tool, a LWD tool, or in a fixed manner about a completed wellbore. The measured streaming potentials are generated by drilling with an overbearing pressure, slitting the mudcake in a borehole, acid injection, or any of various other manners which causes fluid movement. The data obtained is interpreted to locate fractures, measure formation permeability, estimate formation pressure, monitor drilling fluid loss, detect abnormal pressure, etc. Particularly, a streaming potential voltage transient having a double peak profile signifies the presence of a formation fracture.

Apparatus for measuring streaming potentials and determining earth formation characteristics

Completion apparatus for measuring streaming potentials and determining earth formation characteristics

Methods and devices are provided for investigating an earth formation use electro-kinetics and/or electro-osmosis measurements. In one example, the method includes creating a pressure difference in the earth formation proximate to a wellbore; measuring a generated electro-kinetic property of the earth formation proximate to the wellbore, the generated electro-kinetic property generated by the pressure difference; applying an electric field to the earth formation proximate to the wellbore; measuring a generated pressure change in the earth formation proximate to the wellbore, the generated pressure change generated by the electric field; and determining wettability of the earth formation proximate to the wellbore by the use of the measurement of the generated electro-kinetic property and the measurement of the generated pressure change.

Wettability from electro-kinetic and electro-osmosis measurements

Logging-while-drilling apparatus and methodologies for measuring streaming potential in an earth formation are provided. The apparatus and methodologies can be utilized to find information relevant to the drilling operations. In particular, since the streaming potential measurement relates directly to fluid flow, the streaming potential measurements can be used to track flow of fluids in the formation. In turn, this information may be used to find information relevant to the drilling operations, such as under-balanced drilling conditions, abnormal formation pressures, open fractures, the permeability of the formation, and formation pressure.

While-drilling apparatus for measuring streaming potentials and determining earth formation characteristics and other useful information

While-drilling methodology for determining earth formation characteristics and other useful information based upon streaming potential measurements

While-drilling methodology for estimating formation pressure based upon streaming potential measurements

Methods for locating formation fractures and monitoring well completion using streaming potential transients information

While-drilling apparatus for measuring streaming potentials and determining earth formation characteristics

A system that is usable with a subterranean well that has a casing includes an apparatus that is associated with production of fluid from the well and is located downhole in the well in a passageway of the casing. The system also includes a sensor that is located downhole near the apparatus in the passageway and is adapted to measure a characteristic of the formation fluids and rock located outside of the casing.

Downhole measurement apparatus and technique

Wireline apparatus for measuring steaming potentials and determining earth formation characteristics

A system for reservoir control. The system allows segregated production of fluids, e.g. water and oil, to control the fluid-fluid interface. Downhole sensors are utilized in providing data about the location of the interface. This permits the proactive monitoring and control of the interface prior to unwanted intermingling of fluids, e.g. oil and water, during production.

System and method for separately producing water and oil from a reservoir

The borehole imaging apparatus of the present invention includes a tool having an array of voltage electrode buttons mounted on a non-conductive pad. A current source and a current return are preferably located on the non-conductive pads at opposite ends thereof. The locations of the current source and return are designed to force a current to flow in the formation parallel to the pad face and non-parallel to the formation boundary layers. According to a method of the invention, the voltage difference between a pair of buttons in the array is proportional to the resistivity of the formation bed adjacent to the buttons. The ratio of voltage differences between two nearby pairs of electrode buttons provides a quantitative measurement of the ratio of shallow resistivity. The resolution of the image produced by the new tool is determined only by the spacing of the buttons. The tool according to the invention produces much better images than the prior art tools when used in OBM wells. In order to assure that current flow is not tangential to bed boundaries, it is preferred that the non-conductive pad be provided with a pair of orthogonal current sources and current returns. According to a presently preferred embodiment of the invention, the voltage electrodes are arranged in a matrix having offset rows and measurements are made for adjacent electrodes in two dimensions.

Methods and apparatus for imaging earth formation with a current source, a current drain, and a matrix of voltage electrodes therebetween

Methods for locating an oil-water interface in a petroleum reservoir include taking resistivity and pressure measurements over time and interpreting the measurements. The apparatus of the invention includes sensors preferably arranged as distributed arrays. According to a first method, resistivity and pressure measurements are acquired simultaneously during a fall-off test. Resistivity measurements are used to estimate the radius of the water flood front around the injector well based on known local characteristics. The flood front radius and fall-off pressure measurements are used to estimate the mobility ratio. According to a second method, resistivity and pressure measurements are acquired at a variety of times. Prior knowledge about reservoir parameters is quantified in a probability density function (pdf). Applying Bayes' Theorem, prior pdfs are combined with measurement results to obtain posterior pdfs which quantify the accuracy of additional information. As new measurements are acquired, posterior pdfs, updated for expected temporal variations, become prior pdfs for the new measurements. According to a third method, uncertainty about the reservoir parameters is represented by Gaussian pdfs. The relationship between measurements and reservoir parameters is locally approximated by a linear function. Uncertainties are quantified by a posterior covariance matrix.

Methods and apparatus for dynamically estimating the location of an oil-water interface in a petroleum reservoir

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Pearland, TX, United States of America

Min-Yi Chen